MON-498 An Innocuous Adrenal Incidentaloma Proved to Be an Adrenal Ganglioneuroma

Abstract Disclosure: G. Umarji: None. K. Desai: None. N.V. Kagita: None. M. Stezzi: None. S.A. Jabbour: None. Adrenal ganglioneuromas constitute <2% of all adrenal incidentalomas. Ganglioneuromas belong to the neuroblastic group of tumors. They originate from sympathetic ganglia, including the adrenal medulla, and are benign. A 23-year-old female was referred to endocrinology for a workup of an adrenal incidentaloma discovered during an emergency room visit for abdominal pain. CT scan of the abdomen with contrast reported a right 3.7 x 2.5 x 3 cm adrenal nodule without any further details. History was significant for intermittent palpitations, for which she reduced her caffeine intake. She denied sweating, pallor, easy bruising, weakness, and unintentional weight changes. Abdominal pain had resolved, which was thought to be from irritable bowel syndrome (IBS). Past medical history included class 3 obesity, cholelithiasis, migraine, and IBS. There was no history of hypertension and hypokalemia and no family history of adrenal disorders. Vital signs were BP 128/84 mmHg, HR 70 beats/min, and body mass index (BMI) 45.35 kg/m2. Physical examination was significant for moon facies, slight dorsocervical hump with no skin atrophy or wide violaceous striae. Hormonal workup was as follows: Plasma-free metanephrines - 10.7 pg/mL (0-88), plasma normetanephrine - 30.9 pg/mL (0-210.1), 24-hour urine-free cortisol - 36 microg/24h (6-42). Magnetic Resonance Imaging (MRI) of the abdomen with and without contrast showed 4.2 x 2.8 cm heterogenous R adrenal nodule, the posterior aspect of the mass demonstrated heterogenous increased T2-weighted signal posteriorly with mildly hypointense signal anteriorly. Opposed phase imaging was restricted due to respiratory motion artifact. The patient underwent a robotic-assisted laparoscopic radical right adrenalectomy. Pathology showed a 5.7 cm adrenal ganglioneuroma, extending beyond the adrenal into the peri-adrenal adipose tissue. Tumor cells were positive for S100, Neurofilament and focally for synaptophysin, predominantly in ganglion cells. Ganglioneuroma (GN) is a rare tumor comprised of ganglion cells and Schwannian stroma. 21% of GN can be seen in the adrenal glands. Adrenal GN are more commonly seen in females. They are hormonally silent but sometimes can produce catecholamines. The gold standard for diagnosis is histological features, including mature, large neuronal ganglion cells in a Schwannian stroma. Immunohistochemical staining is positive for S-100, vimentin, synaptophysin, and neuron-specific enolase. We present a fascinating case of adrenal incidentaloma in a young female that turned out to be an adrenal ganglioneuroma. Presentation: Monday, July 14, 2025