Multiple endocrine neoplasia type 2A

A form of multiple endocrine neoplasia type 2 (MEN2) syndrome characterized by medullary thyroid carcinoma in association with pheochromocytoma (one or both adrenal glands can be affected) and/or primary hyperparathyroidism (caused by parathyroid adenoma). Onset is typically later than in MEN2B, before 35 years of age. Diarrhea is the most frequent systemic symptom. Patients can develop Hirschsprung disease and, less frequently, cutaneous lichen amyloidosis or excessive production of adrenocorticotropic hormone.