Curative en bloc resection of a laterally spreading mixed-nodular papillary tumor with endoscopic submucosal dissection: a case report.

A 56-year-old man was referred to our hospital with epigastric pain for 3 months. A white light image revealed a laterally spreading mixed-nodular tumor at the duodenal major papilla ([Fig. 1]), diagnosed as a tubular adenoma by biopsy. Narrow-band imaging with magnifying endoscopy demonstrated distinct demarcation, irregular micro-vessel plus surface pattern, and positive white opaque substance (WOS). After signed informed consent, we performed endoscopic submucosal dissection (ESD) using dental floss traction with a supine position ([Video 1]) and captured a resection specimen of 30 × 35 mm ([Fig. 2]).