Overview of the 2022 WHO Classification of Parathyroid Tumors

Normocalcemic Presentation of a Giant Polycystic Parathyroid Carcinoma

A 70-year-old woman presented with a large anterior cervical mass. Computed tomography and ultrasonography revealed a 70-mm polycystic structure adjacent to the right lobe of the thyroid gland, extending to its caudal aspect. Serum calcium and TSH levels were normal, whereas the serum intact PTH level was slightly elevated. Fine-needle aspiration showed cytology findings consistent with nodular goiter. After 20 months, the tumor was smaller on ultrasound but was completely solid. Serum PTH levels were markedly elevated, and Tc-99m sestamibi scintigraphy revealed striking hyperactivity of the mass. The patient underwent right hemithyroidectomy with en bloc tumor resection. Pathological analysis revealed capsular, thyroid, and venous invasion. Immunohistochemical staining was positive for PTH and galectin-3, and a high mitotic index was observed. Based on these findings, parathyroid carcinoma was diagnosed. Parafibromin staining was positive, resulting in the exclusion of etiology associated with CDC73 pathogenic variants. After 10 months, the patient was clinically free of recurrent disease. This case illustrates an atypical presentation of parathyroid carcinoma with early normocalcemia, followed by overt hyperparathyroidism, possibly because of tumor transformation.

Diagnostic and Surgical Challenges in Parathyroid Neoplasia: An Extensive Analysis of a Single Endocrine Surgery Center Cohort of Patients

BACKGROUND

Parathyroid neoplasia is a heterogeneous group of tumors, including parathyroid adenoma (PA), atypical parathyroid tumors (aPTs), and parathyroid carcinoma (PC). Differential diagnosis, especially preoperatively, between parathyroid carcinoma and the other two entities is challenging. The purposes of this study were to highlight the main differences between different parathyroid tumors and to evaluate how combined PC suspicion and intraoperative adjuncts can influence surgical decision-making and outcome-related issues.

METHODS

We performed a retrospective study of a database of patients diagnosed with parathyroid tumors who underwent surgical treatment at our endocrine surgery referral center between June 2019 and July 2024. Demographic, clinical, biochemical, imaging, intraoperative, immunohistochemical, and follow-up data were analyzed.

RESULTS

A total of 83 cases were included in our study, divided for analysis into PA (n = 67), aPT (n = 9) and PC (n = 7) subgroups. The clinical profile of the cohort showed a significant difference (p < 0.05) between the PA, aPT, and PC subgroups regarding the presence of palpable tumors (0% vs. 11.11% vs. 14.29%), both bone and kidney involvement (14.93% vs. 44.44% vs. 85.71%), and extensive disease beyond bone and kidney involvement (4.48% vs. 44.44% vs. 71.43%). PTH levels over five times the normal value were present at significantly different rates (p < 0.001), with higher rates in the aPT and PC subgroups (55.56% and 85.71%, respectively) compared with the PA subgroup (7.46%). Also, a significant difference (p < 0.001) was observed when analyzing extreme albumin-corrected serum calcium elevations over 14 mg/dL, with much higher rates in the PC subgroup (71.43%) compared to PA (1.49%) and aPT (33.33%). On preoperative ultrasonography, a significantly higher number of PCs presented diameters ≥ 3 cm (p < 0.001), depth-to-width ratios (D/W) ≥ 1 (p = 0.003), suspicious delineation (p < 0.001), and suspicious echotexture features (p < 0.001), compared to PAs. On preoperative US performed by the surgeon, suspicious features for thyroid cancer were identified in five more patients compared to the four identified by the initial US evaluation, and all (10.84% of all patients) were confirmed on final histopathology as papillary thyroid cancers. Intraoperatively, a significant difference (p < 0.001) regarding parathyroid macroscopic suspicious features, including adhesions to the thyroid gland, was seen between subgroups. When analyzing only cases with en bloc resection, we found that, in all PC cases, a combined preoperative suspicion was present, and in five cases an intraoperative suspicion was raised. Immunohistochemical data showed significantly different median Ki-67 indices between subgroups (1, 2, and 5; p = 0.008) and a different parafibromin staining profile between PC and aPT. Regarding intraoperative neuromonitoring use, a significantly lower incidence of voice changes related to the external branch of the superior laryngeal nerve was observed in the monitoring vs. non-monitoring group (57.14% vs. 12.5%, p = 0.019).

CONCLUSIONS

Our findings confirm that, in a multimodal and combined diagnostic approach, early pre- and intraoperative PC suspicion can be raised in order to optimize surgical treatment and, thus, favorably influence the outcome. Utilizing all resources available, including intraoperative parathormone determination, laryngeal nerve neuromonitoring, and immunohistochemistry staining, can bring extra benefit to the management of these challenging cases.

[Genetic profiling of parathyroid tumours: lifting the veil of mystery]

Primary hyperparathyroidism (PHPT) is a common endocrine disorder characterized by autonomous secretion of parathyroid hormone by altered parathyroid glands. In most cases PHPT is a sporadic disease, 5-10% of observations are genetically determined syndromal and non-syndromal forms. Studies of families with hereditary forms of PHPT have led to the discovery of key oncosuppressor genes and proto-oncogenes whose somatic mutations underlie the development of many sporadic parathyroid tumors. Another interest in the pathogenesis of primary hyperparathyroidism is studying mechanisms of epigenetic regulation in tumor tissue. In the first part of this review, we will discuss the classification, morphology, and etiology of PHPT. In the second part, we will present a summary of the most important studies using genetic analysis, classified according to the method used.

The impact of management traps on surgical strategies in parathyroid benign and malignant tumors-related PHPT: a retrospective cohort study

Background

Reducing the incidence rate of persistent/recurrent HPT after surgery is the key to the treatment of PHPT. The pitfalls of preoperative, intraoperative, and postoperative management in PHPT patients and their potential impact on surgical strategies need to be comprehensively investigated.

Methods

The demographic, biochemical, radiological results and other clinical data of the enrolled 112 patients with primary hyperparathyroidism undergoing surgical treatment were obtained from our database in this retrospective cohort study. One-way analysis of variance was used for normally distributed variables, and Kruskal-Wallis H test was used for non-normally distributed variables. Pearson's chi-square test or Fisher's exact test was used for categorical variables, as appropriate.

Results

The patients were divided into parathyroid adenoma group and atypical parathyroid tumor + parathyroid carcinoma group. The serum calcium levels, serum PTH levels in the APT+PC group were higher than those with benign lesions, but there was some overlap; and the clinical data showed no specificity in the differentiation of benign and malignant parathyroid tumors. A more significant finding in this cohort was that the tumor size was significantly larger in persistent/recurrent HPT group than in non-persistent/recurrent group (30.0 ± 12.6 mm vs.19.1± 8.3 mm, p < 0.01).

Conclusion

In PHPT, there are pitfalls in preoperative, intraoperative, and postoperative management of parathyroid tumors, which affect the choice of surgical strategies. It is prudent to utilize the tumor-free margin En bloc resection in a variety of parathyroid neoplasms, in order to seek the chance of cure and avoid reoperation as much as possible.

Germline mutations of GCM2 cause a novel variant of hereditary primary hyperparathyroidism

Primary hyperparathyroidism (pHPT) occurs as hereditary disease in approximately 10% of cases. GCM2 germline mutations have been recently described as responsible for the development of a novel variant of hereditary pHPT. This study aimed to determine the features of GCM2-related pHPT. Demographics, laboratory, and surgical data were assessed in a series of 17 index cases carrying GCM2 mutations undergoing surgery for pHPT. The GCM2 germline pathogenic variant c.1181 A>C p.(Tyr394Ser) was detected in 59% of cases. GCM2-related pHPT was diagnosed at a median age of 57 years (range 32-82) with a Female/Male ratio 1.8. Preoperative median calcemia was 2.89 mmol/L (range 2.69-3.8). Family history of pHPT was absent in 65% of cases. Complete clinical, surgical and follow-up data were available for 13 patients. At initial surgery, bilateral neck exploration with subtotal parathyroidectomy was performed in 46% of patients; achieving cure in all cases at a median follow-up of 51 months (range 7-60). In the remaining cases undergoing selective parathyroidectomy, a persistent pHPT occurred in 3 cases; recurrent pHPT in 1 patient (after a disease-free interval of 4 years) while 3 are disease free at a mean follow-up of 21 months. Thus, at an overall prolonged follow-up (median 48 months, range 7-216), multiglandular involvement occurred in 77% of cases. GCM2 germline mutations may cause hereditary pHPT, even if it may mimic sporadic variant due to the absence of familial history and late onset. The main feature is multiglandular involvement, needing bilateral neck exploration and subtotal parathyroidectomy to achieve long-term cure.

An Updated Perspective of the Clinical Features and Parathyroidectomy Impact in Primary Hyperparathyroidism Amid Multiple Endocrine Neoplasia Type 1 (MEN1): Focus on Bone Health

Background: Multiple endocrine neoplasia type 1 (MEN1)-related primary hyperparathyroidism (MPHPT) belongs to genetic PHPT that accounts for 10% of all PHPT cases, being considered the most frequent hereditary PHPT (less than 5% of all PHPT). Objective: We aimed to provide an updated clinical perspective with a double purpose: to highlight the clinical features in MPHPT, particularly, the bone health assessment, as well as the parathyroidectomy (PTx) impact. Methods: A comprehensive review of the latest 5-year, English-published, PubMed-accessed original studies. Results: The sample-based analysis (n = 17 studies) enrolled 2426 subjects (1720 with MPHPT). The study design was retrospective, except for one prospective and one case-control study. The maximum number of patients per study was of 517. Female predominance (an overall female-to-male ratio of 1.139) was confirmed (except for three studies). Age at MPHPT diagnosis (mean/median per study): 28.7 to 43.1 years; age at PTx: 32 to 43.5 years. Asymptomatic PHPT was reported in 38.3% to 67% of MPHPT. Mean total calcium varied between 1.31 and 2.88 mmol/L and highest PTH was of 317.2 pg/mL. Two studies reported similar PTH and calcaemic levels in MPHPT vs. sporadic PHPT, while another found higher values in MPHPT. Symptomatic vs. asymptomatic patients with MPHPT had similar PTH and serum calcium levels (n = 1). Osteoporosis (n = 8, N = 723 with MPHPT) was reported in 10% to 55.5% of cases, osteopenia in 5.88% to 43.9% (per study); overall fracture rate was 10% (of note, one study showed 0%). Lower bone mineral density (BMD) at DXA (n = 4) in MPHPT vs. sporadic PHPT/controls was found by some studies (n = 3, and only a single study provided third distal radius DXA-BMD assessment), but not all (n = 1). Post-PTx DXA (n = 3, N = 190 with MPHPT) showed a BMD increase (e.g., +8.5% for lumbar spine, +2.1% for total hip, +4.3% for femoral neck BMD); however, post-operatory, BMD remains lower than controls. Trabecular bone score (TBS) analysis (n = 2, N = 142 with MPHPT vs. 397 with sporadic PHPT) showed a higher prevalence of reduced TBS (n = 1) or similar (n = 1). PTx analysis in MPHPT (n = 14): rate of subtotal PTx of 39% to 66.7% (per study) or less than subtotal PTx of 46.9% (n = 1). Post-PTx complications: persistent PHPT (5.6% to 25%), recurrent PHPT (16.87% to 30%, with the highest re-operation rate of 71% in one cohort); hypoparathyroidism (12.4% to 41.7%). Genetic analysis pointed out a higher risk of post-PTx recurrence in exon 10 MEN1 pathogenic variant. Post-PTx histological exam showed a multi-glandular disease in 40% to 52.1% of MPHPT, and a parathyroid carcinoma prevalence of 1%. Conclusions: MPHPT remains a challenging ailment amid a multi-layered genetic syndrome. Current data showed a lower age at MPHPT diagnosis and surgery than found in general population, and a rate of female predominance that is lower than seen in sporadic PHPT cases, but higher than known, for instance, in MEN2. The bone involvement showed heterogeneous results, more consistent for a lower BMD, but not necessarily for a lower TBS vs. controls. PTx involves a rather high rate of recurrence, persistence and redo surgery. About one out of ten patients with MPHPT might have a prevalent fracture and PTx improves the overall bone health, but seems not to restore it to the general population level, despite the young age of the subjects. This suggests that non-parathyroid components and potentially menin protein displays negative bone effects in MEN1.

Importance of early detection in multiple endocrine neoplasia type 1: Clinical insights and future directions

Multiple endocrine neoplasia type 1 (MEN1) is an autosomal-inherited syndrome involving multiple endocrine tumors. It is characterized by multiple mutations in the tumor suppressor gene MEN1, which is located on chromosome 11q13. As main etiology of MEN1 is genetic mutations, clinical symptoms may vary. In this editorial, we comment on the article by Yuan et al. This article describes a case of (MEN1) characterized by low incidence and diagnostic complexity. MEN1 commonly presents as parathyroid, pancreatic, and pituitary tumors. Diagnosis requires a combination of serologic tests, magnetic resonance imaging, computed tomography, endoscopic ultrasonography, immunologic and pathology. The diagnosis is unique depending on the site of disease. Surgical resection is the treatment of choice for MEN1. The prognosis depends on the site of origin, but early detection and intervention is the most effective.

Vitamin D receptor: a possible biomarker for sporadic parathyroid adenoma?

Parathyroid adenoma is the main cause of primary hyperparathyroidism. The genetic basis of the disease is still unclear. Vitamin D receptor (VDR) is involved in parathormone regulation. The aim of this study is to evaluate Vitamin D receptor expression in sporadic parathyroid adenoma. Fifty-one patients with parathyroid adenoma and 51 healthy volunteers were enrolled in the study and genetic and immunohistochemical studies were conducted. VDR polymorphism TaqI was correlated with parathyroid adenoma development, while VDR stained positive in immunohistochemical study. Our study suggests VDR as a major contributor to sporadic parathyroid adenoma formation in Greek population.

A retrospective study on a nomogram combining clinical and ultrasound parameters for differentiating solitary parathyroid adenoma from carcinoma or atypical tumors

Objective

Parathyroid carcinoma (PC) and atypical parathyroid tumor (APT) are rare malignant parathyroid disorders with varying degrees of recurrence risk. The aim of this study was to determine an effective model for discriminating PC/APT among solitary parathyroid lesions.

Methods

A total of 439 patients with histologically confirmed primary hyperparathyroidism were retrospectively enrolled. The training cohort comprised 207 patients, the validation cohort comprised 52 patients from Hospital I, and the external validation cohort comprised 180 patients from Hospital II. All patients were diagnosed in the parathyroid adenoma (PA) group and the APT/PC group. The clinical and ultrasonic features of the two patient groups were compared. Multivariate logistic regression analysis was conducted to identify independent risk factors for APT/PC. A nomogram was built based on multivariate logistic regression analysis. Model discrimination was assessed using receiver operating characteristic (ROC) curve analysis. The area under the curve (AUC), sensitivity, specificity, and accuracy were reported. Decision and calibration curve analyses were performed to assess the clinical value and calibration of each model, respectively.

Results

In the training set, there were 181 cases of PA and 26 cases of APC/PC. Intact parathyroid hormone (iPTH) [odds ratio (OR): 1.019, 95% confidence interval (CI): 1.008-1.032], shape (OR: 16.625, 95% CI: 5.922-51.883), and relation with the thyroid capsule (OR: 3.422, 95% CI: 1.455-9.152) were independent predictive factors associated with the risk of APT/PC. The AUCs for training and internal and external validation were 0.929, 0.962, and 0.965, respectively. The accuracy, sensitivity, and specificity were 86%, 96%, and 85% in the training cohort; 92%, 100%, and 90% in the validation cohort; and 88%, 100%, and 88% in the external validation cohort, respectively. In addition, calibration plots graphically showed good agreement in the presence of the APT/PC group between risk estimation by the nomogram and histopathologic confirmation of surgical specimens. DCA in the current study showed that the nomogram was more effective than all-patient treatment or no treatment over a wide range of threshold probabilities.

Conclusions

Ultrasonic features in combination with iPTH levels may be an applicable model for predicting potentially malignant parathyroid tumors and has a better potential to facilitate preoperative decision-making.

A pathologist-AI collaboration framework for enhancing diagnostic accuracies and efficiencies

In pathology, the deployment of artificial intelligence (AI) in clinical settings is constrained by limitations in data collection and in model transparency and interpretability. Here we describe a digital pathology framework, nuclei.io, that incorporates active learning and human-in-the-loop real-time feedback for the rapid creation of diverse datasets and models. We validate the effectiveness of the framework via two crossover user studies that leveraged collaboration between the AI and the pathologist, including the identification of plasma cells in endometrial biopsies and the detection of colorectal cancer metastasis in lymph nodes. In both studies, nuclei.io yielded considerable diagnostic performance improvements. Collaboration between clinicians and AI will aid digital pathology by enhancing accuracies and efficiencies.

Impact of adipocytes on ultrasound evaluation of parathyroid adenomas

PURPOSE

Parathyroid lipoadenomas are difficult to recognize preoperatively; hence, they may remain undetected. Difficulty in recognition is thought to be due to the adipocytes present in the tumor. This study aimed to clarify the impact of adipocytes as a component of parathyroid adenomas on ultrasound evaluation.

METHODS

Eighteen parathyroid adenoma cases, in which the adipose tissue accounted for more than 10% of the tumors, were included in this study. Of these, five were consistent with lipoadenomas. Twenty-five consecutive patients with parathyroid adenoma without adipocytes were used as controls.

RESULTS

Ultrasonography revealed a lipoadenoma detection rate of 20.0%. This increased to 80.0% at re-examinations performed after obtaining information from other imaging modalities. Compared with parathyroid adenoma cases with no adipocytes or few adipocytes, the frequencies of ill-defined margins, iso- and/or hyperechogenicity, heterogeneous consistency with a two-tone pattern, poor vascular flow, no polar artery, and no hyperechoic line were significantly higher in parathyroid lipoadenoma cases. The hyperechoic and isoechoic areas in tumors with a two-tone pattern correspond to adipocyte- and parathyroid cell-rich areas, respectively. The lipoadenoma tumor sizes measured using ultrasound tended to be smaller than the actual sizes.

CONCLUSIONS

The characteristic ultrasound findings of lipoadenomas were clearly different from those of parathyroid adenomas with or without adipocytes. We believe that our findings may contribute to an increased detection rate of lipoadenomas and allow us to consider them in the differential diagnosis.

Primary hyperthyroidism complicated by primary hyperparathyroidism: a case report and literature review

Background

The clinical occurrence of primary hyperthyroidism (PH) combined with primary hyperparathyroidism (PHPT) is exceedingly rare. There remains considerable debate regarding the necessity of iodine use prior to surgery for hyperthyroidism and whether thyroid function should be normalized before proceeding with the operation. Furthermore, the decision on whether to perform total parathyroidectomy or subtotal parathyroidectomy due to parathyroid hyperplasia must be based on a comprehensive assessment by a multidisciplinary team (MDT).

Case presentation

Herein, we report a rare case of concurrent PH, caused by Graves' disease(GD), and PHPT. Through the collaboration of a MDT, we developed a personalized preoperative preparation and surgical plan for the patient, successfully managing the postoperative complications.

Conclusion

Clinicians should maintain a high level of suspicion for PHPT in hyperthyroid patients with hypercalcemia. Additionally, the decision regarding the preoperative use of iodine, the normalization of thyroid function before surgery, and the surgical approach to parathyroid hyperplasia should be determined through effective preoperative assessment, imaging studies, and MDT collaboration. This strategy allows for the formulation of individualized treatment plans, mitigating the risks of postoperative hyperthyroid crises, recurrence of PHPT, and permanent parathyroid insufficiency.

An Analysis of Primary Hyperparathyroidism in Individuals Diagnosed with Multiple Endocrine Neoplasia Type 2

Background: Primary hyperparathyroidism (PHPT) represents a multi-faced disease with a wide spectrum of manifestations. Familial forms of PHPT (affecting up to 10% of the cases) involve a particular category that encompasses a large range of hereditary syndromes, including parathyroid hyper-function, frequently in the setting of a multi-glandular disease. Objective: The aim was to analyze the most recent findings regarding PHPT in multiple endocrine neoplasia type 2 (MEN2) to a better understanding of the timing with respect to the associated ailments, MEN2-related PHPT (MEN2-PHPT) clinical and genetic particularities, optimum diagnostic, and overall management, particularly, surgical outcomes. Methods: This was a PubMed-based compressive review with regard to the latest data published in English from January 2020 until January 2025, using the following keywords: "primary hyperparathyroidism" and "multiple endocrine neoplasia", "multiple endocrine neoplasia type 2", "MEN2", or "MEN2A". We included original full-length studies of any study design that provided clinically relevant data in MEN2-PHPT and excluded reviews, meta-analysis, and case reports/series. Results: A total of 3783 individuals confirmed with MEN2 or RET pathogenic variants carriers were analyzed across 14 studies that provided data on PHPT. The prevalence of MEN2-PHPT subjects varied between 7.84% and 31.3%, with particularly low rates in non-index patients (3.8%). PHPT was the first syndrome manifestation in 0.9% of MEN2 patients. In terms of gender distribution, females represented 42.85% or 54.9% (similar rates between women and men, and only a single cohort showed a female rate up to 80%). Most subjects were diagnosed with PHPT and underwent surgery in the third or fourth decade of life. The highest median age at MEN2 diagnosis was 42 years. The youngest patients were RET pathogenic variants carriers who underwent (genetic) screening with median ages of 12 or 14 years. RET pathogenic variants analysis (n = 10/14 studies) showed that 16.67% of patients with p.Cys634Arg and 37.5% of those with p.Cys611Tyr had symptomatic PHPT, while those with p.Cys618Phe and p.Leu790Phe were asymptomatic. Timing analysis with respect to the medullary thyroid carcinoma diagnosis showed synchronous PHPT diagnosis in 80% and metachronous in 10% of MEN2 patients; with respect to MEN2-pheochromocytoma, synchronous diagnosis of PHPT was found in 56%, while pheochromocytoma was identified before PHPT in 22% of the cases and after PHPT in 22%. Studies (n = 10/14, N = 156 subjects with MEN2-PHPT) on parathyroidectomy identified that 72.7% to 100% of the individuals underwent surgery, typically performed in adulthood, at ages spanning from a mean of 34.7 to 48.5 years. The post-surgery outcomes varied (e.g., the rate for persistent PHPT was of 0%, 8% to 16.7%; recurrent PHPT of 12.5% to 23%; permanent hypoparathyroidism of 33% to 46%; permanent unilateral vocal cord palsy of 0% up to16.7%). Data regarding the number of involved glands (n = 7, N = 77): the prevalence of multi-glandular disease was pinpointed between 12.5% and 50%. Conclusions: MEN2-PHPT involved unexpected high rates of single-gland involvement (from 33.3% to 87.5%), probably due to an early detection across genetic screening. Traditional female higher prevalence in PHPT was not confirmed in most MEN2 cohorts. As expected, a younger age at PHPT diagnosis and surgery than seen in non-MEN2 patients was identified, being tidily connected with the syndromic constellation of tumors/malignancies. Overall, approximately, one out of ten patients were further confirmed with MEN2 starting with PHPT as the first clinically manifested element.

Primary exploration of cell-free DNA in the plasma of patients with parathyroid neoplasms using next-generation sequencing

BACKGROUND AND AIMS

Plasma cell-free DNA (cfDNA) has been used to monitor gene mutations and diagnose tumors. Discriminating parathyroid carcinoma (PC) from parathyroid adenoma (PA) before surgery is difficult because of the overlap in clinical features between parathyroid neoplasms. We aimed to detect cfDNA mutations in plasma samples from PC and PA patients before surgery to predict the CDC73 status in tumor tissue and help in the differential diagnosis of parathyroid neoplasms.

MATERIALS AND METHODS

Eighteen PC patients and 13 PA patients were enrolled. Plasma cfDNA was detected using next-generation sequencing, with DNA from matched peripheral white blood cells used as a control. CDC73 gene mutations were detected via whole-exome sequencing or parafibromin staining via immunohistochemistry of tumor tissues. Logistic regression was used to evaluate the ability of cfDNA mutations to predict the CDC73 status in tumor tissue and for differential diagnosis. CDC73 gene mutation or parafibromin staining loss were defined as CDC73 abnormalities.

RESULTS

One PC patient was not tested for CDC73 abnormalities due to the absence of tumor specimen. CDC73 abnormalities were not detected in all 13 PA patients, whereas 10 PC patients harboured CDC73 abnormalities in tumor specimens (P = 0.001). Among the 10 patients, CDC73 mutations were identified in the cfDNA of 8 patients. In another 20 patients without CDC73 abnormalities in tumors, CDC73 mutation was detected in the cfDNA of 4 patients. Using the CDC73 status in cfDNA, the area under the receiver operating characteristic curve (AUC) for predicting CDC73 abnormalities in tumor tissue was 0.80 (95% CI: 0.622-0.978), and the AUC for predicting malignancy was 0.795 (95% CI 0.632-0.958).

CONCLUSION

This study is the first attempt to evaluate the gene mutation status of parathyroid neoplasms through the deep sequencing of plasma cfDNA, which could also help to identify PC prior to surgery.

Basic-Clinical Analysis of Parathyroid Cancer

Parathyroid cancer (PC) presents clinically as a case of hyperparathyroidism associated with local compression symptoms. The definitive diagnosis of PC is complex as it requires unequivocal criteria of invasion in postoperative biopsy. Given the difficulty in confirming the diagnosis of PC, attempts have been made to address this problem through the search for biomarkers, mainly using immunohistochemistry. Within this theme, the phenomenon of epithelial-mesenchymal transition and cancer stem cell markers have been scarcely studied; this could eventually help discriminate between a diagnosis of parathyroid adenoma or carcinoma. On the other hand, identification of oncogenes and tumor suppressing genes, as well as epigenetic markers such as miRNAs, lncRNAs, and circRNAs all play a crucial role in tumorigenesis and have enormous potential as diagnostic tools. Furthermore, proteomic-based and inflammatory markers have also been described as diagnostic aids for this uncommon neoplasm. This review presents a clinical approach to the disease, as well as providing a state-of-the-art analysis of basic biomarkers in diagnosis and future projections in this field.

Glycomic profiling of parathyroid neoplasms via lectin microarray analysis

PURPOSE

Parathyroid carcinoma (PC) is a rare malignancy with a poor prognosis. Diagnosis of PC is often difficult in clinical practice and efficient diagnostic markers are still needed for differential diagnosis. Aberrant glycosylations of glycoproteins were identified with lectin microarray in various cancers, while relevant information is lacking in PC.

METHODS

In this study, 8 PC and 6 parathyroid adenoma (PA) tissues were assessed using a microarray consisting of 70 lectins. Overall lectin-specific glycosylation patterns were compared between PA and PC tissues. Lectins with significant differential response between PC and PA were further validated by lectin histochemistry.

RESULTS

The difference in signal intensities was found in 71.4% (50/70) of the lectins between the two groups (P < 0.05). The vast majority of PCs had higher intensity signals than PAs (PCs vs. PAs, ratio >1) and amaranthus caudatus (ACL) showed the most significantly different response between them (ratio = 2.45). Lectin histochemistry further confirmed higher ACL intensity in PCs than in PAs. The differentially expressed glycans in PC tissues were primarily glucose, mannose, and galactose-based.

CONCLUSION

PC presented unique glycomic features and ACL may serve as a candidate diagnostic marker for PC.

Adolescent primary hyperparathyroidism

Adolescent primary hyperparathyroidism (PHPT) is a rare endocrine disorder bearing distinctions from the adult form. This review examines its unique aspects, focusing on clinical presentation, genetic etiologies, genotype-phenotype correlations, and therapeutic management. Adolescent PHPT often has a genetic basis, whether familial, syndromic, or apparently sporadic, and identifying the underlying genetic cause is important for patient care. The clinical presentation is predominantly symptomatic worldwide. Unique manifestations in this age group include rickets, short stature, and slipped capital femoral epiphysis. Genotype-specific differences are evident in the adolescent PHPT characteristics. Diagnostic evaluation requires careful interpretation of biochemical and dual-energy X-ray absorptiometry findings using age and gender-specific reference ranges, with targeted screening for syndrome-associated neoplasms. Surgery remains the cornerstone of management. Current knowledge gaps in their management include treatment protocols for multiple endocrine neoplasia type 1-associated PHPT, the efficacy and safety of nonsurgical options, and long-term post-surgical outcomes.

Parathyroid carcinoma: New insights

Parathyroid carcinoma (PC) is a rare malignancy, comprising 1 % of all cases of primary hyperparathyroidism (PHPT). This narrative review explores recent advances in PC management, with a focus on molecular insights, diagnostic advancements, surgical innovations, and emerging targeted therapies. Manuscripts published between 2023 and 2024 were obtained from PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials (CENTRAL). The review highlights advances in biochemical markers, such as circulating tumour cells (CTCs), and imaging modalities such as 18F-FDG PET/CT and 4D-CT, which are improving diagnostic accuracy. Surgical resection remains central to localised and metastatic disease management. For patients with widespread metastatic or unresectable disease, newer targeted approaches such as tyrosine kinase inhibitors (TKIs), temozolomide, and immune checkpoint inhibitors (ICIs) may offer clinical benefit to specific patient cohorts. This review identifies future research areas to improve outcomes and recommends that patients with advanced PC continue to be managed in centres of excellence.

Pilot Study of Plasma miRNA Signature Panel for Differentiating Single vs Multiglandular Parathyroid Disease

CONTEXT

The ability to differentiate sporadic primary hyperparathyroidism (sPHPT) caused by a single parathyroid adenoma (PTA) from multiglandular parathyroid disease (MGD) preoperatively, as well as definitely diagnose sPHPT in difficult patients, would enhance surgical decision-making.

OBJECTIVE

This work aimed to identify miRNA (miR) signatures for MGD, single- and double-PTA, as well as cell-free miRNA (cfmiR) in plasma samples from patients with single-PTAs to use as biomarkers.

METHODS

A total of 47 patients with sPHPT (single-PTA n = 32, double-PTA n = 12, MGD n = 9). Preoperative plasma samples from 16 single-PTA and 29 normal healthy donors (NHDs). All specimens were processed and analyzed for 2083 miRs using HTG EdgeSeq miR whole-transcriptome assay and normalized using DESeq2 to identify differentially expressed (DE) miRs. MiR classifiers were identified using Random Forest. Main outcome measures were receiver operating characteristic curves and areas under the curve.

RESULTS

MiR signatures distinguished normal parathyroid from MGD and PTA as well as MGD from PTA in tissue samples. Common miRs were found in the single-PTA and double-PTAs. Data integration identified a 27-miR signature in single-PTA tissue samples compared to the rest of the tissue samples. In plasma samples analysis, significant cfmiRs were DE in single-PTA patients compared to NHD. Of those, only 9 miRNAs/cfmiRs were found DE both in tissue and plasma samples from patients diagnosed with a single PTA (AUC = 76%).

CONCLUSION

Twenty-seven miRs were consistently found DE in single-PTA tissue and plasma samples. Data integration showed a 9-cfmiR signature with potential clinical utility to preoperatively diagnose sPHPT caused by a single PTA, which could decrease more invasive parathyroid explorations.

Chapter 8: Management of aggressive forms of primary HPT: Parathyroid carcinoma and atypical parathyroid tumor

Parathyroid carcinoma is extremely rare, affecting 1% of cases of primary hyperparathyroidism. For this reason, management is poorly codified and requires expertise in specialized center. PC is genetically determined in a quarter to a third of cases, notably involving the CDC73 gene coding for parafibromin. Since 2004, malignancy has been diagnosed on both macroscopic and microscopic invasion criteria, as set out in the WHO 2022 histopathological classification. Surgery is an essential part of treatment. Resection must be oncological, after prior medical treatment for hypercalcemia that are often severe, and be supported by imaging studies to guide the surgical procedure. After incomplete resection with no possibility of reoperation, adjuvant external radiotherapy should be discussed, given the high risk of local recurrence, even if its value is debated. The recurrence rate for PC is 30-67%. Overall 5-year survival ranges from 60 to 95%. In cases of localized or oligometastatic recurrence, locoregional treatments are preferred. There is no standard treatment for metastatic disease, but the literature review suggests possible benefit from targeted anti-angiogenic therapy. Extensive tumor genotyping is recommended to screen for targetable alterations in driver genes. All parathyroid carcinoma cases should be reviewed in a specialized tumor board. Patients operated on for atypical parathyroid tumors or parathyroid tumors with loss of immunohistochemical expression of parafibromin also require long-term monitoring.

Chapter 13: Changes in 2022 WHO classification of parathyroid tumors

The latest 2022 WHO classification of the parathyroid tumors incorporates recent data on parathyroid pathophysiology, in particular from genetic sequencing. It highlights histological features potentially indicative of underlying genetic abnormalities, because of their implications for patient management. Immunohistochemical markers can help characterize parathyroid lesions and molecular screening. This new classification is a reminder of the imperative need to provide pathologists with comprehensive clinical and paraclinical information for accurate pathological lesion characterization.

An exceptionally rare case of a giant parathyroid adenoma with carcinoma-like presentation

Giant parathyroid adenoma (GPA) is an extremely rare cause of primary hyperparathyroidism (PHPT) and may sometimes mimic parathyroid carcinoma (PC). Parathyroid carcinoma is also a very rare entity. Both preoperative and postoperative diagnosis of the two conditions remains a challenge. The purpose of this article is to present the diagnostic and therapeutic approach used for a 76-year-old female patient with a GPA measuring 5.4 × 2.3 cm, mimicking PC. The patient was referred to our clinic for the management of severe hypercalcemia revealed during the neurological evaluation of psychiatric and cognitive symptoms, confusion, weakness, and bone pain. PHPT was confirmed based on the patient's biochemical profile, which showed extremely high levels of serum calcium and parathyroid hormone (PTH). Wholebody computed tomography revealed a large nodule below the inferior pole of the right lobe of the thyroid gland and no further pathology in other organs. En bloc resection of the tumor with removal of the ipsilateral hemithyroid and other involved tissues was performed. Histopathological evaluation was diagnostic for a GPA. Post-surgery hungry bone syndrome (HBS) developed and was treated. However, the patient succumbed 3 weeks later due to septic shock. GPA is an exceptionally rare endocrine tumor that should be suspected along with PC in patients with significantly elevated levels of PTH and calcium, and/or palpable neck mass. In our case, diagnosis was based principally on histopathological examination together with clinical presentation, biochemical profile, and imaging studies. Resection of the tumor remains the treatment of choice.

FLCN Variants in Parathyroid Carcinoma and Atypical Parathyroid Tumors

Parathyroid carcinoma (PC) and atypical parathyroid tumors (APT) are incompletely understood and pose challenges in definitive diagnosis. FLCN sequence variants have recently been linked to PC and APT. Inactivating mutations in the ubiquitously expressed FLCN tumor suppressor gene, encoding folliculin, cause Birt-Hogg-Dubé syndrome (BHD), a rare tumor predisposition syndrome. Germline inactivating FLCN variants, accompanied by somatic allelic loss, were reported in 2 unrelated patents with PC, both with clinical features, but no diagnosis, of BHD. Somatic frameshift variants of likely pathogenicity were reported in 1 patient with PC and 1 with APT. On the other hand, neither PC nor APT has been reported in sizeable BHD series. To better understand the frequency of FLCN variants in PC and APT, we analyzed a series of 10 patients with sporadic PC and 14 with APT by direct Sanger DNA sequencing. We identified no inactivating FLCN mutations in any of the PC or APT samples examined. A germline missense variant (p.Gly325Val), predicted as benign/tolerated, was seen in 1 PC and a synonymous variant in 1 APT. The absence of pathogenic mutations detected in our series of PC and APT further suggests that FLCN variants are rare in these tumors. Nevertheless, the potential roles of FLCN in the pathogenesis of PC and APT merits further consideration and study.

Whole-exome Sequencing of Atypical Parathyroid Tumors Detects Novel and Common Genes Linked to Parathyroid Tumorigenesis

CONTEXT

Atypical parathyroid tumor (APT) represents a neoplasm characterized by histological features typical of parathyroid carcinoma (PC) but lacking local infiltration and/or distant metastasis, leading to uncertainty regarding its malignant potential.

OBJECTIVE

To characterize the molecular landscape and deregulated pathways in APT.

METHODS

Whole-exome sequencing (WES) was conducted on 16 APTs. DNA from tumors and matched peripheral blood underwent WES using Illumina HiSeq3000.

RESULTS

A total of 192 nonsynonymous variants were identified. The median number of protein-altering mutations was 9. The most frequently mutated genes included BCOR, CLMN, EZH1, JAM2, KRTAP13-3, MUC16, MUC19, and OR1S1. Seventeen mutated genes belong to the Cancer Gene Census list. The most consistent hub genes identified through STRING network analysis were ATM, COL4A5, EZH2, MED12, MEN1, MTOR, PI3, PIK3CA, PIK3CB, and UBR5. Deregulated pathways included the PI3 K/AKT/mTOR pathway, Wnt signaling, and extracellular matrix organization. Variants in genes such as MEN1, CDC73, EZH2, PIK3CA, and MTOR, previously reported as established or putative/candidate driver genes in benign adenoma (PA) and/or PC, were also identified in APT.

CONCLUSION

APT does not appear to have a specific molecular signature but shares genomic alterations with both PA and PC. The incidence of CDC73 mutations is low, and it remains unclear whether these mutations are associated with a higher risk of recurrence. Our study confirms that PI3 K/AKT/mTOR and Wnt signaling represents the pivotal pathways in parathyroid tumorigenesis and also revealed mutations in key epigenetic modifier genes (BCOR, KDM2A, MBD4, and EZH2) involved in chromatin remodeling, DNA, and histone methylation.

The road ahead: a brief guide to navigating the 2022 WHO classification of endocrine and neuroendocrine tumours

The most recent WHO classification of endocrine and neuroendocrine tumours has brought about significant changes in the diagnosis and grading of these lesions. For instance, pathologists now have the ability to stratify subsets of thyroid and adrenal neoplasms using various histological features and composite risk assessment models. Moreover, novel recommendations on how to approach endocrine neoplasia involve additional immunohistochemical analyses, and the recognition and implementation of these key markers is essential for modernising diagnostic capabilities. Additionally, an improved understanding of tumour origin has led to the renaming of several entities, resulting in the emergence of terminology not yet universally recognised. The adjustments in nomenclature and prognostication may pose a challenge for the clinical team, and care providers might be eager to engage in a dialogue with the diagnosing pathologist, as treatment guidelines have not fully caught up with these recent changes. Therefore, it is crucial for a surgical pathologist to be aware of the knowledge behind the implementation of changes in the WHO classification scheme. This review article will delve into the most significant diagnostic and prognostic changes related to lesions in the parathyroid, thyroid, adrenal glands and the gastroenteropancreatic neuroendocrine system. Additionally, the author will briefly share his personal reflections on the clinical implementation, drawing from a couple of years of experience with these new algorithms.

Temporal research trends in parathyroid surgery

BACKGROUND

Progress has been observed in the pathophysiology of calcium homeostasis, localization studies, and intraoperative adjuncts in parathyroid surgery. The aim of this study is to gain a comprehensive perspective on the research landscape of parathyroid surgery over time.

METHODS

A search of the Web of Science Core Collection was conducted to identify publications on parathyroid surgery from 1985 to 2024. Keywords were manually curated, and their frequencies were calculated based on the publication year.

RESULTS

Publications on secondary hyperparathyroidism have decreased in recent years, but those on calcimimetics, tertiary hyperparathyroidism, and parathyroid cancer have increased. Publications related to sestamibi scans have decreased, while research on four-dimensional computed tomography and positron emission tomography has increased. Research on fluorescence and ablation treatment has recently been on the rise. The citation count per publication was positively correlated with the number of contributing institutions.

CONCLUSION

We provide an overview of contemporary research themes and emerging topics related to parathyroid surgery. The endocrine surgery community could benefit from more inter-institutional partnerships to foster scientific progress.

Molecular Pathophysiology of Parathyroid Tumorigenesis-The Lesson from a Rare Disease: The "MEN1 Model"

Primary hyperparathyroidism represents the third most prevalent endocrine disease in the general population, consisting of an excessive secretion of parathyroid hormone from one or, more frequently, more of the parathyroid glands, leading to a dysregulation of calcium homeostasis. Schematically, its development occurs primarily by pathophysiological events with genetic mutation, at the germline and/or somatic level, that favor the neoplastic transformation of parathyroid cells and promote their aberrant proliferation, and mutations determining the shift in the PTH "set-point", thus interfering with the normal pathways of PTH secretion and leading to a "resetting" of Ca2+-dependent PTH secretion or to a secretion of PTH insensitive to changes in extracellular Ca2+ levels. Familial syndromic and non-syndromic forms of primary hyperparathyroidism are responsible for approximately 2-5% of primary hyperparathyroidism cases and most of them are inherited forms. The history of the genetic/molecular studies of parathyroid tumorigenesis associated with multiple endocrine neoplasia type 1 syndrome (MEN1) represents an interesting model to understand genetic-epigenetic-molecular aspects underlying the pathophysiology of primary hyperparathyroidism, both in relation to syndromic and non-syndromic forms. This minireview aims to take a quick and simplified look at the MEN1-associated parathyroid tumorigenesis, focusing on the molecular underlying mechanisms. Clinical, epidemiological, and observational studies, as well as specific guidelines, molecular genetics studies, and reviews, have been considered. Only studies submitted to PubMed in the English language were included, without time constraints.

Minimally Invasive Sampling of Mediastinal Lesions

This narrative review examines the existing literature on minimally invasive image-guided sampling techniques of mediastinal lesions gathered from international databases (Medline, PubMed, Scopus, and Google Scholar). Original studies, systematic reviews with meta-analyses, randomized controlled trials, and case reports published between January 2009 and November 2023 were included. Four authors independently conducted the search to minimize bias, removed duplicates, and selected and evaluated the studies. The review focuses on the recent advancements in mediastinal sampling techniques, including EBUS-TBNA, EUS-FNA and FNB, IFB, and nodal cryobiopsy. The review highlights the advantages of an integrated approach using these techniques for diagnosing and staging mediastinal diseases, which, when used competently, significantly increase diagnostic yield and accuracy.

Cohort review of patients with parathyroid cancer in End Stage Renal Disease (ESRD)

BACKGROUND AND HYPOTHESIS

Parathyroid carcinoma (PTTC) is a rare malignant endocrine tumor seen in up to 1-2% of all cases of primary hyperparathyroidism. However, incidence of parathyroid carcinoma in renal hyperparathyroidism is a rare phenomenon. We aimed to evaluate the outcomes of PTTC in renal hyperparathyroidism published in the literature.

METHODS

Cohort review of parathyroid cancer cases reported in Medline (via PubMed), COCHRANE and EMBASE between the period 1985 - 2023 in patients with renal hyperparathyroidism.

RESULTS

A total of 48 patients (20 M: 28F), with a mean age of 49.8 (± 11.7 SD: range 20-75) years. Dialysis vintage was for a period of 8.9 (± 7.2; range 6 months to 40 years). The mean preoperative values were as follows: serum corrected calcium-2.87 IQR 2.56-3.01), PTH - 221.8 (IQR 86.6 -257.2 pmol/L) and serum phosphate - 2.07 (IQR 1.72-2.28) mmol/L. Preoperative imaging was in the form of ultrasound of the neck in 21 of 48 (44%), MIBI scan in 27/48 (56%), contrast enhanced computerized tomography in 14/48 (29%) and MRI neck in 1/48 (2%). The mean size of the cancer was 2.7 (± 1.35) cm and weight of the gland ranged between 0.9 to 4.98 g. 18/48 (37%) patients underwent a total parathyroidectomy and 30/48 (63%) had subtotal parathyroidectomy. En bloc excision of the tumour along with the thyroid along and central compartment lymph nodes was only performed in 12/48 (25%), of whom 9 (19%) had it performed at index surgery, whereas in the rest was done for persistent or recurrent disease. After a mean follow up of 34 months, 14 (29%) had local recurrence, 1 (2%) had distant metastasis to the skeletal system, and 12 (25%) to the lungs. Cohort mortality was 6 (13%) due to refractory hypercalcemia.

CONCLUSIONS

Parathyroid carcinoma in renal hyperparathyroidism is rare but when encountered, en bloc excision with parathyroidectomy provides the best chance of cure. Recurrences can be difficult to treat but may be needed to treat intractable hypercalcaemia.

Heterogeneous Transcriptional Landscapes in Human Sporadic Parathyroid Gland Tumors

The expression of several key molecules is altered in parathyroid tumors due to gene mutations, the loss of heterozygosity, and aberrant gene promoter methylation. A set of genes involved in parathyroid tumorigenesis has been investigated in sporadic parathyroid adenomas (PAds). Thirty-two fresh PAd tissue samples surgically removed from patients with primary hyperparathyroidism (PHPT) were collected and profiled for gene, microRNA, and lncRNA expression (n = 27). Based on a gene set including MEN1, CDC73, GCM2, CASR, VDR, CCND1, and CDKN1B, the transcriptomic profiles were analyzed using a cluster analysis. The expression levels of CDC73 and CDKN1B were the main drivers for clusterization. The samples were separated into two main clusters, C1 and C2, with the latter including two subgroups of five PAds (C2A) and nineteen PAds (C2B), both differing from C1 in terms of their lower expression of CDC73 and CDKN1B. The C2A PAd profile was also associated with the loss of TP73, an increased expression of HAR1B, HOXA-AS2, and HOXA-AS3 lncRNAs, and a trend towards more severe PHPT compared to C1 and C2B PAds. C2B PAds were characterized by a general downregulated gene expression. Moreover, CCND1 levels were also reduced as well as the expression of the lncRNAs NEAT1 and VLDLR-AS1. Of note, the deregulated lncRNAs are predicted to interact with the histones H3K4 and H3K27. Patients harboring C2B PAds had lower ionized and total serum calcium levels, lower PTH levels, and smaller tumor sizes than patients harboring C2A PAds. In conclusion, PAds display heterogeneous transcriptomic profiles which may contribute to the modulation of clinical and biochemical features. The general downregulated gene expression, characterizing a subgroup of PAds, suggests the tumor cells behave as quiescent resting cells, while the severity of PHPT may be associated with the loss of p73 and the lncRNA-mediated deregulation of histones.

Advances in the management of parathyroid carcinoma

Parathyroid carcinoma (PCA) is a rare malignancy accounting for approximately 1% of all patients with primary hyperparathyroidism. It is characterised by excessive parathyroid hormone (PTH) production. This manuscript reviews recent advances in the management of parathyroid carcinoma, focusing on molecular insights, diagnostic modalities, surgical innovations, adjuvant therapies, and emerging targeted treatments. Recently published manuscripts (between 2022 and 2023) were obtained from Medical Literature Analysis and Retrieval System Online (Medline), Excerpta Medica (Embase), Cochrane Central Register of Controlled Trials (CENTRAL), and European Union Drug Regulating Authorities Clinical Trials (EudraCT). These were assessed for their relevance in terms of the diagnosis and management of patients with PCA. This manuscript explores the role of genetic profiling and presents case studies illustrating successful management strategies. The manuscript also discusses the ongoing challenges in the management of parathyroid carcinoma, suggesting future research directions and potential therapeutic avenues.

Clinical course of atypical parathyroid neoplasm with soft tissue extension

BACKGROUND AND OBJECTIVES

The American Joint Committee on Cancer (AJCC) TNM staging system defines atypical parathyroid neoplasia (APN) as tumor in situ (Tis) and reserves the definition of parathyroid carcinoma (PC) to parathyroid tumor with invasion into surrounding structures. Because the parathyroid gland has no true capsule, "extension" with APN versus microscopic "invasion" of surrounding soft tissue can be difficult and confusing for clinicians. We aimed to determine the clinical course of atypical parathyroid neoplasm with and without soft tissue extension and parathyroid carcinoma with only soft tissue invasion (pT1) and to report the outcomes.

METHODS

Following an IRB-approved protocol, we identified all patients treated for parathyroid neoplasm or cancer at our single tertiary care cancer center from 1990 to 2021. We excluded all patients with evidence of clinical or pathologic gross invasion into surrounding structures (pT2 or higher), lymph node involvement, or metastatic disease. By definition, this excluded all cases where the distinction was clinically evident to the surgeon at the time of the operation based on finding a hard, firm, sticky, or discolored parathyroid gland. Only patients with pathologic T1 (pT1) parathyroid carcinoma or APN were included. All pathologic examinations were independently re-reviewed by a single designated expert senior endocrine pathologist. The definition of APN strictly followed the WHO definition of a clinically worrisome lesion having features including fibrous bands or increased mitotic rate, necrosis, or trabecular growth that did not meet robust criteria for frank invasion. Pathologic T1 disease was defined as invasion limited to soft tissue. Analyses were performed using R version 4.0.2 and Jamovi.

RESULTS

Of all PC patients at our institution, only 71 met the strict inclusion criteria of APN or pT1. Forty-four patients had pT1 disease and 27 had APN: 12 of the APN had soft tissue extension, and 15 had no soft tissue extension. The groups were similar with regard to age at diagnosis (p = 0.328). The average follow-up duration was 84 months from initial surgical intervention. Of the 12 with APN, one patient (1/12; 8%) with soft tissue extension recurred, developed distant metastases, and subsequently died during follow up. Of the 44 patients with pT1 PC, six developed distant metastases and 13 (13/44; 30%) died during the follow-up period. One patient with APN and soft tissue extension recurred and died and no patient with APN and no soft tissue extension died.

CONCLUSIONS

Patients with APN and extension into soft tissue have a clinical course similar to that of APN without soft tissue extension. APN with soft tissue extension is a different disease from pT1 disease with invasion of soft tissue. The pTis classification appears justified for APN with and without soft tissue extension.

Head-to-head: Should Ki67 proliferation index be included in the formal classification of pulmonary neuroendocrine neoplasms?

The reporting of lung neuroendocrine neoplasms (NENs) according to the 2021 World Health Organisation (WHO) is based on mitotic count per 2 mm2, necrosis assessment and a constellation of cytological and immunohistochemical details. Accordingly, typical carcinoid and atypical carcinoid are low- to intermediate-grade neuroendocrine tumours (NETs), while large-cell neuroendocrine carcinoma (NEC) and small-cell lung carcinoma are high-grade NECs. In small-sized diagnostic material (cytology and biopsy), the noncommittal term of carcinoid tumour/NET not otherwise specified (NOS) and metastatic carcinoid NOS have been introduced with regard to primary and metastatic diagnostic settings, respectively. Ki-67 antigen, a well-known marker of cell proliferation, has been included in the WHO classification as a non-essential but desirable criterion, especially to distinguish NETs from high-grade NECs and to delineate the provisional category of carcinoid tumours/NETs with elevated mitotic counts (> 10 mitoses per mm2) and/or Ki-67 proliferation index (≥ 30%). However, a wider use of this marker in the spectrum of lung NENs continues to be highly reported and debated, thus witnessing a never-subsided attention. Therefore, the arguments for and against incorporating Ki-67 in the classification and clinical practice of these neoplasms are discussed herein in detail.

Neuroendocrine neoplasms of head and neck, genitourinary and gynaecological systems, unknown primaries, parathyroid carcinomas and intrathyroid thymic neoplasms: ESMO Clinical Practice Guideline for diagnosis, treatment and follow-up

•This Clinical Practice Guideline provides key recommendations for managing rare endocrine tumours. •Neuroendocrine neoplasms of different origins, parathyroid carcinoma and intrathyroid thymic neoplasms are included. •The guideline covers clinical imaging and pathological diagnosis, staging and risk assessment, treatment and follow-up. •The authors comprise a multidisciplinary group of experts from different institutions and countries in Europe. •Recommendations are based on available scientific data and the authors’ collective expert opinion.

Parathyroid carcinoma and atypical parathyroid tumor: analysis of an Italian database

OBJECTIVE

Atypical parathyroid tumor (aPT) and parathyroid carcinoma (PC) are extremely rare parathyroid neoplasms, accounting together for <2% of all parathyroid tumors. They often present an overlapping clinical phenotype, sharing clinical, biochemical, and some histological features. They are distinguished only by the presence of local invasion, and lymph nodes or distant metastasis, which are all absent in aPTs. To date, only few studies have compared clinical presentation and features between aPTs and PCs. Our purpose was to conduct a retrospective study on a multicenter Italian database of aPT and PC patients.

DESIGN AND METHODS

We comparatively analyzed main features of aPT (n = 57) and PC (n = 74) patients collected at 15 major endocrinology and endocrine surgery centers in Italy.

RESULTS AND CONCLUSIONS

Atypical parathyroid tumors and PCs showed no significant differences in many clinical features and presented similar values of elevated parathyroid hormone and total serum calcium. Renal complications, namely nephrolithiasis and nephrocalcinosis, appeared to be more common in PC, with a significantly higher rate of renal colic, regardless of total serum calcium levels and 24-h calciuria. Parathyroid carcinomas showed significantly higher postoperative disease persistence and recurrence rates, presumably due to an uncomplete resection of the primary tumor in 23.5% of cases and/or presence of unremoved active metastasis, but they had similar disease-free mean time after surgery than aPT. To deepen the study of malignant parathyroid tumors, the institution of a novel Italian retro-prospective multicenter registry of aPTs and PCs is currently ongoing, and a dedicated PC European registry has been recently activated.

Predictive Ability of Rule of 3 in Parathyroid Cancer: Outcomes from a South Asian Cohort

BACKGROUND

Preoperative diagnosis of parathyroid cancer (PC) where possible allows for en-bloc resection of the tumour, which is associated with excellent prognosis. The rule of >3 (size of tumour larger than 3 cm; corrected calcium more than 3 mmol/L) as proposed by Schulte and Talat has a specificity of 95% in predicting malignancy in parathyroid neoplasms. We looked at the impact of rule of 3 in predicting malignancy and outcomes on intervention in a South Asian cohort.

METHODS

Patients who underwent parathyroid surgery between 2010 and 2023 at two tertiary referral centres were assessed. Patients with PC were selected and their clinicopathological parameters, treatment modalities, and outcomes were analysed.

RESULTS

Thirteen of 336 (3.8%) patients with a mean age of 61.8 (±17.5) years were diagnosed with PC during the study period. The highest mean preoperative values were PTH (92.4 ± 66.27 pmol/L), highest corrected calcium (3.21 ± 0.28 mmol/L), and alkaline phosphatase (419 IU/mL). Nine patients underwent en-bloc excision while the other had focussed parathyroidectomy. Recurrences were recorded in 2 (28.5%) patients over a mean follow-up period of 69 (±48.6) months. One patient with lung metastasis underwent video-assisted thoracic surgery. There was no disease specific mortality in this cohort during the study period.

CONCLUSIONS

In our experience, the predictive rule of 3 has low sensitivity to suspect PC preoperatively, resulting in limited usefulness in clinical practice. Outcomes appear to be less favourable with higher recurrence rates in cases where less than en-bloc resection is performed.

Vascular mimicry and mosaic vessels in parathyroid tumours: a new diagnostic approach?

AIMS

Evaluation of 'alternative' vascularisation in human cancer is considered an important prognostic parameter; the 2022 WHO classification of parathyroid tumours despite progresses in clinical triaging of patients strongly emphasises new histopathological parameters to properly stratify these lesions. 'Alternative' and 'classic' vessels were here investigated for the first time in parathyroid tumours for their possible histopathological and clinical relevance during progression.

METHODS

Using a double CD31/PAS staining, microvessel density (MVD, 'classic' CD31+ vessels), mosaic vessel density (MoVD, 'alternative' CD31+/-vessels) and vessel mimicry density (VMD, 'alternative' CD31-/PAS+ vessels) were evaluated in 4 normal parathyroid glands (N), 50 Adenomas (A), 35 Atypical Tumours (AT) and 10 Carcinomas (K).

RESULTS

Compared with N, MVD significantly increased in A (p=0.012) and decreased in K (p=0.013) with vessel counts lower than in AT and A (p<0.001). MoVs and VMs, absent in normal tissue, were documented in non-benign parathyroid lesions (AT, K) (p<0.001), with MoVs and VMs most represented in AT and K, respectively (p<0.001), in peripheral growing areas. Vessel distribution was correlated to neoplastic progression (r=-0.541 MVD; r=+0.760 MoVD, r=+0.733 VMD), with MVD decrease in AT and K inversely related to MoVD and VMD increase (r=-0.503 and r=-0.456).

CONCLUSIONS

'Alternative' vessel identification in parathyroid tumours is crucial because it: (1) explains the paradox of non-angiogenic tumours, consisting in a new bloody non-endothelial vessel network and (2) helps pathologists to unmask worrisome lesions. Furthermore, detection of alternative vascular systems in human tumours might explain the limited success of antiangiogenic therapies and encourage new oncological studies.

Large atypical parathyroid tumor - a diagnostic conundrum

Atypical parathyroid tumor (APT) is a rare neoplasm of the parathyroid gland, which shows atypical cytological or architectural features and lacks definite diagnosis criteria for malignancy. These cases can cause diagnostic challenges owing to their rarity and similarity with thyroid neoplasm on imaging and fine needle aspiration cytology. Also, differentiating APT from giant parathyroid adenoma or parathyroid carcinoma can be challenging based on clinical, imaging or cytological features. A 49-year-old male presented with clinical features of hyperparathyroidism. On laboratory evaluation, his serum calcium and serum parathyroid hormone was elevated. Imaging studies suggested a possibility of left inferior parathyroid neoplasm, and fine needle aspiration cytology showed features suggestive of parathyroid neoplasm. However, exact categorization of parathyroid tumor was difficult in pre-operative work-up. Possibilities of giant parathyroid adenoma as well as parathyroid carcinoma were considered. A final diagnosis of an atypical parathyroid tumor was made after detailed histopathological evaluation given focal capsular invasion but lack of unequivocal evidence of malignancy in the resected specimen. APT is a rare neoplasm of uncertain malignant potential. Knowledge of the radiological and pathological features will be helpful in accurately identifying the lesion and avoiding misdiagnosis.

Combination approach for CDC73-related parathyroid carcinoma in an adolescent female patient: a case report and literature review

Parathyroid carcinoma (PC) is extremely rare in children and adolescent. PC is more often sporadic, but also it could be associated with germline mutations. The clinical features of primary hyperparathyroidism (PHPT) are nonspecific in children and adolescent, which delays the diagnosis for years. This case of PC in a pediatric patient, caused by germline heterozygous pathogenic variant in exon 1 of the CDC73 gene (c.70 G > T, p. Glu24Ter) is the first to be reported in Russia. Due to the rarity of pediatric parathyroid malignancy, the diagnosis of this endocrine neoplasm remains a challenge. The main difficulties that we faced in the management of the patient were the morphological confirmation of diagnosis, multiple surgical interventions, and disseminated PC metastases. We describe a 13-year-old girl with delayed diagnosis of PC and subsequent local recurrence after several surgeries, who underwent specific radiation therapy that allowed controlling hypercalcemia.

RadioGraphics Update: Parathyroid CT and Primary Hyperparathyroidism

Editor's Note.-RadioGraphics Update articles supplement or update information found in full-length articles previously published in RadioGraphics. These updates, written by at least one author of the previous article, provide a brief synopsis that emphasizes important new information such as technological advances, revised imaging protocols, new clinical guidelines involving imaging, or updated classification schemes.

The clinicopathological features of lung metastases of parathyroid cancinoma

Parathyroid carcinoma(PC) is an extremely rare malignant tumor of the parathyroid glands. The lung is the most common target organ for PC distant metastases. In this study, twelve patients diagnosed with PC with lung metastases were enrolled in the study. Hematoxylin and Eosin(H&E) stained, immunohistochemical stained and next-generation sequencing (NGS) of a 425-gene panel were performed on tumor tissue samples. At the same time, we also evaluated its histopathologic characteristics. The results indicate that the microscopic examination of metastatic lesions reveals the same structure and characteristics as PC; the tumor was composed of relatively uniform cells organized in nests and separated by thin fibrous bands and abundant blood vessels. Immunohistochemical evaluation of Ki67, CyclinD1, PTH, SYN, CgA, and CD56 was useful in diagnosing PC with lung metastases. The most frequently genetic alterations were mutations of CDC73 and copy number variation (CNV) of MCL1, with a mutation rate of 25 %. In addition, the mutations of CDC73, ATM, TP53, ALK, ERBB2, MAP3K4, TSC1, CCND1 and CNV of CDK4, MCL1, SMARCB1 overlap between metastatic lesions and primary lesions. In conclusions, PC is a rare endocrine malignant tumor that is very difficult to diagnose preoperatively and prone to clinical recurrence or distant metastasis. Genetic mutations, presentation and histological characteristic were the basis for diagnosing PC with lung metastases.

Dual concentric echo sign of ultrasound in primary hyperparathyroidism: The clinical and histopathologic features and differentiation from lymph nodes

Context

Ultrasound (US) is the most economical and widely used method for detecting lesions in parathyroid regions. Identifying typically parathyroid adenomas as hypoechoic nodules with clear margins. However, 10 % of lesions exhibit atypical features, such as the dual concentric sign, and the cognition of them still needs to be improved.

Objective

To promote understanding of clinical and histopathological features for parathyroid lesions with the dual concentric echo sign and to investigate its pathogenesis and methods for distinguishing from cervical lymph nodes to improve US diagnostic accuracy.

Methods

Retrospectively, patients were categorized into three groups: Group 1, with 36 patients showing parathyroid lesions with dual concentric echo signs; Group 2, with 40 patients displaying classic hypoechoic parathyroid lesions; and Group 3, comprising 36 patients with identified lymph nodes, which were all examined from January 2018 to December 2019. The clinical data on demographics, clinical symptoms, serum levels, histopathologic findings, and US image characteristics were thoroughly reviewed.

Results

According to the clinical data, no significant differences in demographics or lesion sizes were observed in Group 1 and Group 2 (p > 0.05). No significant variances were noted in biochemical markers, including PTH, T-25OHD, and ALP. However, a notable difference was identified in adjusted serum calcium levels, which were significantly lower in Group 1 compared to Group 2 (p < 0.05). Additionally, the proportion of asymptomatic patients was significantly higher in Group 1 compared to Group 2 (p < 0.05). Pathological examination revealed that all lesions with dual concentric echo signs were parathyroid adenomas. The isoechoic central region predominantly corresponded to areas of loose edema, while the hypoechoic peripheral layer was primarily associated with chief and/or oncocytic cells. By comparing the ultrasonography of Groups 1 and 3, the parathyroid lesions with dual concentric echo signs exhibited significant distinctions from lymph nodes in size, blood flow classification, vascular distribution, and anatomical location (p < 0.05).

Conclusion

The parathyroid lesions with dual concentric echo signs in US corresponded to specific histopathological manifestations and relatively mild clinical features in the patients, this finding may increase the likelihood of incidental detection of parathyroid lesions by US. Attention to the details of size, location, and blood flow, especially, may aid US physicians in differentiating parathyroid adenomas from cervical lymph nodes.

Incidental synchronous intrathyroidal parathyroid carcinomas and papillary thyroid microcarcinoma with compressive neck mass and primary hyperparathyroidism: case report and literature review

BACKGROUND

Parathyroid carcinoma (PC) is a rare malignancy, often diagnosed incidentally through postoperative pathological examination. The occurrence of nodular goiter, intrathyroidal parathyroid carcinoma, contralateral parathyroid adenoma (PA), and papillary thyroid microcarcinoma (PTMC) is extremely uncommon, which prompted us to report our case experience.

CASE PRESENTATION

We describe a 67-year-old male who presented with a cervical mass causing tracheal compression, which prompted him to seek medical advice. Based on preoperative auxiliary examination results from color Doppler ultrasound, SPECT parathyroid imaging, and blood tests, he was initially diagnosed with a suspected parathyroid adenoma and nodular goiter. Excision of the right lobe and isthmus of the thyroid, and left superior parathyroid gland was conducted, which were sent to intraoperative frozen pathological examination. During intraoperative observation, adhesion around the right thyroid lobe was discovered. Consequently, right central area lymph node dissection was performed due to suspicion of an aggressive malignant tumor. Histology and immunohistochemistry analysis revealed incidental intrathyroidal parathyroid carcinoma, contralateral parathyroid adenoma, classical papillary thyroid microcarcinoma, and nodular goiter.

CONCLUSION

Parathyroid carcinoma should be highly suspected when extremely high levels of PTH and severe hypercalcemia are present, which cannot be simply explained by a preoperatively localized parathyroid adenoma, especially when suspicious malignant adhesion is found during intraoperative exploration. In cases where multifocal thyroid nodules are associated with increased uptake of 99Tc-sestamibi, the possibility of coexisting carcinomas should be considered, not only for thyroid malignancy but also for the potential presence of intrathyroidal parathyroid carcinoma.

Imaging Recommendations for Diagnosis and Management of Primary Parathyroid Pathologies: A Comprehensive Review

Parathyroid pathologies are suspected based on the biochemical alterations and clinical manifestations, and the predominant roles of imaging in primary hyperparathyroidism are localisation of tumour within parathyroid glands, surgical planning, and to look for any ectopic parathyroid tissue in the setting of recurrent disease. This article provides a comprehensive review of embryology and anatomical variations of parathyroid glands and their clinical relevance, surgical anatomy of parathyroid glands, differentiation between multiglandular parathyroid disease, solitary adenoma, atypical parathyroid tumour, and parathyroid carcinoma. The roles, advantages and limitations of ultrasound, four-dimensional computed tomography (4DCT), radiolabelled technetium-99 (99mTc) sestamibi or dual tracer 99mTc pertechnetate and 99mTc-sestamibi with or without single photon emission computed tomography (SPECT) or SPECT/CT, dynamic enhanced magnetic resonance imaging (4DMRI), and fluoro-choline positron emission tomography (18F-FCH PET) or [11C] Methionine (11C -MET) PET in the management of parathyroid lesions have been extensively discussed in this article. The role of fluorodeoxyglucose PET (FDG-PET) has also been elucidated in this article. Management guidelines for parathyroid carcinoma proposed by the American Society of Clinical Oncology (ASCO) have also been described. An algorithm for management of parathyroid lesions has been provided at the end to serve as a quick reference guide for radiologists, clinicians and surgeons.

Acute pancreatitis and refractory hypercalcemia in the third trimester caused by parathyroid carcinoma

BACKGROUND

Hypercalcemia can be a rare contributor to acute pancreatitis (AP) in pregnancy. This is primarily due to primary hyperparathyroidism (PHPT), resulting from parathyroid carcinoma. We exhibited a case report to analyze the diagnosis and treatment during the onset of hypercalcemia-induced AP.

CASE PRESENTATION

A 32-year-old primigravida presented with acute pancreatitis near full-term gestation. Following a cesarean delivery, there was a reduction in serum amylase and peripancreatic exudate, but her serum calcium concentrations persistently elevated over 4.0 mmol/L. Interventions to lower the hypercalcemia were only temporarily effective, until a high serum parathyroid hormone (PTH) concentration of 1404 pg/mL was detected. Ultrasound revealed a 31 mm × 24 mm hypoechoic oval nodule in the left lower lobe of the thyroid gland. She underwent a parathyroidectomy, resulting in a dramatic decrease in serum PTH level, from preoperative levels of 2051 pg/mL to 299 pg/mL just 20 minutes after removal. Similarly, her serum calcium declined from 3.82 mmol/L to 1.73 mmol/L within 24 hours postoperatively. The final histopathology suggested parathyroid carcinoma.

CONCLUSION

When refractory hypercalcemia is present, serum PTH levels should be measured to determine PHPT. Parathyroidectomy is the optimal strategy for alleviating hypercalcemia and clarifying the underlying pathology.

Sporadic Parathyroid Adenoma: A Pilot Study of Novel Biomarkers in Females

Background and Objectives: Parathyroid adenoma is a distinct cause of primary hyperparathyroidism, with the vast majority being sporadic ones. Proteomic analysis of parathyroid adenomas has proposed a large number of related proteins. The aim of this study is to evaluate the immunohistochemical staining of ANXA2, MED12, MAPK1 and VDR in parathyroid adenoma tissue. Materials and Methods: Fifty-one parathyroid adenomas were analyzed for ANXA2, MED12, MAPK1 and VDR expressions. Tissue was extracted from formalin-fixed paraffin-embedded parathyroid adenoma specimens; an immunohistochemical study was applied, and the percentage of allocation and intensity were evaluated. Results: ANXA2 stained positively in 60.8% of all cell types, while MED12 had positive staining in 66%. MAPK1 expression was found to be negative in total, although a specific pattern for oxyphil cells was observed, as they stained positive in 17.7%. Finally, VDR staining was positive at 22.8%, based on nuclear staining. Conclusions: These immunohistochemical results could be utilized as biomarkers for the diagnosis of sporadic parathyroid adenoma. It is of great importance that a distinct immunophenotype of nodule-forming cells in a positive adenoma could suggest a specific pattern of adenoma development, as in hereditary patterns.

Long-term survival in a patient with metastatic parathyroid carcinoma harboring an EGFR sensitizing mutation: a case report

Parathyroid carcinoma (PC) is a rare and aggressive endocrine malignancy with limited treatment options. Current treatments such as chemotherapy and radiotherapy have demonstrated limited efficacy. Here, we report the case of a male patient who presented with symptoms including polydipsia, polyuria, and joint pain. Further examination revealed a neck lump, hypercalcemia, and hyperparathyroidism, leading to a diagnosis of PC after en bloc surgery. Seven months later, the patient developed local recurrence and lung metastases, which were resected via left lateral neck dissection and thoracoscopic wedge resection. A 422-gene panel test revealed the presence of epidermal growth factor receptor (EGFR) p.L858R (c. T2573G) mutation, which may sensitize the EGFR-tyrosine kinase inhibitor response, and phosphatidylinositol-4,5-bisphosphate 3-kinase, catalytic subunit alpha (PIK3CA) p.E545KV (c. G1633A) mutation. After multidisciplinary treatment discussions, the patient was treated with the multi-target tyrosine kinase inhibitor, anlotinib, resulting in survival benefits for 19 months. This case highlights the potential of targeted therapy in terms of long-term survival in patients with distant metastatic PC, as well as the importance of precision therapy guided by genome sequencing to identify potential therapeutic targets.

4D SPECT/CT: A Hybrid Approach to Primary Hyperparathyroidism

Our rationale was to review the imaging options for patients with primary hyperparathyroidism and to advocate for judicious use of 4-dimensional (4D) SPECT/CT to visualize diseased parathyroid glands in patients with complex medical profiles or in whom other imaging modalities fail. We review the advantages and disadvantages of traditional imaging modalities used in preoperative assessment of patients with primary hyperparathyroidism: ultrasound, SPECT, and 4D CT. We describe a scheme for optimizing and individualizing preoperative imaging of patients with hyperfunctioning parathyroid glands using traditional modalities in tandem with 4D SPECT/CT. Using the input from radiologists, endocrinologists, and surgeons, we apply patient criteria such as large body habitus, concomitant multiglandular disease, multinodular thyroid disease, confusing previous imaging, and unsuccessful previous surgery to create an imaging paradigm that uses 4D SPECT/CT yet is cost-effective, accurate, and limits extraneous radiation exposure. 4D SPECT/CT capitalizes on the strengths of SPECT and 4D CT and addresses limitations that exist when these modalities are used in isolation. In select patients with complicated clinical parameters, preoperative imaging with 4D SPECT/CT can improve accuracy yet remain cost-effective.

The significance of an immunohistochemical marker-based panel in assisting the diagnosis of parathyroid carcinoma

PURPOSE

Parathyroid carcinoma (PC) is an endocrine malignancy with a poor prognosis. However, the diagnosis of PC is still a difficult problem. A model with immunohistochemical (IHC) staining of 5 biomarkers has been reported from limited samples for the differential diagnosis of PC. In the present study, a series of IHC markers was applied in relatively large samples to optimize the diagnostic model for PC.

METHODS

In this study, 44 patients with PC, 6 patients with atypical parathyroid tumors and 57 patients with parathyroid adenomas were included. IHC staining for parafibromin, Ki-67, galectin-3, protein-encoding gene product 9.5 (PGP9.5), E-cadherin, and enhancer of zeste homolog 2 (EZH2) was performed on formalin-fixed, paraffin-embedded tissue samples. The effects of clinical characteristics, surgical procedure, and IHC staining results of tumor tissues on the diagnosis and prognosis of PC were evaluated retrospectively.

RESULTS

A logistic regression model with IHC results of parafibromin, Ki-67, and E-cadherin was created to differentiate PC with an area under the curve of 0.843. Cox proportional hazards analysis showed that negative parafibromin staining (hazard ratio: 3.26, 95% confidence interval: 1.28-8.34, P = 0.013) was related to the recurrence of PC.

CONCLUSION

An IHC panel of parafibromin, Ki-67 and E-cadherin may help to distinguish PC from parathyroid neoplasms. Among the 6 IHC markers and clinical features examined, the risk factor related to PC recurrence was parafibromin staining loss.