SAT-231 A Case of Metastatic Pheochromocytoma Associated with Beckwith-Wiedemann Syndrome

Abstract Introduction: Beckwith-Wiedemann Syndrome (BWS) is an autosomal dominant disorder of chromosome 11p15 that results in increased IGF-2 and CDK1NC. This leads to excessive cell proliferation and tumor formation. The following highlights a case of metastatic pheochromocytoma in a patient with BWS. Clinical Case: A 30-year-old male presented with sudden onset blurry vision without any associated complaints. His past medical history was significant for BWS. His family history was negative for uncontrolled hypertension, sudden death, thyroid cancer or hyperparathyroidism. Physical examination was notable for an elevated systolic blood pressure of 200/160 mm of hg and fundoscopy revealed features of hypertensive emergency. Laboratory investigations revealed an elevated plasma normetanephrine [10445 pg/ml (normal: <148)], metanephrine [93 pg/ml (normal: <57)], total metanephrine [10538 pg/ml (normal: <205)], epinephrine [134 pg/ml (normal:<50)], norepinephrine [23526 pg/ml (normal: 112-658), total catecholamine level [23660 (normal: 123-671pg/ml)] and dopamine [403 pg/ml (normal<30)] levels. His PTH, corrected serum calcium, gastrin, insulin, carcinoembryonic antigen, calcitonin levels and basal metabolic panel were all normal. MRI of the abdomen demonstrated bilateral adrenal nodules with a large mass encasing the celiac axis along with evidence of hepatic lesions. I-123 MIBG scan showed mild radioactive tracer uptake in the adrenal nodules and mass near the celiac axis but not in the hepatic lesions. PET scan confirmed MRI findings and was negative for any evidence of malignancy in the chest, pelvis and skeleton. MRI of the brain was negative for metastasis as well as pituitary abnormalities. Ultrasound-guided liver biopsy was positive for malignant cells that stained positive for chromogranin and synaptophysin confirming the diagnosis of metastatic pheochromocytoma. He was treated with phenoxybenzamine, diltiazem and lisinopril. He underwent cycles of cyclophosphamide, vincristine and dacarbazine. Genetic testing revealed a variant in SDHD gene which was of uncertain significance. Repeat biochemical testing on follow up after a year and a half showed a decreased plasma normetanephrine [487pg/ml] and metanephrine levels [110 pg/ml] in comparison to his levels on presentation. Repeat imaging revealed a decrease in tumor burden including bilateral adrenal nodules, celiac axis mass and hepatic metastases. Conclusion: This is an unusual case of malignant pheochromocytoma in the absence of SDHB mutation in a patient with BWS. Genetic causes in these patients are yet to be determined. However, genes H19 and KCNQ1OT1 have been implicated in addition to IGF-2 and CDK1NC