Parathyroid carcinoma

Insights into Hyperparathyroidism-Jaw Tumour Syndrome: From Endocrine Acumen to the Spectrum of CDC73 Gene and Parafibromin-Deficient Tumours

A total of 1 out of 10 patients with primary hyperparathyroidism (PHP) presents an underlying genetic form, such as multiple endocrine neoplasia types 1, 2A, etc., as well as hyperparathyroidism-jaw tumour syndrome (HJT). We aimed to summarise the recent data, thus raising more awareness regarding HJT, from the clinical perspective of PHP in association with the challenges and pitfalls of CDC73 genetic testing and parafibromin staining. This narrative review included a sample-focused analysis from the past decade according to a PubMed search. We identified 17 original human studies (≥4 patients per article). The mean age at disease onset was between 20.8 and 39.5 years, while the largest study found that 71% of patients had HJT recognised before the age of 30. Males and females seemed to be equally affected, in contrast with sporadic PHP. PHP represented the central manifestation of HJT, occurring as the first manifestation in up to 85% of HJT cases. A biochemistry panel found a mean serum calcium level above the level of 12 mg/dL in PHP. PTH was elevated in HJT as well, with average values of at least 236.6 pg/mL. The most frequent pathological type in PHP was a parathyroid adenoma, but the incidence of a parathyroid carcinoma was much higher than in non-HJT cases (15% of all parathyroid tumours), with the diagnosis being established between the age of 15 and 37.5. In some families up to 85% of carriers suffered from a parathyroid carcinoma thus indicating that certain CDC73 pathogenic variants may harbour a higher risk. An important issue in HJT was represented by the parafibromin profile in the parathyroid tumours since in HJT both parathyroid adenomas and carcinomas might display a deficient immunoreactivity. Another frequent manifestation in HJT was ossifying fibromas of the jaw (affecting 5.4% to 50% of patients; the largest study found a prevalence of 15.4%). HJT was associated with a wide variety of kidney lesion (mostly: kidney cysts, with a prevalence of up to 75%, and renal tumours involved in 19% of patients). The risk of uterine lesions seemed increased in HJT, especially with concern to leiomyomas, adenofibromas, and adenomyosis. The underlying pathogenic mechanisms and the involvement of CDC73 pathogenic variants and parafibromin expression are yet to be explored. Currently, the heterogeneous expression of parafibromin status and, the wide spectrum of CDC73 mutations including the variety of clinical presentations in HJT, make it difficult to predict the phenotype based on the genotype. The central role of HJT-PHP is, however, the main clinical element, while the elevated risk of parathyroid carcinoma requires a special awareness.

Is there a role for liquid biopsy in the surveillance of parathyroid carcinoma?

BACKGROUND

Parathyroid carcinoma is a rare malignancy with high recurrence rates. Liquid biopsy is a stratifying tool in disease recurrence/progression in other malignant processes. This study sought to assess the feasibility and application of liquid biopsy in parathyroid carcinoma and its impact on surveillance.

METHODS

Retrospective review of a prospectively maintained database of adults treated for parathyroid carcinoma at a tertiary care center (2017-2023). Demographics, clinical characteristics, and laboratory variables were collected. Circulating cell-free deoxyribonucleic acid enrichment and circulating tumor cell enumeration were obtained from serial blood samples.

RESULTS

A total of 25 patients were identified-64% were male patients, with a median age of 56 years (interquartile range 45-63). Fifty blood samples were collected postoperatively. At first, circulating tumor cell enumeration, 56% (14/25) of patients had no evidence of disease, and 32% (8/25) had distant metastasis. Median follow-up was 53 months (interquartile range 23-107). At the last follow-up, 40% (10/25) of patients were found to have distant metastasis. Serial circulating tumor cell enumeration was performed in 52% of patients, median highest circulating tumor cell was (interquartile range 1-22). Circulating cell-free deoxyribonucleic acid was assessed in 64% of patients (16/25). There was no difference in circulating tumor cells or circulating cell-free deoxyribonucleic acid between those with distant metastasis and those without distant metastasis. The most common mutation identified was TP53, present in 88% of circulating cell-free deoxyribonucleic acid samples with a mutation. Circulating cell-free deoxyribonucleic acid and parathyroid hormone levels were not found to have any association (r = -0.27, P = .39), but parathyroid hormone and circulating tumor cell had a linear relationship (r = 0.76, P < .001).

CONCLUSION

Liquid biopsy appears to be a feasible tool in parathyroid carcinoma surveillance. The relationship between circulating cell-free deoxyribonucleic acid and parathyroid hormone levels remains unclear, and the association between circulating tumor cell enumeration and parathyroid hormone levels may be impactful. The finding that TP53 mutation is more prevalent in patients with distant metastasis may impact further management.

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.

Secondary Mediastinal Bleeding Caused by Parathyroid Adenocarcinoma: A Case Report

Introduction

The clinical picture of parathyroid tumors is mainly related to hypercalcemia such as kidney stones and bone and muscle pain. However, spontaneous cervical hemorrhage due to parathyroidoma bleeding is rare with clinical manifestations of the painful swelling and bruising of the neck accompanied by dysphagia and dyspnea.

Case presentation

We report a case of a 71-year-old female patient who presented with acute cervical swelling and extensive bleeding spreading from the neck to the abdomen and 2 flanks. Investigation of patients revealed increased parathyroid hormone levels and hypercalcemia. The neck ultrasound showed the thyroid nodules in 2 lobes, and goiter plongeant on the right. Computed tomography scan images showed a hematoma spreading from the right side of the neck to the mediastinum.

Result

The patient required emergency surgery due to dyspnea and hemodynamic instability. The preoperative diagnosis was cervical bleeding with the likely cause being thyroid nodule rupture. However, during the surgery, the bleeding source was determined to be the right parathyroid tumor located deeply below the superior mediastinum. The patient's histopathological result of the tumor is parathyroid adenocarcinoma.

Conclusion

From our experience, the hemorrhage from parathyroid tumor should be considered as a cause of acute neck bleeding when no history of trauma or surgery is identified. Post-surgery histopathological analyses of the tumor are very important to detect parathyroid adenocarcinoma.

Parathyroid Carcinoma Presenting as Recurrent Primary Hyperparathyroidism and Neck Mass: A Case Report

Parathyroid carcinoma is a rare endocrine neoplasm that accounts for <1% of cases of primary hyperparathyroidism. The management of parathyroid carcinoma is a challenge due to the high rate of local recurrence of the tumour. We report the case of a middle-aged north Indian woman who presented with recurrent primary hyperparathyroidism due to parathyroid carcinoma. She presented with a recurrent palpable hard neck mass and underwent radical dissection of the neck six times. At the time of writing this report, she was referred for external beam radiotherapy to the neck. Parathyroid carcinoma is a rare malignancy with an indolent but tenacious course. Complete resection at the time of initial surgery determines the prognosis of the neoplasm. Chemotherapy and radiotherapy are usually ineffective. Hypercalcaemia needs to be aggressively managed. A multidisciplinary team is required to effectively manage parathyroid carcinoma.

Genomic and transcriptomic profiling reveal molecular characteristics of parathyroid carcinoma

Genomic and transcriptomic profiling has enhanced the diagnostic and treatment options for many cancers. However, the molecular characteristics of parathyroid cancer remain largely unexplored, thereby limiting the development of new therapeutic interventions. Herein, we conducted genomic and transcriptomic sequencing of 50 parathyroid tissues (12 carcinomas, 28 adenomas, and 10 normal tissues) to investigate the intrinsic and comparative molecular features of parathyroid carcinoma. We confirmed multiple two-hit mutation patterns in cell division cycle 73 (CDC73) that converged to biallelic inactivation, calling into question the presence of a second hit in other genes. In addition, allele-specific repression of CDC73 in copies with germline-truncating variants suggested selective pressure prior to tumorigenesis. Transcriptomic analysis identified upregulation of the expression of E2F targets, KRAS and TNF-alpha signaling, and epithelial-mesenchymal transition pathways in carcinomas compared to adenomas and normal tissues. A molecular classification model based on carcinoma-specific genes clearly separated carcinomas from adenomas and normal tissues, the clinical utility of which was demonstrated in two patients with uncertain malignant potential. A deeper analysis of gene expression and functional prediction suggested that Wilms tumor 1 (WT1) is a potential biomarker for CDC73-mutant parathyroid carcinoma, which was further validated through immunohistochemistry. Overall, our study revealed the genomic and transcriptomic profiles of parathyroid carcinoma and may help direct future precision diagnostic and therapeutic improvements.

Acute presentation of giant parathyroid adenoma extending to the mediastinum: A case report

INTRODUCTION AND IMPORTANCE

Primary hyperparathyroidism is the most common cause of hypercalcemia in outpatients. Giant parathyroid adenomas are rare and can present diagnostic and therapeutic challenges. The clinical presentation is often insidious, and acute presentation is uncommon.

CASE PRESENTATION

Herein we report a case of primary hyperthyroidism secondary to giant parathyroid adenoma in a 54-year-old woman presenting with acute and severe hypercalcemia. Preoperative laboratory exams indicated elevated values of parathormone and serum calcium. CT scan and parathyroid scintigraphy showed a giant right inferior parathyroid adenoma measuring 6 cm in its largest diameter extending to the mediastinum. Despite its size and extension, the gland was successfully managed through a transcervical parathyroidectomy. The patient is actually asymptomatic and normocalcemic after a follow up of 3 years.

CLINICAL DISCUSSION

Giant parathyroid adenomas can cause severe hypercalcemia. Imaging studies are crucial for preoperative localization. A classic transcervical approach can be used to remove giant adenomas, even when they extend into the anterior mediastinum. Despite their size, giant parathyroid adenomas have a good prognosis if they are removed surgically.

CONCLUSIONS

Hypercalcemia associated with a giant, functional parathyroid adenoma can be life-threatening. It is management is urgent. It is both medical and surgitforward, and various morphologiccal including correction of hypercalcemia and parathyroidectomy.

Novel PRUNE2 Germline Mutations in Aggressive and Benign Parathyroid Neoplasms

Parathyroid tumors are mostly sporadic but can also occur in familial forms, including different kinds of genetic syndromes with varying phenotypes and penetrance. Recently, somatic mutations of the tumor suppressor gene PRUNE2 were found to be frequent in parathyroid cancer (PC). The germline mutation status of PRUNE2 was investigated in a large cohort of patients with parathyroid tumors from the genetically homogenous Finnish population, 15 of which had PC, 16 atypical parathyroid tumors (APT), and 6 benign parathyroid adenomas (PA). Mutations in previously established hyperparathyroidism-related genes were screened with a targeted gene panel analysis. Nine PRUNE2 germline mutations with a minor allele frequency (MAF) of <0.05 were found in our cohort. Five of these were predicted to be potentially damaging and were identified in two patients with PC, two with APT, and three with PA. The mutational status was not associated with the tumor group nor related to the clinical picture or severity of the disease. Still, the frequent finding of rare germline mutations of PRUNE2 may point to the gene playing a role in the pathogenesis of parathyroid neoplasms.

Clinical and genetic analysis of atypical parathyroid adenoma compared with parathyroid carcinoma and benign lesions in a Chinese cohort

CONTEXT

The malignant potential and molecular signature of atypical parathyroid adenoma (APA) remain elusive. Data from Asia are still lacking.

DESIGN AND SETTING

This was a retrospective study on a large APA cohort in a single center from mainland China.

METHODS

A total of 320 patients with primary hyperparathyroidism (PHPT), containing 79 APA, 79 Parathyroid cancer (PC) and 162 benign lesions cases, were enrolled after surgery for collection of clinical data and genetic analysis.

RESULTS

APA patients showed earlier mean onset age than benign group (46.9 ± 17.1 vs. 52.0 ± 14.3 yrs). Less bone involvement and gastrointestinal symptoms were presented in APA compared to PC (35.4% vs. 62.0%, and 17.7% vs. 41.8%), while more urolithiasis was seen in APA than in benign lesions (57.0% vs. 29.6%). The APA group had moderate hypercalcemia (mean 3.02 ± 0.44mmol/L) with elevated serum PTH (median 593.0pg/ml) and proportion of hypercalcemic crisis as 22.8%, all higher than those of benign lesions but lower than those of PC group. The recurrence/no remission rate of the APA group was significantly lower than that of the PC and similar to the benign group (5.1% vs. 31.6% vs. 3.1%). Germline CDC73 mutation was the most common molecular abnormality in both PC and APA subjects. APA patients with nonsynonymous germline variants showed earlier onset age (28.5 ± 16.9 vs. 48.1 ± 17.7 yrs) and more cases developing no remission/recurrence (25.0% vs. 0.0%).

CONCLUSIONS

Patients with APA presented clinical and biochemical characteristics much less severe than PC and resembling the benign neoplasms, with a relatively good prognosis. Germline gene variations were associated with earlier onset and probably more recurrence of PHPT in APA.

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.

Atypical parathyroid adenoma: A case report

The atypical parathyroid adenoma is a histological diagnosis. It is a parathyroid tumor with atypical histological features different from an adenoma and not similar enough to be considered as a carcinoma. It has an uncertain malignant potential. We report the case of a 55-year-old woman, diagnosed with severe hypercalcemia during her follow-up with the rheumatologist for osteoporosis. The laboratory testing led to the detection of a very important level of parathormone PTH 1325.62 pg/ml (20 fold the normal level), confirming the diagnosis of primary hyperparathyroidism. Investigations of the potential causes led to the presence of a large left inferior parathyroid adenoma. The patient was operated and on the examination of the removed tissue, the histopathological examination concluded to an atypical parathyroid adenoma, and the post-operatory PTH level dropped significantly to 152 pg/ml. The atypical parathyroid adenoma is a very rare tumor, and the diagnosis is still a challenge, the outcome of patients is not well known yet, there for the surveillance is important and must be regularly.

Updates of Genomics and Proteomics of Parathyroid Carcinoma

Parathyroid carcinoma is a rare disease that needs an additional diagnostic tool and wide therapeutic options. The genomics and proteomics approach may help to find the tools to improve the prognosis of the disease by early detection and metastatic control. The findings from genomics were mainly CDC73, PRUNE2, CCND1, and genes related to PI3K/AKT/mTOR and Wnt pathways. CDC73, PRUNE2, and CCND1 were closely related to each other, and PRUNE2 and CCND1 genes are related to expression levels of parafibromin protein, which may aid in supporting the definite diagnosis of the disease. PI3K/AKT/mTOR and Wnt pathways could be a potential therapeutic target for the disease, which needs further basket trials to prove the concept. In this review, current findings from genomics and proteomics studies in parathyroid carcinoma were reviewed.

Serum calcium levels are associated with cognitive function in hypoparathyroidism: a neuropsychological and biochemical study in an Italian cohort of patients with chronic post-surgical hypoparathyroidism

PURPOSE

Hypoparathyroidism (HypoPT) is a rare endocrine disease and conventional therapy is based on calcium and vitamin D analogues. Conventional therapy does not restore calcium homeostasis and patients complain with neuropsychological symptoms, which have been evaluated with nonspecific self-administered questionnaires. This study aims to evaluate cognitive functions of patients with chronic post-surgical (PS)-HypoPT compared to a control population, using a standardized neuropsychological approach and evaluating the relationship with serum calcium (Alb-Ca).

METHODS

Observational, monocentric study on 33 patients with PS-HypoPT and 24 controls, in whom biochemical testing and a standardized neuropsychological assessment by a trained psychologist were performed.

RESULTS

In patients with PS-HypoPT, low Alb-Ca correlated with a worse performance on semantic memory abilities and executive function, as suggested by a significant inverse correlation between Alb-Ca and Trail Making Test A (TMT-A) scores (r = - 0.423; p = 0.014) and by a positive correlation with Semantic Fluency Test scores (SF)(r = 0.510; p = 0.002). PS-HypoPT patients with Alb-Ca ≤ 8.9 mg/dl had a significantly lower test performance compared with PS-HypoPT patients with Alb-Ca > 8.9 mg/dl, both at the TMT-A test (mean score: 34.53-18.55; p < 0.0001) and at SF test (mean score: 41.94-48.68; p = 0.01) and also a significantly lower test performance compared with control patients' group at TMT-A (mean score: 34.53-25.5; p = 0.0057).

CONCLUSIONS

Patients with chronic PS-HypoPT in conventional therapy do not show a severe cognitive impairment; however, cognitive functions namely visuo-spatial attention, executive function and semantic memory appear to be modulated by Alb-Ca and impaired by its low levels.

Preoperative inflammatory markers for predicting parathyroid carcinoma

OBJECTIVE

Parathyroid carcinoma is a rare tumor among parathyroid tumors. Aspiration cytology and needle biopsy are generally not recommended for diagnostic purposes because they cause dissemination. Therefore, it is commonly diagnosed by postoperative histopathological examination. In this study, we investigated whether preoperative inflammatory markers can be used as predictors of cancer in patients with primary hyperparathyroidism.

DESIGN

This was a retrospective study.

METHODS

Thirty-six cases of parathyroid carcinoma and 50 cases of parathyroid adenoma (PA) operated with the diagnosis of primary hyperparathyroidism and confirmed histopathologically at Ito Hospital were included in this study. Preoperative clinical characteristics and inflammatory markers (neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio, and lymphocyte-to-monocyte ratio (LMR)) were compared and their values in preoperative prediction were evaluated and analyzed.

RESULTS

Preoperative intact-parathyroid hormone (P = 0.0003), serum calcium (P = 0.0048), and tumor diameter (P = 0.0002) were significantly higher in parathyroid carcinoma than in PA. LMR showed a significant decrease in parathyroid carcinoma (P = 0.0062). In multivariate analysis, LMR and tumor length diameter were independent predictors. In the receiver operating characteristics analysis, the cut-off values for LMR and tumor length diameter were 4.85 and 28.0 mm, respectively, for parathyroid cancer prediction. When the two extracted factors were stratified by the number of factors held, the predictive ability improved as the number of factors increased.

CONCLUSION

In the preoperative evaluation, a combination of tumor length diameter of more than 28 mm and LMR of less than 4.85 was considered to have a high probability of cancer.

Manifestations of hyperparathyroidism in the jaws: Concepts, mechanisms, and clinical aspects

Hyperparathyroidism is one of the most common endocrine disorders worldwide. In countries where routine biochemical screening is not common, symptomatic hyperparathyroidism predominates. Its manifestations include skeletal alterations, calcification of soft tissues, kidney stones, and functional alterations in other systems. Notably, jaw alterations can be the first clinical sign of hyperparathyroidism, including brown tumor, renal osteodystrophy, osteitis fibrosa, and leontiasis ossea, and knowing such conditions is of core importance for the multidisciplinary diagnosis and management of hyperparathyroidism. We aimed to perform a concise review, systematizing the concepts and mechanisms underlying hyperparathyroidism and associated gnathic alterations. In addition, a detailed description of the clinical aspects of the jaw manifestations is presented.

Mortality factors in recurrent parathyroid cancer: a pooled analysis

INTRODUCTION

Parathyroid cancer is a rare disease with high recurrence rate. The prognostic factors for recurrent parathyroid cancer are yet to be ascertained. We aimed to establish the association between recurrent parathyroid cancer and previously reported prognostic factors.

MATERIALS AND METHODS

We conducted a PubMed search using the keywords 'parathyroid cancer', 'parathyroid neoplasm', and 'hypercalcemia' during 1966-2019 and included 3272 articles. We focused on 73 patients with recurrent parathyroid cancer from 55 studies. We conducted a survival analysis using the Cox proportional hazards model with 95% confidence interval.

RESULTS

For the 73 patients included in the analysis, the mean age (± standard deviation) was 44 ± 13.2 years, wherein 36 patients were women (49.3%). During the 5236 person-months at risk (mean follow-up 71.7 months, range 3-264), 38 patients died. The incidence of local recurrence, lymph-node metastasis, lung metastasis, and bone metastasis were 60.3, 12.3, 56.2, and 24.7, respectively. Bone metastasis, disease-free interval < 1 year, and total surgeries < 3 were significant prognostic factors in univariate analysis (log-rank test P = 0.0063, P = 0.0006, and P = 0.0056, respectively). In the multivariate-adjusted analysis, the mortality risk was significantly increased in patients with bone metastasis with a hazard ratio (HR) of 4.83 (95% CI 1.16-20.2; P = 0.03), disease-free interval <=1 year of 5.92 (95% CI 1.85-18.99; P = 0.003), and total surgeries <3 of 11.29 (95% CI 2.82-45.22; P = 0.001), considering these as possible predictive prognostic factors.

CONCLUSION

Bone metastasis, duration of disease-free interval, and total number of surgeries predict survival in recurrent parathyroid cancer.

Parathyroid Carcinoma: Incidence, Survival Analysis, and Management: A Study from the SEER Database and Insights into Future Therapeutic Perspectives

Introduction: Parathyroid carcinoma (PC) is an extremely rare entity, with a frequency of 0.005% of all malignancies. Most data related to this rare disease are limited to case series and a few database studies. We present a large database study that aims to investigate the demographic, clinical, and pathological factors, prognosis, and survival of PC. Methods: Data of parathyroid carcinoma were extracted from the Surveillance, Epidemiology, and End Results (SEER) diagnosed between 1975 and 2016. Results: PC had a slightly higher incidence in men (52.2%, p < 0.005), the majority of cases affected Caucasians (75.4%, p < 0.005), and the mean age at diagnosis was 62 years. Histologically, 99.7% were adenocarcinomas not otherwise specified (p < 0.005), well-differentiated (p < 0.005), and 2−4 cm (p < 0.001) in size among the patients with available data. In cases with staging provided, most PC were organ-confined (36.8%, p < 0.001). Lymph nodes were positive in 25.2% of cases where lymph node status was reported. The main treatment modality was surgery (97.2%), followed by radiation alone (2%), and very few received chemotherapy alone (0.8%), p < 0.005. Five-year follow-up was available for 82.7% of the cases. Those who underwent surgery only or radiation alone had 5-year survivals of 83.8% and 72.2%, respectively (p < 0.037). Multivariable analysis identified tumor size >4 cm, age > 40 years, male sex, Caucasian race, distant spread, and poorly differentiated grade as independent risk factors for mortality (p < 0.001). Conclusion: PC is a very rare tumor mostly affecting Caucasian individuals in the fifth decade. Older age, poor histologic differentiation, and distant metastasis are associated with a worse prognosis. Surgical resection offers the best survival outcome. To better understand the pathogenesis and factors affecting survival, all PC patients should be enrolled in national and international registries.

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.

The Long Non-Coding BC200 Is a Novel Circulating Biomarker of Parathyroid Carcinoma

Long non-coding RNAs (lncRNAs) are an important class of epigenetic regulators involved in both physiological processes and cancer development. Preliminary evidence suggested that lncRNAs could act as accurate prognostic and diagnostic biomarkers. Parathyroid cancer is a rare endocrine neoplasia, whose management represents a clinical challenge due to the lack of accurate molecular biomarkers. Our previous findings showed that human parathyroid tumors are characterized by a different lncRNAs signature, suggesting heterogeneity through the different histotypes. Particularly, we found that the lncRNA BC200/BCYRN1 could represent a candidate biomarker for parathyroid carcinomas (PCas). Here we aimed to extend our preliminary data evaluating whether BC200 could be an accurate non-invasive biomarker of PCas to support the clinical management of patients affected by parathyroid tumors at diagnosis, prognosis and follow-up. To provide a non-invasive point-of-care for parathyroid carcinoma diagnosis and follow-up, we analyzed BC200 expression in patients' serum through digital PCR. Our results show that BC200 counts are higher in serum from patients harboring PCa (n=4) compared to patients with parathyroid adenoma (PAd; n=27). Further, in PAd patients circulating BC200 levels are positively correlated with serum total calcium. Then, we found that BC200 is overexpressed in metastatic PCas (n=4) compared to non-metastatic ones (n=9). Finally, the lncRNA expression in PCa patients' serum drops are reduced after parathyroidectomy, suggesting its possible use in the post-operative setting for patients follow-up. Overall, these findings extend the knowledge on BC200 in parathyroid tumors, supporting its role as a useful biomarker for management of PCa.

Diagnosis and treatment of liver metastases of parathyroid carcinoma

INTRODUCTION

Parathyroid carcinoma (PC) is a very rare endocrine malignancy occurring in less than 1% of all cases of primary hyperparathyroidism (pHPT). The liver is the second most common target organ for distant metastases of PC, but no guidelines are available for the diagnosis and treatment of liver metastases. In this study, we attempted to summarize the characteristics of the diagnosis and treatment of liver metastases based on our patients and other cases reported in the literature.

MATERIALS AND METHODS

The files of all patients diagnosed with PC with liver metastases summarized at our center between 2000 and 2022 were reviewed, and three datasets from Medline, Web of Science, and Embase were systematically searched to identify relevant articles.

RESULTS

Three patients with liver metastases from our center and 11 patients from the literature were included in the study. All patients had pHPT with borderline remission of hypercalcemia after each operation. A total of 71.4% of the patients' liver lesions were found by abdominal CT scans, while 35.7% were found by MRI, PET-CT, and fine-needle aspiration biopsy (FNAB), which were also helpful for diagnosis. Eight of nine patients (88.9%) who underwent surgery, radiofrequency ablation (RFA), or transcatheter arterial embolization (TAE) were alive, and only one postoperative patient died after a follow-up of 60 months.

CONCLUSIONS

PC is a rare malignant tumor prone to recurrence and metastasis, and postoperative reviews should be carried out routinely. Abnormally elevated parathyroid hormone (PTH) and serum calcium can indicate recurrence or metastasis. Enhanced CT and MRI can provide valuable support for the diagnosis of liver metastases, but whether [18F]FDG-PET-CT, [18F]FCH-PET-CT, or [11C]choline-PET-CT can be used as a diagnostic basis requires further study. Resection of liver metastases, segmental hepatectomy, or RFA can significantly improve patients' symptoms.

Nontraditional Aspects of Sporadic Primary Hyperparathyroidism

Nontraditional aspects of primary hyperparathyroidism refer to the condition's rheumatic, gastrointestinal, cardiovascular, and neuropsychological effects. Although gastrointestinal and rheumatic symptomatology were features of classical primary hyperparathyroidism, they do not seem to be a part of the modern presentation of primary hyperparathyroidism. In contrast, neuropsychological symptoms such as altered mood and cognition, as well as cardiovascular disease, have been associated with the form of primary hyperparathyroidism seen today, but the relationship is not clearly causal. Evidence does not support reversibility after parathyroidectomy and therefore none of the nontraditional manifestations are considered sole indications for recommending surgery at this time.

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.

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.

Primary hyperparathyroidism: Disease of diverse genetic, symptomatic, and biochemical phenotypes

Genetic, symptomatic, and biochemical heterogeneity of patients with primary hyperparathyroidism (PHPT) has become apparent in recent years. An in-depth, evidence-based review of the phenotypes of PHPT was conducted. This review was intended to provide the resulting information to surgeons who operate on patients with hyperparathyroidism. This review revealed that the once relatively clear distinction between familial and sporadic PHPT has become more challenging by the finding of various germline mutations in patients with seemingly sporadic PHPT. On the one hand, the genetic and clinical characteristics of some syndromes in which PHPT is an important component are now better understood. On the other hand, knowledge is emerging about novel syndromes, such as the rare multiple endocrine neoplasia type IV (MEN4), in which PHPT occurs frequently. It also revealed that, currently, the classical array of symptoms of PHPT is seen rarely upon initial presentation for evaluation. More common are nonspecific, nonclassical symptoms and signs of PHPT. In areas of the world where serum calcium levels are checked routinely, most patients today are "asymptomatic" and they are diagnosed after an incidental finding of hypercalcemia; however, some of them have subclinical involvement of bones and kidneys, which is demonstrated on radiographs, ultrasound, and modern imaging techniques. Last, the review points out that there are three distinct biochemical phenotypes of PHPT. The classical phenotype in which calcium and parathyroid hormone levels are both elevated, and other disease presentations in which the serum levels of calcium or intact parathyroid hormone are normal. Today several, distinct phenotypes of the disease can be identified, and they have implications in the diagnostic evaluation and treatment of patients, as well as possible screening of relatives.

Non-functional water clear cell parathyroid carcinoma masquerading as medullary thyroid carcinoma

Parathyroid carcinoma is a rare neuroendocrine tumor. Non-functional parathyroid carcinomas are exceedingly rare neoplasms which generally present at an advanced disease stage, and occasionally can masquerade as medullary thyroid carcinoma.

The input of GATA-3 in the identification of parathyroid carcinoma diagnosis: Case report with review of literature

Introduction

and Importance: Parathyroid carcinoma is an exceptional cancer, with significant morbidity and mortality, associated with parathyroid hormone (PTH) mediated hypercalcemia.

Case presentation

We report a case of parathyroid carcinoma with a difficult histological diagnosis. This case illustrates the usefulness of the immunohistochemical marker “GATA-3” in parathyroid differentiation especially in tumours.

Clinical discussion

The diagnosis of parathyroid carcinoma is challenging without the knowledge of the clinical information, laboratory finding, and radiographic imaging studies. The immunohistochemistry is useful tool in these cases to identify the parathyroid origin of neoplasia. GATA-3 is a transcription factor that is involved in the embryonic development of the parathyroid glands and in adult parathyroid cell proliferation.

Conclusion

It is concluded that GATA-3 is a very sensitive and relatively specific immunohistochemical marker for parathyroid differentiation that can assist in the differential diagnosis of parathyroid tumours.

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Input of GATA-3 in the identification of parathyroid carcinoma.

Primary Hyperparathyroidism: A Narrative Review of Diagnosis and Medical Management

Primary hyperparathyroidism (PHPT) is the most common cause of hypercalcemia in the outpatient setting. Symptomatic presentation includes non-specific signs and symptoms of hypercalcemia, skeletal fragility, nephrolithiasis and nephrocalcinosis. The majority of individuals present at an asymptomatic stage following routine biochemical screening, without any signs or symptoms of calcium or parathyroid hormone (PTH) excess or target organ damage. Indications for surgery have recently been revised as published in recent guidelines and consensus statements. Parathyroidectomy is advised in patients younger than 50 years old and in the presence of either significant hypercalcemia, impaired renal function, renal stones or osteoporosis. Surgery is always appropriate in suitable surgical candidates, however, medical management may be considered in those with mild asymptomatic disease, contraindications to surgery or failed previous surgical intervention. We summarized the optimal medical interventions available in the care of PHPT patients not undergoing parathyroidectomy. Calcium and vitamin D intake should be optimized. Antiresorptive therapy may be used for skeletal protection in patients with an increased fracture risk. Cinacalcet, a calcimimetic agent, has been shown to effectively lower serum calcium and PTH levels. The effect of medical treatment on the reduction in fracture risk is unknown and should be the focus of future research.

A Pediatric Parathyroid Carcinoma: An Unusual Clinical Presentation and Mini-review

INTRODUCTION

Primary hyperparathyroidism (PHPT) is a rare condition in the pediatric population. Parathyroid carcinoma (PC) is a very uncommon cause of PHPT, accounting for < 1% of pediatric PHPT cases. It is challenging to distinguish between parathyroid adenoma (PA), the most common cause of PHPT, and PC. In this report, we described a young female who presented with a history of progressive limping and was finally diagnosed with PC.

CASE PRESENTATION

A 15-year-old girl presented with progressive limping and bone pain for 8 years. She was referred by an orthopedic surgeon because of elevated intact parathyroid hormone (iPTH) for further evaluation. Physical examination revealed a large, firm, and non-tender neck mass, left hip tenderness, and limited range of motion. The initial biochemistry tests showed a borderline high calcium level of 10.8 mg/dl, an elevated iPTH level of 2876 pg/mL, and a decreased phosphorus level of 2.4 mg/dL. The ^99mTechnetium (Tc) sestamibi scan displayed early intense activity in the right thyroid lobe persisting in the three-hour repeat scan, compatible with a parathyroid lesion. The patient underwent right-sided neck exploration and parathyroidectomy. Intraoperative and pathology findings confirmed the diagnosis of PC. Immunohistochemistry (IHC) staining revealed creatine kinase (CK) and CD31 in endothelial cells of the tumor. Ki67 staining was also positive in 2% - 3% of tumor cells. The whole exome sequencing (WES) study was negative for cell division cycle 73 (CDC73) and multiple endocrine neoplasia 1 (MEN1) genes.

CONCLUSIONS

PC should be considered as a differential diagnosis of PHPT in the pediatric population, even in the presence of mild hypercalcemia.

Parathyroid carcinoma with sarcomatoid differentiation: a case report and literature review

Background

Parathyroid carcinoma (PC) is a rare thyroid tumor. PC with sarcomatoid differentiation(PCSD) is even rarer and its exact etiology remains unclear. We here report a case of PCSD, and present the clinicopathological features and pathological diagnosis and review the literature.

Case presentation

A 71-year-old man presented with a mass of 4.5 cm × 3.5 cm in the right neck. The tumor was composed of nest-like transparent cells, and the septum had heterotypic rhabdoid cells with sarcomatoid differentiation. Immunophenotype was as follows: myogenic differentiation 1(MyoD1), myogenin and desmin were positive; clear cells were positive for chromogranin A(CGA), synaptophysin(Syn) and GATA-3; and Ki-67 proliferation index was 40%. Hematoxylin and eosin staining and immunohistochemistry were performed. The patient was diagnosed with PCSD, and died 6 months after surgery.

Conclusions

PCSD is a rare type of primary parathyroid tumor with high malignancy and poor prognosis. Definitive diagnosis should be based on histopathological morphology and immunophenotype, and surgical treatment should be performed as soon as possible.

Factors related to a non-localising technetium 99m sestamibi scan result during parathyroid adenoma imaging in primary hyperparathyroidism

OBJECTIVES

The aim of this study is to investigate factors that are associated with having a non-localising ^99m Tc-sestamibi scan.

DESIGN

A retrospective study was performed on patients that underwent parathyroid surgery performed within a single institution between 2001 and 2018.

SETTING

Single tertiary centre for parathyroid surgery.

PARTICIPANTS

230 patients underwent surgery for primary hyperparathyroidism due to a solitary parathyroid adenoma and had preoperative ^99m Tc-sestamibi imaging.

MAIN OUTCOME MEASURES

Variables including age, gender, intra-operative location of parathyroid adenoma, adenoma weight and pre- and postoperative calcium and parathyroid hormone levels were investigated through univariate and multivariate analysis to identify any association with having a non-localising (negative) ^99m Tc-sestamibi scan result.

RESULTS

Multivariate analysis identified that right-sided adenomas (P = .038), superior adenomas (P = .042) and a lower preoperative PTH level (P = .034) were all individual factors associated with having a negative ^99m Tc-sestamibi scan result. Although the weight of the adenoma was significant on univariate analysis (P = .029), this was not demonstrated on multivariate analysis (P = .422).

CONCLUSION

Factors that were associated with having non-localising ^99m Tc-sestamibi scan were right-sided adenomas, superior adenomas and lower preoperative PTH level. Further large prospective multicentre studies are needed to further evaluate these initial findings.

Radiofrequency Ablation of Parathyroid Adenomas: Safety and Efficacy in a Study of 10 Patients

PURPOSE

To evaluate safety and effectiveness of ultrasound-guided percutaneous radiofrequency ablation of parathyroid adenoma in surgically unfit patients with hypercalcemia because of hyperparathyroidism.

MATERIALS AND METHODS

A retrospective review of hospital records from Jan 2012 to Dec 2018 revealed 10 patients, who had undergone ablation for solitary parathyroid adenoma. All 10 patients suffered from hyperparathyroidism because of parathyroid adenoma, resulting in hypercalcemia. These patients were surgically unfit because of comorbidities. Pre-ablation serum calcium and serum parathormone levels were measured and compared with the levels after the ablation.

RESULTS

Mean serum calcium level decreased significantly from 2.81 ± 0.17 mmol/L pre-ablation to 2.42 ± 0.17 mmol/L 72 h after ablation and parathyroid hormone levels became normal in all patients within 7 days. Seven patients remained normo-calcaemic at 6 months follow-up with no signs and symptoms of hyperparathyroidism. One patient with pancreatitis died after 15 days because of pre-existing multi-organ failure. Two patients were lost to follow-up before 6 months.

CONCLUSION

Radiofrequency ablation of parathyroid adenoma is a safe and effective alternate treatment method for symptomatic hypercalcemia in surgically unfit patients suffering from primary hyperparathyroidism because of parathyroid adenoma.

Evocalcet in patients with primary hyperparathyroidism: an open-label, single-arm, multicenter, 52-week, dose-titration phase III study

INTRODUCTION

Primary hyperparathyroidism (PHPT) is caused by parathyroid adenoma, primary parathyroid hyperplasia, or parathyroid carcinoma. For some patients with PHPT controlling serum calcium levels is critical.

MATERIALS AND METHODS

We conducted an open-label, single-arm, 52-week, phase III study in Japanese patients with hypercalcemia due to PHPT to demonstrate efficacy and safety of evocalcet, a new calcimimetic. Patients with intractable PHPT (n = 13), postsurgical recurrence (n = 2), and parathyroid carcinoma (n = 3) were enrolled. Evocalcet administration started at a dose of 2 mg once or twice daily and was titrated to achieve the target serum corrected calcium (cCa) concentration (≤ 10.3 mg/dL) for two consecutive weeks (maximal dose 24 mg/day).

RESULTS

Fourteen patients achieved the target (77.8%; 95% confidence interval [CI] 52.4-93.6). The lower limit of 95% CI exceeded the predetermined reference limit (11%), and thus, efficacy was confirmed. Of 18 patients, 12 (66.7%; 95% CI 41.0-86.7) showed decreased serum cCa of ≥ 1.0 mg/dL from the baseline for two consecutive weeks during the titration phase. Sixteen patients entered the maintenance phase, and 15 patients completed the study. Treatment-emergent adverse events (TEAEs) were recorded in 18/18 patients (100%) and drug-related TEAEs in 8/18 (44.4%). The most commonly observed drug-related TEAE was nausea (2/18 patients). No unexpected drug-related TEAEs were observed. All drug-related TEAEs were mild in severity. No patient discontinued the study because of drug-related TEAEs.

CONCLUSION

Evocalcet demonstrated long-term effectiveness in reducing serum cCa concentrations and safety without any unexpected drug-related TEAEs in PHPT patients.

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 Mysterious Paratracheal Mass: Parathyroid Carcinoma

Parathyroid carcinoma is a rare cause of primary hyperparathyroidism. We detail a 60-years-old gentleman who was otherwise healthy presented to the hospital due to acute encephalopathy. He was subsequently found to have parathyroid carcinoma as the cause of the acute encephalopathy with impressive serum calcium and parathyroid hormone levels. The parathyroid carcinoma was later surgically resected with the diagnosis confirmed via pathology specimen. The patient was safely discharged from the hospital with recommendations of close routine outpatient followup.

Parathyroid Carcinoma: An Up-to-Date Retrospective Multicentric Analysis

Parathyroid carcinoma (PC) is a rare disease responsible for about 1% of primary hyperparathyroidism (PHPT) cases. PC usually has an indolent course, tough to differentiate from the benign causes of PHPT, and the only certain diagnosis is histologic. The gold standard surgical treatment is the en bloc resection associated with the homolateral thyroid loboistmectomy. The aim of this study was to underline the main differences between PC and benign PHPT, along with gathering epidemiological knowledge relative to PC in our region. Data from the regional cancer network (Rete Oncologica del Piemonte e della Valle d'Aosta) since 2007 have been reported, including 21 patients from three hospitals (AO S. Croce e Carle of Cuneo, AOU Città della Salute of Turin, and ASL Città di Torino). The incidence of the disease, gender, age at time of diagnosis, presence of renal and bone symptoms, serum calcium and PTH levels, surgical technique performed, and percentage of recurrence were analysed. PC data were than compared with a series of patients affected by benign PHPT, referred to ASL Città di Torino, Maria Vittoria Hospital, from 2007 to 2019. A PC incidence of 0.05 cases per 100,000 inhabitants was found in our region. Benign forms occurred more frequently in females (p=0.0002), while PC equally occurred in males and females and affected younger patients (p=0.026). Serum calcium and PTH levels were significantly higher in PC patients; accordingly, typical PHPT symptoms were more frequently reported in PC than in benign PHPT. In the PC group, the en bloc resection shows a 13 times lower risk for relapse compared with all the other surgical techniques. PC is equally gender distributed, and the average patients' age is in the fifth decade of life. It is usually functioning, with greater biochemical activity and multiple symptoms. A not-radical surgical resection is associated with a higher recurrence rate. A meticulous presurgical evaluation of PHPT patients showing PC's evocative features is mandatory to obtain a complete disease extirpation.

Parathyroid carcinoma arising from auto-transplanted parathyroid tissue after Total Parathyroidectomy in chronic kidney disease patient: a case report

BACKGROUND

Secondary hyperparathyroidism is a common complication in patients with chronic kidney disease that requires vigilant treatment due to its high mortality rate. Pharmacologic therapy is recommended as an initial treatment; if there is no response, a total parathyroidectomy is performed. In some cases, surgery is accompanied by auto-transplantation of parathyroid tissue.

CASE PRESENTATION

The patient was diagnosed with chronic kidney disease and received a kidney transplant. However, due to rejection of the transplanted kidney, medical nephrectomy was carried out and routine hemodialysis was initiated and observed. At this time, secondary hyperparathyroidism with elevated parathyroid hormone and hyperphosphatemia developed and pharmacologic treatment was applied. However, there was no response to pharmacologic treatment; therefore, total parathyroidectomy with auto-transplantation was performed. Eight years after surgery, a growing mass was observed in the transplantation site, accompanied by an elevation of parathyroid hormone. A complete resection of the mass was performed, and the patient was diagnosed with parathyroid carcinoma. Additional adjuvant radiation therapy was ordered, and the patient is being monitored.

CONCLUSIONS

This is a rare but remarkable case of parathyroid carcinoma arising from auto-transplanted parathyroid tissue after total parathyroidectomy in a patient with secondary hyperparathyroidism. We suggest caution should be taken when choosing to auto- transplant parathyroid tissue and that careful postoperative observation should be performed.

Parathyroid Cancer: A Review

Parathyroid cancer is one of the rarest causes of primary hyperparathyroidism and tends to present with more severe symptoms than its more benign counterparts. This article details various aspects of the disease process, including epidemiology, clinical presentation, and a step-wise diagnostic process for parathyroid cancer. This includes laboratory assessments as well as a proposed staging system. The en bloc principle of surgical intervention is detailed, as well as the current role of adjuvant treatments. A general guide to surveillance and the natural history of the disease is also outlined.

Parathyroid Cancer: A Review

Parathyroid cancer is one of the rarest causes of primary hyperparathyroidism and tends to present with more severe symptoms than its more benign counterparts. This article details various aspects of the disease process, including epidemiology, clinical presentation, and a step-wise diagnostic process for parathyroid cancer. This includes laboratory assessments as well as a proposed staging system. The en bloc principle of surgical intervention is detailed, as well as the current role of adjuvant treatments. A general guide to surveillance and the natural history of the disease is also outlined.

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.

Challenges in the treatment of parathyroid carcinoma: a case report

INTRODUCTION

Parathyroid carcinoma (PC) is a rare neoplasm with a high rate of recurrence and an indolent course. It is frequently functional, causing nearly 1% of the cases of primary hyperparathyroidism (HPT), and in some cases, it may be complicated by brown tumors, mimicking bone metastases. Synchronous parathyroid and papillary thyroid carcinomas are rare.

CASE REPORT

We present a patient with HPT due to PC, misdiagnosed at first evaluation, which exhibited multiple hypermetabolic lytic lesions in the skeleton, suggesting bone metastases. Their regression after PTH reduction suggested the diagnosis of brown tumors due to severe HPT. Given the persistence of HPT, the patient underwent a number of neck surgeries, and a papillary thyroid microcarcinoma with a nodal metastasis was diagnosed. A genetic test discovered a previously unreported mutation of the CDC73 (HRPT2) gene, codifying for parafibromin and resulting in a premature stop codon (c.580A>Tp.Arg194). Because of the persistence of HPT, cinacalcet therapy was started in order to control hypercalcemia.

CONCLUSION

This is a very unusual patient with a newly discovered variant of the CDC73 gene and a phenotype characterized by recurrent PC, brown tumors, and N1a metastasized thyroid carcinoma. The present case confirms that PC may not exhibit clear malignant properties at first assessment, contributing to inadequate initial surgical treatment. Although infrequently, PC can be associated with papillary thyroid cancer. The diagnosis of brown tumor should be considered in patients with severe HPT and multiple destructive bone lesions mimicking metastases on PET/CT imaging.

Current concepts in parathyroid carcinoma: a single Centre experience

BACKGROUND

Parathyroid carcinoma is a rare neoplasm that may present sporadically or in the context of a genetic syndrome. Diagnosis and management are challenging due to the lack of clinical and pathological features that may reliably distinguish malignant from benign disease.

METHODS

From January 2013 to December 2017, from 358 consecutive patients affected by parathyroid diseases, 3 patients with parathyroid carcinoma were treated at our academic Department of General Surgery. We present our experience as illustrative of the different features of clinical presentation of parathyroid carcinoma and review its management considering the recent relevant literature.

RESULTS

Case 1: A 62-year-old man was hospitalized for left-sided palpable neck mass, hypercalcemia and elevated PTH. US-guided FNA was suspect for parathyroid carcinoma. A large cystic mass was excised in bloc with total thyroidectomy and central neck dissection. Genetic studies framed a pathologically confirmed parathyroid carcinoma within MEN1 syndrome. Case 2: A 48-year-old woman with hypothyroidism had total thyroidectomy performed for a suspect for right follicular thyroid lesion. Pathology revealed parathyroid carcinoma. Case 3: A 47 year-old man was admitted for hypercalcaemic crisis and renal failure in the context of PHPT. A lesion suggestive on US and MIBI scan for parathyroid adenoma in the right lower position was removed by mini-invasive approach. Pathology revealed parathyroid cancer and patient had completion hemythyroidectomy and central neck dissection.

CONCLUSION

Parathyroid cancer is a particularly rare endocrine malignancy, however it should be suspected in patients with primary hyperparathyroidism when severe hypercalcemia is associated to cervical mass, renal and skeletal disease. Parathyroid surgery remains the mainstay of treatment. Radical tumour resection and expedited treatment in a dedicated endocrine Center represent crucial prognostic factors.

Characterization of a novel CDC73 gene mutation in a hyperparathyrodism-jaw tumor patient affected by parathyroid carcinoma in the absence of somatic loss of heterozygosity

Hyperparathyrodism-jaw tumor (HPT-JT) syndrome is an autosomal dominant disorder. Loss of function of the cell division cycle protein 73 homolog (CDC73) gene is responsible for the syndrome. This gene encodes an ubiquitously expressed 531 amino acid protein, parafibromin, that acts as a tumor suppressor. Loss of heterozygosity (LOH) of the CDC73 locus in many HPT-JT associated parathyroid tumors from patients with germline mutation is in accordance with Knudson's "two-hit" model for hereditary cancer. A 41-year-old man with mandible ossifying fibroma suffered from severe hypercalcemia due to parathyroid carcinoma (PC). Genetic analysis was performed to evaluate germinal and somatic CDC73 gene mutation as well as real-time qRT-PCR to quantify CDC73 mRNA, miR-155 and miR-664 expression levels. Immunohistochemistry and Western blotting (WB) assay were carried out to evaluate parafibromin protein expression. A novel heterozygous nonsense mutation, c.191-192 delT, was identified in the CDC73 gene. No CDC73 LOH was found in PC tissue, nor any differences in expression levels for CDC73 gene, miR-155 and miR-664 between PC and parathyroid adenoma control tissues. On the contrary, both immunohistochemistry and WB assay showed an approximate 90% reduction of parafibromin protein expression in PC. In conclusion, this study describes a novel germinal mutation, c.191-192 delT, in the CDC73 gene. Despite normal CDC73 gene expression, we found a significant decrease in parafibromin. We hypothesize that a gene silencing mechanism, possibly induced by microRNA, could play a role in determining somatic post-transcriptional inactivation of the wild type CDC73 allele.

Deficiency in the secreted protein Semaphorin3d causes abnormal parathyroid development in mice

Primary hyperparathyroidism (PHPT) is a common endocrinopathy characterized by hypercalcemia and elevated levels of parathyroid hormone. The primary cause of PHPT is a benign overgrowth of parathyroid tissue causing excessive secretion of parathyroid hormone. However, the molecular etiology of PHPT is incompletely defined. Here, we demonstrate that semaphorin3d (Sema3d), a secreted glycoprotein, is expressed in the developing parathyroid gland in mice. We also observed that genetic deletion of Sema3d leads to parathyroid hyperplasia, causing PHPT. In vivo and in vitro experiments using histology, immunohistochemistry, biochemical, RT-qPCR, and immunoblotting assays revealed that Sema3d inhibits parathyroid cell proliferation by decreasing the epidermal growth factor receptor (EGFR)/Erb-B2 receptor tyrosine kinase (ERBB) signaling pathway. We further demonstrate that EGFR signaling is elevated in Sema3d ^-/- parathyroid glands and that pharmacological inhibition of EGFR signaling can partially rescue the parathyroid hyperplasia phenotype. We propose that because Sema3d is a secreted protein, it may be possible to use recombinant Sema3d or derived peptides to inhibit parathyroid cell proliferation causing hyperplasia and hyperparathyroidism. Collectively, these findings identify Sema3d as a negative regulator of parathyroid growth.

A Young Male with Parafibromin-Deficient Parathyroid Carcinoma Due to a Rare Germline HRPT2/CDC73 Mutation

Hyperparathyroidism, commonly observed in asymptomatic middle-aged women, with mild hypercalcemia, is usually caused by a benign adenoma. Some cases present with more severe manifestation and greater hypercalcemia. Within this spectrum, several familial/genetic associations have been discovered. While the majority are caused by benign disease, adenomas, or hyperplasia, a small proportion (< 1%) are associated with malignant tumors and present with more severe symptoms. Although usually sporadic, recent reports document various gene mutations that strongly predispose to the development of parathyroid carcinoma. An increasing number of cases of hyperparathyroidism, benign or malignant, require and benefit from genetic analysis. We describe a 25-year-old male with hyperparathyroidism presenting with a pathological fracture, brown tumors, hypercalcemia, and markedly elevated parathyroid hormone levels. There was no family history of hyperparathyroidism or jaw tumors. Surgical removal revealed a single large tumor confirmed to be malignant. Immunohistochemical analysis revealed the absence of parafibromin and decreased APC (adenomatosis polyposis coli) expression. Genetic analysis revealed a rare germline nonsense mutation (R76X) in the parafibromin gene, HRPT2/CDC73. Parathyroid carcinoma should be suspected as a cause of hyperparathyroidism when clinical manifestations are severe, particularly in young individuals, < 59 years. Immunohistochemistry may lead to suspicion for a germline mutation as a significant contributor despite absence of a family history. The discovery of a germline mutation in parathyroid carcinoma alters the clinical management of the index case and that of family members. Long-term follow-up studies of such patients are necessary to develop evidence-based clinical guidelines.

Non-surgical management of primary hyperparathyroidism

The purpose of this chapter is to discuss the options available for patients with primary hyperparathyrodism (PHPT) not undergoing parathyroidectomy (PTx). Adequate hydration should be recommended in all patients. Calcium intake should not be restricted and vitamin D deficiency should be corrected aiming at a serum concentration of 25OHD of >20 ng/mL or even higher (>30 ng/mL according to some opinion leaders). Pharmacologic therapy is not an alternative to PTx and could be considered in patients who meet the surgical criteria but unwilling to undergo PTx, as well as in patients with an increased risk of surgery or failed surgery. Targeted therapy includes antiresorptive drugs for skeletal protection and cinacalcet for lowering serum calcium. Combined therapy can be an option when appropriate. Pregnant women should be treated conservatively (hydration) and surgery, if needed, performed in the second trimester of pregnancy. Severe hypercalcemia is a life-threatening condition and requires immediate intensive treatment.

Classical complications of primary hyperparathyroidism

Traditionally, classical complications of primary hyperparathyroidism are mainly represented by skeletal, kidney and gastrointestinal involvement. The old picture of osteitis fibrosa cystica is no longer commonly seen, at least in the western world. However, new imagining techniques have highlighted deterioration of skeletal tissue in patients with primary hyperparathyroidism not captured by traditional DXA measurement. Concerning the kidney, the most common consequences of excessive parathyroid hormone secretion are hypercalciuria and kidney stones; however, the exact pathogenesis of urinary stone formation is still unknown. The 2013 International Congress on the management of Asymptomatic Primary Hyperparathyroidism, emphasized the role of imaging techniques for early discovery of both skeletal and renal complications in asymptomatic patients. Gastrointestinal manifestations include acid-peptic disease, constipation, pancreatitis and gall stone disease. More studies are needed in this area to find the exact pathophysiological mechanism underlying these manifestations and the effect of parathyroid surgery.

Parathyroid carcinoma

Parathyroid carcinoma (PC) is a rare disease with an indolent behavior due to the low malignant potential. The etiology is unknown. Somatic mutations of CDC73 gene, the same gene involved in the hyperparathyroidism-jaw tumor syndrome, can be identified in up to 70% of patients with PC and in one-third of cases the mutations are germline. Therefore, in patients who carry germline CDC73 gene mutations, its finding permits to identify the carriers among relatives and sometimes to early detect a parathyroid lesion in such subjects. The diagnosis of PC is commonly made after surgery, however there are some clinical/biochemical features that should raise the suspicion of PC, namely markedly elevated serum calcium and PTH levels, a large parathyroid lesion with suspected ultrasonographic features of malignancy, the damages of kidney and bones. The best chance of cure is the complete surgical resection with the en-bloc excision at the first operation, however several recurrences are often observed during the follow-up. Since PC is an indolent tumor with long-lasting survival and the death is due to complications of untreatable hypercalcemia, multiple surgical interventions with debulking of tumoral tissues along with medical treatment for reducing hypercalcemia are often needed. Patients with PC should be followed up along their lifetime.