Morphologic progression of pedunculated submucosal invasive colon cancer.

To clarify the morphologic progression of pedunculated submucosal invasive colon cancers, we assessed the morphologic changes in 50 such cancers according to the volume of cancer in the submucosal layer. The shape of the head of the polyp was defined at the widest slice as round, concave, or semicircular with a horizontal head (SHH). As the cancer invaded the submucosa, the peduncle of the submucosal invasive cancer thickened and the structure of the head progressively collapsed, causing its shape to change from round to concave to SHH. The proliferating cell nuclear antigen (PCNA) expression (labeling index, LI), determined at the deepest point of submucosal invasion, showed a significant correlation with the morphologic progression among round, concave, and SHH cancers as 36.4 +/- 12.1%, 42.3 +/- 11.8%, and 62.1 +/- 12.5%, respectively (P < 0.05). Results indicate that the PCNA-LI may be a useful marker for the morphologic progression of pedunculated submucosal invasive colon cancers.