MON-LB068 Incidental Finding of a Functioning Corticomedullary Mixed Adrenal Tumor

Abstract

Background: Incidental adrenal adenoma prevalence ranges from 0.4-4% and reaches up to 10% in older patients, but only 10-15% secrete excess amounts of hormones. Functioning adrenal tumors composed of corticomedullary mixed cells are very rare. Clinical Case: A 78-year-old female patient with a 2-year history of slowly progressive involuntary weight-loss (20kg), recent diagnosis of type 2 diabetes, and incidental finding upon abdominal ultrasound of a right adrenal mass, is admitted to our hospital due to a left hip fracture. She denied hypertension. Physical examination revealed no signs of hypercortisolism and/or catecholamine excess other than tachycardia (120bpm). Abdominal CT Scan showed an enlarged right adrenal mass, 2.7x3.3cm, 40UH. Institutional laboratory results were consistent with a pheochromocytoma: Metanephrines: 180pg/mL (n<65 pg/mL), Normetanephrines: 356 pg/mL (n<196 pg/mL), and an ACTH-independent Cushing Syndrome: elevated 24-hour urinary cortisol: 628.3nmol/L (n<110nmol/L), abnormal 1mg overnight Dexamethasone test: Cortisol 8am: 14.4mcg/dL (positive >1.8mcg/dL), normal ACTH: 19.97pg/mL (n:7-62pg/mL) and DHEASO4: 161.21mcg/dL (n:25-460mcg/dL). Fasting glycemia: 142mg/dL. Laparoscopic right adrenalectomy is performed. Postoperative results: normal Cortisol 8am: 18.6mcg/dL (n:4.46-22.1mcg/dL), fasting glycemia: 94mg/dL. Histological and immunohistochemistry results showed a mixed corticomedullary adrenal tumor with pheochromocytoma (chromogranin A+++, synaptophysin+++), ganglioneuroma (S100+++, synaptophysin ++) and cortical adenoma ((inhibin +++, Melan A +++) components, capsular invasion but no evident angioinvasion. Conclusion: This case is one of the very few reports of a functioning mixed cell tumor with adrenal cortical, medullary and neural lineage in a single gland confirmed by immunohistochemistry. Key words: corticomedullary tumor, mixed adrenal tumor, pheochromocytoma, Cushing’s syndrome