Challenges and pitfalls in the management of parathyroid carcinoma: 17-year follow-up of a case and review of the literature

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.

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.

Local resection versus radical surgery for parathyroid carcinoma: A National Cancer Database analysis

INTRODUCTION

Parathyroid carcinoma (PC) is rare and often diagnosed incidentally after local resection (LR) for other indications. Although recommended treatment has traditionally been radical surgery (RS), more recent guidelines suggest that LR alone may be adequate. We sought to further investigate outcomes of RS versus LR for localized PC.

MATERIALS AND METHODS

PC patients from 2004 to 2015 with localized disease were identified from the National Cancer Database, then stratified by surgical therapy: LR or RS. Demographic and clinicopathologic data were compared. Cox proportional hazard models were constructed to estimate associations of variables with overall survival (OS). OS was estimated from time of diagnosis using Kaplan-Meier curves.

RESULTS

A total of 555 patients were included (LR = 522, RS = 33). The groups were comparable aside from LR patients having higher rates of unknown nodal status (66.9% versus 39.4%; p = 0.003). By multivariable analysis, RS did not have a significant association with OS (hazard ratio (HR) = 0.43, 95% confidence interval (95%CI) = 0.10, 1.83; p = 0.255), nor did positive nodal status (HR = 0.66, 95%CI = 0.09, 5.03; p = 0.692) and unknown nodal status (HR = 1.30, 95%CI = 0.78, 2.17; p = 0.311). There was no difference in OS between the LR and RS groups, with median survival not reached by either group at 10 years (median follow-up = 60.4 months; p = 0.20).

CONCLUSIONS

There was no difference in OS between LR and RS for localized PC. RS and nodal status may not impact survival as previously identified, and LR should remain a valid initial surgical approach. Future higher-powered studies are necessary to assess the effects of surgical approaches on morbidity and oncologic outcomes.

Case Report: Abdominal Lymph Node Metastases of Parathyroid Carcinoma: Diagnostic Workup, Molecular Diagnosis, and Clinical Management

Parathyroid carcinoma (PC) is an orphan malignancy accounting for only ~1% of all cases with primary hyperparathyroidism. The localization of recurrent PC is of critical importance and can be exceedingly difficult to diagnose and sometimes futile when common sites of recurrence in the neck and chest cannot be confirmed. Here, we present the diagnostic workup, molecular analysis and multimodal therapy of a 46-year old woman with the extraordinary manifestation of abdominal lymph node metastases 12 years after primary diagnosis of PC. The patient was referred to our endocrine tumor center in 2016 with the aim to localize the tumor causative of symptomatic biochemical recurrence. In view of the extensive previous workup we decided to perform [18F]FDG-PET-CT. A pathological lymph node in the liver hilus showed slightly increased FDG-uptake and hence was suspected as site of recurrence. Selective venous sampling confirmed increased parathyroid hormone concentration in liver veins. Abdominal lymph node metastasis was resected and histopathological examination confirmed PC. Within four months, the patient experienced biochemical recurrence and based on high tumor mutational burden detected in the surgical specimen by whole exome sequencing the patient received immunotherapy with pembrolizumab that led to a biochemical response. Subsequent to disease progression repeated abdominal lymph node resection was performed in 10/2018, 01/2019 and in 01/2020. Up to now (12/2020) the patient is biochemically free of disease. In conclusion, a multimodal diagnostic approach and therapy in an interdisciplinary setting is needed for patients with rare endocrine tumors. Molecular analyses may inform additional treatment options including checkpoint inhibitors such as pembrolizumab.

Prognostic role of parafibromin staining and CDC73 mutation in patients with parathyroid carcinoma: A systematic review and meta-analysis based on individual patient data

BACKGROUND AND OBJECTIVE

Parathyroid carcinoma (PC) is a rare malignant neoplasm with a relatively poor prognosis. The loss of parafibromin expression or the presence of CDC73 mutation has been found to be remarkably associated with malignancy in parathyroid tumours. However, the prognostic role of them in PC has not yet been shown due to sampling limitations. We conducted a systematic review and meta-analysis based on individual patient data to clarify the performance of parafibromin immunohistochemical staining and CDC73 gene sequencing in predicting outcomes for patients PC.

METHODS

Published studies from PubMed/MEDLINE, EMBASE, Cochrane and Scopus Databases were searched using the terms 'parafibromin', 'CDC73', 'HRPT2' and 'parathyroid' to identify eligible studies. From the included studies, the survival data of patients with PC were extracted, and a Cox proportional hazards model was used to assess hazard ratio (HR) for disease-free survival (DFS) and overall survival (OS).

RESULTS

A total of 193 patients from 9 studies were included in this survival analysis. Negative immunohistochemical staining of parafibromin was shown to be a risk factor for recurrence/metastasis (HR 2.73, P = .002) and death (HR 2.54, P = .004). Patient age ≥ 50 years was significantly related to lower OS (HR 2.37, P = .004) but not to DFS. CDC73 mutation was not statistically related to DFS or OS.

CONCLUSIONS

Negative parafibromin staining indicated a higher risk of recurrence/metastasis and mortality. The immunohistochemical staining of parafibromin seems to be more promising in predicting outcomes for patients with PC than the sequencing of CDC73.

[Unexpected Postoperative Diagnosis of Parathyroid Carcinoma]

Unexpected Postoperative Diagnosis of Parathyroid Carcinoma Abstract. Parathyroid carcinoma is a rare endocrine malignancy. It typically presents itself with similar clinical features as seen in patients with primary hyperparathyroidism caused by a parathyroid adenoma. Due to overlapping clinical manifestations, imaging findings and pathological characteristics, the differentiation between benign and malignant parathyroid disease poses a diagnostic challenge, especially prior to surgery. We report the case of a 67-year-old male who presented with symptomatic hypercalcemia and primary hyperparathyroidism. During resection of the enlarged parathyroid gland, suspicious macroscopic features were noticed and the histopathology finding confirmed the malignancy. Parathyroid carcinoma is rarely diagnosed preoperatively, which is mainly due to the lack of distinctive symptoms or morphological features suggesting a malignant disease. As parathyroid carcinoma often has a genetic background, knowledge of mutation status and family history is of high relevance. Surgery with complete resection of the parathyroid carcinoma is the mainstay for a successful treatment and a good prognosis.

Current and future treatments for parathyroid carcinoma

Parathyroid carcinoma (PC) is a rare disease and presents clinical challenges in diagnosis, management and adjuvant treatment. Rarely diagnosed preoperatively, PC is often discovered in the treatment of primary hyperparathyroidism. PC is predominantly treated surgically with minimal additional treatments available. Given the rarity of the disease, current and future efforts, as discussed in this article, are focused on increasing preoperative diagnosis, recognizing genetic patterns and pathologic markers and delineating nonsurgical options for patients with advanced disease.

Prognostic Scoring System to Risk Stratify Parathyroid Carcinoma

BACKGROUND

Parathyroid carcinoma is a rare endocrine malignancy that lacks an established system for risk categorization. This study evaluated a prognostic scoring system for recurrence-free survival (RFS) of patients with parathyroid carcinoma.

STUDY DESIGN

Patients diagnosed and confirmed to have parathyroid carcinoma and who were treated between 1980 and 2016 at The University of Texas MD Anderson Cancer Center were studied retrospectively. Univariate and multivariate Cox proportional hazards regression analyses of RFS were conducted. A prognostic scoring system was created based on multivariate analysis.

RESULTS

Sixty-eight patients were evaluated. After a median follow-up of 4.6 years, 26 patients experienced a recurrence. The Kaplan-Meier RFS rates were 85% at 1 year (95% CI 77% to 95%), 67% at 2 years (95% CI 55% to 81%), and 51% at 10 years (95% CI 36% to 72%) after initial operation. Multivariate analysis demonstrated that age older than 65 years, serum calcium level >15 mg/dL, and vascular invasion were negatively correlated with RFS rate. Combining these adverse variables into a prognostic scoring system, we stratified patients into 3 risk groups: low (0 variable; 2-year RFS rate, 93%), moderate (1 variable; 2-year RFS rate, 72%), and high (2 variables; 2-year RFS rate, 27%) (p = 0.001 [log-rank test]; concordance index, 0.70; 95% CI 0.47 to 0.92).

CONCLUSIONS

A prognostic scoring system using vascular invasion, age, and serum calcium level at initial parathyroidectomy can be used to predict RFS. This categorization might be helpful for clinical decisions relative to the timing and use of adjuvant therapy. Comprehensive validation using multiple cohorts will be needed to confirm applicability.

Evaluation of malignant parathyroid tumours in two European cohorts of patients with sporadic primary hyperparathyroidism

Purpose

Parathyroid carcinoma (PC) is remarkable for its rare occurrence and challenging diagnostics. PC accounts for 0.1–5 % cases of primary hyperparathyroidism (PHPT). The differentiation from benign tumours is difficult even by morphological criteria. To address these issues, we assessed the PC frequency in two separate European PHPT cohorts and evaluated the demographic, clinical, morphological and molecular background.

Methods

A retrospective study was carried out, using continuously maintained database (2005–2014) of PHPT patients from two tertiary referral university hospitals in Europe. The demographic, clinical data and frequency of PC among surgically treated PHPT was detected. Immunohistochemistry (IHC) was performed to detect parafibromin, representing protein product of HRPT2 gene and proliferation marker Ki-67.

Results

Both PHPT cohorts were characterised by close mean age values (58.6 and 58.0 years) and female predominance. The frequency of PC differed significantly between the cohorts: 2.1 vs. 0.3 %; p = 0.004. PC was characterised by invariable complete loss of parafibromin contrasting with parathyroid adenomas. The proliferation fraction was similar in both PC cohorts (10.6 and 11.0 %). PC showed significantly higher proliferation fraction than typical parathyroid adenomas (1.6 %), atypical adenomas (1.6 %) or adenomas featuring focal loss of parafibromin (2.2 %).

Conclusions

PC frequency can range significantly between the two European cohorts. The differences can be attributable to selection bias of patients referred for surgery and are not caused by discordant definition of malignant parathyroid histology. Diffuse loss of parafibromin and increased proliferation fraction by Ki-67 are valuable adjuncts in PC diagnostics due to significant differences with various clinical and morphological subtypes of adenoma.

Parathyroid cancer

Parathyroid carcinoma is an exceedingly rare endocrine malignancy first described in 1933. It accounts for between 0.5% and 5% of all cases of primary hyperparathyroidism. Parathyroid carcinoma is unusual among endocrine malignancies, being more hormonally active than its benign counterpart. Parathyroid carcinoma poses a diagnostic challenge both clinically and histologically due to the lack of features which can definitively distinguish malignant from benign disease early in its clinical course. Here, we describe the clinical features of the disease, and present the current opinion on optimal management. Further, we analyse the most recent histological advances made to aid in the diagnosis and management of this rare, but potentially devastating, disease.

Case of parathyroid carcinoma with a highly aggressive clinical course

We describe a 59-year-old woman who presented with pathological osteoporosis, cerebral infarction, hypercalcemia, and markedly high parathyroid hormone levels. The diagnosis was primary hyperparathyroidism, and parathyroidectomy was performed. Histopathological examination showed parathyroid adenoma. Surgical exploration for recurrent parathyroid carcinoma was undertaken at 2 and 3 years after the initial neck resection. Pulmonary metastasis was diagnosed at 4 years after the initial surgery.Despite treatment with intravenous bisphosphonates, her calcium and parathyroid hormone (PTH) levels remained elevated, and leg amputation was performed following the development of arteriosclerosis obliterans at 6 years after the initial neck resection. The prognosis for parathyroid carcinoma is often difficult to predict due to recurrence.

Hypercalcemia in the Intensive Care Unit: A Review of Pathophysiology, Diagnosis, and Modern Therapy

Hypercalcemia may be seen in a variety of clinical settings and often requires intensive management when serum calcium levels are dramatically elevated. All of the many etiologies of mild hypercalcemia can lead to severe hypercalcemia. Knowledge of the physiologic mechanisms involved in maintaining normocalcemia and basic pathophysiology is essential for making a timely diagnosis and hence prompt institution of etiology-specific therapy. The development of new medications and critical reviews of traditional therapies have changed the treatment paradigm for severe hypercalcemia, calling for a more limited role for aggressive isotonic fluid administration and furosemide and an expanded role for calcitonin and the bisphosphonates. Experimental therapies such as denosumab show promise.

Unusual case of solitary functioning bone metastasis from a "parathyroid adenoma": imagiologic diagnosis and treatment with percutaneous vertebroplasty--case report and literature review

BACKGROUND

Parathyroid carcinoma is a rare endocrine malignancy that accounts for a small percentage of patients with primary hyperparathyroidism. Here, an unusual patient with parathyroid carcinoma misdiagnosed as a parathyroid adenoma was reported. A solitary L4 vertebral metastasis, which was localized by technetium-99m-labelled methoxyisobutyl isonitrile ((99m)Tc-MIBI) single photon emission computed tomography (SPECT)/computed tomography (CT) fusing images, was successfully treated with percutaneous vertebroplasty (PVP) for the first time.

PATIENT AND METHODS

A 53-year-old man with primary hyperparathyroidism and a palpable mass in the right neck was referred. A right unilateral parathyroidectomy was performed. A pathological diagnosis of parathyroid adenoma was made; however, hyperparathyroidism persisted with a serum calcium of 4.51 mmol/L and a PTH of 3235 pg/mL. Early and delayed images of the (99m)Tc-MIBI whole-body scan revealed abnormal (99m)Tc-uptake in the lower abdomen. The delayed (99m)Tc-MIBI SPECT/CT fusion images found that the lower abnormal (99m)Tc-MIBI uptake was located in the area of osteolytic destruction of the L4 vertebra. A bone metastasis from parathyroid carcinoma was diagnosed based on histopathological evaluation and immunohistochemical staining. PVP was performed to treat the osteolytic destruction of the L4 vertebra. The PTH level decreased to normal within 1 week after PVP.

CONCLUSION

(99m)Tc-MIBI SPECT/CT scan may be a useful and suitable method by which to localize functioning distant metastases from the parathyroid cancer when serum PTH and calcium levels remain greatly elevated after parathyroidectomy. PVP may be an effective procedure in eliminating cancer cells, reducing serum PTH levels, preventing bone fractures, and improving the quality of life of patients.

Parathyroid carcinoma: challenges in diagnosis and treatment

Parathyroid carcinoma is a malignant neoplasm affecting 0.5% to 5.0% of all patients with primary hyperparathyroidism. Since it was first described by De Quervain in 1904 to this day, it continues to defy diagnosis and treatment because of its rarity, overlapping features with benign parathyroid disease, and lack of distinct characteristics. En bloc surgical extirpation of the tumor with clear margins remains the best curative treatment. Although prolonged survival is possible with recurrent or metastatic disease, cure is rarely achievable. Efficacy of adjuvant therapies, such as radiotherapy and chemotherapy, in management of persistent, recurrent, or metastatic disease has been disappointing.

Diagnosis and management of parathyroid cancer

Parathyroid cancer is rare, but often fatal, as preoperative identification of malignancy against the backdrop of benign parathyroid disease is challenging. Advanced genetic, laboratory and imaging techniques can help to identify parathyroid cancer. In patients with clinically suspected parathyroid cancer, malignancy of any individual lesion is established by three criteria: demonstration of metastasis, specific ultrasonographic features, and a ratio >1 for the results of third-generation:second-generation parathyroid hormone assays. Positive findings for all three criteria dictate an oncological surgical approach, as appropriate radical surgery can achieve a cure. Mutation screening pinpoints associated conditions and asymptomatic carriers. Molecular profiling of tumour cells can identify high-risk features, such as differential expression of specific micro-RNAs and proteins, and germ line mutations in CDC73, but is unsuitable for preoperative assessment owing to the potential risks associated with biopsy. A validated, histopathology-based prognostic classification can identify patients in need of close follow-up and adjuvant therapy, and should prove valuable to stratify clinical trial cohorts: low-risk patients rarely die from parathyroid cancer, even on long-term follow-up, whereas 5-year mortality in high-risk patients is around 50%. This insight has improved the approach to parathyroid cancer by enabling risk-adapted surgery and follow-up.

Parathyroid carcinoma presenting as normocalcemic hyperparathyroidism

Parathyroid carcinoma (PC) is a rare malignancy, with an indolent but progressive course. Long-term survival is largely dependent on the extent of the primary surgical resection. Hence, pre- or intraoperative suspicion of malignancy is of great importance. We describe the case of a 62-year-old woman with a 2-year history of asthenia and mental depression. Her past medical history was significant for osteoporosis. A diagnosis of primary normocalcemic hyperparathyroidism was established and the patient underwent surgery. PC was suspected intraoperatively because of the size and appearance of the parathyroid mass (a grayish, lobulated 3.5 cm mass). Thus, aggressive surgery (en bloc resection) was performed, along with bilateral neck exploration. Pathological examination of the specimens confirmed the suspicion of PC, demonstrating vascular invasion and extracapsular infiltration into adjacent soft tissue. Immunohistochemical staining revealed an elevated Ki-67 score (8.43%; cut-off value 5%). The mean area of silver-stained nucleolar organizer regions (AgNOR) was high (4.972 μm(2)), indicating an elevated proliferation rate. Serum calcium and parathyroid hormone levels normalized postoperatively, and the patient's 5-year outcome was good. The present case provides evidence that parathyroid malignancy cannot be excluded a priori based on normocalcemic hyperparathyroidism, emphasizing the variability in clinical presentation. Moreover, Ki-67 expression and AgNOR analysis confirmed their additional value in complementing the histological evaluation of a parathyroid malignant mass.