FRI264 A Case Of Composite Pheochromocytoma And Ganglioneuroma

Disclosure: D. He: None. J. Pullman: None. S. Stefan: None. B.Y. Wong: None. Background: Pheochromocytomas are catecholamine-secreting tumors that arise from chromaffin cells in the adrenal medulla or paraganglia. Representing 1-9% of pheochromocytomas, composite pheochromocytomas are rare tumors composed of pheochromocytoma and neural tumor components such as neuroblastoma, ganglioneuroblastoma, ganglioneuroma or peripheral nerve sheath tumor(1). We present a case of composite pheochromocytoma and ganglioneuroma. Clinical Case: A 69-year-old man presented with recurrent dyspnea at rest, diaphoresis and tachycardia. He was diagnosed with heart failure with reduced ejection fraction and management included metoprolol 50 mg daily. On work-up, he was incidentally found to have a 1.2 cm left upper lobe lung lesion and an indeterminate 2.4 cm right adrenal mass on CTA chest. PET/CT scan showed an intensely avid left upper lobe lung nodule and a right adrenal mass with mild FDG uptake (SUV max 3.8). MRI abdomen demonstrated a 3.1 cm right adrenal lesion with a mildly thickened enhancing rim and a central enhancing nodular component suspicious for pheochromocytoma, metastases, schwannoma or ganglioneuroma. He then had a stroke with mild residual right-sided weakness. Oncological work-up of his lung and adrenal lesions eventually directed tissue sampling to biopsy of the adrenal lesion and pathology was consistent with pheochromocytoma. Subsequent biochemical evaluation revealed elevated plasma metanephrines of 194 pg/mL (<= 57 pg/mL), plasma normetanephrines of 474 pg/mL (<= 148 pg/mL), 24-hour urine metanephrines of 389 mcg (90-315 mcg) and 24-hour urine normetanephrines of 428 mcg (122-676 mcg). Pre-operatively, he was placed on phenoxybenazmine 10 mg twice daily and metoprolol 62.5 mg every 8 hours. The patient then underwent right adrenalectomy. The tumor nodule was adherent to and dissected off the inferior vena cava. Pathology showed composite pheochromocytoma with a small component of ganglioneuroma. Conclusion: This rare case of a composite pheochromocytoma with ganglioneuroma was diagnosed through histopathology as composite pheochromocytomas are clinically and radiographically indistinguishable from pheochromocytomas(1). Management of composite pheochromocytomas with ganglioneuroma is similar to the management of pheochromocytomas, and surgical resection remains the first line treatment. Combined alpha and beta-adrenergic blockade is recommended to prevent intraoperative hypertensive crisis. However, more studies are needed to further understand these rare composite pheochromocytomas. References: 1.Shida Y, Igawa T, Abe K, Hakariya T, Takehara K, Onita T, Sakai H. Composite pheochromocytoma of the adrenal gland: a case series. BMC Res Notes. 2015 Jun 24;8:257. doi: 10.1186/s13104-015-1233-6. PMID: 26104921; PMCID: PMC4477526. Presentation: Friday, June 16, 2023