Difference between hyperplastic polyp traditional serrated adenoma and sessile serrated adenoma HPs are characterized by serrated crypt lumens that are lined by colonic epithelial cells that lack dysplasia TSAs are polyps that show serrated crypt lumens with stratified pencil-like nuclei at the base of crypts that resemble the ones seen in tubular adenoma. Some authors have described ectopic crypt …
Depressed or flat adenoma Endoscopically, the adenoma shows subtle depression in the mucosa or may be flat. Histologically, the adenomatous glands show long, tubular architecture with a narrow opening at the surface and are lined by dysplastic epithelium. These tend to have high-grade dysplasia more often than the tubular adenomas and are more aggressive.
What are the genetic abnormalities in conventional CRCs? Colorectal adenocarcinomas usually arise from adenomas and can be sporadic (85%) or syndromic. These are graded as well, moderately, or poorly differentiated based on the glandular differentiation. The variants include mucinous (greater than 50% mucinous morphologic characteristics) and signet ring cell carcinomas (greater than 50% signet ring cell morphologic characteristics). Histologically, …
Intramucosal carcinoma in an adenoma Invasion of dysplastic glands into the lamina propria is intramucosal carcinoma. In the colon, it is equivalent to high-grade dysplasia, because it is not associated with metastatic potential and a polypectomy with negative margins should suffice.
What are the histologic features of conventional adenomas? Tubular adenomas have a tubular architecture with the surface epithelium showing low-grade dysplasia that extends downward in the base. These can show focal areas of high-grade dysplasia with architectural complexity and marked cytologic atypia. Focal high-grade dysplasia does not have a metastatic potential. The tubulovillous adenomas show a combination …
Differential diagnosis of polypoid lesions that can mimic adenoma Mucosal prolapse, solitary rectal ulcer syndrome, colitis cystica profunda, eroded polypoid hyperplasia: These are seen in rectosigmoid colon as an ulcerated or a polypoid lesion in patients with history of constipation or straining during defecation. The histologic examination shows surface erosion, epithelial hyperplasia with distorted and dilated …
Histologic features of microscopic colitis Microscopic colitis encompasses collagenous and lymphocytic colitis. Both of these conditions present as chronic watery diarrhea, are associated with autoimmune diseases, and show a near normal endoscopic examination. Histologically, collagenous colitis shows thickened subepithelial collagen layer that has irregular edges, is infiltrated by a few lymphocytes and eosinophils, and has dilated vessels. A few IELs …