MON-381 A Missed Case of Pheochromocytoma in NF1 Patient Presenting as Pre-Eclampsia

Background Neurofibromatosis type 1 (NF1) is a rare autosomal dominant disorder manifesting with skin lesions and neurofibromas. An increased risk of pheochromocytoma and paraganglioma (PPGL) is known with an estimated incidence of 0.1-5.7%(1). While some data suggested screening for PPGL in NF1 patients(2), this has not been emphasized on guidelines or in practice. Herein, we report a case of pheochromocytoma diagnosed in a patient with NF1 shortly after a pre-eclampsia complicated pregnancy. Clinical case A 25 year old woman with NF1 had poorly controlled hypertension, palpitations, and anxiety during her first pregnancy attributed to pre-eclampsia. She presented to the ED shortly post-partum with episodes of palpitations, tachycardia, hypotension, and GI symptoms. A CT scan of the abdomen and pelvis identified a heterogeneous, well-defined, 35 HU, left adrenal mass measuring 4.9 x 4.5 x 4.2 cm. Biochemical data noted elevated plasma metanephrines (2.42 nmol/L, n<0.49 nmol/L) and normetanephrines (15.85 nmol/L, n<0.89 nmol/L). 24 hour urinary metanephrines (1292 ug/g, n<300 ug/g), normetanephrines (4769 ug/g, n<44 ug/g), norepinephrine (731 ug/g, n<45 ug/g), and epinephrine (77 ug/g, n<20 ug/g) were elevated. She was started on an alpha-adrenergic receptor blockade (in addition to her beta and calcium channel blockers) 3 weeks, and metyrosine 3 days before she underwent a left laparoscopic adrenalectomy. A few weeks after surgery, she was able to stop all blood pressure and anxiety medications. She asked about PPGL screening in her daughter as she carries the NF1 mutation. Clinical Lesson PPGL occur in a small but meaningful number of patients with NF1, and can be associated with significant morbidity and mortality if not detected. The current guidelines suggests screening for PPGL need not be considered unless indicated by signs or symptoms. This case emphasize the significance of biochemical screening for PPGL in NF1 patients prior to elective surgical procedures and conception to avoid fatal complications. References 1. Walther, McClellan M., et al. "von Recklinghausen′ s disease and pheochromocytomas." The Journal of urology 162.5 (1999): 1582-1586. 2. Gruber, Lucinda M., et al. "Pheochromocytoma and paraganglioma in patients with neurofibromatosis type 1." Clinical endocrinology 86.1 (2017): 141-149.