The most prevalent tumors associated with ectopic ACTH secretion are small cell lung carcinomas (SCLC) (3.3% to 50%), bronchial carcinoid (5% to 40%), islet cell tumor of the pancreas (7.5% to 25%), thymic carcinoid (5% to 42%), and pheochromocytoma (2.5% to 25%) [7,8]. This evidence concerns the gene POMC and pheochromocytoma.