A 46-year-old man was found to be positive for occult blood at a medical checkup and was revealed to have a 14-cm tumor on the right side of abdominal aorta by a subsequent abdominal CT scan. The endocrinology laboratory data showed elevations in the levels of serum noradrenaline, and ectopic pheochromocytoma was suspected.
The tumor was compressing the inferior vena cava and portal vein, the superior mesenteric artery and the pancreas. Since it would be difficult to cure by operation, neoadjuvant therapy was started using radioisotope therapy by I-131 metaiodobenzylguanidine (131I-MIBG) and chemotherapy (CVD therapy ; cyclophosphamide, vincristine, dacarbazine). He was treated with three courses of radioisotope therapy and 16 courses of chemotherapy, which significantly reduced the tumor size. This made radical resection possible ; we were able to avoid the merger excision of great vessels and other organs.
On pathological and immunopathological findings, the tumor was diagnosed as ectopic pheochromocytoma. Regarding the safety and curability of the treatment, neoadjuvant therapy may be useful in treating very large tumors that show invasion of other organs.