SUN-LB35 Using Chromogranin A to Unmask the Great Masquerader: A Case Reportof a Minimally Symptomatic Pheochromocytoma

/Background: Pheochromocytomas are rare neoplasms, occurring in less than 0.2% of the population. The classic triad of symptoms includes hypertension, headaches and sweating. An increasing number of patients with pheochromocytomas that are diagnosed at a pre-symptomatic stage.Clinical Case A 69 yo male being worked up for hematuria and possible bladder cancer was referred to endocrinology due to a 3 cm x 3 cm right adrenal “incidentaloma.” The mass was noted to be heterogeneously enhancing on CT adrenal protocol, suggesting pheochromocytoma, adrenal carcinoma or metastasis. He endorsed no clinical symptoms of hormone excess and blood pressure was controlled HCTZ. He was found to have elevated serum metanephrines (184 pg/mL, nl <57) and noremetanephrine (608 pg/dL, nl <148) and total metanephrines (792 pg/dL, nl <205). Other hormonal determinations were normal including cortisol (9AM, 8.97 ug/dL, nl 3-22), DHEAS 66 mcg/dL (25-240), estradiol 23 pg/mL (<39), 17 OHD 60 ng/dL, ACTH 37 (6-50), free testosterone 43.6, total testosterone 396, androstenedione 63 (20-220). Further testing revealed 24 hour urine metanephrine and catecholeamines; urinary metanehrine 2025, noremetanephrine 1729, total 2442 and epinephrine 48, norepinephrine 336 and dopamine 112 which were 2-3 times the upper limit of normal. Because the patient consumed significant amount of caffeine (10 cups of coffee and cola daily), these studies were repeated after caffeine washout. Repeat serum testing revealed metanephrine at the upper limit of normal (metanephrine 47, noremetanphrine 146, respectively). Chromogranin A levels were elevated before (626 units) and after PPI discontinuation, (539 units, nl 25-140). Given the biochemical results and size of mass, he was referred him surgical resection. He was treated pre-operatively with doxazosin and underwent an uncomplicated right adrenalectomy via posterior right retroperitoneoscopic. Pathology was consistent with pheochromocytoma without capsular invasion. Immunohistochemical stains were characteristic of pheochromocytoma, positive for synaptophysin, chromogranin, and S100 but negative for Cytokeratin AE1/AE3 and calretinin. Conclusion: We present the case of a patient with a clinically asymptomatic pheochromocytoma. The diagnosis was supported by elevations in chromogranin and catecholamine metabolites, although the latter results were mixed and clouded by potential confounding factors such as heavy caffeine intake. The case demonstrates that with early detection, screening should include patients with no symptoms and otherwise low risk of disease. Decisions on surgical resection should be based on clinical suspicion, symptoms, imaging, tumor size and biochemical findings given the aggressive nature of these tumors and their malignant potential.