Ectopic ACTH Syndrome Due to Occult Bronchial Carcinoid

Cushing syndrome (CS) is certainly one of the most challenging endocrine disorders. The greatest problem involves the differentiation between Cushing disease and ectopic ACTH syndrome. We report a patient with ACTH-dependent CS who elsewhere underwent unsuccessful transsphenoidal surgery for a pituitary microadenoma. In our institution, high resolution CT didnʼt show any chest tumor but laboratory data were consistent with ectopic ACTH secretion.Only In-111 Octreoscan, integrated with SPECT-CT and virtual bronchoscopy, allowed the diagnosis of ectopic Cushing syndrome due to occult bronchial carcinoid. Successful surgery was then performed.