Detection of paranasal ectopic adrenocorticotropic hormone-secreting pituitary adenoma by Ga-68-DOTANOC positron-emission tomography-computed tomography.

Ectopic adrenocorticotropic hormone (ACTH)-secreting tumors account for approximately 10% of Cushing's syndrome (CS). We present an extremely rare case of a patient with CS caused by an ectopic ACTH-secreting pituitary adenoma (EAPA) of the ethmoid sinus. The tumor was identified by positron-emission tomography-computed tomography (PET/CT) using the somatostatin receptor analogue Ga-68-DOTANOC. Transnasal endoscopic resection was performed and the patient showed significant clinical improvement with normalization of the endocrine pituitary axis. Immunostaining showed a somatostatin receptor 2 and 5-positive ACTH-producing adenoma. In patients with ectopic ACTH secretion, Ga-68-DOTANOC-PET/CT may play an important role in the localization of EAPA. Transnasal endoscopic resection is the therapy of choice.