GASTROINTESTINAL STROMAL TUMOR OF THE RECTUM TREATED WITH NEOADJUVANT IMATINIB FOLLOWED BY TRANSANAL ENDOSCOPIC MICROSURGERY

The gastrointestinal stromal tumor (GIST) is a rare type of tumor that expresses CD117 oncogene that can be detected by immunohistochemistry2. The most common sites of GISTs are stomach (70%), and small intestine (20%), while rectum is comprised in only 3% of the cases5. Although a rare condition, the GIST located in the distal rectum may require an abdominoperineal resection. There is no data to support the use of Imatinib (Gleevec from Novartis, Basel, Switzerland), a selective inhibitor of tyrosine quinase, as neoadjuvant therapy. However, the last session consensus for the treatment of GIST, suggests that this form of therapy can be used in some cases where anal sphincter is involved7. The objective of this report is to describe a case of GIST distal rectum in the rectovaginal septum with partial invasion of the anal sphincter, which was successfully treated by neoadjuvant therapy with imatinib followed by the technique of transanal endoscopic microsurgery (TEM). The results are compared with experience in the literature.