[Two Cases of Intrapelvic Schwannoma]

A 67-year-old man (case 1) and 65-year-old man (case 2) were incidentally found to have a tumor in the retrovesical region. Computed tomography and magnetic resonance imaging demonstrated a solid tumor at the right side of the rectum. 2-Deoxy-2-[fluorine-18] fluoro-D-glucose (FDG) -positron emission tomography revealed uptake at the tumor. Both patients were cured by tumor resection. Histological diagnosis was benign schwannoma. In case 2, it was difficult to diagnose the tumor as schwannoma by imaging studies. We made a histological diagnosis by transrectal needle biopsy of the tumor before the operation. Schwannoma is located mostly in the limbs and the head and neck, but rarely in the intrapelvic cavity. We expect that the transrectal needle biopsy is valuable for diagnosing the retrovesical tumor.