Ectopic ACTH Syndrome with Bilateral Pheochromocytoma in Multiple Endocrine Neoplasia Type 2A

Abstract

Multiple endocrine neoplasia type 2A (MEN 2A) is an autosomal dominant syndrome characterized by the presence of medullary thyroid carcinoma, pheochromocytoma, and hyperparathyroidism. MEN 2A arises due to a germline missense mutation of the RET proto-oncogene. Specific RET mutation analysis has revolutionized the diagnosis and therapy of this disorder, and early thyroidectomy may have lowered the morbidity and mortality associated with these diseases. Ectopic adrenocorticotropic hormone (ACTH) syndrome is characterized by hypercortisolism due to the hypersecretion of ACTH outside of the pituitary gland; the most common causes are malignancies, but rarely adrenal pheochromocytoma may be the cause. We describe here a case of ectopic ACTH syndrome with bilateral pheochromocytoma in a 29-year-old man with MEN 2A presenting with medullary thyroid carcinoma and hyperparathyroidism. MEN 2A was confirmed by the detection of the RET proto-oncogene mutation. The laboratory results were compatible with ectopic ACTH syndrome. Immunohistochemical studies of the pheochromocytoma tissue confirmed the etiology of the ACTH secretion. This is the first confirmed case of the ectopic ACTH syndrome with bilateral pheochromocytoma in a Korean patient with MEN 2A. (J Korean Endocr Soc 24:265~271, 2009)