To investigate the clinical diagnosis and treatment of Cushing's syndrome caused by adrenal pheochromocytoma.

Clinical data of one case of Cushing's syndrome caused by the right adrenal pheochromocytoma admitted to our hospital in December 2015 were retrospectively analyzed and literature review was performed. The female patient, aged 45 years old, was admitted to endocrinology department of our hospital due to recurrent headache for six months accompanied by dizziness, polyuria and weight loss for 2 months. Preoperative diagnosis prompted Cushing's syndrome caused by adrenal pheochromocytoma. Preoperative preparations were delivered according to Cushing's syndrome and pheochromocytoma. Laparoscopic resection of the right adrenal tumor was performed via the retroperitoneal approach.

Endocrine examination prompted that adrenocorticotropic hormone (ACTH) and cortisol levels were higher than the upper limit. The large- and small-dose dexamethasone suppression tests were not inhibited. Blood catecholamines levels were all elevated, especially the adrenaline. The clonidine test was not inhibited. Both the methoxy adrenaline and methoxy norepinephrine levels were enhanced. Chest CT plain scan and PET-CT failed to identify suspected source of ectopic ACTH. Adrenal MR demonstrated diffuse thickening of the inferior and lateral branches of bilateral adrenal glands. A circular mass with clear margin was detected between the inferior and lateral branches of the right adrenal gland, which was potentially considered as adrenal pheochromocytoma. She was orally administered with metyrapone to inhibit the production of cortisol. Conventional dose of phenoxybenzamine was delivered during preoperative preparation. Laparoscopic resection of the right adrenal tumor was performed via the retroperitoneal approach. Pathological examination hinted the possibility of right adrenal pheochromocytoma accompanied with hyperplasia in the adrenal cortical zone. Immunohistochemistry revealed CgA (+) and ACTH (+). ACTH and cortisol levels were decreased to normal range after surgery. The re-examination at postoperative 6 months suggested that the symptoms of hypertension and diabetes mellitus were mitigated.

Cushing's syndrome induced by pheochromocytoma is a rare disease. Surgical resection is an effective treatment. Full preoperative preparations should be performed according to both pheochromocytoma and Cushing's syndrome.