Endogenous Cushing's syndrome complicated by Pneumocystis carinii pneumonia

We report a case of Pneumocystis carinii pneumonia in a patient with ectopic production of adrenocorticotropic hormone (ACTH). The patient presented with Cushing's syndrome caused by a malignant thymic carcinoid. Pneumocystis carinii pneumonia should be considered in the differential diagnosis of pneumonia in patients with endogenous Cushing's syndrome.