For most, a transanal excision of an upper rectal lesion is difficult and may not be feasible. Upper rectal lesions may necessitate a formal trans-abdominal bowel resection, which carries an increased risk for postoperative morbidities. Transanal Endoscopic Microsurgery (TEM) is another option for rectal lesions, but not for the upper rectum, which is covered by the visceral peritoneum. Therefore, a combined laparoscopic rectal mobilization along with a transanal excision of an upper rectal mass is the most appropriate method of excising a benign lesion.

This is the case of a 56-year-old woman, who 2 years prior on screening colonoscopy, was discovered to have a submucosal mass at 15cm on the left lateral wall of the upper rectum. Pathology was consistent with neuroma. She underwent a repeat colonoscopy, 2 years later, which showed that the mass had increased in size. The differential diagnosis based on the biopsy included neurofibromatosis or a Gastro-Intestinal Stromal Tumor (GIST). At this time, she was referred for a colorectal consultation. On exam, the lesion was not palpable. On rectal ultrasound the lesion measured 1x3cm with extension into muscularis propria.

Four cannulas were placed into the abdomen. Then using laparoscopic techniques, the rectum and sigmoid colon were mobilized. The rectum was then intussuscepted into the operating rectoscope. Full thickness transanal excision was then performed transanally. Finally, a leak test was performed to ensure that there were no rectal defects.

Postoperatively, the patient did well tolerating general diet on post-operative day 1 and discharged home on post-operative day 2. The pathology revealed intestinal ganglioneuromatosis with positive S-100 stain and a negative c-kit stain consistent with neurofibroma. This condition is associated with Cowden's disease and MEN IIb.

Therefore, laparoscopic rectal mobilization extends the realm of transanal excision of benign upper rectal lesions. This approach obviates the need for a formal bowel resection with the resultant increased risks.