Colonic adenomas: stereology and growth mechanisms.

Stereologic methods were used to determine the amount of growth of colonic adenomatous polyps. Epithelial surfaces were increased from 12 to 226 times compared with the normal mucosa of origin, including the epithelium of the crypts. The number of cells was increased from 12 to 370 times. The supposed villi of the polyps are in reality branched folia, and the crypts between them are slit-like, permitting flow of ingesta through them. The increase in the number of cells is not primarily dependent on mitotic activity but more on amitotic nuclear fragmentation.