Multiple endocrine neoplasia (MEN IIB) with Cushing's syndrome due to medullary thyroid carcinoma producing corticotropin-releasing hormone.

We describe a case of Cushing's syndrome caused by a medullary thyroid carcinoma (MCT) secreting corticotropin-releasing-hormone (CRH) in a young woman presenting mucosal neuromas located on the top of the tongue and eyelid areas. Laboratory studies showed, basally and after dexamethasone suppression test, serum cortisol and plasma pituitary corticotrophin (ACTH) levels agreed with an ectopic Cushing's syndrome. Immunohistochemical studies of the MCT tissue revealed a production of CRH and scattered cells containing vasopressin but not ACTH peptides. This is the first demonstrated case of a CRH-secreting tumor in multiple endocrine neoplasia (MEN IIB) syndrome.