Parathyroid carcinoma

Parathyroid carcinoma is a rare malignant tumor originating from the parathyroid glands, characterized by excessive production of PTH, which results in severe hypercalcemia and associated complications.

Parathyroid carcinoma is generally sporadic but can also develop as part of specific syndromes, such as hyperparathyroidism-jaw tumor syndrome and MEN1 or multiple endocrine neoplasia 2A. Common mutations identified in patients with parathyroid carcinoma include HRPT2/CDC73 and CCND1. Mutation in the HRPT2/CDC73 gene leads to reduced expression of parafibromin and the calcium-sensing receptor.

The incidence of parathyroid carcinoma in the US is estimated at 0.36 per 1,000,000 person-year and accounts for less than 1% of all primary hyperparathyroidism cases.

Risk factors include environmental exposures and prior head and neck radiotherapy.

Functioning parathyroid carcinoma presents with primary hyperparathyroidism and symptoms and signs related to hypercalcemia. Nonfunctioning parathyroid carcinoma usually presents with a palpable solid neck mass, dysphagia, and change in voice due to laryngeal nerve palsy. Parathyroid carcinoma is often detected postoperatively and is associated with a high rate of recurrence.

The prognosis of parathyroid carcinoma is generally poor, with a high rate of recurrence and a significant number of patients developing multiple disease recurrences. The reported overall survival rates are 78-91% at 5 years and 60-72% at 10 years.