8234 Composite Pheochromocytoma-Ganglioneuroma: Two Clinical Cases Presenting To St. Elizabeth’s Medical Center

Abstract Disclosure: M. El Najjar: None. E. Naous: None. C. Blake: None. A.T. Sweeney: None. Introduction: Pheochromocytomas (PCCS) are rare catecholamine producing tumors that originate from the chromaffin cells of the adrenal medulla. In 3-9% of cases, they may be accompanied by other tumors. Ganglioneuromas are the most encountered tumor type that occur with PCC and are termed composite PCC-GN. The entity is very rare with < 35 cases reported. Herein, we present 2 cases of composite PCC-GN. Case Presentation: Patient 1 (Pt1) & Patient 2 (Pt2): were 35- & 54-year-old obese females. Pt1 had controlled hypertension and symptoms of anxiety along with palpitations, diaphoresis and flushing. Pt2 had type 2 diabetes and complained of abdominal pain. Metabolic studies showed elevated total plasma fractionated metanephrines(MNs). MNs in Pt1 and Pt2 were: 76 and 61pg/ml respectively (normal <57 pg/ml) and normetaneprines levels were 161 and 116pg/ml respectively (normal <148 pg/ml). Abdominal computed tomography (CT) scans demonstrated right adrenal masses in both cases with Pt1 having a 2.3 x 2.3 x 2.6 cm mass (Figure1) with smooth margins measuring 36 Hounsfield units (HU) on non-contrast(NC) CT imaging with 0% washout on delayed imaging after IV contrast. Pt2 on NCCT had a 4.5 x 3.5 cm right adrenal mass measuring 73 HU and a subsequent abdominal MRI(Figure2) demonstrated the mass to have heterogenous signal intensity. Both patients were prepared with pre-operative a and b blockade and underwent laparoscopic robotic adrenalectomies without complications. Pathological analyses in both cases revealed composite PCC-GN. Pt2 underwent genetic testing which did not reveal any known mutations. Surveillance in both patients demonstrated no recurrence. Clinical lesson: The clinical presentation of PCC-GNs is indistinguishable from isolated PCCs. The definitive diagnosis is through histopathological analysis. Histologically the composite tumor is composed of two distinct patterns with PCC showing angular cells with granular, basophilic cytoplasm, arranged in nests, while GNs show ganglion cells in fibrous stroma. Immunohistochemistry show the PCCs staining for chromogranin A and synaptophysin while GNs stain for S-100 protein and neurofilament antibody. Most cases occur in patients between 40 - 60 years old. Most PCC-GNs are functional, with increased MNs. PCC-GN composite tumors may occur sporadically but have also been described as part of syndromes such as MEN2A and NF1. The definitive treatment for PCC-GN is complete surgical excision which is associated with an excellent prognosis. The probability of recurrence is low though distant metastases have rarely been reported. Therefore, lifetime surveillance is critical. Presentation: 6/3/2024