Gastrointestinal stromal tumor of the rectum: report of three cases.

Gastrointestinal stromal tumors (GISTs) account for about 0.2% of all malignancy of gastrointestinal tumors and rarely arise in the rectum. We experienced three patients with large GISTs in the rectum. Case 1 (66-year-old man) underwent abdominoperineal resection (APR) for intrapelvic mass. The tumor was 90 mm and diagnosed to be a Kit-positive GIST. Case 2 (81-year-old woman) underwent right hemicolectomy for concurrent ascending colon cancer by a local physician. In our Hospital, APR was performed for intrapelvic mass. The tumor was 90 mm and diagnosed to be a Kit-positive GIST. Ten months after surgery, multiple liver tumors developed. She received oral imatinib for metastases. Case 3 (83-year-old woman) was yielded a diagnosis of Kit-positive GIST by a percutaneous biopsy. Imatinib was given preoperatively. However, adverse reactions occurred and the drug was withdrawn. APR was performed. The tumor was 70 mm. At present, Case 1 and 3 patients are alive without recurrence.