巨大直腸gastrointestinal stromal tumor（GIST）の1切除例

A 75-year old woman, complaining of prolapse of the uterus, was detected a giant tumor in therectum by abdominal CT scan. Enhanced CT revealed a heterogeneous mass in the pelvic cavitymeasuring 8 cm. MRI demonstrated a mass in the rectovaginal seputum, showing heterogeneoushigh intensity on T1 and T2 weighed image. Abdominoperineal excision of the rectum was performed.Macroscopically, the resected specimen showed a solid tumor with central hemorrhagicnecrosis, 10×5 cm in size. Histological examination showed fascicular proliferated spindle-shapedcells invaded to subserosa. Immunohistochemical studies showed a GIST of the rectum withpositive staining for c-kit and CD34, and negative staining for α-SMA, S-100 protein. No evidenceof recurrence has been found in the 2 years since. We report a case of giant GIST of the rectum.Because the risk of the recurrence depends on operation curability adequate resection margin isneeded for surgical approach for GIST.