Differential diagnosis of ACTH-dependent CS is a challenging clinical issue, as up to 20% of ACTH-secreting pituitary adenomas are not visualized by magnetic resonance imaging (MRI) with gadolinium and the sensitivity of other methods to detect ACTH-producing carcinoid tumors after the first visualization is no more than 43% (3). This evidence concerns the gene POMC and Cowden syndrome 1.