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Polyps are either pedunculated (attached to the intestinal wall by a stalk) or sessile (grow directly from the wall). [5] [6]: 1342 In addition to the gross appearance categorization, they are further divided by their histologic appearance as tubular adenoma which are tubular glands, villous adenoma which are long finger like projections on the surface, and tubulovillous adenoma which has ...
Colorectal adenoma Type Risk of containing malignant cells Histopathology definition Tubular adenoma 2% at 1.5 cm [4] Over 75% of volume has tubular appearance. [5] Tubulovillous adenoma 20% to 25% [6] 25–75% villous [5] Villous adenoma 15% [7] to 40% [6] Over 75% villous [5] Sessile serrated adenoma (SSA) [8] Basal dilation of the crypts ...
The serrated polyposis syndrome (SPS) is a relatively rare condition characterized by multiple and/or large serrated polyps of the colon. Serrated polyps include SSLs, hyperplastic polyps, and traditional serrated adenomas. Diagnosis of this disease is made by the fulfillment of any of the World Health Organization's (WHO) clinical criteria. [4]
Sessile polyps larger than 2 cm usually contain villous features, have a higher malignant potential, and tend to recur following colonoscopic polypectomy. [18] Although polyps do not carry significant risk of colon cancer, tubular adenomatous polyps may become cancerous when they grow larger. Larger tubular adenomatous polyps have an increased ...
For example, adenomatous polyps in the colon may be pedunculated (lobular head with a long slender stalk) or sessile (broad base). The adenomatous proliferation is characterized by different degrees of cell dysplasia ( atypia or loss of normal differentiation of epithelium) irregular cells with hyperchromatic nuclei, stratified or ...
A sessile serrated adenoma or traditional serrated adenoma is suspected if there is either of the following: [4] Nuclear stratification; Loss of polarity; Dysplasia; A sessile serrated adenoma is suspected in case of any of the following: [4] Size ≥0.5 cm; Location in right colon; If both are present, it is almost always an SSA.
Traditional serrated adenoma seen under microscopy with H&E stain, showing serrated crypts. SPS may occur with one of two phenotypes: distal or proximal. [6] The distal phenotype may demonstrate numerous small polyps in the distal colon and rectum, whereas the proximal phenotype may be characterized by relatively fewer, but larger polyps in the proximal colon (cecum, ascending colon, etc.). [6]
Colorectal adenocarcinoma is distinguished from a colorectal adenoma (mainly tubular and ⁄or villous adenomas) mainly by invasion through the muscularis mucosae. [10] In carcinoma in situ (Tis), cancer cells invade into the lamina propria, and may involve but not penetrating the muscularis mucosae. This can be classified as an adenoma with ...