A Case Of Laterally Spreading Tumor Of The Rectum Treated By Endoscope-Assisted Transanal Tumor Resection

Background: Curability and function should be considered in resection of a rectal lateral spreading tumor (LST).Methods: We performed endoscopic transanal resection for a rectal LST extending to the pectinate line to preserve anal function and avoid a colostomy in 1 case and describe our procedure below. An 80-year-old man with a group 5 adenocarcinoma tub1/2 and no metastasis was considered for transanal resection because of his refusal of a colostomy and for staging and preservation of anal function. A strategy involving endoscopic submucosal dissection for mucosal cutting at the proximal side and for submucosal dissection of the maximum area at the anal side of the tumor was chosen, considering the tumor size. With the patient in a jackknife position, the tumor was marked circumferentially with coagulation dots, after which MucoUp with bosmin was injected into the submucosa at the proximal side. Mucosal and submucosal dissection was performed using DualKnife to remove the largest possible area toward the anal side. Transanal resection was performed under direct vision using an anal retractor, wherein the mucosa was cut circumferentially by extending the existing resection line along with removal of the submucosa.Results: En bloc resection with clear margins was achieved. Postoperatively, retroperitoneal emphysema was observed on a computed tomography scan, which resolved after 1 week of fasting. The patient was discharged 20 days postoperatively. Neither recurrence nor metastasis has been observed 1 year postoperatively.Conclusions: Our procedure enabled successful resection of a rectal LST with negative margins and preservation of anal function.