villous adenoma):
Tubular Adenoma: 5% risk of cancer
Tubulovillous adenoma: 20% risk of cancer
Villous adenoma: 40% risk of cancer
Size of polyp:
<1 cm =<1% risk of cancer
1–2 cm=10% risk of cancer
>2 cm=50% risk of cancerNormally an adenoma that is greater than 0.5 cm is treated. Gallery
NICE classification
In colonoscopy, colorectal polyps can be classified by NICE (Narrow-band imaging International Colorectal Endoscopic):

Treatment
Polyps can be removed during a colonoscopy or sigmoidoscopy using a wire loop that cuts the stalk of the polyp and cauterises it to prevent bleeding. Many "defiant" polyps—large, flat, and otherwise laterally spreading adenomas—may be removed endoscopically by a technique called endoscopic mucosal resection (EMR), which involves injection of fluid underneath the lesion to lift it and thus facilitate endoscopic resection. Saline water may be used to generate lift, though some injectable solutions such as SIC 8000 may be more effective. Minimally invasive surgery is indicated for polyps that are too large or in unfavorable locations, such as the appendix, that cannot be removed endoscopically. These techniques may be employed as an alternative to the more invasive colectomy. Follow-up
By United States guidelines, the following follow-up is recommended:

References
External links
Villous Adenoma – Medscape
In the early 1990s Dutch scientists Arnold Reuser and Ans van der Ploeg were able to show that using alpha-glucosidase containing phosphorylated mannose residues purified from bovine testes increased the enzymes activity in normal mouse muscles.Later in 1998, Dr. Yuan-Tsong Chen and colleagues at Duke University, using the enzyme produced in Chinese Hamster Ovary cells  demonstrated for the first time that the enzyme can clear the glycogen and improved the muscle function in Pompe disease quail. The results of the work at Duke were impressive with one treated bird recovering to the point of being able to fly again.This was followed by production of clinical grade alpha-glucosidase in Chinese hamster ovary (CHO) cells and in the milk of transgenic rabbits. This work eventually culminated in the start of clinical trials with the first clinical trial including 4 babies receiving enzyme from rabbit milk at Erasmus MC Sophia Childrens Hospital and 3 babies receiving enzyme grown in CHO cells at Duke University in 1999. The currently approved Myozyme is manufactured by Genzyme Corp. in Cambridge, Massachusetts. Its development was a complex process. Genzyme first partnered with Pharming Group NV who had managed to produce acid alpha-glucosidase from the milk of transgenic rabbits. They also partnered with a second group based at Duke University using Chinese hamster ovary cells. In 2001, Genzyme acquired Novazyme which was also working on this enzyme. Genzyme also had its own product (Myozyme) grown in CHO cells under development.