Endocrine Abstracts

Introduction: Primary hyperparathyroidism is usually caused by parathyroid adenoma or hyperplasia. Parathyroid carcinoma is a rare cause of hyperparathyroidism with a frequency ranged from 0.3 to 2.1%. Features that increase the likelihood of parathyroid carcinoma in patients with primary hyperparathyroidism are larger tumor size, symptomatic disease, marked hypercalcemia, and very high serum parathyroid hormone (PTH) concentrations. Preoperative localization studies do not reliably distinguish carcinoma from adenoma, so the diagnosis is typically made at the time of surgery.

Case report: Sixty-five-year-old asymptomatic patient with diabetes mellitus and arterial hypertension was referred to our outpatient clinic because of a chance discovery of hypercalcemia, with calcium 2.79 mmol/l (normal range 2.2–2.6 mmol/l), ionized-calcium 1.58 mmol/l (1.12–1.23 mmol/l) and intact parathyroid hormone (iPTH) 194 ng/l (10–65 ng/l). The patient underwent an ultrasonography of neck region and a subtraction thyroid scan. Investigations did not confirm any neck mass. We performed a choline PET CT that showed a larger cystic mass on the right side of thyroid gland, suspicious for parathyroid carcinoma. Before surgery he did CT scan of neck and thorax, which showed a large tumor (4×3×5 cm in size) of parathyroid gland, without distant metastases. The patient was referred to a thoracic surgeon. Histological findings of resected tumor confirmed a parathyroid carcinoma. His serum calcium and iPTH concentrations after surgery were normal (Ca 2.12 mmol/l, iPTH 30 ng/l).

Conclusion: Primary hyperparathyroidism is often recognized as a result of biochemical screening. The majority are asymptomatic patients with mildly elevated serum calcium concentrations. Although there is an overlap in the clinical in biochemical presentation of benign parathyroid disease and parathyroid cancer, there are some features that increase the likelihood of parathyroid cancer, one of them is tumor size. So even in asymptomatic patients, localization studies can help you to determine the right management and best decision for each individual case.