The endoscopic appearance of the lesion was concerning for a nonpolypoid colorectal neoplasm (NP-CRN), especially when considering the patient's history of inflammatory bowel disease (IBD). In contrast with polypoid neoplasms, such as pedunculated or sessile lesions, NP-CRNs are nonprotruding and flat, depressed, or only superficially elevated. This lesion had multiple features of an NP-CRN, including superficial elevation, obscured vascular pattern, discoloration with uneven erythema, and irregular nodularity. Biopsies showed that the lesion was indeed a neoplasm, a villiform low-grade dysplasia, which was confirmed by an expert gastrointestinal pathologist.
Pseudopolyps are small-to-large protruding masses of nonneoplastic scar tissue that are commonly found in scattered clusters in the setting of IBD colitis. They are formed from granulation tissue during the cycle of inflammation and healing. This lesion was not consistent in appearance or histology with a pseudopolyp.
Sessile serrated adenomas are relatively flat polypoid neoplasms that can be difficult to identify on colonoscopy, as they are often covered with bile-stained mucus. Sessile serrated adenomas are typically located in the proximal colon and are usually 1 cm or larger in diameter when detected. Sessile serrated adenomas differ histologically from adenomatous polyps but are still neoplastic lesions with malignant potential, in contrast to nonneoplastic serrated hyperplastic polyps. The case lesion had some endoscopic features of, but was more irregular in appearance than, a typical sessile serrated adenoma. It also proved not to be a sessile serrated adenoma upon histologic review.
Active Crohn disease on colonoscopy is characterized by ulceration, ranging from small aphthous ulcers to larger linear and/or serpiginous ulcers, with acute and chronic inflammation seen on histology. None of these features were seen with this lesion.
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Cite this: Arthur M. Barrie. A Proximal Ascending Colon Lesion of a Crohn Disease Patient - Medscape - Aug 13, 2015.