Parathyroid carcinoma

Clinicopathological spectrum, management, and outcome of ectopic parathyroid carcinoma: Experience with 24 cases

PURPOSE

Ectopic parathyroid carcinoma (EPC) is a rare clinical entity with multiple diagnostic pitfalls, making surgical cures challenging. We assessed the clinicopathological spectrum and outcome of EPCs.

METHODS

In this retrospective cohort study, 24 EPCs were identified from 133 PC patients treated at a tertiary referral center. The relationship between clinicopathological findings and locations was analyzed.

RESULTS

The locations of EPCs were predominantly intrathyroidal (62.5%), followed by 16.7% in the mediastinum, 8.3% in the retropharyngeal space, 8.3% in the carotid sheath, and 4.2% in the upper neck. Intrathyroidal EPC patients experienced higher serum calcium (p = 0.020), a higher rate of vascular invasion (p = 0.040), and a slightly higher incidence of non-R0 initial resection (p = 0.092) than those in other ectopic locations. Intrathyroidal EPC patients also suffered a trend of higher upper aerodigestive tract (UAT) invasion rate (p = 0.070) and higher risks of distant metastasis (p = 0.037) than the other PC patients. The 5-year disease-free survival rate after surgery was slightly compromised at 41.5% in intrathyroidal EPC patients compared with 77.8% among those in other ectopic locations (p = 0.143) and 59.7% among the other PC patients (log-rank = 3.194; p = 0.074), though without statistical significance.

CONCLUSION

Intrathyroidal EPC might cause a more biochemically and invasively distinct PC picture compared with other PCs. Special caution should be exercised in the preoperative diagnosis and management of such cases.

Risk Factors of Distant Metastatic Parathyroid Carcinoma and Insights into Therapeutic Perspectives

BACKGROUND

Distant metastatic parathyroid carcinoma (DM-PC) is a rare but often lethal entity with limited data about prognostic indicators. We sought to investigate the risk factors, patterns, and outcomes of DM-PC.

METHODS

In this observational cohort study, 126 patients who underwent surgery for PC at a tertiary referral center from 2010 to 2023 were enrolled, among whom 38 had DMs. Univariate and multivariate Cox regression analyses were used to assess the effects of prognostic factors on DM.

RESULTS

The cumulative incidence of DM was 14.1%, 33.8%, and 66.9% at 5, 10, and 20 years in the duration of disease course, respectively. DM-PC patients suffered a worse 5-year overall survival of 37.1% compared with 89.8% in the non-DM patients (p < 0.001). DM-PC patients also suffered more previous operations (p < 0.001), higher preoperative serum calcium (p<0.001) and parathyroid hormone (PTH) levels (p < 0.001), lower frequencies of R0 resection (p < 0.001), higher rates of pathological vascular invasion (p = 0.020), thyroid infiltration (p = 0.027), extraglandular extension (p = 0.001), upper aerodigestive tract (UAT) invasion (p < 0.001), and lymph node metastasis (p < 0.001). Multivariate Cox regression revealed that non-R0 resection (HR 6.144, 95% CI 2.881-13.106, p < 0.001), UAT invasion (HR 3.718, 95% CI 1.782-7.756, p < 0.001), and higher preoperative PTH levels (HR 1.001, 95% CI 1.000-1.001, p = 0.012) were independent risk factors of DM.

CONCLUSIONS

Upper aerodigestive tract invasion and higher preoperative PTH levels might be risk factors for possible metastatic involvement of PC. R0 resection and closer surveillance should be considered in such cases to minimize the risk of DM and to optimize patient care.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Effectiveness and safety of the radiofrequency ablation of single hyperfunctioning parathyroid lesions suggestive of adenomas in primary hyperparathyroidism

INTRODUCTION

Radiofrequency ablation (RFA) has emerged as a minimally invasive approach to single parathyroid adenoma in primary hyperparathyroidism; however, there is limited evidence on its effectiveness.

OBJECTIVE

To evaluate the effectiveness and safety of RFA to treat hyper-functioning parathyroid lesions suggestive of adenomas.

MATERIAL AND METHODS

A prospective study was conducted in consecutive patients with primary hyperparathyroidism treated with RFA for single parathyroid lesions in our reference center between November 2017 and June 2021. Pre-treatment (baseline) and follow-up analytical data were gathered on total protein-adjusted calcium, parathyroid hormone [PTH], phosphorus, and 24-h urine calcium. Effectiveness was defined as complete response (normal calcium and PTH), partial response (reduced but not normalized PTH with normal serum calcium), or disease persistence (elevated calcium and PTH). SPSS 15.0 was used for statistical analysis.

RESULTS

Four of thirty-three enrolled patients were lost to the follow-up. The final sample comprised 29 patients (22 females) with mean age of 60.93 ± 13.28 years followed up for a mean of 16.29 ± 7.23 months. Complete response was observed in 48.27%, partial response in 37.93%, and hyperparathyroidism persistence in 13.79%. Serum calcium and PTH levels were significantly lower at 1 and 2 years of post-treatment than at baseline. Adverse effects were mild, with two cases of dysphonia (self-limited in one patient) and no cases of hypocalcaemia or hypoparathyroidism.

CONCLUSION

RFA may be a safe and effective technique to treat hyper-functioning parathyroid lesions in selected patients.

Parathyroid carcinoma in a patient with primary hyperparathyroidism mimicking parathyroid adenoma

Primary hyperparathyroidism caused by parathyroid carcinoma is extremely rare. Clinically, it is very challenging to differentiate between parathyroid carcinoma and adenoma. The correct diagnosis is made based on the histopathology of the resection specimen. This case report presents a woman in her 40s with body aches, knee joint pain, and fatigue, along with chronic kidney disease. Ultrasonography revealed a large hyperechoic lesion in the left parathyroid gland. Serum calcium, parathyroid hormone, urea, and creatinine levels were increased. The inferior parathyroid gland was surgically removed, and histopathological evaluation confirmed a diagnosis of parathyroid carcinoma. Unfortunately, many patients do not undergo complete resection due to a lack of a correct diagnosis during the initial surgery.

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.

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

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

Surgery for primary hyperparathyroidism

Primary hyperparathyroidism (PHPT) is a hypercalcemic disorder that occurs when one or more parathyroid glands produces excessive parathyroid hormone (PTH). PHPT is typically treated with surgery, and it remains the only definitive therapy, whose techniques have evolved over previous decades. Advances in preoperative localization exams and the intraoperative PTH monitoring have become the cornerstones of recent parathyroidectomy techniques, as minimally invasive techniques are appropriate for most patients. Nevertheless, these techniques, are not suitable for PHPT patients who are at risk for multiglandular disease, especially in those who present with familial forms of PHPT that require bilateral neck exploration. This manuscript also explores other conditions that warrant special consideration during surgical treatment for PHPT: normocalcemic primary hyperparathyroidism, pregnancy, reoperation for persistent or recurrent PHPT, parathyroid carcinoma, and familial and genetic forms of hyperparathyroidism.

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.

Synchronous parathyroid carcinoma and papillary thyroid carcinoma

The simultaneous occurrence of parathyroid carcinoma and nonmedullary thyroid carcinoma is unusual. We report the case of 60-year-old woman who was found to have concurrent parathyroid carcinoma with severe clinical manifestations of primary hyperparthyroidism in addition to an incidental papillary thyroid carcinoma. Parathyroid hormone level was 569 pg/ml (normal range 10-65), and the serum calcium concentration was 13.83 mg/dl (normal range, 8.8-10.4). Preoperative investigation found a large 3 cm anterior cervical nodule suggestive of parathyroid adenoma. Total thyroidectomy and left parathyroidectomy were performed, and the final anatomopathological examination of the operative specimen concluded the coexistence of papillary microcarcinoma and parathyroid carcinoma. Although parathyroid carcinoma is an uncommon cause of hypercalcemia, it should be considered when severe hypercalcemia is observed, and in case of coexistence of thyroid nodules. The possibility of both malignancies must also be considered since parathyroid and nonmedullary thyroid carcinoma rare cases have previously been reported.

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

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

Synchronous Parathyroid Carcinoma and Noninvasive Follicular Thyroid Neoplasm With Papillary-Like Nuclear Features

Parathyroid carcinoma is a rare cause of primary hyperparathyroidism. Compared to parathyroid adenoma, parathyroid cancer is more likely to be associated with marked levels of serum parathyroid hormone (PTH) and hypercalcemia with severe clinical manifestations. Noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) is a rare variant of papillary thyroid cancer. Here, we report the case of a middle-aged woman who presented with multiple fractures and neck swelling. Neck ultrasound and fine-needle aspiration cytology revealed a provisional diagnosis of thyroid carcinoma. Parathyroid and bone scan were performed because of primary hyperparathyroidism and hypercalcemia and established the diagnosis of hyperfunctioning right-sided parathyroid tumor. Right parathyroidectomy and total thyroidectomy were performed, and the histopathological report confirmed the diagnosis of parathyroid carcinoma and NIFTP. The synchronic coexistence between parathyroid cancer and thyroid neoplasms is an extremely rare condition that prompted us to report this case.

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.

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

BACKGROUND

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

CASE PRESENTATION

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

CONCLUSIONS

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

[Parathyroid carcinoma: a rare and aggressive tumor]

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

Parathyroid Carcinoma: A Single-Institution Experience with an Emphasis on Histopathological Features

Parathyroid carcinoma (PC) is a rare malignancy that poses a diagnostic challenge on histologic examination. We analyzed various clinicopathologic features of PC. Pathology reports and slides were reviewed to evaluate the diagnostic histopathologic features of archived cases of PC from the years of 2004-2018. The study cohort comprised twenty cases of PC. The median age was 49 years (range 21-73 years) with equal gender distribution (M:F = 1:1). Most patients presented with symptoms of hypercalcemia (n = 7, 54%). Serum calcium and serum parathyroid hormone were elevated in all but one patient. The right inferior parathyroid was commonly involved (n = 8/14, 57%). The mean tumor size was 2.4 cm (range 0.8-3.5 cm). On frozen section examination, PC was diagnosed in 8 out of 9 cases. Vascular (n = 19/20, 95%) and soft tissue invasion (n = 10/20, 50%) were the most common characteristic histologic findings. Capsular invasion was identified in all cases. Perineural invasion or metastasis at presentation was absent in all cases. Other histological features noted were intratumoral fibrous bands (70%), nodular growth pattern (70%), moderate nuclear atypia (30%), prominent nucleoli (20%), and necrosis (20%). Regional lymph nodes were negative for metastatic disease in all cases (n = 10). Eight out of 16 patients received adjuvant radiotherapy. Follow-up was available in 16 cases (median 21.5 months). Two patients died of disease. Vascular and soft tissue invasion are the most common diagnostic histologic features of PC. Capsular invasion is important to distinguish PC from its benign counterparts. Intraoperative frozen section examination can be used for accurate diagnosis and surgical management.

Giant parathyroid adenoma presenting with a pathological left clavicular fracture: An extremely rare case report

INTRODUCTION

Parathyroid gland has a distinct physiologic and endocrinologic role in the body system. Primary hyperparathyroidism is the most common cause of hypercalcemia with a marked female dominance. It is characterized by hypercalcemia, hypophosphatemia and elevated parathyroid hormone. Parathyroid adenoma, parathyroid hyperplasia and parathyroid carcinoma form the differential diagnosis. Giant parathyroid adenomas are rarely symptomatic than non-giant parathyroid adenomas and parathyroid carcinoma.

CASE PRESENTATION

A 41 years old previously healthy male patient with undetectable surgical and familial history presenting with left clavicle fracture by mild trauma. He was diagnosed for primary hyperparathyroidism after the finding of multiple bony lesions and elevated serum calcium and Parathyroid hormone. Preoperative imaging aided in diagnosis of a parathyroid lesion and secondary bone resorption lesions (brown tumors). After adequate medical treatment and preparation, selective right lower parathyroidectomy was held, and the final pathology came with a giant parathyroid adenoma.

CONCLUSION

Primary hyperparathyroidism should be suspected when dealing with a hypercalcemic patient having osteolytic bony lesions. Distinguishing Parathyroid adenoma from carcinoma is a challenging and essential preoperative step in planning and surgical procedure.

A Case of Parathyroid Adenocarcinoma and Hyperparathyroidism, When "CRAB" Symptoms Are Not due to a Plasma Cell Myeloma

A previously well 49-year-old patient presented to our hospital with symptomatic hypercalcaemia complaining of polyuria and polydipsia, as well as abdominal and lower back pain (serum/ionized calcium at 3.66 milli mole/l and 1.90 milli moles/l). At admission, he had a normocytic anemia (Hb, 99 g/L) and acute kidney injury (creatinine at 161 μM). His parathyroid hormone (PTH) levels were at 67.6 pico moles/l. A plain X-ray of the lumbar spine showed the presence of a lytic lesion in the L4 vertebrae. CT and MRI confirmed this to be a destructive lesion. A subsequent pan CT scan showed a 2.8 cm complex nodule in the left lobe of the thyroid posteriorly. Excisional biopsy of the resected mass was associated with an infiltrative cellular parathyroid neoplasm with solid and nested architectural growth pattern admixed with hemorrhage and focal calcifications. The tumor showed lymphovascular and perineural invasion. At the time of workup and despite the absence of a positive SPEP/UPEP, a bone marrow biopsy was requested to rule out multiple myeloma. His normocellular bone marrow biopsy showed marked paratrabecular fibrosis and extensive bony remodelling but no metastatic invasion. The diagnosis of a metastatic parathyroid carcinoma was made. He is subsequently considered for palliative radiotherapy to the primary tumor bed and the lumbar spine. In addition, a role for immunotherapy with ipilimumab and nivolumab in context of clinical trials is envisioned and he is being considered for enrollment.

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

Background

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

Methods

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

Results

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

Conclusions

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

ATYPICAL RECURRENCE OF PARATHYROID CARCINOMA FOLLOWING INFLIXIMAB THERAPY IN A PATIENT WITH ULCERATIVE COLITIS

Objective

Parathyroid carcinoma (PTC) has a high rate of recurrence, which typically occurs within 5 years of diagnosis involving locoregional sites. Immunosuppressive therapies pose a theoretical increased risk of malignancy. We report an atypical case of PTC recurrence in a patient receiving infliximab therapy for ulcerative colitis (UC).

Methods

Main diagnostic tests performed included calcium and parathyroid hormone (PTH) levels, computed tomography, and a venous sampling study.

Results

A patient with PTC, who was "cured" by parathyroidectomy, presented with recurrent hypercalcemia 21 years after his initial diagnosis. He had recently been diagnosed with UC and was started on infliximab. His serum PTH level was elevated. After negative routine neck imaging studies and sestamibi scan, he underwent selective venous sampling with PTH measurements, which localized the source lesion to the thoracic wall. Subsequent imaging showed multiple left lung and pleural nodules, which were surgically resected. Hypercalcemia abated after surgery, but quickly returned and was recalcitrant to treatment with cinacalcet and zoledronic acid. Further imaging demonstrated recurrent lung metastases, some along the left diaphragm. He underwent 2 additional surgical resections, after which PTH and calcium levels normalized. Infliximab was replaced with vedolizumab for treatment of UC.

Conclusion

Atypical presentation of PTC may occur in the context of immunosuppressive therapy. Venous sampling with PTH measurements can aid in localization of atypical metastatic PTC. Additional surveillance for PTC recurrence may be prudent following the initiation of immunosuppressive therapy in patients with a history of PTC.

Cancer-derived immunoglobulin G: A novel marker for differential diagnosis and relapse prediction in parathyroid carcinoma

OBJECTIVE

A differential diagnosis between malignant and benign parathyroid lesions is difficult due to their overlapping clinicopathological characteristics. As such, molecular markers are urgently needed. Cancer-derived immunoglobulin G (CIgG) is a novel molecule playing important roles in carcinogenesis. The present study aimed to investigate the clinical significance of CIgG in parathyroid neoplasms.

PATIENTS

Fifty patients with parathyroid carcinoma (PC), 50 patients with parathyroid adenoma (PA) and 9 patients with parathyroid hyperplasia (PH) were retrospectively enrolled in the current study.

MEASUREMENTS

Immunohistochemistry was used to assess CIgG expression in these patients. The performance of CIgG expression in the differential diagnosis between parathyroid lesions was assessed by receiver operating characteristic (ROC) curves. The associations between CIgG expression and clinical outcomes were also analysed by Kaplan-Meier survival curves and Cox proportional hazards models.

RESULTS

The expression level of CIgG was significantly higher in PC patients than in PA or PH patients (P < .001). CIgG expression discriminated PC from PA or PH, with an area under the ROC curve of 0.84 (76% sensitivity and 88% specificity). High CIgG expression was significantly associated with worse disease-free survival (DFS) in PC patients (P = .018) and was validated as an independent risk factor for DFS in the multivariable Cox regression analysis (P = .002).

CONCLUSIONS

The ability of CIgG expression both in the differential diagnosis between malignant and benign parathyroid lesions and in the prognosis prediction for PC was shown in the present study. CIgG might be used as a novel biomarker of parathyroid lesions in future clinical practice.

Ultrasound combined with biochemical parameters can predict parathyroid carcinoma in patients with primary hyperparathyroidism

PURPOSES

Parathyroid cancer (PC) is rare, but fatal condition. Preoperative prediction of PC remains challenging but meaningful. The aim of this study was to determine an effective model to predict PC in patients with parathyroid lesions >1.5 cm.

METHODS

In this retrospective case-control study, we enrolled 30 patients with PC matched to 60 patients with parathyroid adenoma or hyperplasia by admission year. All patients were diagnosed with primary hyperparathyroidism (pHPT) and had parathyroid lesions >1.5 cm. Ultrasonic features of the two patient groups, as well as demographic, clinical, and biochemical characteristics were retrospectively compared. Best subset selection and multivariate logistic regression analysis were conducted to identify the independent risk factors of PC. ROC curve and decision curve analysis were developed to evaluate the applicability of the new model.

RESULTS

The best subset selection method and multiple logistic regression analysis showed that ultrasonic features of DR (two diameters' ratio of the lesion) and tumor infiltration in conjunction with intact parathyroid hormone (iPTH) level (collective model) were independent predictors of malignancy. Meanwhile, DR, shape, and tumor infiltration (ultrasound model) were found to be risk factors when only ultrasonic features were included in the multivariate analysis. The decision curve analysis showed that collective model outperforms ultrasound model with a better net benefit and a wider range of threshold probabilities.

CONCLUSIONS

Ultrasonic features in combination with iPTH level may be an applicable model for predicting PC and has a better potential to facilitate decision-making preoperatively.

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.

Atypical presentation of oncocytic parathyroid adenoma masquerading as metastatic carcinoma

Parathyroid carcinoma is the rarest endocrine malignancy. Definitive diagnosis is challenging as it is difficult to distinguish malignant from benign disease. A 71-year-old man presented with weight loss and hypercalcaemia. CT scans revealed multiple lung nodules and lytic bone lesions that were consistent with metastatic dissemination. Technetium-99m-sestamibi-single-photon emission computed tomography scan showed an abnormal uptake in the right thyroid lobe. Fine-needle aspiration (FNA) was performed on three occasions. The patient underwent parathyroidectomy with ipsilateral hemithyroidectomy without postoperative complications. Microscopic examination showed a parathyroid neoplasm with fibrosis and intravascular tumour on a background of unremarkable thyroid parenchyma. This resulted in an initial impression of parathyroid carcinoma. Further review by two independent pathologists provided a final diagnosis of oncocytic parathyroid adenoma. This case highlights the subjectivity and interobserver variation with endocrine histological examination. FNA can induce changes that mimic parathyroid carcinoma on histology. An index of suspicion for benign parathyroid adenomas should be maintained.

Genome-wide analysis of differentially expressed lncRNA in sporadic parathyroid tumors

Diagnosis of parathyroid carcinoma on histological examination is challenging. Thousands of differentially expressed lncRNAs were identified on the microarray data between parathyroid cancer and adenoma samples. Four lncRNAs were significantly dysregulated in further validation. The "lncRNA score" calculated from these lncRNAs differentiated parathyroid carcinomas from adenomas. LncRNAs serve as biomarkers for parathyroid cancer diagnosis.

INTRODUCTION

Diagnosis of parathyroid carcinoma (PC) on histological examination is challenging. LncRNA profile study was conducted to find diagnostic biomarkers for PC.

METHODS

LncRNA arrays containing 91,007 lncRNAs as well as 29,857 mRNAs were used to assess parathyroid specimen (5 carcinomas and 6 adenomas). Bioinformatics analyses were also conducted to compare the microarray results between parathyroid carcinomas and adenomas (PAs). Differentially expressed lncRNAs of 11 PCs and 31 PAs were validated by real-time quantitative PCR.

RESULTS

On the microarray data between PC and PA samples (fold change ≥ 2, P < 0.05), 1809 differentially expressed lncRNAs and 1349 mRNAs also were identified. All carcinomas were clustered in the same group by clustering analysis using dysregulated lncRNAs or mRNAs. Four lncRNAs (LINC00959, lnc-FLT3-2:2, lnc-FEZF2-9:2, and lnc-RP11-1035H13.3.1-2:1) identified were significantly dysregulated in further RT-PCR validation. The global "lncRNA score" calculated from the lncRNAs above also differentiated parathyroid carcinomas from adenomas.

CONCLUSIONS

LncRNA profiling shows distinct differentially expressed lncRNAs in parathyroid neoplasm. They may play a key role in parathyroid cancer and serve as potential biomarkers to distinguish parathyroid cancers from parathyroid adenomas.

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.

Preliminary exploration of potential molecular therapeutic targets in recurrent and metastatic parathyroid carcinomas

Parathyroid carcinoma (PC) is a rare endocrine malignancy. Surgical resection is curative for local lesions, while effective therapies are lacking for recurrent or metastatic PCs. To study whether targeted therapies could be applied in recurrent or metastatic PCs, potential therapeutic targets were identified with next-generation sequencing (NGS). DNA was extracted from formalin-fixed, paraffin-embedded (FFPE) sections from 19 recurrent or metastatic PC samples. A panel of 560 genes was sequenced with NGS to identify genomic alterations at an average sequencing depth of 581×. In total, 190 genomic alterations were identified. Nine PC samples (47%) harbored at least one potentially actionable genomic alteration including in the after genes: ROS1 (5/19; 26%), PTEN (3/19; 16%), TSC1 (2/19; 11%), PIK3CA (1/19; 5%), AKT1 (1/19; 5%), MTOR (1/19; 5%), ERBB2 (1/19; 5%), NTRK1 (1/19; 5%), IDH1 (1/19; 5%) and FGFR3 (1/19; 5%). CDC73 mutations were detected in 9/19 (47%) PC samples. Additional recurrent genomic alterations were identified in MSH2 (15/19; 79%), AR (9/19; 47%), BCR (8/19; 42%), SLC45A3 (6/19; 32%), MAGI1 (5/19; 26%), ZNF521 (4/19; 21%), KMT2C (4/19; 21%) and NOTCH4 (4/19; 21%). Our study identified a relatively high frequency of potentially actionable genomic alterations in PC patients in a Chinese population for the first time. A series of recurrent mutant genes was detected as well. Our study contributes to both the selection of novel targeted therapies for PC and further molecular understanding of this refractory malignancy.

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.

Preoperative localization modalities in primary hyperparathyroidism: Correlation with postoperative cure

BACKGROUND

Accurate preoperative localization is critical to the success of minimally invasive parathyroidectomy. This investigation aimed to assess the correlation among preoperative imaging results, intraoperative findings, and postoperative cure rates in patients undergoing operation for primary hyperparathyroidism.

METHODS

A retrospective review of all patients who underwent operation for primary hyperparathyroidism between June 2010 and March 2016 was performed.

RESULTS

During the study period, 398 patients underwent parathyroidectomy. The overall cure rate was 97.5%. The ultrasonography performed by the surgeon was superior to the ultrasonography performed by the radiologist and to the sestamibi scan in lateralizing the adenoma correctly (80% vs 62% vs 70%, P < .001, respectively), and had the greatest sensitivity (93%) and accuracy (80%) among all tests (P < .001). Age ≥65 was found to be associated with lesser cure rates (94% vs 99.2%, P = .003). The number of positive preoperative studies correlated with cure rate, ranging from 80% for patients with 0 positive studies, to 100% in those with 4 positive studies (P = .0004). In patients with a negative sestamibi and an ultrasonography performed by the radiologist, there was no significant difference in the cure rates among those with no preoperative computed tomography, a positive preoperative computed tomography, or a negative preoperative computed tomography.

CONCLUSION

An ultrasonography performed by an experienced surgeon is an extremely valuable preoperative localization modality. The cure rate obtained is proportional to the number of positive imaging studies. In patients with negative ultrasonography performed by a nonexperienced radiologist and a negative sestamibi scan, the performance of computed tomography does not seem to increase cure rate. Patients with no positive preoperative scans represent a challenging subgroup, with cure rates of approximately 80%.

Hyperparathyroidism

Primary hyperparathyroidism is a common endocrine disorder of calcium metabolism characterised by hypercalcaemia and elevated or inappropriately normal concentrations of parathyroid hormone. Almost always, primary hyperparathyroidism is due to a benign overgrowth of parathyroid tissue either as a single gland (80% of cases) or as a multiple gland disorder (15-20% of cases). Primary hyperparathyroidism is generally discovered when asymptomatic but the disease always has the potential to become symptomatic, resulting in bone loss and kidney stones. In countries where biochemical screening tests are not common, symptomatic primary hyperparathyroidism tends to predominate. Another variant of primary hyperparathyroidism has been described in which the serum calcium concentration is within normal range but parathyroid hormone is elevated in the absence of any obvious cause. Primary hyperparathyroidism can be cured by removal of the parathyroid gland or glands but identification of patients who are best advised to have surgery requires consideration of the guidelines that are regularly updated. Recommendations for patients who do not undergo parathyroid surgery include monitoring of serum calcium concentrations and bone density.

A retrospective study of elevated post-operative parathormone in primary hyperparathyroid patients

We retrospectively analyzed the relationship between normocalcemic parathormone elevation (NPE) and recurrence of primary hyperparathyroidism (pHPT) after surgery, as well as the risk factors of NPE. Out of 309 patients with pHPT that underwent parathyroidectomy. Six months after surgery, 75 patients exhibited NPE with high preoperative serum levels of alkaline phosphatase, calcium and intact parathyroid hormone (iPTH), postoperative day 1 iPTH, and large parathyroid volume. 15 exhibited NPE at 2 years after surgery with low serum vitamin D levels. Postoperative serum iPTH levels gradually normalized in most patients. Multivariate analysis showed that male patients were at greater risk for postoperative NPE (p<0.05). Only 3 of 309 patients showed recurrence during the follow-up period. NPE may not predict recurrent hyperparathyroidism or incomplete parathyroidectomy for benign parathyroid lesions. Postoperative NPE thus appears to be a response to severe hyperparathyroidism and vitamin D deficiency.

A case of hypercalcemia with double pathology

Hypercalcemia has many causes including primary hyperparathyroidism, malignancy, and other rare etiologies. In most of the cases, hypercalcemia is secondary to one etiology. In this case, we are reporting hypercalcemia with two causes. The initial workup showed primary hyperparathyroidism due to parathyroid adenoma. But because all features were not fully explained by primary hyperparathyroidism, further work-up revealed multiple myeloma. This case represents coexistence of two different diseases, which was rarely reported in the literature previously. Usually, the co-diagnosis was made subsequently after failure to correct hypercalcemia. In our case, both diagnoses were established at the same time of the patient’s presentation as of high suspicion. Establishing the diagnosis early will aid in the initiation of treatment in a timely fashion.

Postoperative local-regional radiation therapy in the treatment of parathyroid carcinoma: The MD Anderson experience of 35 years

PURPOSE

We aimed to investigate outcomes of locoregional radiation therapy (XRT) in parathyroid carcinoma (PC) patients at a single institution over 35 years.

METHODS AND MATERIALS

Retrospective review of PC patients who received postoperative locoregional XRT (1980-2015). Patients were grouped according to XRT after PC initial operation or after salvage surgery. All patients with a histopathological diagnosis of PC who had postoperative locoregional XRT at our institution were included. All patients with a histopathological diagnosis of uncertain malignancy, suggestive for malignancy, or atypical parathyroid tumors and those who had XRT outside our institution were excluded.

RESULTS

Eight patients received XRT, 4 in each group, with a median follow-up of 12.5 years. The 4 patients who had XRT after initial surgery all had an oncologic operation, including ipsilateral thyroid lobectomy and central neck dissection, and all of these patients were disease-free at last follow-up. Of the 4 patients who received XRT after salvage surgery, only 1 remained disease free. There were no major complications/long-term side effects associated with XRT.

CONCLUSIONS

XRT is well tolerated as postoperative locoregional treatment of patients with PC. Whether it is needed, and the timing of administering XRT, remains to be established.

Hyperparathyroidism caused by distant pulmonary lesions and parathyromatosis after ethanol injection/parathyroidectomy for secondary hyperparathyroidism

Secondary hyperparathyroidism (SHPT) treatment includes parathyroidectomy and percutaneous ethanol injection therapy (PEIT), which are invasive procedures. The condition in which benign hyperfunctioning parathyroid tissue is distributed throughout the neck and mediastinum is termed parathyromatosis. Here, we present the case of a 51-year-old woman who began hemodialysis in 1986 due to chronic kidney disease of unknown etiology and developed SHPT in 1999. She underwent 6 rounds of PEIT followed by total a parathyroidectomy with partial forearm autotransplantation. Between 2011 and 2013, surgeons removed several nodules from her pulmonary and cervical regions and the transplanted masses from her forearm; all showed hyperplasia but exhibited no histological evidence of malignancy. Damage to the parathyroid capsule after repeated PEITs may cause local cervical recurrence and pulmonary lesions, although distant lesions are extremely rare in SHPT. This case is of interest due to the possible association between PEIT and parathyromatosis and distal lesions.

Preoperative diagnosis and prognosis in 40 Parathyroid Carcinoma Patients

OBJECTIVE

Parathyroid carcinoma (PC) is a rare disease which is difficult to diagnose preoperatively and predict prognosis. The goal of this study was to analyse the preoperative predictive factors and prognostic factors in PC patients and to evaluate the possibility of diagnosing PC preoperatively.

DESIGN, SETTING AND PATIENTS

This is a retrospective study from Jan 2000 to Aug 2015 conducted in Shanghai Ruijin Hospital.

MEASUREMENTS

Comparisons were made between 40 parathyroid carcinoma patients and 282 patients with benign parathyroid lesions during the same period. All patients underwent parathyroid surgery, and the results were certified by paraffin pathology. Prognostic factors were analysed in the 40 PC patients.

RESULTS

Patients with higher levels of intact parathyroid hormone (P < 0·001, OR = 1·001, CI: 1·000-1·002), calcium (P = 0·008, OR = 3·395, CI: 1·382-8·341) and a larger parathyroid volume (P = 0·001, OR = 2·023, CI: 1·333-3·071) were more likely to have PC. Local excision (P = 0·008, OR = 4·992, CI: 1·533-16·252), stage III in the Schulte staging system (P = 0·039, OR = 9·600, CI: 1·12-82·322), high risk in the Schulte Risk Classification (P = 0·012, OR = 5·466, CI: 1·448-20·628) and first surgery by other medical teams (P = 0·008, OR = 4·992, CI: 1·496-15·037) were associated with PC recurrence. Calcium (P = 0·01, OR = 7·270, CI: 1·611-32·812), intact parathyroid hormone (P = 0·037, OR = 1·001, CI: 1·000-1·001), local excision (P = 0·009, OR = 6·875, CI: 1·633-28·936) and recurrence (P = 0·014, OR = 7·762, CI: 1·504-40·055) were associated with death.

CONCLUSIONS

A preoperative diagnostic system may provide a new method to distinguish PC from benign parathyroid lesions before surgery. For PC patients who did not undergo en-bloc resection at first operation, timely further surgery may offer a second chance of cure. Early diagnosis and surgery are pivotal to reduce mortality in PC patients.

An unusual mediastinal parathyroid carcinoma coproducing PTH and PTHrP: A case report

Parathyroid carcinoma (PTCA) is a rare disease, and ectopic PTCA is particularly rare. Parathyroid hormone-related protein (PTHrP) expression in PTCA has not been previously described in the relevant literature to the best of our knowledge. The present study reports a unique case with a mediastinal parathyroid carcinoma producing parathyroid hormone (PTH) and PTHrP. A 53-year-old man presented with hyperparathyroidism symptoms, including fatigue, chest pain, dizziness, muscular soreness, polyuria, night sweats and renal stones. However, neck ultrasound revealed no significantly abnormal thyroid or parathyroid nodules. Tc99m methoxyisobutylisonitrile (Tc99m-MIBI) scintigraphy scanning indicated an ectopic mediastinal parathyroid adenoma. Histopathological examination revealed PTCA, and the tumor tissue was coproducing PTH and PTHrP. The patient underwent successful surgical operation. Serum calcium and PTH levels remained within normal ranges, and there was no tumor recurrence observed at a 3-year follow-up appointment. Although rare, ectopic parathyroid glands may lead to malignant disease. Clinical symptoms, biochemical tests, ultrasound and Tc99m-MIBI scintigraphy scanning may assist with the diagnosis of this disease. Hypersecretion of PTHrP and PTH contributed collaboratively to the pathogenesis of hypercalcemia due to PTCA. Complete surgical resection with microscopically negative margins is the recommended treatment for PTCA and offers the best chance of a cure.

5-Hydroxymethylcytosine discriminates between parathyroid adenoma and carcinoma

Background

Primary hyperparathyroidism is characterized by enlarged parathyroid glands due to an adenoma (80–85 %) or multiglandular disease (~15 %) causing hypersecretion of parathyroid hormone (PTH) and generally hypercalcemia. Parathyroid cancer is rare (<1–5 %). The epigenetic mark 5-hydroxymethylcytosine (5hmC) is reduced in various cancers, and this may involve reduced expression of the ten-eleven translocation 1 (TET1) enzyme. Here, we have performed novel experiments to determine the 5hmC level and TET1 protein expression in 43 parathyroid adenomas (PAs) and 17 parathyroid carcinomas (PCs) from patients who had local invasion or metastases and to address a potential growth regulatory role of TET1.

Results

The global 5hmC level was determined by a semi-quantitative DNA immune-dot blot assay in a smaller number of tumors. The global 5hmC level was reduced in nine PCs and 15 PAs compared to four normal tissue samples (p < 0.05), and it was most severely reduced in the PCs. By immunohistochemistry, all 17 PCs stained negatively for 5hmC and TET1 showed negative or variably heterogeneous staining for the majority. All 43 PAs displayed positive 5hmC staining, and a similar aberrant staining pattern of 5hmC and TET1 was seen in about half of the PAs. Western blotting analysis of two PCs and nine PAs showed variable TET1 protein expression levels. A significantly higher tumor weight was associated to PAs displaying a more severe aberrant staining pattern of 5hmC and TET1. Overexpression of TET1 in a colony forming assay inhibited parathyroid tumor cell growth.

Conclusions

5hmC can discriminate between PAs and PCs. Whether 5hmC represents a novel marker for malignancy warrants further analysis in additional parathyroid tumor cohorts. The results support a growth regulatory role of TET1 in parathyroid tissue.

Electronic supplementary material

The online version of this article (doi:10.1186/s13148-016-0197-2) contains supplementary material, which is available to authorized users.

Non-functional parathyroid carcinoma: a case report and review of the literature

Non-functional parathyroid carcinoma is an exceedingly rare disease with 31 reported cases since 1909. Because of the scarce number of cases of non-functional parathyroid carcinoma, there are no evidence-based recommendations for its optimal treatment. Surgery, including en bloc resection of the carcinoma, ipsilateral thyroid lobe and isthmus together with a neck dissection only in case of lymph node involvement, is the main treatment for non-functioning parathyroid carcinoma. The patient usually has a poorer prognosis because of detection at advanced stages, the relative ineffectiveness of adjuvant treatment modalities and the lack of adequate parameters for clinical follow-up. In this report, we present a case of non-functional parathyroid carcinoma at our institution, and we review the previous literature to discuss the latest advances in the diagnosis and treatment of this rare disease.

Clinicopathological correlates of hyperparathyroidism

Hyperparathyroidism is a common endocrine disorder with potential complications on the skeletal, renal, neurocognitive and cardiovascular systems. While most cases (95%) occur sporadically, about 5% are associated with a hereditary syndrome: multiple endocrine neoplasia syndromes (MEN-1, MEN-2A, MEN-4), hyperparathyroidism-jaw tumour syndrome (HPT-JT), familial hypocalciuric hypercalcaemia (FHH-1, FHH-2, FHH-3), familial hypercalciuric hypercalcaemia, neonatal severe hyperparathyroidism and isolated familial hyperparathyroidism. Recently, molecular mechanisms underlying possible tumour suppressor genes (MEN1, CDC73/HRPT2, CDKIs, APC, SFRPs, GSK3β, RASSF1A, HIC1, RIZ1, WT1, CaSR, GNA11, AP2S1) and proto-oncogenes (CCND1/PRAD1, RET, ZFX, CTNNB1, EZH2) have been uncovered in the pathogenesis of hyperparathyroidism. While bi-allelic inactivation of CDC73/HRPT2 seems unique to parathyroid malignancy, aberrant activation of cyclin D1 and Wnt/β-catenin signalling has been reported in benign and malignant parathyroid tumours. Clinicopathological correlates of primary hyperparathyroidism include parathyroid adenoma (80-85%), hyperplasia (10-15%) and carcinoma (<1-5%). Secondary hyperparathyroidism generally presents with diffuse parathyroid hyperplasia, whereas tertiary hyperparathyroidism reflects the emergence of autonomous parathyroid hormone (PTH)-producing neoplasm(s) from secondary parathyroid hyperplasia. Surgical resection of abnormal parathyroid tissue remains the only curative treatment in primary hyperparathyroidism, and parathyroidectomy specimens are frequently encountered in this setting. Clinical and biochemical features, including intraoperative PTH levels, number, weight and size of the affected parathyroid gland(s), are crucial parameters to consider when rendering an accurate diagnosis of parathyroid proliferations. This review provides an update on the expanding knowledge of hyperparathyroidism and highlights the clinicopathological correlations of this prevalent disease.

Tumour nuclear oestrogen receptor beta 1 correlates inversely with parathyroid tumour weight

Primary hyperparathyroidism (PHPT) is a common endocrinopathy, frequently caused by a parathyroid adenoma, rarely by a parathyroid carcinoma that lacks effective oncological treatment. As the majority of cases are present in postmenopausal women, oestrogen signalling has been implicated in the tumourigenesis. Oestrogen receptor beta 1 (ERB1) and ERB2 have been recently identified in parathyroid adenomas, the former inducing genes coupled to tumour apoptosis. We applied immunohistochemistry and slide digitalisation to quantify nuclear ERB1 and ERB2 in 172 parathyroid adenomas, atypical adenomas and carcinomas, and ten normal parathyroid glands. All the normal parathyroid glands expressed ERB1 and ERB2. The majority of tumours expressed ERB1 (70.6%) at varying intensities, and ERB2 (96.5%) at strong intensities. Parathyroid carcinomas expressed ERB1 in three out of six cases and ERB2 in five out of six cases. The intensity of tumour nuclear ERB1 staining significantly correlated inversely with tumour weight (P=0.011), and patients whose tumours were classified as ERB1-negative had significantly greater tumour weight as well as higher serum calcium (P=0.002) and parathyroid hormone levels (P=0.003). Additionally, tumour nuclear ERB1 was not expressed differentially with respect to sex or age of the patient. Levels of tumour nuclear ERB2 did not correlate with clinical characteristics. In conclusion, decreased ERB1 immunoreactivity is associated with increased tumour weight in parathyroid adenomas. Given the previously reported correlation with tumour-suppressive signalling, selective oestrogen receptor modulation (SERMs) may play a role in the treatment of parathyroid carcinomas. Future studies of SERMs and oestrogen treatment in PHPT should consider tumour weight as a potential factor in pharmacological responsiveness.