All the following polyps are premalignant except

Hamartomatous polyps (juvenile polyp is also a hamartomatous polyp) by definition do not have malignant potential. They are characterized by overgrowth of normal components of colon, such as epithelium and connective tissue. These hamartomatous polyps are seen in following syndromes - Familial juvenile polyposis, Cronkhite - Canada and Peutz-Jeghers syndromes. Unlike solitary juvenile (hamartomatous) polyps, polyps associated with Familial juvenile polyposis and Peutz Jeghers syndrome may degenerate into adenomas and eventually into carcinomas. There is increased risk of gastrointestinal as well as extragastrointestinal malignancies in the syndromes. -Manigots me chapter 23