Bronchopulmonary carcinoid presenting as dexamethasone suppressible Cushing's syndrome

Cushing's Syndrome is an endocrine condition with complex diagnostic pathways. Cortisol suppression from high dose dexamethasone usually points to the pituitary as the cause. We present the case of a patient with dexamethasone suppressible Cushing's Syndrome from a bronchopulmonary carcinoid tumor. The tumor was only able to be localized with bronchoscopy. Our objective is to inform other physicians of dexamethasone suppressible carcinoid tumors which may require bronchoscopy to localize.

A 52-year-old female presented with signs and symptoms of Cushing's Syndrome. Cortisol and ACTH levels were significantly elevated. High dose dexamethasone suppressed cortisol production. However, no pituitary source was found. Standard imaging did not localize an ectopic source. The patient continued to have significant morbidity from the hypercortisolism. In order to avoid adrenalectomy, a bronchoscopy was empirically performed which revealed a bronchopulmonary carcinoid tumor.

Bronchopulmonary carcinoid tumor should be in the differential diagnosis of dexamethasone suppressible Cushing's Syndrome if a pituitary source is not localized. Also, we suggest that bronchoscopy be added to the diagnostic algorithm when conventional imaging studies fail to reveal the ectopic source. This may result in cure of the carcinoid malignancy as well as the Cushing's Syndrome.