Cushing syndrome due to ectopic adrenocorticotropic hormone secretion

Gushing syndrome (CS) caused by ectopic adrenocorticotropic hormone (ACTH) production (EA) poses major challenges diagnostically by mimicking the pitu itary-dependent form of CS and therapeutically by producing severe, life-th reatening hypercortisolemia. This retrospective follow-up study describes t he clinical characteristics and course of EA in a large referral center. Co mputer-based cross-index codes fur EA, CS, and bilateral adrenalectomy were used to identify patients treated at the Mayo Clinic between 1956 and 1998 , EA was confirmed in 106 patients. Gender distribution showed a slight fem ale predominance (61:45). Bronchial carcinoid was the most frequent cause o f EA (25%), followed by islet cell cancer (16%), small-cell lung carcinoma (11%), medullary thyroid cancer (8%), disseminated neuroendocrine tumor of unknown primary source (7%), thymic carcinoid (5%), pheochromocytoma (3%), disseminated gastrointestinal carcinoid (1%), and other tumors (8%). No tum or was found in 16% of patients. Altogether, 28 patients were managed medic ally, and the others underwent curative tumor resection (13 patients) or bi lateral adrenalectomy (65 patients). Surgically treated patients had longer survival, but this was most likely affected by treatment bias, The diagnos es of CS and ACTH-secreting neoplasm were usually concurrent, although, the re were remarkable cases in which the two conditions were diagnosed several years apart. Curative resection of the tumor producing EA was possible in a small proportion of patients (12%). When curative resection is not possib le, patients who are reasonable surgical candidates are likely to benefit f rom adrenalectomy. Additional experience with bilateral laparoscopic adrena lectomy should increase the number of patients who benefit from adrenal-dir ected surgery.