Adrenocorticotropic Hormone-Producing Pheochromocytoma in a Patient with Adrenal Incidentaloma

Pheochromocytomas are challenging and life-threatening neoplasms. They can secrete a great vari-ety of hormones and peptides apart from catecholamines. A case of adrenocorticotropic hormone (ACTH)-secreting adrenal pheochromocytoma, which caused Cushing's syndrome, is presented herein. A 60-year-old female was referred for an adrenal mass evaluation. It was detected incidentally during the assessment of her back and abdominal pain. She suffered from high blood pressure for 30 years and diabetes mellitus for 15 years. The computerized abdominal tomography showed a 46 x 35 mm cystic necrotic mass on the right side at 17-20 Hounsfield units, consistent with a non-adeno-matous lesion. Laboratory analysis identified elevated levels of catecholamine and hypercortisolism. She underwent an adrenalectomy. Histological features were characteristic of pheochromocytoma. Immunostaining also confirmed the tumor was expressing ACTH. A diagnosis of ACTH-producing pheochromocytoma was made. The catecholamine metabolites were normal post adrenalectomy. Two months after the surgery, we assessed her for hypercortisolism. The dexamethasone suppres-sion test was negative for endogenous hypercortisolism. This is a very rare cause of ectopic Cushing syndrome due to incidentally detected pheochromocytoma.