Endocrine Abstracts

Hyperparathyroidism occurs in most patients with MEN Type 1 but the association of MEN type-1 with parathyroid carcinoma has only been described previously in one patient. In this report, we describe two further cases of parathyroid carcinoma presenting in association of MEN type 1 syndrome.

The first patient was a 69-year-old woman who presented with severe hyperparathyroidism and tracheal compression by a mediastinal mass which was shown histologically to be a parathyroid carcinoma with a second similar lesion in the neck. She was treated with total parathyroidectomy followed by resection of the mediastinal mass with resolution of the hypercalaemia. Remarkably, she also reported primary amenorrhea and was found to have an invasive lactotroph pituitary adenoma which we treated with cabergoline. MRI of the pancreas revealed a small lesion characteristic of an islet-cell tumour which was clinically and biochemically non-functioning.

The second patient was a 32-year-old man who presented with intractable dyspepsia associated with raised serum gastrin concentration. A tumour was localised to the neck of the pancreas by endocopic unltrasound and the calcium stimulation catheter suggested the presence of both a gastrinoma and an insulinoma although he had no hypoglycaemic symptoms. He has surgical resection of the pancreatic islet cell tumour with symptomatic improvement. Additional investigations revealed hypercalcaemia and raised serum parathyroid hormone concentration. Neck exploration revealed two parathyroid glands only. One of the parathyroid glands contained a tumour with fibrous banding, extra-capsular extension and moderate Ki 67 staining; features which are highly suggestive of carcinoma. The patient was also found to have bilateral adrenal hyperplasia with abnormal cortisol dynamics and suppressed serum ACTH suggesting ACTH-independent cortisol secretion. Pituitary MRI was normal.

These two case reports show that parathyroid carcinoma can occur, albeit rarely, in the context of MEN type 1. Interestingly, neither patient demonstrated a classical germ-line mutation in the menin gene.