A nonfunctioning parathyroid carcinoma misdiagnosed as a follicular thyroid nodule

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 value of Tc-99m-MIBI SPECT/CT in parathyroid carcinoma with lung metastasis: a case report and literature review

Purpose

Parathyroid carcinoma (PC) is an extremely rare disease, typically presenting with marked elevations of serum calcium concentrations and associated with significantly increased parathyroid hormone (PTH) levels. Although it progresses slowly, approximately25% of PC patients have lung metastases. In the present study, we aimed to evaluate the role of technetium-99m methoxy isobutyl isonitrile (Tc-99m-MIBI; sestamibi) SPECT/CT scintigraphy in the preoperative localization of parathyroid adenomas, incidental metastases findings of PC, and ectopic parathyroid tissue.

Methods

We presented a rare case alongside a review of the relevant literature.

Results

We described an unusual case of a 25-year-old female patient with co-occurrence of PC and lung metastasis. The primary PC lesion showed no radioactive uptake, while the lung metastasis presented as a hyperfunctioning nodule, successfully localized using Tc-99m-MIBI SPECT/CT and confirmed through surgical and pathological examination.

Conclusions

This case emphasized the uniqueness of Tc-99m-MIBI SPECT/CT imaging in diagnosing PC and metastatic lesions. The appropriate application of this technique may help avert the aggressive clinical progression of PC.

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.

Papillary thyroid carcinoma associated with non‑functioning parathyroid carcinoma with Warthin's tumor of the parotid gland: A case report and brief literature review

Multiple neck pathologies occurring simultaneously are a rare condition. The present study describes an extremely rare case of papillary thyroid carcinoma, non-functioning parathyroid carcinoma (PC) and Warthin's tumor of the parotid gland. A 59-year-old male presented with a 3-month history of anterior neck swelling. The neck ultrasound revealed a left-sided thyroid nodule associated with pathological lymph nodes. There was a parotid gland mass. A fine-needle aspiration of the left parotid mass was not diagnostic, although the left thyroid nodule revealed a malignancy with metastasis to the left cervical group lymph nodes. The patient underwent total thyroidectomy, left central and left lateral cervical lymph node dissection. A superficial parotidectomy was also performed. A histopathological examination revealed three different pathologies: Papillary thyroid microcarcinoma, PC and Warthin's tumor. The simultaneous occurrence of a Warthin's tumor, papillary thyroid microcarcinoma and PC is an unusual condition. The concurrent findings of these three pathologies have not yet been reported in the literature, at least to the best of our knowledge. The synchronous findings of PTC, non-functioning PC and Warthin's tumor are extremely rare, yet possible. Surgical intervention remains the most appropriate treatment strategy.

Treatment and outcome of metastatic parathyroid carcinoma: A systematic review and pooled analysis of published cases

Background

Parathyroid carcinoma (PC) is an extremely rare malignant tumor with an incidence of about 6 new cases per 10 million inhabitants per year. While several papers have been published on treatments and outcomes of PC patients with loco-regional disease, little is known about the prognosis, treatment strategies, and prognostic factors of patients with distant metastasis.

Materials and methods

We performed a systematic review and a pooled analysis of histopathologically confirmed PC cases published in literature using the following keywords: “metastasis–metastatic–secondary nodes” AND “parathyroid carcinoma”. Original case reports and case series reporting metastatic parathyroid carcinoma were included. Data from 58 articles were extracted in a piloted form by five reviewers on a shared database.

Results

Seventy-nine patients with metastatic PC were identified between 1898 and 2018. Ten (13%) patients had synchronous metastases, while metachronous metastases occurred in 43 (54%) patients. The remaining 26 patients developed metastatic disease concomitantly to local recurrence. Primary hyperparathyroidism guided the diagnosis of metastatic recurrence in 58 (73%) patients. Surgery was the main primary approach adopted, as it was performed in 43 (54%) patients. Twenty (25%) patients underwent systemic antineoplastic therapy, consisting of chemotherapy, immunotherapy, tyrosine kinase inhibitors, and hexestrol therapy. Bone resorption inhibitors had a limited efficacy in the long-term control of hypercalcemia. After a median follow-up of 37.5 months, 43 (55%) patients died, 22 (51%) due to the consequences of uncontrolled PHPT. The median overall survival was 36 months (range: 1–252). Surgery was associated with a better OS (HR 0.48, 95% CI 0.26–0.88), whereas bone metastases represented a negative prognostic factor (HR 2.7, 95% CI 1.4–5.2).

Conclusion

Metastatic PC has a relatively poor prognosis. The main goals of treatment are to counteract tumor growth and control hypercalcemia. Surgery of metastases is the best approach to achieve rapid control of PHPT and longer survival. Target therapies and immunotherapy deserve to be extensively tested in metastatic PC and strategies to better control hypercalcemia should be implemented.

Immunohistochemical Profile of Parathyroid Tumours: A Comprehensive Review

Immunohistochemistry remains an indispensable tool in diagnostic surgical pathology. In parathyroid tumours, it has four main applications: to detect (1) loss of parafibromin; (2) other manifestations of an aberrant immunophenotype hinting towards carcinoma; (3) histogenesis of a neck mass and (4) pathogenetic events, including features of tumour microenvironment and immune landscape. Parafibromin stain is mandatory to identify the new entity of parafibromin-deficient parathyroid neoplasm, defined in the WHO classification (2022). Loss of parafibromin indicates a greater probability of malignant course and should trigger the search for inherited or somatic CDC73 mutations. Aberrant immunophenotype is characterised by a set of markers that are lost (parafibromin), down-regulated (e.g., APC protein, p27 protein, calcium-sensing receptor) or up-regulated (e.g., proliferation activity by Ki-67 exceeding 5%) in parathyroid carcinoma compared to benign parathyroid disease. Aberrant immunophenotype is not the final proof of malignancy but should prompt the search for the definitive criteria for carcinoma. Histogenetic studies can be necessary for differential diagnosis between thyroid vs. parathyroid origin of cervical or intrathyroidal mass; detection of parathyroid hormone (PTH), chromogranin A, TTF-1, calcitonin or CD56 can be helpful. Finally, immunohistochemistry is useful in pathogenetic studies due to its ability to highlight both the presence and the tissue location of certain proteins. The main markers and challenges (technological variations, heterogeneity) are discussed here in the light of the current WHO classification (2022) of parathyroid tumours.

Giant parathyroid tumours in primary hyperparathyroidism: a systematic review

PURPOSE

Giant parathyroid adenoma (GPA) can present with severe biochemical derangement similar to the clinical presentation of parathyroid carcinoma (PC). This study aims to present the current evidence on surgical management of GPAs in primary hyperparathyroidism.

METHODS

A systematic review of the literature on GPAs was conducted following the PRISMA guidelines. Data on clinical, biochemical, preoperative diagnostic, and surgical methods were analysed.

RESULTS

Sixty-one eligible studies were included reporting on 65 GPAs in eutopic, ectopic mediastinal, and intrathyroidal locations (61.5%, 30.8%, and 7.7%, respectively). A palpable neck mass was present in 58% of GPAs. A total of 90% of patients had symptoms including fatigue, skeletal pain, pathological fracture, nausea, and abdominal pain. Ninety percent of patients had significant hypercalcaemia (mean 3.51 mmol/L; range: 2.59-5.74 mmol/L) and hyperparathyroidism with PTH levels on average 14 times above the upper limit of the normal reference. There was no correlation between the reported GPA size and PTH nor between GPA weight and PTH (p = 0.892 and p = 0.363, respectively). Twenty-four percent had a concurrent thyroidectomy for suspicious features, intrathyroidal location of GPA, or large goitre. Immunohistochemistry such as Ki-67, parafibromin, and galectin-3 was used in 18.5% of cases with equivocal histology. Ninety-five percent of GPAs were benign with 5% reported as atypical adenomas.

CONCLUSION

The reported data on GPAs are sparse and heterogeneous. In GPAs with suspicious features for malignancy, en bloc resection with concurrent thyroidectomy may be considered. In the presence of equivocal histological features, ancillary immunohistochemistry is advocated to differentiate GPAs from atypical adenomas and PCs.

Parathyroid Carcinoma and Ectopic Secretion of Parathyroid hormone

The most common causes of hypercalcemia are primary hyperparathyroidism (PHPT) and malignancy. Parathyroid carcinoma (PC), causing a severe PHPT, is the rarest parathyroid tumor. A diagnosis of PC is challenging because the clinical profile overlaps with that of benign counterpart. Surgery is the mainstay treatment. CDC73 mutations have been detected in up to 80% of sporadic PCs. Ectopic production of parathyroid hormone (PTH) by malignant nonparathyroid tumors is a rare condition accounting for less than 1% of hypercalcemia of malignancy. PTH secretion can be considered an aberration in the tissue specificity of gene expression and may involve heterogeneous molecular mechanisms.

Non-functioning oxyphilic parathyroid carcinoma: a case report

Background

Non-functioning parathyroid carcinoma is an extremely rare malignancy among endocrine tumors. We report a case in which non-functional oxyphilic parathyroid carcinoma was diagnosed from clinical symptoms and pathological diagnosis.

Case presentation

The patient was a 42-year-old man with no medical or family history of note. He had presented to a local hospital with a neck mass 2 months earlier. Medullary thyroid carcinoma was diagnosed and he was referred to our department. A 3.5-cm mass was observed in the left thyroid lobe. Laboratory data for thyroid functions, thyroglobulin, anti-thyroglobulin antibodies, anti-thyroid peroxidase antibodies, serum calcium, and parathyroid hormone (PTH) were all within normal ranges. Ultrasonography revealed a 40-mm irregular, hypoechoic mass throughout the left thyroid lobe. Follicular thyroid tumor was suspected from fine-needle aspiration cytology. Left lobectomy was performed. Pathological features revealed a thick fibrous capsule around the tumor, and a thick fibrous band was observed inside the tumor. Both capsular invasions and vascular invasions were observed. Tumor cells were eosinophilic and displayed solid growth. Immunohistochemically, tumor cells were negative for thyroid transcription factor-1, negative for thyroglobulin, negative for chromogranin A (positive for normal parathyroid tissue within the nodule), positive for PTH, and positive for parafibromin. Ki-67 labeling index was 10%. Based on these findings, non-functional oxyphilic parathyroid carcinoma was diagnosed. One and a half years postoperatively, calcium and PTH were within normal ranges, and he has shown no evidence of recurrence or metastasis.

Conclusions

Non-functioning oxyphilic parathyroid carcinoma is an extremely rare malignancy, and definitive diagnosis is difficult to obtain preoperatively. Few reports have been made worldwide, and information on the long-term prognosis is scarce. Long-term surveillance by imaging is mandatory, since no indices that can be used as a marker for postoperative recurrence and metastasis have been identified.

Giant parathyroid adenoma and challenges with preoperative differentiation from malignancy

Giant parathyroid adenomas are rare and underreported benign tumours of parathyroid gland. Preoperative differentiation between giant parathyroid adenoma (GPA) and parathyroid carcinoma can be challenging, as they both may present as a large parathyroid tumour with hyperparathyroidism. Very few GPAs had been described in the literature, with only 60 cases including our present case. We report a case of GPA and the preoperative diagnostic challenges we faced in differential diagnosis of a potential parathyroid malignancy. As a parathyroid malignancy could not be excluded preoperatively the parathyroid tumour was excised en bloc with surrounding thyroid lobe. The histology was contributory to exclude parathyroid malignancy confirming a benign GPA.

A Woman with a 27-Year History of Hyperparathyroidism and Hypercalcemia Who Was Diagnosed with Low-Grade Parathyroid Carcinoma

BACKGROUND Parathyroid carcinoma (PC), accounting for 0.005% of all cancers, is responsible for less than 1% of all cases of primary hyperparathyroidism, and equally affects males and females, usually in 4th or 5th decades of life. PC can occur sporadically and can be associated with congenital genetic syndromes such as hyperparathyroidism-jaw tumor syndrome (HPT-JT), isolated familial hyperparathyroidism, or multiple endocrine neoplasia 1 and 2 syndromes. Surgery is the main treatment, with a limited role of radio- and chemotherapy, which allows 49-77% of patients to survive 10 years. In this work we report the case of a patient with parathyroid carcinoma, whose treatment required 13 surgeries over a period of 27 years, together with radiotherapy and pharmacological treatment. CASE REPORT A 51-year-old woman was first diagnosed with primary hyperparathyroidism in 1993 at the age of 23. From 1993 to present, she underwent 13 surgeries and 33 courses of radiotherapy due to recurrent lesions, which initially had a character of parathyroid adenomas, then parathyromatosis, and finally were diagnosed as parathyroid carcinoma. The patient also required and currently requires complex pharmacological treatment to control the calcemia and manage the complications of the primary disease. Supervision by the multidisciplinary professional medical team allows the patient to lead a normal life with good control of the disease. CONCLUSIONS Parathyroid carcinoma is a rare disease with a number of complications; however, obtaining satisfactory long-term survival with acceptable quality of life is achievable.

Parathyroid carcinoma coexisting with multiple parathyroid adenomas: a case report

Primary hyperparathyroidism is usually caused by parathyroid adenoma; however, parathyroid carcinoma is a rare cause. We report a rare case of 74-year-old female of primary hyperparathyroidism caused by parathyroid carcinoma (PC) and coexisting multiple parathyroid adenomas. She was referred to our hospital for primary hyperparathyroidism and a suspected thyroid tumor. She had no family history of malignant tumor. Computed tomography (CT) and ultrasonography of the neck revealed some masses posterior to both thyroid lobes. Those masses were believed to be parathyroid lesions. However, another mass located posterior to the right upper thyroid lobe seemed to be heterogeneous, which indicated a malignant thyroid tumor as well as parathyroid tumor. The preoperative diagnosis was multiple parathyroid adenoma and suspicious incidental thyroid carcinoma. Therefore, the patient underwent total parathyroidectomy and thyroidectomy. The histopathological diagnosis was parathyroid carcinoma coexisting with multiple parathyroid adenomas. There was no evidence of recurrence at 1 year after the surgery. It was difficult to diagnose PC preoperatively. Few rare cases of PC coexisting with parathyroid adenoma in multiple endocrine neoplasia type 1 (MEN1) have been reported. Therefore, careful follow-up was necessary considering the possibility of MEN1, though she did not wish for a genetic examination.

MANAGEMENT OF ENDOCRINE DISEASE: Unmet therapeutic, educational and scientific needs in parathyroid disorders

PARAT, a new European Society of Endocrinology program, aims to identify unmet scientific and educational needs of parathyroid disorders, such as primary hyperparathyroidism (PHPT), including parathyroid cancer (PC), and hypoparathyroidism (HypoPT). The discussions and consensus statements from the first PARAT workshop (September 2018) are reviewed. PHPT has a high prevalence in Western communities, PHPT has a high prevalence in Western communities, yet evidence is sparse concerning the natural history and whether morbidity and long-term outcomes are related to hypercalcemia or plasma PTH concentrations, or both. Cardiovascular mortality and prevalence of low energy fractures are increased, whereas Quality of Life is decreased, although their reversibility by treatment of PHPT has not been convincingly demonstrated. PC is a rare cause of PHPT, with an increasing incidence, and international collaborative studies are required to advance knowledge of the genetic mechanisms, biomarkers for disease activity, and optimal treatments. For example, ~20% of PCs demonstrate high mutational burden, and identifying targetable DNA variations, gene amplifications and gene fusions may facilitate personalized care, such as different forms of immunotherapy or targeted therapy. HypoPT, a designated orphan disease, is associated with a high risk of symptoms and complications. Most cases are secondary to neck surgery. However, there is a need to better understand the relation between disease biomarkers and intellectual function, and to establish the role of PTH in target tissues, as these may facilitate the appropriate use of PTH substitution therapy. Management of parathyroid disorders is challenging, and PARAT has highlighted the need for international transdisciplinary scientific and educational studies in advancing in this field.

Non-functioning parathyroid cystic tumour: malignant or not? Report of a case

Parathyroid carcinoma (PC) is a very rare endocrine tumour, usually characterized by symptoms such as a neck mass, dysphonia, severe hypercalcemia exceeding 140 mg/L and elevated serum parathyroid hormone levels, even more than 5 times the upper limit of normal. Non-functioning parathyroid cancer is extremely rare and, in this case, its pre-operative diagnosis is often difficult. A 54-year old female patient, referring dysphagia and dysphonia, underwent neck ultrasound and neck CT. A left thyroid nodule, probably cystic, was found. It presented caudal extent on anterior mediastinum causing compression of the left lateral wall of the trachea. The preoperative calcemia was into the normal range. The patient underwent left thyroid lobectomy. Histological exam showed a cystic lesion, immunohistochemically originating from parathyroid that oriented for carcinoma. The 18 months follow-up did not show a residual-recurrent disease. The parathyroid origin of a neck lesion could not be suspected before surgery when specific laboratory tests are not available and clinical effects of hyperparathyroidism syndrome are not present. Histological features are not always sufficient for the differential diagnosis between the parathyroid adenoma and carcinoma. The immunohistochemistry is an useful tool that can aid to reach the definite diagnosis.

Association of parathyroid carcinoma and thyroid disorders: A clinical review

Parathyroid carcinoma is a rare malignancy, which usually occurs as a sporadic disease, and less frequently in the setting of genetic syndromes. Despite the association of parathyroid and thyroid disorders being quite common, the coexistence of parathyroid carcinoma and thyroid disease is rare. We reviewed the pertinent literature. The terms "parathyroid carcinoma" and "thyroid disease, hyperthyroidism, thyrotoxicosis, hypothyroidism, thyroid nodule(s), Graves' disease, autonomously functioning thyroid nodules" were used both separately and in reciprocal conjunction to search MEDLINE for articles published from January 2007 to March 2016. The search was prompted by the observation of a never reported association of autonomously functioning thyroid nodules and parathyroid carcinoma. Two hundred and twenty-one parathyroid carcinoma patients have been described during the last 10 years. Neck ultrasonography and parathyroid scintigraphy are the most common instrumental studies used in detecting parathyroid lesions. Serum parathyroid hormone and calcium levels are high in the majority of parathyroid carcinoma patients. Only 21 patients with parathyroid carcinoma and thyroid disorders were found. Our patient is the first casual association between parathyroid carcinoma and autonomously functioning thyroid nodules reported in literature and diagnosed using parathyroid and thyroid scintigraphies. Parathyroid carcinoma is a very rare endocrine tumor and association with thyroid disease is not frequent. Parathyroid carcinoma pre-operative diagnosis is often difficult also because available literature data are not homogenous and there is not a common operative guideline. Our case confirms the role of parathyroid scintigraphy, encouraging the association with thyroid scintigraphy, especially in the presence of (multi)-nodular goiter in order to address the most appropriate surgical management.

Fine needle cytology pre-surgical differentiation of parathyroid neoplasms: Is it reliable?

BACKGROUND

Fine needle cytology (FNC) of a parathyroid neoplasia (PN) is reliable, but needs to be confirmed by Parathormone (PTH) and Thyroglobulin (TG) immunoassay on needle washing or by immunocytochemistry (ICC) evaluation. The differentiation between parathyroid adenoma (PA), atypical adenoma (PAA) and carcinoma (PC) is difficult on histology or even impossible on FNC. The aim of this study was to evaluate possible cytological criteria to classify FNC-PN further.

METHODS

Twenty-three FNC samples of PN and parathyroid cysts were rather then have been reviewed. The series includes 18 PNs, 4 cysts and 1 Thyr3B (histologically diagnosed as PA). Cytological features were: cellularity, patterns (follicular, solid or papillary), clear, oncocytic, isolated cells, nuclear atypia, cytoplasmic inclusions, nucleoli and mitoses. Data were compared with the histological controls.

RESULTS

Seventeen PNs, 2 cysts and 1 Thyr3B FNC samples were histologically diagnosed as PA (16), PAA (2) and PC (2). Two cysts and 1 PN were not confirmed histologically. Cytological features and incidences were: high cellularity (1 PA, 1 PAA, 2 PCs), follicular (8 PAs, 1 PAA), solid (5 PAs, 1 PC), papillary pattern (1PA, 1 PAA, 1 PC), clear cells (4 PAs, 1 PAA, 2 PCs), oncocytic cells (6 PAs, 1 PAA, 2 PCs), isolated cells (5 PAs, 2 PAAs, 2 PCs), nuclear atypia (2 PAs, 1 PAA, 2 PCs), cytoplasmic inclusions (4 PAs, 2 PCs), nucleoli (2 PCs) and mitoses (2 PCs).

CONCLUSION

Evident nucleoli and mitoses may suggest the differentiation between PA and PC. However, further investigations are required to confirm these preliminary observations.

Update on parathyroid carcinoma

INTRODUCTION

Parathyroid carcinoma (PC) is a rare endocrine disorder, commonly causing severe primary hyperparathyroidism (PHPT). PC is mainly a sporadic disease, but it may occur in familial PHPT. Patients with PC usually present markedly elevated serum calcium and PTH. The clinical features are mostly due to the effects of the excessive secretion of PTH rather than to the spread of tumor. At times, the diagnosis can be difficult.

PURPOSE

The aim of this work is to review the available data on PC, and focus its molecular pathogenesis and the clinical utility of CDC73 genetic testing and immunostaining of its product, parafibromin. The pathological diagnosis of PC is restricted to lesions showing unequivocal growth into adjacent tissues or metastasis. Inactivating mutations of the cell division cycle 73 (CDC73) gene have been identified in up to 70 % of apparently sporadic PC and in one-third are germline. Loss of parafibromin immunostaining has been shown in most PC. The association of CDC73 mutations and loss of parafibromin predicts a worse clinical outcome and a lower overall 5- and 10-year survival.

CONCLUSIONS

The treatment of choice is the en bloc resection of the tumor. The course of PC is variable; most patients have local recurrences or distant metastases and die from unmanageable hypercalcemia.