Some adenomatous polyps are attached to the wall of the colon or
rectum by a stalk (pedunculated 
). Some have a broad base with little or
no stalk (sessile ).
Polyps are also classified based on the type of tissue they
contain:1
-
Tubular (T) adenomas are
the most common type. About 80% to 86% of polyps contain this type of tissue.
Tubular adenomas are the least likely type of polyp to develop into colon
cancer.
-
Villous (V) adenomas are the least
common type. About 3% to 16% of polyps contain this type of tissue. Villous
adenomas are the most likely type of polyp to become
cancerous.
-
Tubulovillous (TV) adenomas are a
combination of tubular and villous tissue types. About 8% to 16% of polyps
contain this type of tissue and are more likely than tubular (T) but less
likely than villous (V) adenomas to develop into cancer.
Cancer risk of different polyps
1
| | Smaller than 1 cm | 1 cm to 2 cm | Larger than 2 cm |
|---|
| Tubular (T) |
1% chance of containing cancer
|
10% chance of containing cancer
|
35% chance of containing cancer
|
|---|
| Tubulovillous (TV) |
4% chance of containing cancer
|
7% chance of containing cancer
|
46% chance of containing cancer
|
|---|
| Villous (V) |
10% chance of containing cancer
|
10% chance of containing cancer
|
53% chance of containing cancer
|
|---|
Citations
Itzkowitz SH, Rochester J (2006). Colonic polyps and
polyposis syndromes. In M Feldman et al., eds., Sleisenger and Fordtran's Gastrointestinal and Liver Disease, 8th ed., vol. 2, pp.
2713-2757. Philadelphia: Saunders/Elsevier.
Itzkowitz SH, Rochester J (2006). Colonic polyps and
polyposis syndromes. In M Feldman et al., eds., Sleisenger and Fordtran's Gastrointestinal and Liver Disease, 8th ed., vol. 2, pp.
2713-2757. Philadelphia: Saunders/Elsevier.
