[Thymic carcinoid tumor with Cushing syndrome].

A case of a 71-year-old male with ectopic adrenocorticotropic polypeptide (ACTH)-producing thymic carcinoid tumor presenting Cushing's syndrome was reported. This patient had symptoms of fatigue and a polyposia for 2 years before a mediastinal tumor was detected. Chest computed tomography (CT) scan demonstrated an anterior mediastinal mass, and serum ACTH and cortisol level revealed very high. Secretion of cortisol was not inhibited in an 8-mg dexamethazone suppression test. We diagnosed ectopic ACTH-producing tumor, and performed complete excision of the thymus including thymic tumor. Histologically, the tumor demonstrated typical carcinoid with the positivity of ACTH immunostaining. After the operation, ACTH and cortisol levels were reduced and the clinical symptoms were improved rapidly. We have concluded that it is important to control serum perioperative cortisol level for the prevension of morbidity.