Adrenocorticotropic hormone-producing pheochromocytoma: analysis of clinical cases

Ectopic secretion of ACTH from non-pituitary tumors, referred to as ectopic ACTH syndrome (EAS), accounts for about 10–20% of Cushing’s syndrome (CS). Ectopic hormone-secreting pheochromocytomas (Pheo) are rare. The first publication of association between pheochromocytoma and Cushing’s syndrome by Roux is dated 1955. Pheochromocytoma represents a rare cause of hypercortisolism, accounting for less than 5 % of ectopic Cushing’s syndrome while less than 1 % of pheochromocytomas is accompanied by Cushing’s syndrome.We are reporting 4 cases of ACTH-secreting pheochromocytoma presenting as Cushing’s syndrome. Data from 4 patients were analysed. There were 4 women from 50 to 63 years old. All patients had a clinical presentation of hypercorticoidism. Their levels of adrenocorticotropic hormone in plasma, 24-hour urinary free cortisol and urinary catecholamine were high. Computed tomography scan of the abdomen in all cases revealed a mass in the left adrenal gland. Left sided adrenalectomy was performed under treatment with a-blocker doxazosin and b-blocker atenolol. Histological examination revealed in 3 cases – pheocromocytoma and in 1 case corticomedullary mixed tumor of the adrenal gland. Additional immunostaining (IHC)of these tumors showed positive immunostaining for chromogranin and ACTH. The IHC search for somatostatin receptors of subtype 2 and 5 (SSTR2, SSTR5) was performed in 3 cases and showed predominately expression SSTR2. The case index of Ki-67 ranged, from 0,5 to 4%. Biochemical signs of hypercortisolism rapidly began to disappear after surgery. Follow up of the patients during the next 2 years on average was with disease remission.