Background: Colorectal neoplasms with a type V(I) pit pattern include various lesions, such as adenomas, intramucosal cancers, and submucosal carcinomas.
Methods: We analyzed 96 colorectal neoplasms with a type V(I) pit pattern and identified six different variants: (1) unclear outline of the pit; (2) irregular margins of the pit; (3) narrowing of the pit; (4) ragged array of the pit; (5) high residual density of the pit; (6) abnormal branching of the pit. We examined the relationship between the appearance of each V(I) pit pattern and histology, including the depth of invasion.
Results: In univariate logistic regression analysis the unclear outline, irregular margins, and narrowing of the pit were significantly associated with a submucosal (SM) invasion ≥1000 μm (P < 0.01). In multivariate logistic regression analysis, unclear outline of the pit was shown to be the only significant predictor of highly invasive submucosal cancer (odds ratio = 24.20, P < 0.0001). Regarding tumor morphology, the following were significantly associated with an SM invasion ≥1000 μm: in protruded type, ragged array (P = 0.022), irregular margins of the pit (P = 0.011), and unclear outline of the pit (P < 0.01); in flat type, irregular margins of the pit (P < 0.01) and unclear outline of the pit (P < 0.01); and in the depressed type, narrowing of the pit (P = 0.015) and unclear outline of the pit (P < 0.01).
Conclusions: Subclassification of the type V(I) pit pattern is useful for determining the depth of invasion of colorectal neoplasms.