Incidence of malignancy is maximum in -
Incidence of malignancy is maximum in villous adenoma ie upto 30-70% in comparison to Tubular adenoma (1-3%)
Juvenile polyp (hamartomatous polyp) and Hyperplastic polyp are non-neoplastic epithelial tumors of intestine. There is no increased risk of malignancy.
Tubular adenoma & villous adenoma are benign neoplastic lesion, but have propensity to become malignant.
Tubular adenoma  (also k/a Adenomatous polyp)
account for over 90% of colonic adenomas
1-3% incidence of carcinoma
Although the risk of cancer is small, the high frequency of these polyps in the population makes them the most important precancerous colonic lesions.

Villous adenoma


are uncommon, comprising less than 10% of colonic adenomas
have a 30-70% incidence of carcinoma
Villous adenoma
Juvenile polyps
Hyperplastic polyps
Tubular adenoma