Determining depth of invasion by VN pit pattern analysis in submucosal colorectal carcinoma

The aim of this study was to clarify whether the pit pattern on the surface of submucosal colorectal carcinoma is associated with level of invasion. We examined the VN pit-pattern (loss or decrease of pits with an amorphous structure) area of the tumor surface in 18 submucosal carcinomas that were classified based on gross appearance as either superficial or broad based sessile polypoid tumors. Pit pattern determination was made according to a previously reported system. We then evaluated the relation between the VN pit-pattern area, the maximum diameter of the VN pit-pattern area obtained stereoscopically after resection, and the depth of submucosal invasion. There was a significant correlation between the area and maximum diameter of the VN pit-pattern segment. There was also significant correlation between the maximum diameter of the VN pit-pattern area and the depth of submucosal invasion. Lesions with a maximum VN pit-pattern area diameter <5 mm showed a depth of submucosal invasion of <1500 microm. In submucosal colorectal carcinoma of the superficial or broad based sessile polypoid type in gross appearance, measurement of the maximum VN pit-pattern area diameter allows estimation of the depth of submucosal invasion.