Image Description
Malignancy in Familial Adenomatous Polyposis: Untreated FAP patients develop colorectal cancer in 100% of cases usually by age 40 years. Malignant transformation has been reported as early as 9 years of age. On the other hand, cancer formation is delayed to around 50-55 years of age in attenuated FAP. The morphologic features and distribution of colorectal cancers in FAP are similar to the sporadic colorectal cancers; however, the frequency of multiple synchronous tumors is much greater (almost 48% of cases).
The image shows one of the thousands of adenomatous polyps from a case of FAP.
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.