Cushing’s syndrome is an endocrine condition with complex diagnostic pathways. Cortisol suppression from high-dose
dexamethasone suppression tests usually points to the pituitary as the cause. We present a patient with high-dose dexamethasone
suppressible Cushing’s syndrome from a bronchopulmonary carcinoid tumor. A 30-year-old male presented with signs and
symptoms of Cushing’s syndrome. Cortisol and ACTH levels were significantly elevated. High-dose dexamethasone test suppressed
cortisol production. However, no pituitary source was found. In chest-computed tomography a well-differentiated mass was
seen, octreotide scan localized somatostatin-positive tumor in the same place, which revealed a bronchopulmonary carcinoid
tumor. Bronchopulmonary carcinoid tumor should be kept in the mind in the differential diagnosis of Cushing’s syndrome with
suppression of the high-dose dexamethasone test if a pituitary source is not localized.