SAT-229 Bilateral Pheochromocytoma as Incidental Finding in a Patient with Neurofibromatosis Type 1

Background. In contrast to other genetic syndromes associated with Pheochromocytoma and Paraganglioma (PPGL) in which yearly biochemical screening is recommended, in neurofibromatosis due to the low penetrance of these tumors, screening is only recommended when there is clinical suspicion(1). Given that signs and symptoms of catecholamine excess are vague and non-specific, clinicians should keep a low threshold for biochemical testing in these patients. Clinical Case. 70 year old female with Neurofibromatosis type 1 (NF-1) diagnosed at age 24, hypertension and atrial fibrillation, was referred to our institution after being found incidentally with bilateral adrenal nodules. She had a 2 year history of poorly controlled, labile hypertension. Treatment at the time of presentation included doxazosin, metoprolol, valsartan and hydralazine. She denied other symptoms of catecholamine excess. Further workup revealed elevated 24 hour urine normetanephrine at 2,530 mcg (ULN 500 mcg) and metanephrine at 1,325 mcg (ULN 290 mcg). Serum metanephrines were also elevated with free metanephrine of 1.6 nmol/L (ULN 0.5 nmol/L) and free normetanephrine of 4.1 nmol/L (ULN 0.9 nmol/L). Her biochemical metanephrine profile was consistent with pheochromocytomas in NF-1. MIBG uptake confirmed the presence of bilateral pheochromocytomas. She underwent a complete right adrenalectomy and a left cortical sparing adrenalectomy. Her adrenocortical function remains adequate. Post operatively while her blood pressures were no longer labile, she continued to require anti-hypertensive therapy. Conclusion. Patients who are at risk of developing pheochromocytomas and paragangliomas due to genetic syndromes or known germline mutations need ongoing clinical follow and biochemical testing for timely case detection. While in NF-1 pheochromocytomas are usually unilateral and present during early adulthood, they can present with bilateral disease and later in life(2). During surgical treatment, even with unilateral disease, adrenocortical function should be preserved when possible(3). Hypertension may persist despite complete surgical resection. References 1. Lenders JWM, Duh Q-Y, Eisenhofer G, et al. Pheochromocytoma and Paraganglioma: An Endocrine Society Clinical Practice Guideline. The Journal of Clinical Endocrinology & Metabolism. 2014;99(6):1915-1942. 2. Moramarco J, El Ghorayeb N, Dumas N, et al. Pheochromocytomas are diagnosed incidentally and at older age in neurofibromatosis type 1. Clinical endocrinology. 2017;86(3):332-339. 3. Neumann HPH, Tsoy U, Bancos I, et al. Comparison of Pheochromocytoma-Specific Morbidity and Mortality Among Adults With Bilateral Pheochromocytomas Undergoing Total Adrenalectomy vs Cortical-Sparing Adrenalectomy. JAMA network open. 2019;2(8):e198898.