Fig. 11.

Method for measuring depth of SM invasion. a When it is possible to identify or estimate the location of the muscularis mucosae, depth of SM invasion is measured from the lower border of the muscularis mucosae. b, c When it is not possible to identify or estimate the location of the muscularis mucosae, depth of SM invasion is measured from the surface layer of the muscularis mucosae. (b) Sessile lesion; (c) pedunculated lesion. d For pedunculated lesions with a tangled muscularis mucosae, depth of SM invasion is measured as the distance between the point of deepest invasion and the reference line, which is defined as the boundary between the tumor head and the stalk. e Invasion by pedunculated lesions that is limited to within the head is defined as “head invasion”