Endoscopic submucosal dissection for giant colorectal laterally spreading tumor 33 cm in diameter.

A 77-year-old male presented with recurrent diarrhea for more than 2 years, aggravated and a 1-month history of a rectal mass. High-definition white light colonoscopy showed an approximately circumferential elevated lesion from about 12 cm from the anus to the dentate line, with surface nodules of different sizes, some surfaces slightly congested, and internal hemorrhoids. The patient was diagnosed with a giant laterally spreading tumor-granular nodular mixed type (LST-G-M) of the rectum with the possibility of local malignant transformation and treated with single-tunnel assisted endoscopic submucosal dissection (ESD) at the patient's request. Histopathology of the specimen showed villous tubular adenoma with local carcinogenesis, 33*12cm in size, negative margins, no lymphovascular invasion. No bleeding or perforation was observed during or after procedure, and no stenosis was scrutinized at 2 months later.