A Case of Rectal GIST Treated by Robotic Surgery

Abstract

A 68-year-old man was pointed out to have a tumor of about 5 cm in diameter in the lower rectum (3 cm above the anal verge) by a CT scan for an external injury. Although a biopsy was not effective for pathological diagnosis, colonoscopy, FDG-PET, and MRI scan strongly indicated that this rectal submucosal tumor might be a rectal gastro-intestinal stromal tumor (GIST) without distant metastasis. The tumor had protruded out of the rectal wall, and appeared to widely come into contact with the levator ani muscle. Robot-assisted rectal intersphincteric resection was performed for this case. Using the multi-joint function specific for the robotic surgery, an anus-preserving surgery was safely performed without breakage of the tumor's capsule. There was no postoperative complication after the surgery. Since the rectal tumor was pathologically proved to be a c-kit-positive GIST by immunohistochemistry, adjuvant therapy with imatinib was started according to the Japanese GIST Guideline. We conclude that the robotic surgery is effective for lower rectal GISTs, especially for the difficult cases (e.g., large tumor, narrow pelvis, male, and obese). It enables us to preserve the anal function and to perform safe and radical resection.