Incidentally Discovered Adrenal Mass With Mild Autonomous Cortisol Secretion and Pheochromocytoma

Adrenal incidentalomas are adrenal masses detected on imaging performed for conditions unrelated to suspected adrenal disease. While pheochromocytomas and adrenal cortical adenomas are well-recognized entities, their coexistence with autonomous cortisol secretion (ACS) within a single lesion is rare and presents diagnostic and therapeutic challenges. A 53-year-old woman was incidentally found to have a left adrenal mass during imaging performed for evaluation of obstructive jaundice. She had hypertension but no classic symptoms of pheochromocytoma or overt Cushing's syndrome. Adrenal-protocol non-contrast CT showed an attenuation of -13 Hounsfield units (HU), suggestive of a benign adrenal adenoma. Biochemical evaluation revealed non-suppressible cortisol on the overnight dexamethasone suppression test (ONDST) and low-dose dexamethasone suppression test (LDDST), along with suppressed adrenocorticotropic hormone (ACTH), consistent with mild autonomous cortisol secretion (MACS). Additionally, 24-hour urinary fractionated normetanephrine levels were elevated, with normal fractionated metanephrine levels, confirming catecholamine excess. Preoperatively, she was managed with alpha- and beta-blockade, followed by open left adrenalectomy. Intraoperatively, she developed hypertension requiring nitroprusside infusion, and postoperatively she experienced transient hypotension, which was managed with intravenous fluids and hydrocortisone. Histopathology revealed a collision tumor with features of adrenal cortical adenoma and pheochromocytoma. Postoperatively, her requirement for antihypertensive drugs decreased from three to one. Repeat 24-hour urinary fractionated normetanephrine levels were normal at four weeks after surgery. This case highlights the importance of comprehensive biochemical and imaging assessment in adrenal incidentalomas. The tumor's dual-secretory nature necessitated meticulous perioperative management to prevent complications, and recognition of such rare entities is crucial for optimizing surgical and medical outcomes.