Abstract
We report a case of rectal GIST penetration associated with Fournier's gangrene during imatinib administration. A 59-year-old man reporting anal pain and constipation was found in computed tomography (CT) to have a 12-cm mass in the pelvic cavity diagnosed by percutaneous needle biopsy as a rectal gastrointestinal stromal tumor (GIST). Two months after treatment was started with imatinib of 400 mg/day, the tumor had shrunk to 7 cm, but the man was admitted four months later due to gluteal pain. Digital examination at admission showed no abnormality except for tenderness at the tumor site. CT on day 4 after admission showed the tumor had shrunk to 5 cm but a gas shadow was found surrounding the rectum, suggesting rectal GIST penetration. The next day, the man was found to have scrotal swelling and tenderness of the perineum, followed by redness associated with crepitations in the groin spreading to the abdominal wall, leading to a diagnosis of Fournier's gangrene. We immediately removed necrotic tissue and conducted incision and drainage. The man's subsequent course was good and he was discharged on postoperative day 58. During GIST treatment with imatinib, consideration should be given for possible perforation of the gastrointestinal tract due to imatinib's dramatic antitumor effect.
