Endoscopic submucosal dissection of a nonpolypoid superficial neoplasm of the terminal ileum.

A 73-year-old man underwent colonoscopy for recurrent diffuse abdominal pain. Previous colonoscopy, routine laboratory tests, and a fecal occult blood test had all shown normal results. At retrograde ileoscopy, a 25-mm laterally spreading tumor, nongranular pseudodepressed type (LST-NG PD; type 0-IIa-IIc according to the Paris classification), was diagnosed 5cm proximal to the ileocecal valve (●" Fig.1). The lesion was characterized as noninvasive by chromoendoscopy and narrow-band imaging using colorectal classifications: it was not villous, the pit pattern was small tubular (type IIIs by Kudo), and the capillary pattern showed thin no-uniform vessels surrounding the crypts (type 3A by Sano) (●" Fig.2). Endoscopic submucosal dissection (ESD) was performed using a pediatric colonoscope (PCF-Q180AI; Olympus, Japan) and a hood with a small-caliber tip (ST-hood; Fujifilm; Japan) under CO2 insufflation. The procedure started with the incision of the ileal mucosa at the oral side and then moved progressively from the anal to the oral side using a non-insulated knife (Dual knife; Olympus). Diffuse fibrosis (●" Fig.3a) and a 2-mm translucent mucus-like nodule (●" Fig.3b,c) were encountered in the submucosa beneath the lesion during dissection. The ESD was completed en bloc within 100 minutes (●" Fig.4; ●" Video 1). The resection site was closed using four clips (Resolution clip; Boston Scientific, USA), and no adverse events occurred.