Colon Polyps : Architectural Patterns
Adenomatous polyps are subdivided into tubular, tubulovillous, and villous categories based on the glandular architecture.
Tubular adenomas have at least 75% tubular component consisting of round or oval glandular (tubular) profiles. Tubular adenomas are generally small and show low-grade dysplasia. They comprise 80%-85% of all colonic adenomas.
Villous adenomas show slender villous processes on the surface in 75% or more of the tumor. Pure villous adenomas are quite uncommon and comprise between 3% and 15% of all colonic adenomas. The larger the adenoma, the greater the frequency of villous component. Villous adenomas are more likely to show high-grade dysplasia.
Tubulo-villous adenomas show a mixture of the two patterns. They make up 8% to 16% of all colonic adenomas.