Background and study aims A 54-year-old man was diagnosed with a rectal tumor extending through the submucosal
layer. The patient refused surgery and therefore endoscopic submucosal dissection
(ESD) was pursued. The lesion exhibited the muscle retraction sign. After dissecting circumferentially around the fibrotic area by double tunneling method,
a myotomy was performed through the internal circular muscle layer, creating a plane
of dissection between the internal circular muscle layer and the external longitudinal
muscle layer, and a myectomy was completed.
The pathologic specimen verified T1b grade 1 sprouting adenocarcinoma with 4350 µm
invasion into the submucosa with negative resection margins.
