Abstract
A 61-year-old man see for complaining of anal bleeding and pain, and was found in Colonoscopy to have a giant submucosal tumor with central ulceration in the rectum. Computed tomography and magic resonance imaging showed a 12cm heterogeneous mass in the pelvic space invading the prostate. FDG-PET showed abnormal tracer accumulation in the tumor, which was diagnosed as gastrointestinal stromal tumor (GIST) with prostate invasion and resected radically using total perineal exenteration. The resected specimen showed hemorrhagic necrosis of a massive tumor. The mitotic count was 13 per 50 in the high-power field. Immunohistochemical staining detected c-kit and CD34 but was negative for desmin, α-SMA, S-100 protein, and NSE. The tumor was defined as high-risk in risk assessment. We report a case of giant GIST of the rectum resected successfully using total perineal exenteration, following which the patient has remained disease-free for 4 years. Because the risk of the recurrence depends on the operation curability, adequate resection margin is needed for surgical approach for GIST.
