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

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 References 1.Lau S, Chu P, Weiss L. Mixed cortical adenoma and composite pheochromocytoma-ganglioneuroma: an unusual corticomedullary tumor of the adrenal gland. Annals of Diagnostic Pathology 2011;15:185-189 Unless otherwise noted, all abstracts presented at ENDO are embargoed until the date and time of presentation. For oral presentations, the abstracts are embargoed until the session begins. Abstracts presented at a news conference are embargoed until the date and time of the news conference. The Endocrine Society reserves the right to lift the embargo on specific abstracts that are selected for promotion prior to or during ENDO.