Five Cases of Gastrointestinal Stromal Tumor of the Rectum

Gastrointestinal stromal tumor is a relatively new concept. We experienced a GIST case and had experienced four leiomyosarcomas of the rectum by histological findngs. Immunohistochemical re-examination was peformed in all cases, anew, and all four were GIST. A 57-year-old woman complaining of abdominal fullness, constipation, dysuria was referred to the hospital with a diagnosis of pelvic tumor. Various imaging examinations were carried out, and an operation was perfomed under a diagnosis of pelvic tumor. At operation, we found the primary tumor of the rectum and abdominoperineal resection was perfomed. Histologically, the tumor was composed of spindle-shaped cells with an interweaving bundle patters. Immunohistochemically, the tumor was diagnosed as a gastrointestinal stromal tumor (GIST), uncommitted type, malignant. A concept of GIST is spreading, so we need to carry out a further examination of this desease from now.