ODP039 Giant Cystic Pheochromocytoma and GIST in a Patient With NF-1

Abstract

Abstract Introduction Neurofibromatosis-1 (NF-1) is a genetic condition known to be associated with pheochromocytoma. We report a case of giant cystic pheochromocytoma in a patient with NF-1 and hypertensionincidentally found to have gastrointestinal stromal tumor (GIST) at operation. Clinical case: A 60-years old woman presented with a 5-week history of left sided abdominal lump. Her history is significant for NF-1, flank surgery age 5 and hypertension managed by amlodipine. Examination revealed a large nontender left upper quadrant abdominal mass crossing the midline. Computed tomography showed a20. 0×13.1×21.1 cm septate cystic and/or necrotic lesion arising from the left retroperitoneum versus adrenal gland, displacing the kidney anteromedially. Plasma free metanephrine was 3.38 nM (0-0.49) normetanephrine 3.47 nM (0-0.89),urine metanephrine 2605 mcg/day (36-229), urine normetanephrine 1215 mcg/day (95-650). There were no prior images or screens for pheochromocytoma. After preoperative blockade with phenoxybenzamine, open left adrenalectomy was performed. Intraoperative blood pressure fluctuated significantly. Exophytic firm nodules were incidentally noted and removed from the jejunum. Pathology revealed a22.5×21. 0×11.9 cm pheochromocytoma weighing 3058.9 g and five 0.2-0.7 cm gastrointestinal stromal tumors, spindle type. One-month postoperative metanephrine was 0.16 with normetanephrine 0.53 nM. The blood pressure remained normal without antihypertensives. Discussion Giant cystic pheochromocytomas are rare and may be silent. In populations with NF-1 the prevalence of pheochromocytoma is 0.1-7.7% and GIST 1.2% 1–3 . Their co-existence is seen less frequently. Recommendations for pheochromocytoma screening in NF-1 vary, from only hypertensive or symptomatic patients to routinely every 3 years 2–5 . There is no screening test for GIST 1 . Our patient presented at age 60 with the rare combination of clinically giant unilateral cystic pheochromocytoma, with incidental GIST in the setting of NF-1 and hypertension . Conclusion Routine screening for pheochromocytoma in patients with NF-1, especially those with hypertension may lead to earlier diagnosis and treatment.