Adrenal Cushing syndrome with detectable ACTH from an unexpected source

Mixed corticomedullary adrenal tumours (MCMT) are rare. We describe the second reported case of a male patient presenting with hypertension and Cushing syndrome with MCMT. A man aged 48 years presented with hypertension and signs of Cushing syndrome. 24-hour urine cortisol was elevated, with detectable adrenocorticotropic hormone (ACTH). A high-dose dexamethasone suppression test indicated an adrenal or ectopic Cushing syndrome. Plasma metanephrines were normal. A 3 cm left adrenal mass was identified without potential ectopic sources of ACTH on imaging. After induction of anaesthesia for laparoscopic adrenalectomy, the patient developed resistant hypertension with stress-dose hydrocortisone administration. Surgery was cancelled and repeat testing revealed elevated plasma metanephrines. α-Blockade was administered for a presumed coexisting pheochromocytoma, and the patient underwent adrenalectomy. Pathology revealed an MCMT. This case highlights the importance of a thorough biochemical evaluation in patients with adrenal masses to rule out multiple hormone producing tumours.