A 22-year-old woman was referred to our hospital for further examination of an incidentally discovered hypervascular pelvic tumor with a maximum diameter of 10 cm. Although Castleman disease was suspected based on the imaging findings and pathologic findings of the needle biopsy, a definitive diagnosis was not made. Preoperative transcatheter arterial embolization was performed to decrease intraoperative bleeding, and tumor resection was performed on the following day. As for posterior approach prior to anterior approach, the patient was placed in a prone position, and the dorsal aspect of tumor was approached through the dissection of gluteal muscles. Then, dilated branches of the internal iliac vein was found on the tumor capsule, which were safely ligated under direct vision with favorable visual field. Then, the patient was placed in a supine position, the tumor was completely resected by anterior approach without transfusion. Histopathological diagnosis was Castleman disease hyaline vascular type. The patient was discharged without complication and has been free from recurrence for 6 months after surgery.