SAT-500 A Case Report On Recurrent Pheochromocytoma Due To Hereditary Pheochromocytoma- Paraganglioma Syndrome

Abstract Disclosure: H. Marasandra Ramesh: None. A. Paudel: None. F. Manas: None. J. Pamula: None. Introduction: Pheochromocytoma is a tumor arising from adrenal medullary chromaffin cells. Most patients with pheochromocytoma have disease-causing germline mutations and they present at a younger age. Here we present a case of recurrent metastatic pheochromocytoma in a young patient with a loss of SDHB gene in the tumor. Case Presentation: A 25-year-old female with a history of migraine and hypertension was incidentally found to have a 3.5 cm left adrenal nodule. She had long term symptoms of headaches, nausea, dizziness, vision changes, night sweats and palpitations and history of multiple emergency visits for hypertensive emergencies. Lab work showed elevated plasma free total metanephrines (1825 pg/ml, normal < 205 pg/ml) and 24-hour urine total metanephrines (6334 ug/day, normal 140-785 ug/day). Ga-68 Dotatate scan showed increased radiotracer uptake in left adrenal mass. Hereditary paraganglioma- pheochromocytoma panel (including sequencing and deletion/duplication analysis of MAX, NF1, RET, SDHA,SDHAf2, SDHB, SDHC, SDHD, TMEM127, and VHL genes) was negative. She underwent robotic left adrenalectomy. Pathology was consistent with composite pheochromocytoma (pheochromocytoma and ganglioneuroma), 6.5 cm in size, with focal areas of necrosis, extension into margins and extra-adrenal adipose tissue and lymphovascular invasion. SDHB immunostaining revealed loss of SDHB in the tumor. She presented again 3 years later with recurrence of headaches, vision changes, anxiety, night sweats and palpitations. Lab work again showed elevated plasma free total metanephrines (3307 pg/mL, normal < 205 pg/ml) and 24-hour urine total metanephrines (5109 ug/day, normal 140-785 ug/day). CT findings were consistent with recurrent pheochromocytoma adjacent to pancreatic tail, with new metastatic disease involving multiple para-aortic lymph nodes, the right lobe of the liver and skeletal metastasis involving the sacrum and left sixth rib. NM MIBG scan showed no abnormal accumulation, but Ga-68 Dotatate scan showed increased radiotracer uptake in left adrenal mass. She underwent distal pancreatectomy, hepatic wedge resection, splenectomy, and lymphadenectomy and is currently undergoing chemotherapy. Discussion: Malignant pheochromocytoma is diagnosed when there is evidence of metastases at non-chromaffin sites distant from the primary tumor such as lymph nodes, bones, liver, lung, or brain. Larger tumor size (≥5 cm) and young age at diagnosis are predictors of increased risk of malignancy. Usually, about 10 % of pheochromocytomas are malignant but mutations of SDHB gene lead to metastatic disease in 40% or more of affected patients. There are no specific systemic treatment guidelines for metastatic pheochromocytoma however, debulking surgery, chemotherapy, radionuclide therapy, tyrosine kinase inhibitors and immunotherapy are some of the standards of therapy. Presentation: Saturday, July 12, 2025