Endocrine Abstracts

Case: A 50-years-old gentleman underwent cardiac surgery which was complicated by postoperative arrythmias and ischemic stroke. He was found to have raised calcium of 2.9 (2.2–2.6 mmol/l) subsequent to which PTH was tested and found to be raised at 34.2 (1.6–6.9 pmol/l) which increased to 41.2 pmol/l in few days. He was referred for work up and management of primary hyperparathyroidism. An USS of the neck showed 1.5 cm nodule posterior to left thyroid lobe and Sestimibi scan also showed increased tracer uptake on the left side, findings consistent with parathyroid adenoma. During the course of investigations, calcium increased to 3.4 mmol/l and he required hospital admission for acute management of hypercalcaemia. In view of cardiac history and severe hypercalcaemia, he underwent left parathyroidectomy for parathyroid adenoma but histology of the excised gland showed features consistent with Parathyroid Adenocarcinoma. He was investigated to look for metastases. The CT scan of chest and SPECT CT did not show local or distant Metastases. A repeat surgery was undertaken for left hemithyroidectomy which showed no local spread of carcinoma. The calcium and PTH normalized after the surgery until 6 months when PTH increased again up to 11.4 pmol/l but it was found to be associated with hypocalcaemia and low Vitamin D and improved with Vitamin D replacement. He has been having regular follow up and being monitored with calcium and PTH. DEXA bone scan shows improving bone density. There has been no recurrence for 6 years after the surgery.

Discussion: Parathyroid carcinoma is a rare malignancy with incidence of <1% among all hyperparathyroidism cases. There are no distinguishing features or investigations to differentiate adenoma from carcinoma. It is mostly diagnosed on histological examination of the excised parathyroid gland. Raised PTH with hypercalcaemia is usually suggestive of primary hyperparathyroidism but severe hypercalcaemia with markedly raised PTH should raise suspicion of Parathyroid Carcinoma.