Current concepts in parathyroid carcinoma: a single Centre experience

Molecular imaging of thyroid and parathyroid diseases

INTRODUCTION

Molecular imaging of thyroid and parathyroid diseases has changed in recent years due to the introduction of new radiopharmaceuticals and new imaging techniques. Accordingly, we provided an clinicians-oriented overview of such techniques and their indications.

AREAS COVERED

A review of the literature was performed in the PubMed, Web of Science, and Scopus without time or language restrictions through the use of one or more fitting search criteria and terms as well as through screening of references in relevant selected papers. Literature up to and including December 2023 was included. Screening of titles/abstracts and removal of duplicates was performed and the full texts of the remaining potentially relevant articles were retrieved and reviewed.

EXPERT OPINION

Thyroid and parathyroid scintigraphy remains integral in patients with thyrotoxicosis, thyroid nodules, differentiated thyroid cancer and, respectively, hyperparathyroidism. In the last years positron-emission tomography with different tracers emerged as a more accurate alternative in evaluating indeterminate thyroid nodules [18F-fluorodeoxyglucose (FDG)], differentiated thyroid cancer [124I-iodide, 18F-tetrafluoroborate, 18F-FDG] and hyperparathyroidism [18F-fluorocholine]. Other PET tracers are useful in evaluating relapsing/advanced forms of medullary thyroid cancer (18F-FDOPA) and selecting patients with advanced follicular and medullary thyroid cancers for theranostic treatments (68Ga/177Ga-somatostatin analogues).

Spatial transcriptomics reveals prognosis-associated cellular heterogeneity in the papillary thyroid carcinoma microenvironment

BACKGROUND

Papillary thyroid carcinoma (PTC) is the most common malignant endocrine tumour, and its incidence and prevalence are increasing considerably. Cellular heterogeneity in the tumour microenvironment is important for PTC prognosis. Spatial transcriptomics is a powerful technique for cellular heterogeneity study.

METHODS

In conjunction with a clinical pathologist identification method, spatial transcriptomics was employed to characterise the spatial location and RNA profiles of PTC-associated cells within the tissue sections. The spatial RNA-clinical signature genes for each cell type were extracted and applied to outlining the distribution regions of specific cells on the entire section. The cellular heterogeneity of each cell type was further revealed by ContourPlot analysis, monocle analysis, trajectory analysis, ligand-receptor analysis and Gene Ontology enrichment analysis.

RESULTS

The spatial distribution region of tumour cells, typical and atypical follicular cells (FCs and AFCs) and immune cells were accurately and comprehensively identified in all five PTC tissue sections. AFCs were identified as a transitional state between FCs and tumour cells, exhibiting a higher resemblance to the latter. Three tumour foci were shared among all patients out of the 13 observed. Notably, tumour foci No. 2 displayed elevated expression levels of genes associated with lower relapse-free survival in PTC patients. We discovered key ligand-receptor interactions, including LAMB3-ITGA2, FN1-ITGA3 and FN1-SDC4, involved in the transition of PTC cells from FCs to AFCs and eventually to tumour cells. High expression of these patterns correlated with reduced relapse-free survival. In the tumour immune microenvironment, reduced interaction between myeloid-derived TGFB1 and TGFBR1 in tumour focus No. 2 contributed to tumourigenesis and increased heterogeneity. The spatial RNA-clinical analysis method developed here revealed prognosis-associated cellular heterogeneity in the PTC microenvironment.

CONCLUSIONS

The occurrence of tumour foci No. 2 and three enhanced ligand-receptor interactions in the AFC area/tumour foci reduced the relapse-free survival of PTC patients, potentially leading to improved prognostic strategies and targeted therapies for PTC patients.

Parathyroid carcinoma: Imaging features of initial presentation and recurrence. A single center experience

BACKGROUND AND PURPOSE

Parathyroid carcinoma is the rarest endocrine neoplasm with very few published data discussing its imaging appearance with primary focus on ultrasound imaging features. We present our 23 years institutional experience to highlight multimodality imaging evaluation at presentation and at recurrence.

MATERIAL AND METHODS

Retrospective chart review of clinical and pathological diagnosis of parathyroid carcinoma patients presented for initial or recurrent disease management at M.D. Anderson Cancer Center between the period of January 2000 and February 2023 was performed. Imaging findings on US, CT, PET/CT, and technetium-99m sestamibi were analyzed for initial and local recurrent parathyroid carcinoma. We further assess patterns of distant recurrence and its location.

RESULTS

Twenty three patients with pathological and clinical diagnosis of initial (14 patients) or recurrent parathyroid carcinoma (14 patients) were included in this study. US findings of parathyroid carcinoma were larger lesions, increased/irregular vascularity, and non-circumscribed margins. Multiphasic CT findings of parathyroid carcinoma included an arterially enhancing lesion that is hypoenhancing relative to the thyroid and demonstrates no washout on delayed imaging. Highly suggestive findings for recurrent disease included a hypoechoic solid nodule (91.67%) with increased vascularity on ultrasound (81.8%) with corresponding enhancement on CT.

CONCLUSION

Parathyroid carcinoma is a rare malignancy often diagnosed after surgical resection. We provided CT and US imaging features that are helpful in suggesting the diagnosis of parathyroid carcinoma and detection of early local recurrence.

A >50% Intraoperative Parathyroid Hormone Decrease Into Normal Reference Range Predicts Complete Excision of Malignancy in Patients With Parathyroid Carcinoma

INTRODUCTION

The mainstay of successful treatment for parathyroid carcinoma remains complete surgical excision. Although intraoperative parathyroid hormone (ioPTH) monitoring is a useful adjunct during parathyroidectomy for benign primary hyperparathyroidism, its utility for parathyroid carcinoma remains unclear.

METHODS

A retrospective review of 796 patients who underwent parathyroidectomy with ioPTH monitoring for primary hyperparathyroidism revealed 13 patients with parathyroid carcinoma on final pathology from two academic institutions. A systematic review yielded 5 additional parathyroid carcinoma patients. Complete excision of malignancy, or operative success (eucalcemia ≥6 mo. after parathyroidectomy); operative failure (persistent hypercalcemia <6 mo. after parathyroidectomy); and perioperative complications were evaluated. Comparison of the >50% ioPTH decrease alone to >50% ioPTH decrease into normal reference range was analyzed using Chi-squared, Kolmogorov-Smirnov, Kruskal-Wallis tests.

RESULTS

All 18 parathyroid carcinoma patients achieved a >50% ioPTH decrease, and 14 patients also had a final ioPTH level decrease into normal reference range. 93% of patients who met normal parathyroid hormone reference range had operative success, whereas only two of the four (50%) patients with parathyroid carcinoma with a >50% ioPTH decrease alone demonstrated operative success.

CONCLUSIONS

Parathyroidectomy guided by a >50% ioPTH decrease into normal reference range may better predict complete excision of malignant tissue in patients with parathyroid carcinoma compared to >50% ioPTH decrease alone. IoPTH monitoring should be used in conjunction with clinical judgment and complete en bloc resection for optimal treatment and success.

A Rare Occurrence of Ectopic Parathyroid Carcinoma Presenting as a Case of Recurrent Fractures

Ectopic parathyroid tumors are uncommon, accounting for only 6% of parathyroid adenomas, and even fewer cases are attributed to parathyroid carcinomas. While ectopic parathyroid carcinoma in the anterior mediastinum is a rare condition, the occurrence of recurrent skeletal fractures in the presence of mild hypercalcemia is even rarer. In this report, we present the case of a 52-year-old man with a medical history of hypertension, chronic kidney disease, and a previous right-sided intertrochanteric fracture of the femur one year earlier. He presented to the emergency room with left-sided hip pain and shortness of breath due to volume overload. Laboratory tests revealed mild hypercalcemia and hyperparathyroidism, with normal vitamin D levels. An X-ray showed a left neck of femur fracture. Further evaluation with a three-phase skeletal scintigraphy indicated the presence of metabolic bone disease. A contrast-enhanced computed tomography of the chest revealed a solitary soft tissue nodule in the anterior mediastinum, representing an ectopic parathyroid adenoma. The lesion was successfully removed using video-assisted thoracic surgery, and the histopathological analysis confirmed the diagnosis of parathyroid carcinoma. The combination of mild hypercalcemia and recurrent fractures is an unusual presentation of ectopic parathyroid carcinoma, underscoring the importance of considering this condition as a potential cause in similar cases to ensure timely and appropriate treatment.

Case presentation of the smallest non-functional parathyroid carcinoma and review of the literature

INTRODUCTION

Non functional parathyroid carcinoma (PC) is one of the rarest malignant neoplasms. Due to the lack of symptoms and laboratory findings, it is mostly diagnosed in late AQ2 stages, when local invasion and dissemination are already present. However, our case is an exception, because it was detected in early stage, with no local invasion present. We present a case of the smallest non-functional PC yet reported and review of the literature.

CASE PRESENTATION

A 47-year-old woman was admitted to outpatient Clinic where fine-needle aspiration biopsy (FNAB) of bilateral thyroid nodules (slide 1) and central neck mass (slide 2), which was suspected to be an enlarged lymphatic nodule or parathyroid gland was performed. Results came back as Bethesda I-colloid (slide 1), and Bethesda IV (slide 2), stating that it is hard to distinguish thyroid gland oxyphil lesions from parathyroid cells. Total thyroidectomy was performed as well as excision of the left central neck mass, without any involvement of surrounding structures. Pathological examination revealed bilateral thyroid follicular nodular disease, papillary microcarcinoma, and parathyroid carcinoma with vascular and capsular invasion, measuring 10 × 8 × 7 mm. The immunohistochemical profile included positive PTH, Chromogranin A, and negative TTF1.

CONCLUSION

Non-functional PC is usually diagnosed in advanced stages, already involving adjacent structures; however, this case presents a rare example. It is important not to exclude PC as a differential diagnosis in the absence of elevated Ca and PTH serum levels. Follow-up will be difficult, since there are no prognostic parameters to rely on.

Functional and nonfunctional parathyroid carcinoma: two case reports and literature review

Parathyroid carcinoma (PC) is a rare malignant endocrine tumor. It can be divided into functional and non-functional types according to the tumor's ability to secrete parathyroid hormone. Herein, we present a case each of functional and nonfunctional PC. Case 1: Functional PC. The main clinical symptoms were high parathyroid hormone and hypercalcemia with bone injury and other complications. The mass was large, capsulated, and showed vascular invasion. The tumor was surgically removed, along with a part of the tracheal wall and recurrent laryngeal nerve that were invaded by the tumor. The ipsilateral and isthmus thyroid lobe and central lymph nodes were also removed. Medicines were given to lower blood calcium. The patient died 18 months after surgery because of severe pulmonary infection and tracheal stenosis. Case 2: Non-functional PC. The patient showed no obvious clinical symptoms, but physical examination revealed a thyroid nodule. Despite the small diameter, the mass still invaded the surrounding thyroid lobe, fat, and muscle tissue. Surgery was performed to remove the tumor and ipsilateral thyroid lobe and central lymph nodes. The patient survived without recurrence or metastasis. Thus, we believe that the prognosis of PC negatively correlates with the scope of surgery. Early surgery can improve patient prognosis, and physical examination is conducive to early detection of PC. Herein, we provide a description of the diagnostic workup and the treatment approach and review relevant studies. We summarize the clinicopathological characteristics of PC cases to provide evidence for early diagnosis and therapy, to improve patient prognosis.

Management and surgical treatment of parathyroid carcinoma: a 6-year experience of a single centre of endocrine surgery unit

Background

Parathyroid carcinoma (PC) affects 0.1-0.3% of the general population and represents the rarest malignant neoplasms among endocrinological diseases, comprising less than 1%. The best therapeutic treatment and management methods are still debated in the literature. The aim of this study is to evaluate the management and surgical treatment of parathyroid carcinoma after 6 years of enrolment with the Endocrine Surgery Unit of the University Hospital of Bari.

Materials and methods

A retrospective observational study was carried out using a prospectively maintained database of patients affected by primary hyperparathyroidism between January 2017 and September 2022. Consecutive patients over 18 years old with a final histopathological finding of PC were included in the study. Patients with secondary or tertiary hyperparathyroidism, parathyroid hyperplasia, and parathyroid adenoma were excluded. All patients underwent follow-up every 6 months for the first 2 years, and annually thereafter.

Results

In this study, 9 out of 40 patients affected by hyperparathyroidism were included; 6 (66.6%) were female and 3 (33.3%) were male patients, with a median age of 59 years (IQR 46-62). None had a family history of PC. No mortality was recorded while the incidence of recurrence was 22.2%, with a disease-free survival of 8 and 10 months. Parathyroidectomy was performed in five patients, while four patients underwent parathyroidectomy with concurrent thyroidectomy for thyroid goitre. No intraoperative complications were recorded. Open parathyroidectomy was performed with a mini-cervicotomy in seven patients, while two patients underwent robotic surgery. All patients were discharged on the second postoperative day.

Conclusion

PC represents a great challenge in terms of preoperative diagnosis, management and treatment. A surgical approach represents the first best option for PC in referral endocrine surgery units. The early identification of risky patients should be the dominant goal to plan an appropriate therapy and to perform adequate en bloc surgery.

Parathyroid Retrospective Analysis of Neoplasms Incidence (pTRANI Study): An Italian Multicenter Study on Parathyroid Carcinoma and Atypical Parathyroid Tumour

BACKGROUND

Parathyroid cancer (PC) is a rare sporadic or hereditary malignancy whose histologic features were redefined with the 2022 WHO classification. A total of 24 Italian institutions designed this multicenter study to specify PC incidence, describe its clinical, functional, and imaging characteristics and improve its differentiation from the atypical parathyroid tumour (APT).

METHODS

All relevant information was collected about PC and APT patients treated between 2009 and 2021.

RESULTS

Among 8361 parathyroidectomies, 351 patients (mean age 59.0 ± 14.5; F = 210, 59.8%) were divided into the APT (n = 226, 2.8%) and PC group (n = 125, 1.5%). PC showed significantly higher rates (p < 0.05) of bone involvement, abdominal, and neurological symptoms than APT (48.8% vs. 35.0%, 17.6% vs. 7.1%, 13.6% vs. 5.3%, respectively). Ultrasound (US) diameter >3 cm (30.9% vs. 19.3%, p = 0.049) was significantly more common in the PC. A significantly higher frequency of local recurrences was observed in the PC (8.0% vs. 2.7%, p = 0.022). Mortality due to consequences of cancer or uncontrolled hyperparathyroidism was 3.3%.

CONCLUSIONS

Symptomatic hyperparathyroidism, high PTH and albumin-corrected serum calcium values, and a US diameter >3 cm may be considered features differentiating PC from APT. 2022 WHO criteria did not impact the diagnosis.

Clinical and molecular characterization of parathyroid carcinoma in multiple endocrine neoplasia type 1

Nineteen cases of parathyroid carcinoma in patients with multiple endocrine neoplasia type 1 have been reported in the literature, of which 11 carry an inactivating germline mutation in the MEN1 gene. Somatic genetic abnormalities in these parathyroid carcinomas have never been detected. In this paper, we aimed to describe the clinical and molecular characterization of a parathyroid carcinoma identified in a patient with MEN1. A 60-year-old man was diagnosed with primary hyperparathyroidism during the postoperative period of lung carcinoid surgery. Serum calcium and parathyroid hormone levels were 15.0 mg/dL (8.4-10.2) and 472 pg/mL (12-65), respectively. The patient underwent parathyroid surgery, and histological findings were consistent with parathyroid carcinoma. Analysis of the MEN1 gene by next-generation sequencing (NGS) identified a novel germline heterozygous nonsense pathogenic variant (c.978C>A; p.(Tyr326*)), predicted to encode a truncated protein. Genetic analysis of the parathyroid carcinoma revealed a c.307del, p.(Leu103Cysfs*16) frameshift truncating somatic MEN1 variant in the MEN1 gene, which is consistent with MEN1 tumor-suppressor role, confirming its involvement in parathyroid carcinoma etiology. Genetic analysis of CDC73, GCM2, TP53, RB1, AKT1, MTOR, PIK3CA and CCND1 genes in the parathyroid carcinoma DNA did not detect any somatic mutations. To our knowledge, this is the first report of a PC case presenting both germline (first-hit) and somatic (second-hit) inactivation of the MEN1 gene.

Diagnostic dilemma in a rare case of nonfunctional parathyroid carcinoma at a referral facility in Northern Tanzania

Key Clinical Message

Rare cancer originating from parathyroid parenchymal cells. Preoperative diagnosis is often difficult. Presents with normal serum levels of calcium and parathyroid hormone. Treated by en bloc resection. Benefits of adjuvant therapy are unclear.

Abstract

Parathyroid carcinoma is an uncommon endocrine tumor. Its typical presentation is that of primary hyperparathyroidism with elevated serum calcium and parathormone levels. Nonfunctioning carcinoma of the parathyroid gland with normal serum calcium levels is extremely rare. This paper describes a case of nonfunctioning parathyroid carcinoma and brief literature review thereof.

Parathyroid carcinoma: lessons from a rare malignancy of head and neck-a case series

Parathyroid carcinoma (PC) is a very rare head-neck malignancy. Because the symptoms of parathyroid carcinoma are similar to those of benign causes of hyperparathyroidism, it may be not easy to detect it before surgery. The management of PC after initial surgery will be perplexing because of the adequacy of surgery. We wish to describe the difficulties encountered throughout treatment using a literature review. We conducted a retrospective analysis of individuals with parathyroid carcinoma who had treatment at our department between 2017 and 2022. We gathered data on the clinical profile, investigations, management of hypercalcemia, surgical techniques, histopathological features, adjuvant therapy, and outcomes. We treated three patients with parathyroid carcinoma: Two patients with inferior parathyroid carcinoma and one with superior parathyroid carcinoma. Generalized weakness and bony pain are the predominant symptoms. In all cases, the tumor was located using 99Tc MIBI / SPECT scintigraphy and Ultrasonography. Hemithyroidectomy and tumor excision were done as the surgery of choice. All are disease-free at the 12th-month follow-up. We suggested that parathyroid hormone testing be performed in all bony fibrous lesions to rule out hyperparathyroidism. PC is a likely diagnosis when there is noticeable throat swelling, elevated PTH levels greater than 400 IU/L, and serum calcium levels greater than 15 mg/dL.

A Nomogram for Relapse/Death and Contemplating Adjuvant Therapy for Parathyroid Carcinoma

Parathyroid carcinoma (PC) is a rare endocrine malignancy with an increased incidence in the last decade. There is no reliable prognostic staging system for PC. Several hosts, tumors, and tumor microenvironment factors have been negatively correlated with survival in the last decade. Surgical resection with negative margins is still the standard of treatment in PC. Chemo and radiotherapy have no proven beneficial effect. A new promising approach with molecular profiling could lead to adjuvant therapies.

Value of 99m Tc-MIBI SPECT/CT in the localization of recurrent lesions in patients with suspected recurrent parathyroid carcinoma

PURPOSE

Accurate preoperative localization of tumor-bearing lesions is crucial for the successful surgical management of suspected recurrent parathyroid carcinoma. The purpose of this study was to evaluate the diagnostic value of 99m-technetium-labeled methoxyisobutylisonitrile ( 99m Tc-MIBI) single-photon emission computed tomography/computed tomography (SPECT/CT) and cervical ultrasound, individually and in combination, for preoperative localization of recurrent/metastatic lesions. We also analyzed the value of 99m Tc-MIBI SPECT/CT in detecting ectopic lesions in patients with suspected recurrent parathyroid carcinoma.

METHODS

Twenty-nine patients with suspected recurrent parathyroid carcinoma were included in this retrospective cohort study. Patients underwent preoperative 99m Tc-MIBI SPECT/CT and cervical ultrasound. The reference standard was postsurgical histopathology. The sensitivity, specificity, positive predictive value (PPV), negative predictive value, and accuracy of the two diagnostic modalities alone and in combination were analyzed.

RESULTS

Of the 29 patients, histopathological results revealed 48 metastases/recurrent lesions in 26 patients. The diagnostic value of 99m Tc-MIBI SPECT/CT, cervical ultrasound, and the two modalities in combination were compared for the 27 patients who underwent new cervical surgery. Patient-level analysis of the combined use of 99m Tc-MIBI SPECT/CT and cervical ultrasound had the highest sensitivity (100.00%) and accuracy (96.30%). At the lesion level, 99m Tc-MIBI SPECT/CT had the highest specificity and PPV, at 100.00% respectively, whereas the combined use of 99m Tc-MIBI SPECT/CT and cervical ultrasound had the highest sensitivity, at 97.62%. Moreover, 99m Tc-MIBI SPECT/CT detected six ectopic lesions, and five of them showed increased 99m Tc-MIBI uptake.

CONCLUSIONS

The combined use of 99m Tc-MIBI SPECT/CT and cervical ultrasound is the most efficient strategy in the diagnosis of parathyroid carcinoma relapse, whereas 99m Tc-MIBI SPECT/CT is the preferred method for localizing and analyzing cervical and extra-cervical lesions before the new surgery.

Parathyroid carcinoma: Single centre experience

OBJECTIVE

Parathyroid Carcinoma is a rare malignant neoplasm, accounting for less than 1% of primary hyperparathyroidism cases. Parathyroid carcinomas are characterized by markedly elevated levels of PTH, severe hypercalcemia and established target organ damage. The authors report the experience of a single centre regarding the management and outcome of patients with parathyroid carcinomas and revise relevant literature.

DESIGN

Retrospective review of all patients with parathyroid carcinoma evaluated at a tertiary oncologic centre from 1991 until 2021.

RESULTS

Seventeen patients were identified (10 males), with a mean age at diagnosis of 53 ± 16 years and a median follow-up of 16.5 years. Most patients presented with hypercalcemia (n = 15), with a mean serum calcium concentration of 13.5 mg/dl (9.6-16.5) and mean PTH of 1173 pg/ml (276-2500). Hyperparathyroidism-mediated organ damage was observed in most patients (n = 16), with predominant renal (n = 12) and skeletal (n = 9) complications. En bloc surgical resection was performed in nine patients. Three patients underwent adjuvant radiotherapy. Recurrence was observed in 8 cases (47.1%) after a median of 24 months following surgery and no independent predictors of recurrence were identified. The overall survival and disease specific survival at 5-year was 88% and 94%, respectively. CDC73 mutations were present in 38.5% of analysed patients and one patient was diagnosed with MEN1.

CONCLUSION

Parathyroid carcinoma is associated with a significant rate of recurrence and limited effective treatment beyond initial complete surgical resection. Therefore, preoperatively high index of suspicion is paramount to optimize patient care. This is, to our knowledge, the largest Portuguese cohort published so far.

Association of Parathyroid and Differentiated Thyroid Carcinomas: A Narrative Up-To-Date Review of the Literature

Aim: Parathyroid carcinoma (PC) is a rare endocrine malignancy that represents 0.005% of all malignant tumors. Associated PC and differentiated thyroid carcinoma (DTC) is an exceptionally rare condition, and the preoperative diagnostics and proper treatment are challenging. Almost all PCs and the majority of DTCs are diagnosed postoperatively, making correct surgical treatment questionable. Specific guidelines for parathyroid and thyroid carcinomas association treatment are lacking. The purposes of our study were to identify the association between parathyroid and thyroid carcinomas, to analyze the available published data, and to evaluate the possible relationship between preoperative diagnostic and surgical decision-making, and outcome-related issues. Material and methods: We performed a literature review of several databases from the earliest records to March 2022, using controlled vocabulary and keywords to search for records on the topic of PC and WDTC pathological association. The reference lists from the initially identified articles were analyzed to obtain more references. Results: We identified 25 cases of PC and DTC association, 14 more than the latest review from 2021. The mean age of patients was 55, with a female to male ratio of about 3:1. Exposure to external radiation was identified in only one patient, although it is considered a risk factor the development of both PC and DTC. The preoperative suspicion of PC was stated by the authors in only 25% of cases, but suspicion based on clinical, laboratory, ultrasound (US), and fine needle aspiration (FNA) criteria could have been justified in more than 50% of them. With neck ultrasound, 40% of patients presented suspicious features both for PC and thyroid carcinoma. Intra-operatory descriptions of the lesions revealed the highest suspicion (83.3%) of PC, but en bloc resection was recommended and probably performed in only about 50% of the cases. Histopathological examinations of the thyroid revealed different forms of papillary thyroid carcinoma (PTC) in most cases. Postoperative normocalcemia was achieved in 72% of patients, but follow-up data was missing in about 25% of cases. Conclusion: Associated PC and DTC is an exceptionally rare condition, and the preoperative diagnostic and treatment of the patients is a challenge. However, in most cases pre- and intraoperative suspicious features are present for identification by a highly specialized multidisciplinary endocrine team, who can thus perform the optimal treatment to achieve curability.

Near-Infrared Autofluorescence Features of Parathyroid Carcinoma

Introduction

Parathyroid carcinoma is very rare, and intraoperative definitive diagnosis can be elusive with currently available diagnostics. Near-infrared (NIR) autofluorescence is an emerging tool that identifies parathyroid glands in real time. It is not known whether NIR autofluorescence can detect parathyroid carcinoma intraoperatively.

Methods

Patients with preoperative suspicion for parathyroid carcinoma were identified from ongoing studies examining parathyroid autofluorescence with a NIR camera and probe. Specimens from these patients were examined intraoperatively to determine their autofluorescence patterns.

Results

Three patients with suspected parathyroid carcinoma were identified preoperatively. Intraoperative NIR autofluorescence imaging showed a relative lack of autofluorescence for all cases, in contrast to parathyroid adenomas and normal parathyroid glands, which typically exhibit significant autofluorescence. Final pathology confirmed parathyroid carcinoma in all cases.

Conclusion

Parathyroid carcinoma can be difficult to confirm prior to final pathology review. Our 3 cases suggest that absence of NIR autofluorescence may suggest the likelihood of parathyroid carcinoma, but more studies are needed to investigate this experience.

Tumor size rather than the thyroid invasion affects the prognosis of parathyroid carcinoma without lymph node or distant metastasis

PURPOSE

This study aimed to explore the prognostic value of thyroid invasion of parathyroid carcinoma without lymph node or distant metastasis.

METHODS

Two hundred and nine cases of parathyroid carcinoma from the SEER (1989-2014) were eligible for this study. A Chi-squared test, t test, X-tile, Kaplan-Meier curves, and multivariate Cox proportional hazard regression were used for analysis.

RESULTS

Thyroid invasion, sex, race, age, radiation, and surgery were not significantly associated with cancer-specific survival by multivariate analysis. However, tumor size ≥ 4 cm was significantly associated with worse cancer-specific survival (P < 0.001).

CONCLUSION

Thyroid invasion, which was the criterion for T₁ and T₂ staging criteria of parathyroid carcinoma according to the AJCC, did not affect the prognosis of patients with parathyroid carcinoma without local lymph node or distant metastasis. Our study indicates that a tumor size ≥ 4 cm may be an appropriate indicator of T₁ and T₂ cancer staging.

Prognostic Analysis for Patients With Parathyroid Carcinoma: A Population-Based Study

Background

Parathyroid carcinoma (PC) is a rare but often lethal malignancy for which staging system, prognostic indicators, and treatment guidelines are still not established. We aimed to explore the prognostic parameters and construct a nomogram for cancer-specific survival (CSS) of PC.

Methods

A retrospective analysis of 604 PC patients in the SEER database from 2001 through 2018 was performed. All the cases were randomly assigned to the training cohort (n = 424) or the validation cohort (n = 180) at a ratio of 7:3. The Kaplan–Meier method and Cox regression model were applied to estimate the CSS and risk factors, and a nomogram was constructed. The predictive accuracy and discriminative ability of the nomogram in CSS were assessed by concordance index (C-index), the area under the curve (AUC) of receiver operating characteristics (ROC), and the calibration curve.

Results

Age at diagnosis > 70 years [hazard ratio (HR): 3.55, 95% CI: 1.07–11.78, p = 0.039] and tumor size > 35 mm (HR 4.22, 95% CI: 1.67–10.68, p = 0.002) were associated with worse CSS. Compared with distant metastasis, localized (HR 0.17, 95% CI: 0.06–0.47, p = 0.001) and regional lesions (HR 0.22, 95% CI: 0.07–0.66, p = 0.007) showed an improved CSS rate. Parathyroidectomy was the recommended treatment (p = 0.02). The C-index of the nomogram was 0.826, and the AUC for 5-, 10-, and 15-year CSS was 83.7%, 79.7%, and 80.7%, respectively. The calibration curve presented good agreement between prediction by nomogram and actual observation.

Conclusion

Age at diagnosis > 70 years, tumor size > 35 mm, and distant metastasis were independent risk factors for PC-specific mortality. Parathyroidectomy was currently the most recommended treatment for PC. This nomogram provided individualized assessment and reliable prognostic prediction for patients with PC.

MicroRNA Profile Alterations in Parathyroid Carcinoma: Latest Updates and Perspectives

Simple Summary

Despite the considerable development of diagnostic tools, distinguishing between benign and malignant parathyroid tumors poses a significant diagnostic challenge. Epigenetic regulations, including noncoding microRNAs (miRNAs), have recently emerged as a new and promising source of biomarkers. MiRNAs are post-transcriptional regulators of gene expression. These tissue-specific molecules are known to be deregulated between cancer and normal cells. This review delineates changes in miRNA expression in parathyroid carcinoma (PC), advancing our understanding of PC tumorigenesis and emphasizing, at the same time, that miRNAs can be further exploited for diagnostic and therapeutic purposes.

Abstract

Parathyroid tumors are a genetically heterogenous group with a significant variability in clinical features. Due to a lack of specific signs and symptoms and uncertain histopathological criteria, parathyroid carcinomas (PCs) are challenging to diagnose, both before and after surgery. There is a great interest in searching for accurate molecular biomarkers for early detection, disease monitoring, and clinical management. Due to improvements in molecular pathology, the latest studies have reported that PC tumorigenesis is strongly linked to the epigenetic regulation of gene expression. MicroRNA (miRNA) profiling may serve as a helpful adjunct in distinguishing parathyroid adenoma (PAd) from PC and provide further insight into regulatory pathways involved in PTH release and parathyroid tumorigenesis. So far, only a few studies have attempted to show the miRNA signature for PC, and very few overlaps could be found between these relatively similar studies. A global miRNA downregulation was detected in PC compared with normal glands among differentially expressed miRNAs. This review summarizes changes in miRNA expression in PC and discusses the future research directions in this area.

Parathyroid carcinoma presenting with ventricular bigeminy in pregnancy

Parathyroid carcinoma is very rare in pregnancy. Clinical features are similar to primary hyperparathyroidism. A 38-year-old pregnant woman had repeated hospital admissions for palpitations, headaches, dizziness and polydipsia. Blood investigations showed severe hypercalcaemia with raised parathyroid hormone and 24-hour ECG showed ventricular bigeminy and premature ventricular contractions. Neck ultrasound showed a lesion in the right thyroid lobe. Consequently, she underwent an en bloc resection of the right parathyroid and thyroid lobe at 23 weeks gestation. Histology results confirmed parathyroid cancer. This case highlights the complexities of identifying hypercalcaemia in pregnancy due to the overlapping features with common disorders of pregnancy. Early recognition and timely surgical management can prevent maternal and fetal complications. Also, the case demonstrates the value of interprofessional collaboration between different specialities in providing quality care and improving outcomes. An abridged version of this case was presented at European Congress of Endocrinology 2021.

A Bibliometric Analysis of the Landscape of Parathyroid Carcinoma Research Based on the PubMed (2000–2021)

Introduction

The purpose of this study was to assess the landscape of parathyroid carcinoma research during the last 22 years using machine learning and text analysis.

Method

In November 2021, we obtained from PubMed all works indexed under the mesh subject line “parathyroid carcinoma”. The entire set of search results was retrieved in XML format, and metadata such as title, abstract, keywords, mesh words, and year of publication were extracted for bibliometric evaluation from the original XML files. To increase the specificity of the investigation, the Latent Dirichlet allocation (LDA) topic modeling method was applied.

Results

The paper analyzed 3578 papers. The volume of literature related to parathyroid cancer has been relatively flat over the past 22 years. In the field of parathyroid cancer research, the most important topic of clinical interest is the differential diagnosis. Ultrasound and MIBI are the most commonly used imaging methods for localization. In terms of basic research, the mechanisms of gene mutation and local tumor recurrence are the focus of interest.

Conclusion

There are huge unmet research needs for parathyroid carcinoma. Improving the diagnosis rates of parathyroid cancer by clinicians and establishing new and reliable molecular pathological markers and new image localization techniques will continue to be the focus of future research.

Non-Linear Correlation Between Tumor Size and Survival Outcomes for Parathyroid Carcinoma: A SEER Population-Based Cohort Study

BACKGROUND

Parathyroid carcinoma (PC) is a rare malignancy without a commonly acknowledged prognostic assessment and treatment system. This study captures how independent prognostic factors and tumor size correlate with outcomes in patients with PC.

METHODS

The Surveillance, Epidemiology, and End Results database was used to perform a retrospective analysis on PC patients from 2000 to 2018. Univariate and multivariable survival analyses were performed to evaluate cancer-specific survival (CSS) and overall survival (OS), to identify independent prognostic factors in the PC patient population. A generalized additive model was applied to conduct smooth curve fitting and to examine the association between tumor size and relative risk of death.

RESULTS

A total of 590 patients were included. The 5- and 10-year OS were 80.8% and 67.1%, respectively. 5- and 10-year CSS was estimated to be 93.6% and 92.1%, respectively. The association between tumor size and relative risk of death can be generalized as a U-shaped curve. The mortality risk reaches its lowest point when tumor diameter approaches 2cm. At a tumor diameter cutoff of 3cm for CSS and 4cm for OS, there is an abrupt drop in survival rates. Multivariate Cox analysis revealed age, no surgery, and debulking surgery as consistent predictors of lower OS and CSS.

CONCLUSIONS

A non-linear correlation between tumor size and death risk has been identified in patients with PC, along with an accurate size threshold at which survival rates sharply decrease. Further investigation is needed to determine if these trends are seen in other malignancies with promising prognoses.

Contrast-Enhanced Ultrasound Qualitative and Quantitative Characteristics of Parathyroid Gland Lesions

Background and Objectives: preoperative differentiation of enlarged parathyroid glands may be challenging in conventional B-mode ultrasound. The aim of our study was to analyse qualitative and quantitative characteristics of parathyroid gland lesions, using multiparametric ultrasound protocol—B-mode, Colour Doppler (CD), and contrast-enhanced ultrasound (CEUS)—and to evaluate correlation with morphology in patients with hyperparathyroidism (HPT). Materials and Methods: consecutive 75 patients with 88 parathyroid lesions and biochemically confirmed HPT prior to parathyroidectomy were enrolled in the prospective study. B-mode ultrasound, CD, and CEUS were performed with the subsequent qualitative and quantitative evaluation of acquired data. We used 1 mL or 2 mL of intravenous ultrasound contrast agent during the CEUS examination. Correlation with post-surgical morphology was evaluated. Results: seventy parathyroid adenomas were hypoechoic and well contoured with increased central echogenicity (44.3%), peripheral-central vascularization (47%), and polar feeding vessel (100%). Twelve hyperplasias presented with similar ultrasound appearance and were smaller in volume (p = 0.036). Hyperplasias had a tendency for homogenous, marked intense enhancement vs. peripherally enhanced adenomas with central wash-out in CEUS after quantitative analysis. No significant difference was observed in contrasting dynamics, regardless of contrast media volume use (1 mL vs. 2 mL). We achieved 90.9% sensitivity and 72.7% specificity, 93% positive predictive value (PPV), 87.3% negative predictive value (NPV), and 87.3% accuracy in the differentiation of parathyroid lesions prior to post-processing. In a quantitative lesion analysis, our sensitivity increased up to 98%, specificity 80%, PPV 98%, and NPV 80% with an accuracy of 96.4%. Conclusions: CEUS of parathyroid lesions shows potential in the differentiation of adenoma from hyperplasia, regardless of the amount of contrast media injected. The quantitative analysis improved the sensitivity and specificity of differentiation between parathyroid lesions. Hyperplasia was characterized by homogeneous enhancement, fast uptake, and homogeneous wash-out appearance; adenoma—by peripheral uptake, central wash-out, and reduced hemodynamics. The use of CEUS quantification methods are advised to improve the ultrasound diagnostic role in suspected parathyroid lesions.

Radiation Treatment for Inoperable Local Relapse of Parathyroid Carcinoma With Symptomatic Hypercalcemia: A Case Report

BACKGROUND

Parathyroid carcinoma (PC) is an extremely rare malignancy, characterized by slow progression, frequent recurrences and difficult-to-control hypercalcemia which is typically the main contributor to the morbidity and mortality of these patients. Patients often undergo repeated surgical resections, whether or not in combination with adjuvant radiation treatment. The role of radiation therapy within the symptomatic treatment of PC currently remains unclear.

CASE DESCRIPTION

We describe a 30-year-old male patient with an inoperable local relapse of PC and secondary symptomatic hypercalcemia, maximally pharmacologically treated. After a local radiation treatment to a total dose of 70 Gray in 35 fractions serum calcium and parathyroid hormone (PTH) levels decreased, accompanied by improvement of the severe gastro-intestinal disturbances.

CONCLUSION

For patients with inoperable symptomatic PC despite maximal medical treatment who are in a good overall condition, radiation treatment can be considered in well-defined cases to decrease symptoms and improve quality of life.

Management and Outcome of Parathyroid Carcinoma-Induced Primary Hyperparathyroidism: A Single-Centre Experience

BACKGROUND

Parathyroid carcinoma (PC) is the rarest endocrine cancer and an infrequent cause of primary hyperparathyroidism (PHPT), responsible for less than 1% of cases. Due to its rarity, treatment is challenging.

METHODS

A retrospective cohort study on 462 patients referred for parathyroidectomy to Thyroid and Parathyroid Unit at Santi Paolo e Carlo Hospital, Milan, Italy, from 2011 to 2021. We identified and individually described the patients affected with PC. Then, we split all patients treated for PHPT into four groups based on the cause: PC, adenoma, atypical adenoma, and hyperplasia. Patients' demographics, preoperative evaluation results, intraoperative findings, and outcomes for the PC group were compared with groups of PHPT due to benign causes.

RESULTS

Eight cases of PC were identified, five males and three females. Seven cases presented with symptoms of hypercalcemia and one with a neck mass. Five underwent en bloc resections and three local excisions. Histopathological features showed capsular invasion in four patients, capsular and soft tissue invasion in three patients, and vascular invasion in one case. No patients had distant metastasis. One patient was classed as high risk based on the Schulte classification system. All patients treated for PC were alive and disease-free at a mean follow-up of 38.4 months. When compared with other PHPT patients, PC patients were more frequently male and had higher preoperative blood calcium and PTH and lower phosphate levels, larger and heavier parathyroids excised, lower postoperative calcium, and a higher rate of postoperative hypoparathyroidism.

CONCLUSION

Our study highlights some aspects valuable to suspect PC and differentiate PHPT-PC from benign causes of PHPT preoperatively. Preoperative suspicion of malignancy is essential to guarantee the best course of treatment for patients. Although limited for size and follow-up, the excellent outcome of our series seems to support the value of both surgery extension and risk class according to the Schulte classification as possible prognostic factors for recurrence.

The EANM practice guidelines for parathyroid imaging

INTRODUCTION

Nuclear medicine parathyroid imaging is important in the identification of hyperfunctioning parathyroid glands in primary hyperparathyroidism (pHPT), but it may be also valuable before surgical treatment in secondary hyperparathyroidism (sHPT). Parathyroid radionuclide imaging with scintigraphy or positron emission tomography (PET) is a highly sensitive procedure for the assessment of the presence and number of hyperfunctioning parathyroid glands, located either at typical sites or ectopically. The treatment of pHPT is mostly directed toward minimally invasive parathyroidectomy, especially in cases with a single adenoma. In experienced hands, successful surgery depends mainly on the exact preoperative localization of one or more hyperfunctioning parathyroid adenomas. Failure to preoperatively identify the hyperfunctioning parathyroid gland challenges minimally invasive parathyroidectomy and might require bilateral open neck exploration.

METHODS

Over a decade has now passed since the European Association of Nuclear Medicine (EANM) issued the first edition of the guideline on parathyroid imaging, and a number of new insights and techniques have been developed since. The aim of the present document is to provide state-of-the-art guidelines for nuclear medicine physicians performing parathyroid scintigraphy, single-photon emission computed tomography/computed tomography (SPECT/CT), positron emission tomography/computed tomography (PET/CT), and positron emission tomography/magnetic resonance imaging (PET/MRI) in patients with pHPT, as well as in those with sHPT.

CONCLUSION

These guidelines are written and authorized by the EANM to promote optimal parathyroid imaging. They will assist nuclear medicine physicians in the detection and correct localization of hyperfunctioning parathyroid lesions.

Synchronous intrathyroidal parathyroid carcinoma and thyroid carcinoma: case report and review of the literature

BACKGROUND

Parathyroid carcinoma is a rare endocrine malignancy, rarer when synchronous with a non medullary well differentiated thyroid carcinoma. Parathyroid carcinoma accounts of 0.005% of all malignant tumors and it is responsible for less than 1% of primary hyperparathyroidism. The intrathyroidal localization of a parathyroid gland is not frequent with a reported prevalence of 0.2%. Carcinoma of parathyroids with intrathyroidal localization represents an even rarer finding, reported in only 16 cases described in literature. The rare constellation of synchronous parathyroid and thyroid carcinomas has prompted us to report our experience and perform literature review.

CASE PRESENTATION

We herein report a case of a 63-years-old man with multinodular goiter and biochemical diagnosis of hyperparathyroidism. Total thyroidectomy with radio-guide technique using gamma probe after intraoperative sesta-MIBI administration and intraoperative PTH level was performed. The high radiation levels in the posterior thyroid lobe discovered an intrathyroidal parathyroid. Microscopic examination revealed a parathyroid main cell carcinoma at the posterior thyroidal left basal lobe, a classic papillary carcinoma at the same lobe and follicular variant of papillary carcinoma at the thyroidal right lobe. To the best of our knowledge, this is the first case documenting a synchronous multicentric non medullary thyroid carcinomas and intrathyroidal parathyroid carcinoma.

CONCLUSIONS

Our experience was reported and literature review underlining challenging difficulties in diagnostic workup and surgical management was carried out.

[Parathyroid carcinoma: a rare and aggressive tumor]

Parathyroid carcinoma is a very rare disease that is accompanied by a poor prognosis. Diagnosis is based on laboratory tests (calcium, parathyroid hormone), sonography, and scintigraphy. Complete surgical resection is the treatment of choice. Adjuvant therapy is controversial. The lack of treatment guidelines and experience with this disease often delay timely therapy. In the following article, we report on two female patients with parathyroid carcinoma who underwent surgery in our clinic.

Case Report and Systematic Review: Sarcomatoid Parathyroid Carcinoma-A Rare, Highly Malignant Subtype

BACKGROUND

Parathyroid carcinoma (PC) is a rare malignancy, the incidence of which is less than 1/1 million per year. Sarcomatoid parathyroid carcinoma (SaPC) is an extremely peculiar subtype; only three cases have been reported internationally. It consists of both malignant epithelial components and sarcomatoid components (mesenchymal origin) simultaneously. This "confusing" cancer exhibits higher invasiveness, and traditional surgery does not appear to achieve the expectation, which differs significantly from that of general PC.

OBJECTIVE

To characterize the clinicopathologic features of SaPC and explore similarities and differences between SaPC and general PC.

MATERIALS AND METHODS

We collected clinical data of SaPC cases from our center and literature. The SaPC case in our center was presented. To better understand the characteristics of SaPC, we also reviewed clinical information in general PC cases from our center and literature within the last 5 years, and a systematic review was performed for further comparison.

RESULTS

A 60-year-old woman was admitted for a neck mass and hoarseness. After the surgery, she was confirmed as SaPC and ultimately developed local recurrence at 3 months. Together with the reported cases from literature, four cases of SaPC (three cases from literature) and 203 cases of general PC (200 cases from literature) were reviewed. Both tumors showed obvious abnormalities in parathormone (PTH) level and gland size. Compared to general PC, SaPC has a later age of onset (60.50 ± 7.42 vs. 51.50 ± 8.29), relatively low levels of PTH (110.28 ± 59.32 vs. 1,156.07 ± 858.18), and a larger tumor size (6.00 ± 1.63 vs. 3.14 ± 0.70). For SaPC, all four cases were initially misdiagnosed as thyroid tumors (4/4). Spindle cell areas or transitional zones were common pathological features in SaPC cases (3/4).

CONCLUSION

SaPC is a very rare pathologic subtype of PC and appears to be much more easily misdiagnosed as a thyroid tumor. Spindle cell areas or transitional zones are highly possible to be pathological features in its sarcomatoid components. Despite many similarities, there are some differences between SaPC and general PC-SaPC does not show the obvious endocrine feature but stronger aggressiveness. Surgical treatment of SaPC does relieve life-threatening symptoms and improve quality of life even with recurrence in the short term.

Parathyroid Carcinoma in the Setting of Tertiary Hyperparathyroidism: Case Report and Review of the Literature

Introduction

Parathyroid carcinoma is one of the rarest cancers in normal population, and it is extremely uncommon in the setting of tertiary hyperparathyroidism. Indeed, only 24 cases have been reported in the literature. Presentation of the Case. We report the case of parathyroid carcinoma in a 51-year-old man, with a history of end-stage renal disease due to a horseshoe kidney treated with haemodialysis since 2013. He came to our attention due to an increase in calcium and parathyroid hormone serum levels. Neck ultrasound (US) showed a solid hypodense mass, probably the right inferior parathyroid gland, with an estimated size of 25 × 15 × 13 mm; the 99mTc-sestamibi SPECT/CT scan revealed a large radiotracer activity area in the right cervical region, compatible with a hyperfunctioning right inferior parathyroid gland. So, a tertiary hyperparathyroidism diagnosis was made. In April 2018, resection of three parathyroid glands was performed. Histopathological examination demonstrated the right inferior parathyroid gland specimen to be a parathyroid carcinoma, due to the presence of multiple, full-thickness, capsular infiltration foci, and a venous vascular invasion focus. Discussion. Diagnosis of parathyroid carcinoma in tertiary hyperparathyroidism is remarkably complex because of the lack of clinical diagnostic criteria and, in many cases, is made postoperatively at histopathological examination.

Conclusion

To date, radical surgery represents the mainstay of treatment, with a five- and ten-year survival rates overall acceptable.

Parathyroid Carcinoma Shown on 99mTc-Sestamibi Parathyroid SPECT/CT Scan in a Pediatric Patient

A 10-year-old boy presented with back pain. Tc-methylene diphosphonate bone scan demonstrated the sign of metabolic bone disease, suspected due to hyperparathyroidism. Tc-sestamibi parathyroid SPECT/CT demonstrated focal lesion in the lower pole of the right lobe. The pathological examination demonstrated parathyroid carcinoma, which is very rare in pediatric population.

Severe symptomatic hyperparathyroidism-Is it carcinoma?-Case report and literature review

Parathyroid carcinoma is a rare disease, difficult to diagnose and associated with a poor prognosis. It must be suspected preoperatively, based on clinical and imaging grounds, in order to perform the best surgical option and avoid compromising patient's prognosis.

A rare case of three years disease free survival in a locally advanced parathyroid carcinoma successfully excised by complete surgical resection

Parathyroid carcinoma (PC) is one of the rarest malignancies making approximately 0.005% of all cancers. It may arise sporadically or less commonly, in conjunction with genetic endocrine syndromes. Due to the rarity of the disease, no general consensus or definitive guidelines exist for its pre-operative diagnosis, management, or follow up. Surgical tumor removal is the gold standard treatment to prevent its recurrence. Parathyroid carcinoma has a high recurrence rate ranging from 40 to 60% in recent literature. We report a case of a seventy-year-old elderly female with locally advanced parathyroid carcinoma successfully surgically excised completely with a 3 year disease free survival period without adjuvant chemotherapy or radiotherapy.

The Use and Benefit of Adjuvant Radiotherapy in Parathyroid Carcinoma: A National Cancer Database Analysis

Background

The routine use of external beam radiotherapy (EBRT) is not recommended for parathyroid carcinoma (PC). However, case series have demonstrated a potential benefit in preventing local recurrence with EBRT. We aimed to characterize the patient population treated with EBRT and identify any impact of EBRT on overall survival (OS) in parathyroid carcinoma.

Methods

Patients who underwent surgery for PC from 2004 to 2016 were identified from the National Cancer Database. Clinicopathologic variables and OS were compared between patients based on treatment with EBRT. Multivariable logistic and Cox regression models were performed with propensity scores and inverse-probability-weighting (IPW) adjustment to reduce treatment-selection bias in the OS analysis.

Results

A total of 885 patients met the inclusion criteria, with 126 (14.2%) undergoing EBRT. Demographics were similar between the two cohorts (EBRT vs. no EBRT). However, patients treated with EBRT had a higher frequency of regionally extensive disease, nodal metastases, and residual microscopic disease (all p < 0.05). On multivariable analysis, Black race, regional tumor extension, nodal metastasis, and treatment at an urban facility were independently associated with EBRT. The 5-year OS was 85.3% with a median follow-up of 60.8 months. EBRT was not associated with a difference in OS in crude, multivariable, or IPW models. More importantly, 10.5% of patients with completely resected localized disease (M0, N0 or Nx) underwent EBRT without a benefit in OS (p = 0.183).

Conclusions

EBRT is not associated with any survival benefit in the treatment of PC. Therefore, it may be overutilized, particularly in patients with localized disease and complete surgical resection.

Clinical Presentation, Treatment, and Outcome of Parathyroid Carcinoma: Results of the NEKAR Retrospective International Multicenter Study

OBJECTIVE

In this retrospective cohort study, we describe the clinical presentation and workup of parathyroid carcinoma (PC) and determine its clinical prognostic parameters. Primary outcome was recurrence free survival.

SUMMARY BACKGROUND DATA

PC is an orphan malignancy for which diagnostic workup and treatment is not established.

METHODS

Eighty-three patients were diagnosed with PC between 1986 and 2018. Disease-specific and recurrence-free survivals were estimated with the Kaplan-Meier method. Risk factors for recurrence were identified by binary logistic regression with adjustment for age and sex. Thirty-nine tumors underwent central histopathological review.

RESULTS

Renal (39.8%), gastrointestinal (24.1%), bone (22.9%), and psychiatric (19.3%) symptoms were the most common symptoms. Surgical treatment was heterogeneous [parathyroidectomy [PTx)] alone: 22.9%; PTx and hemithyroidectomy: 24.1%; en bloc resection 15.7%; others 37.3%] and complications of surgery were frequent (recurrent laryngeal nerve palsy 25.3%; hypoparathyroidism 6%). Recurrence of PC was observed in 32 of 83 cases. In univariate analysis, rate of recurrence was reduced when extended initial surgery had been performed (P = 0.04). In multivariate analysis low T status [odds ratio (OR) = 2.65, 95% confidence interval (CI) 1.02-6.88, P = 0.045], N0 stage at initial diagnosis (OR = 6.32, 95% CI 1.33-30.01, P = 0.02), Ki-67 <10% (OR = 14.07, 95% CI 2.09-94.9, P = 0.007), and postoperative biochemical remission (OR = 0.023, 95% CI 0.001-0.52, P = 0.018) were beneficial prognostic parameters for recurrence-free survival.

CONCLUSION

Despite a favorable overall prognosis, PC shows high rates of recurrence leading to repeated surgery and postoperative recurrent laryngeal nerve palsy and hypoparathyroidism. In view of the reduced recurrence rate in cases of extended surgery, ipsilateral completion surgery may be considered when PC is confirmed.

Surgical Treatment of Recurrent Metastatic Parathyroid Gland Carcinoma

Aim

We present the case of a 48-year-old male patient who underwent surgery for a recurrent metastatic parathyroid gland carcinoma in the patient’s right paratracheal space of the neck. The patient had undergone surgery for lower right parathyroid gland carcinoma 28 months earlier.

Results

The metastases were resected en bloc with an ipsilateral central neck dissection and with the removal of the enlarged lower left parathyroid gland. After exploration of the remnant parathyroid glands we noticed that lower left parathyroid gland was macroscopically enlarged so we decided to remove it to prevent possible hypercalcemia in future and to also prevent possible recurrence of cancer or development of a new primary, considering the identical embryological origin of the lower parathyroid glands and possibility of synchronous, multiple tumors, which generally follow the same embryological origin if they occur. The patient was also treated with radiation therapy after the surgery.

Conclusion

With the present surgical approach to recurrent metastatic parathyroid gland carcinoma, we aimed to prevent the recurrence of cancer or development of new primary and prevent or delay hypercalcemia in the future with all severe adverse metabolic states associated with high serum calcium levels.

Prevalence of Parathyroid Carcinoma and Atypical Parathyroid Neoplasms in 153 Patients With Multiple Endocrine Neoplasia Type 1: Case Series and Literature Review

Purpose: The occurrence of parathyroid carcinoma (PC) and atypical parathyroid neoplasm (APN) in multiple endocrine neoplasia type 1 (MEN1) is rare. The present paper reports the cases of 3 MEN1-PC/APN patients at our center and discusses the prevalence in a Chinese MEN1 cohort. Methods: This report is a retrospective analysis of 153 MEN1-associated primary hyperparathyroidism (MEN1-HPT) patients at our center, which included 3 MEN1-associated PC/APN (MEN1-PC/APN) patients. The clinical manifestations, biochemical indices, pathological findings, and therapy have been summarized along with the report of the genetic testing of the 3 patients. Results: Of the 153 MEN1-HPT patients, 1 (0.7%) was histopathologically diagnosed with PC and 2 (1.3%) with APN. Three heterozygous mutations were identified in the 3 MEN1-PC/APN patients (c.917 T > G, c.431T > C, and c.549 G > C). The cumulative findings of 3 cases with 18 previously reported MEN1-PC/APN cases revealed that the mean serum calcium (Ca) level was 3.15 ± 0.44 mmol/L and the median parathyroid hormone (PTH) level was 327 pg/mL (214.1, 673.1), both of which were significantly higher as compared to the respective levels in non-PC/APN MEN1 patients at our center [Ca: 2.78 mmol/L [2.61, 2.88], PTH: 185.5 pg/mL [108.3, 297.0]; P = 0.0003, 0.0034, respectively]. Conclusion: MEN 1-PC/APN is a rare disease, with a prevalence of only 2.0% among the MEN1-HPT cohort at our center. The affected patients recorded higher serum Ca level and PTH levels than those with MEN1-associated benign tumors. However, the diagnosis of MEN1-PC/APN is based upon pathology most of the times.