What type of colon cancer polyp has the highest risk for malignancy?

Villous adenomas are the type of colon cancer polyp with the highest risk for malignancy. These polyps are characterized by their finger-like projections and are more likely to harbor dysplasia and progression to colorectal cancer compared to other types of polyps.

The risk associated with villous adenomas is significant; they have a higher percentage of being malignant compared to tubular adenomas and hyperplastic polyps. If a villous adenoma is greater than 2 cm in size, the likelihood of it containing carcinoma increases substantially. Their propensity for malignant transformation is attributed to their architecture and the degree of dysplasia often observed within these lesions.

In contrast, hyperplastic polyps typically have a low risk of malignancy and are generally considered benign. Tubular adenomas and tubulovillous adenomas also carry some risk, but it is generally lower than that of villous adenomas, especially when tubular adenomas are small. Tubulovillous adenomas present an intermediate risk, but their malignancy potential does not reach the levels associated with villous adenomas. Understanding these distinctions is crucial for determining surveillance protocols and the need for removal in the management of colorectal polyps.