Background: Parathyroid carcinoma (PC) is a rare malignancy that is difficult to diagnose preoperatively, and when it is suspected from clinical features and laboratory results, en-bloc resection is performed.

Objective: To retrospectively review the prevalence, clinical presentations, laboratory findings, management modalities, and treatment outcomes of PC cases in the present study tertiary referral hospital.

Materials and Methods: Patients with PC that attended the present center between 2008 and 2019 were included. Demographic data, clinical presentations, preoperative laboratory results, management, and outcomes were retrospectively reviewed.

Results: Ten of 102 cases (9.8%) of the primary hyperparathyroidism were diagnosed as PC. Five were male (50%), and the mean age at diagnosis was 47.90±15.50 years. All PC patients presented with renal or bony manifestations, and five out of nine (45.5%) had palpable neck mass. Mean preoperative parathyroid hormone and serum calcium were 1,688.56±858.84 pg/mL and 15.30±3.27 mg/dL, respectively. In eight of these PC cases (80%), en-bloc resection was performed, and six patients underwent postoperative radiation treatment. Two patients died due to uncontrolled hypercalcemia with distant metastasis at 5.5- and 8-years after diagnosis.

Conclusion: The prevalence of PC among primary hyperparathyroidism is as high in Thailand as in other Asian countries. En-bloc resection is performed when clinical presentations and laboratory results are suggestive of PC. Postoperative radiation is considered in selected cases. Intractable hypercalcemia is the main cause of death.

Keyword: Parathyroid cancer; Parathyroid carcinoma; Primary hyperparathyroidism; Hypercalcemia; Parathyroid carcinoma case series

DOI: doi.org/10.35755/jmedassocthai.2021.06.12435

Received 5 February 2021 | Revised 20 April 2021 | Accepted 21 April 2021