Tubular Adenoma

Excerpt

Colonic adenomas are raised protrusions of colonic mucosa, i.e., polyps formed by glandular tissue. Although a tumor of benign nature, these adenomas are usually considered precancerous and can transform into malignant structures, in contrast to hyperplastic polyps, with no malignant potential.

Depending on the pattern of growth, these tumors can be villous, tubular, or tubulovillous. A polyp with more than 75% villous features, i.e., long finger-like or leaf-like projections on the surface, is called a villous adenoma, while tubular adenomas are mainly comprised of tubular glands and have less than 25% villous features. A tubulovillous adenoma is referred to as an adenoma with both features. Tubular adenomas are the most common type of colonic adenomas, comprising a prevalence of more than 80%.

Although villous adenomas are more likely to become cancerous, this reflects the fact that they generally have the largest surface area due to their villous projections. If adjusted for surface area, all types of adenomas have the same potential to become cancerous.