Multiple endocrine neoplasia 2 (MEN 2)/MEN 2A (Sipple syndrome).

Multiple endocrine neoplasia type 2A (MEN 2A, Sipple syndrome) is an autosomal dominant phakomatosis and is most likely a paracrinopathy. The cardinal manifestations of MEN 2A--medullary thyroid carcinoma, pheochromocytoma, and hyperparathyroidism--indicate that the condition is one of the inherited cancer syndromes. Cutaneous, lichen amyloidosis-like lesions place MEN 2A among the genodermatoses. The gene of MEN 2A, designated as MEN2A, is in the pericentromeric region of chromosome 10; this allows for reliable prenatal and presymptomatic DNA diagnosis.