As expected, most frequently encountered tumors with ectopic ACTH secretion were of pulmonary origin (bronchus carcinoid, pulmonary/small cell lung carcinoma), others included thymic (thymoma/thymic carcinoma), gastro-intestinal (insulinoma, gastrinoma, somatostatinoma, gastric NEC, small bowel carcinoma NET, and carcinoma), pancreatic NET, medullary thyroid carcinoid, olfactory neuroblastoma, and metastatic foci of unknown origin. The gene discussed is POMC; the disease is small cell lung carcinoma.