Gastrointestinal stromal tumor of the rectum resected by laparoscopic surgery: report of a case.

A 53-year-old man visited our hospital with the chief complaint of pain on urination. On digital rectal examination, a rigid immobile tumor mass with a smooth surface was palpated on the anterior wall on the right side of the rectum near the anal canal. Computed tomography (CT) and magnetic resonance imaging (MRI) of the pelvis revealed a heterogeneous tumor mass measuring 6.5 cm in diameter, which occupied the cavity of the lesser pelvis. This rectal tumor was diagnosed to be a gastrointestinal stromal tumor (GIST) based on the results of a transrectal needle biopsy. A laparoscopic abdominoperineal resection of the rectum was performed to remove the mass. The intraoperative findings showed an ambiguous boundary between the tumor and the rectum but clear boundaries between the tumor and the peripheral organs, and the use of a laparoscope allowed for a good separation by providing a good visual field. The bleeding volume was approximately 80 ml and the operative time was 320 min. The macroscopic findings of excised specimens of the mass showed the tumor, measuring 6.5 x 5.5 x 5.0 cm, to be growing extrinsically from the anterior wall on the right side of the rectum. A histological examination of the excised specimens revealed at most 5 mitoses per 50 high-power fields (x 400). The tumor mass was diagnosed to be a GIST of low-grade malignancy based on these findings. The postoperative course was favorable, and there were no postoperative complications. The patient was discharged on the 8th hospital day. Laparoscopic surgery is a minimally invasive surgical procedure for rectal GIST, which is excellent in terms of esthetics. Laparoscopic surgery is therefore considered to be useful for a resection of the rectum, because the magnifying effect allows surgical maneuvers with a favorable visual field within the pelvis.