Multiple endocrine neoplasia: Part II. Sipple's syndrome

Multiple endocrine neoplasia (MEN) type II is a genetically inherited disorder characterized by a combination of medullary carcinoma of the thyroid, phaeochromocytomas and, more rarely, hyperparathyroidism. A subgroup of patients who do not have the same genetic inheritance pattern have in addition a Marfanoid habitus and multiple mucosal neuromas. The phaeochromocytomas cause paroxysmal hypertensive crises due to catecholamine surges, and are diagnosed most easily by elevated levels of urinary vanillylmandelic acid. Medullary carcinoma presents as a thyroid nodule and is often associated with flushing or diarrhoea. Measurement of plasma thyrocalcitonin levels permits diagnosis and detection of affected members of the family. It is unusual for hyperparathyroidism to be asymptomatic or to require treatment. Bilateral adrenalectomy should always be performed since both adrenals are involved, even if an overt tumour is only apparent in one. Total thyroidectomy for medullary carcinoma is indicated once the phaeochromocytomas have been removed. Affected families should be regularly screened to detect overt cases.