A Case of Multiple Endocrine Neoplasia Type II Accompanied by Thyroid Medullary Carcinoma and Pheochromocytomas Expressing Corticotropin-Releasing Factor and Urocortins

A 38-year-old woman with RET gene mutation presented with tumors in her thyroid and bilateral adrenal glands. 131I-metaiodobenzylguanidine scintigraphy revealed accumulation of the radioisotope in both adrenal glands. Both plasma adrenaline and noradrenaline levels were elevated. The circadian rhythms for plasma adrenocorticotropic hormone (ACTH) and cortisol levels were disturbed. Plasma ACTH and cortisol levels failed to be suppressed by an overnight dexamethasone test, suggesting autonomic secretion of ACTH and cortisol, although the patient had no typical Cushingoid features, hypertension, or impaired glucose tolerance. Pathological examination showed that these tumors were pheochromocytoma and thyroid medullary carcinoma, respectively, both of which highly expressed corticotropin-releasing factor, urocortin1, and urocortin3. Together with the endocrinological and pathological observations, the patient was diagnosed as multiple endocrine neoplasia type II with corticotropin-releasing factor- and urocortin-producing tumors that stimulated ACTH and glucocorticoid secretion.