A 67-year-old man was referred to our center for resection of a non-granular lateral spreading tumour (Paris classification T0-IIa) with 15 mm of the transverse colon, with multiple diverticula surrounding the lesion (the closest one within 2-3 mm from the lesion). Narrow-band imaging was suggestive of an adenoma without invasive features (JNET2A). Due to the morphology and proximity of the diverticula, it was proposed for endoscopic submucosal dissection. The procedure took place in the endoscopy unit with anesthetic support. Orise solution (Boston Scientific) was injected to obtain a good submucosal cushion followed by ESD technique with Flush Knife (1,5 mm), with particular care during incision and dissection near the diverticulum. The lesion was successfully resected en bloc without complications and the procedure lasted 20 minutes. Pathologic findings revealed an adenoma with high-grade dysplasia with a negative margin (R0). The post-ESD course was uncomplicated.