Image Description
Villous adenomas show slender finger-like processes on the surface in 75% or more of the tumor. This accounts for granular appearance often seen in gross specimens. Pure villous adenomas are quite uncommon and make up between 3% and 15% of all colonic adenomas. Villous architecture is more frequently seen as a component in Tubulovillous adenomas. The larger the adenoma, the greater the frequency of villous component. Villous adenomas tend to be large and have greater degree of dysplasia.
Distribution: Tubular adenomas 80-85%; Tubulovillous adenomas 8-16%; Villous adenomas 3-15%.
About the Disease
Introduction: A gastrointestinal polyp is any discrete mass of tissue protruding into the lumen. They can occur anywhere in the GI tract but are most common in the colo-rectal region. They may be pedunculated (with a well-defined stalk) or sessile (broad-based with no stalk). Colonic polyps are subdivided into two major groups: non-neoplastic and neoplastic. Non-neoplastic group includes hyperplastic polyps, hamartomatous polyps (juvenile polyps, Peutz-Jeghers polyps), inflammatory polyps and mucosal polyps. Hamartomatous polyps in syndromic settings can show germline mutations in tumor suppressor genes or oncogenes and carry malignant potential. Submucosal lesions may also lift the mucosa giving it a polypoid appearance. Neoplastic polyps show epithelial dysplasia by definition and include adenomas and carcinomas. Adenomas can be tubular, tubulovillous, or villous based on the glandular architecture. Serrated adenomas, which are related to hyperplastic polyps, have malignant potential and are now considered neoplastic. References: 1. Feldman, M., Friedman, L. S., & Brandt, L. J. (2016). Sleisenger & Fordtrans Gastrointestinal & Liver Disease; 10th Edition. Philadelphia, PA. Elsevier Saunders. 2. Goldblum, J. R. et al (2018). Rosai and Ackermans Surgical Pathology; Eleventh Edition. Philadelphia, PA. Elsevier. 3. Kumar, V., Abbas, A. K., & Aster, J. C. (2015). Robbins and Cotran Pathologic Basis of Disease; Ninth Edition. Philadelphia, PA. Elsevier.