SAT-019 From Seizure to Diagnosis: Pheochromocytoma in Neurofibromatosis Type 1

Abstract Disclosure: C. Hirner: None. M. Bhalla: None. V. Ghernautan: None. M. Shari: None. D. Lovre: None. Abstract: Neurofibromatosis type 1 (NF1) is an autosomal dominant disorder caused by NF1 tumor suppressor gene mutations with clinical manifestations ranging from neurological and cutaneous findings to tumors including pheochromocytomas (0.1 to 5.7% incidence, 22% are asymptomatic). Classic pheochromocytoma symptoms include tachycardia, hypertension, and hyperglycemia. We present a case of a patient with history of NF1 admitted for seizures and later diagnosed with a pheochromocytoma. Case Presentation: A 32-year-old male with past medical history of NF1 was admitted to the ICU for status epilepticus. Physical exam revealed BP of 203/137 mmHg, HR 150 bpm, and multiple neurofibromas on his back and lower extremities. Months prior to his presentation he had experienced headaches, palpitations and hypertension that remained uncontrolled despite treatment with four anti-hypertensives. In ICU, he received levetiracetam and nifedipine for seizure and blood pressure management. Laboratory results revealed elevated creatinine, creatinine kinase, and lactic acidosis with no evidence of infectious or autoimmune processes. A brain MRI showed postictal edema, and a renal ultrasound identified a large right adrenal mass. An abdominal CT confirmed a 7.3x5.9x7.1cm adrenal mass displacing the right kidney. Hormonal testing revealed suppressed aldosterone levels <1 ng/dl (0.0-30.0 ng/dl), a renin levels of 2.79 ng/ml/hr (0.167-5.380 ng/ml/hr), markedly elevated plasma normetanephrines 8,156 pg/ml (0.0-210.1 pg/ml) and metanephrines 1,300 pg/ml (0.0-88.0 pg/ml), consistent with a diagnosis of pheochromocytoma. He was transitioned to doxazosin 2mg and carvedilol 3.125mg twice daily for BP control and preoperative preparation. Two months later, he underwent robot-assisted right adrenalectomy with surgical pathology confirming pheochromocytoma. One month postoperatively, his BP was normal without medications, and seizures had not recurred. Discussion: Seizures secondary to pheochromocytoma are often misdiagnosed due to the lack of diagnostic guidelines and poorly understood mechanisms underlying pheochromocytoma-induced seizures. Currently there are no established screening protocols for pheochromocytoma in patients with NF1, despite their increased risk of developing pheochromocytoma. Clinicians caring for patients with NF1 should maintain a high index of suspicion for pheochromocytoma in symptomatic NF1 patients, particularly those with headaches, palpitations, or uncontrolled hypertension. Timely recognition and screening are critical to prevent the cardiovascular and neurological complications from undiagnosed pheochromocytoma. Presentation: Saturday, July 12, 2025