SAT-508 Hidden in Plain Sight: Incidental Discovery of Bilateral Pheochromocytoma in a Patient with Lifelong Hypertension

Abstract Disclosure: U. Irfan: None. S. Shahid: None. R. Thomas: None. A. Zara: None. S.R. Panja: None. Introduction: Pheochromocytomas are rare neuroendocrine tumors that arise from chromaffin cells of the adrenal medulla and typically present with the classic triad of headaches, sweating, and hypertension. Bilateral pheochromocytomas are particularly uncommon, accounting for only 8% of all cases, and are usually strongly associated with hereditary syndromes. While nearly half the cases are symptomatic due to excessive catecholamine secretion, some patients may remain asymptomatic despite significant tumor burden. Case Presentation: A 58-year-old male with hypertrophic cardiomyopathy, early-onset hypertension, and type 2 diabetes was incidentally found to have bilateral adrenal masses on cardiac MRI. Subsequent imaging revealed bilateral heterogeneous adrenal masses measuring 5.7 cm on the left and 4.1 cm on the right. Laboratory evaluation demonstrated markedly elevated plasma and urinary metanephrines (plasma free metanephrine 1146 pg/ml, normetanephrine 2264 pg/ml). Despite significant catecholamine excess, the patient never experienced classic symptoms of pheochromocytoma. Family history was notable for metastatic pheochromocytoma in his sister. Genetic testing identified a RET gene mutation [c.1902C>G (p.Cys634Trp)], confirming Multiple Endocrine Neoplasia type 2A (MEN2A). The patient underwent successful bilateral posterior retroperitoneoscopic adrenalectomy and was started on steroid replacement therapy. Conclusion: This case highlights the importance of thorough evaluation of incidental adrenal masses, even in asymptomatic patients. Significant catecholamine excess in pheochromocytomas may atypically present as sustained hypertension presenting at an early age or other cardiovascular complications such as cardiomyopathy despite absence of paroxysmal symptoms. Early recognition and appropriate management of these tumors is crucial to prevent potentially catastrophic complications. The strong association between bilateral pheochromocytomas and hereditary syndromes, necessitates genetic testing. Presentation: Saturday, July 12, 2025