MON-384 The Dynamic Genetics of Recurrent Paragangliomas: The Importance of Surveillance

BACKGROUND: Paraganglioma (PGL) are tumors that arise from the ganglia of the sympathetic nervous system, and comprise 10% of all sympathetic nervous system tumors. There are at least 16 germline mutations that have been associated with increased risk of PGL. CASE PRESENTATION: A 32 year-old female with a history of PGL status-post resection presented with elevated plasma metanephrines during surveillance follow-up. She was diagnosed with PGL 7 years ago. Plasma free normetanephrine were elevated at 607 pg/ml (ref ≤ 148 pg/ml) and an MRI abdomen demonstrated a 6.6 x 4.5 x 7.8 cm para-aortic retroperitoneal mass. An MIBG scan showed no abnormal activity. She underwent resection of PGL. Postoperative labs showed normal plasma and urine metanephrines. Genetic testing was negative for known related mutations. She reported dizziness and palpitations six years later. Labs revealed elevated free normetanephrine 213 pg/ml and total metanephrine 238 pg/ml (ref ≤ 205 pg/ml). Repeat plasma and urine tests remained elevated, but an MRI abdomen/pelvis and two MIBG scans were unremarkable. The patient remained symptomatic. Six months later, CT abdomen/pelvis showed a retroperitoneal 2.5 x 1.8 x 1.7 cm necrotic mass and an 3.2 x 2.6 x 2.5 cm adnexal cystic lesion concerning for recurrent PGL. Repeat testing confirmed elevated plasma free normetanephrine 511 pg/ml and undetectable free metanephrine. PET/CT abdomen/pelvis demonstrated the retroperitoneal necrotic mass, two lesions anterior to the L3 and L4-L5 vertebral bodies, and a lytic lesion in the right iliac crest. The patient underwent surgical resection of three PGL, all with vascular and capsular invasion. Six months later, plasma and urinary levels were all normal. PET Ga-68 DOTATATE scan demonstrated uptake near the surgical bed and in the aorto-caval groove, suspicious for residual tumors, and several foci of somatostatin receptor positive osseous lesions, suspicious for skeletal metastases. An updated genetic test showed a variant of uncertain significance (VUS) of the SDHA gene. She is currently undergoing treatment with lanreotide. CONCLUSION: This case highlights the importance of continuous surveillance, as well as the swift advancements in genetics associated with paragangliomas and pheochromocytomas. REFERENCES: Fishbein, L.,et al. (2013). Inherited Mutations in Pheochromocytoma and Paraganglioma: Why All Patients Should Be Offered Genetic Testing. Annals of Surgical Oncology, 20(5),1444-1450.