Medicine:Sessile serrated adenoma
| Sessile serrated adenoma | |
|---|---|
| Other names | Sessile serrated polyp (SSP) |
 | |
| Micrograph of a sessile serrated adenoma. H&E stain. | |
| Specialty | Gastroenterology |
| Symptoms | Asymptomatic |
| Complications | Colorectal cancer |
| Diagnostic method | Colonoscopy |
| Treatment | Polypectomy |
A sessile serrated adenoma (SSA) is a premalignant flat (or sessile) lesion of the colon, predominantly seen in the cecum and ascending colon.
SSAs are thought to lead to colorectal cancer through the (alternate) serrated pathway.[1][2] This differs from most colorectal cancer, which arises from mutations starting with inactivation of the APC gene.
Multiple SSAs may be part of the serrated polyposis syndrome.[3]
Signs and symptoms
SSAs, generally, are asymptomatic. They are typically identified on a colonoscopy and excised for a definitive diagnosis and treatment.
Serrated polyposis syndrome
The serrated polyposis syndrome (SPS) is a relatively rare condition characterized by multiple and/or large serrated polyps of the colon. Serrated polyps include hyperplastic polyps, SSA, 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]
Diagnosis
SSAs are diagnosed by their microscopic appearance; histomorphologically, they are characterized by (1) basal dilation of the crypts, (2) basal crypt serration, (3) crypts that run horizontal to the basement membrane (horizontal crypts), and (4) crypt branching. The most common of these features is basal dilation of the crypts.
Unlike traditional colonic adenomas (e.g. tubular adenoma, villous adenoma), they do not (typically) have nuclear changes (nuclear hyperchromatism, nuclear crowding, elliptical/cigar-shaped nuclei).
Low magnification micrograph of a SSA.
Intermediate magnification micrograph of a SSA.
High magnification micrograph of a SSA showing crypt branching.
Treatment
Complete removal of a SSA is considered curative.
Several SSAs confer a higher risk of subsequently finding colorectal cancer and warrant more frequent surveillance. The surveillance guidelines are the same as for other colonic adenomas. The surveillance interval is dependent on (1) the number of adenomas, (2) the size of the adenomas, and (3) the presence of high-grade microscopic features.[5]
Epidemiology
Sessile serrated lesions account for about 25% of all serrated polyps.[6]
History
Sessile serrated adenomas were first described in 1996.[7]
See also
- Polyp table
- Colonic polyps
- Colorectal polyps
- Colorectal carcinoma
- Microsatellite instability
References
- ↑ "[Colorectal serrated adenoma: diagnostic criteria and clinical implications]" (in German). Verh Dtsch Ges Pathol 91: 119–25. 2007. PMID 18314605.
- ↑ Mäkinen MJ (January 2007). "Colorectal serrated adenocarcinoma". Histopathology 50 (1): 131–50. doi:10.1111/j.1365-2559.2006.02548.x. PMID 17204027.
- ↑ Rosty, C.; Parry, S.; Young, JP. (2011). "Serrated polyposis: an enigmatic model of colorectal cancer predisposition.". Pathol Res Int 2011: 157073. doi:10.4061/2011/157073. PMID 21660283.
- ↑ World J Gastroenterol 2012 May 28; 18(20): 2452–2461
- ↑ "Clinical practice. Adenomatous polyps of the colon". N. Engl. J. Med. 355 (24): 2551–7. December 2006. doi:10.1056/NEJMcp063038. PMID 17167138.
- ↑ Crockett, SD; Nagtegaal, ID (October 2019). "Terminology, Molecular Features, Epidemiology, and Management of Serrated Colorectal Neoplasia.". Gastroenterology 157 (4): 949-966.e4. doi:10.1053/j.gastro.2019.06.041. PMID 31323292.
- ↑ Torlakovic, E; Snover, DC (July 2006). "Sessile serrated adenoma: a brief history and current status.". Critical reviews in oncogenesis 12 (1-2): 27-39. doi:10.1615/critrevoncog.v12.i1-2.30. PMID 17078205.
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