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Difference between revisions of "Sessile serrated adenoma"
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| Micro = serrated epithelium, crypt base dilation, crypt branching, boot-shaped glands, horizontal glands | | Micro = serrated epithelium, crypt base dilation, crypt branching, boot-shaped glands, horizontal glands | ||
| Subtypes = | | Subtypes = | ||
| LMDDx = [[hyperplastic polyp]], [[tubular adenoma]] | | LMDDx = [[hyperplastic polyp]], [[tubular adenoma]] when with dysplasia, [[mucosal prolapse]] for left sided lesions or background of [[diverticulosis]] | ||
| Stains = | | Stains = | ||
| IHC = | | IHC = Chromogranin A (completely) -ve | ||
| EM = | | EM = | ||
| Molecular = | | Molecular = | ||
| Line 27: | Line 27: | ||
| Prognosis = | | Prognosis = | ||
| Other = | | Other = | ||
| ClinDDx = normal, hyperplastic polyp | | ClinDDx = normal, hyperplastic polyp, other [[intestinal polyps]] | ||
}} | }} | ||
'''Sessile serrated adenoma''', abbreviated ''SSA'', is a premalignant [[GI polyps|polyp]] of the large bowel. | '''Sessile serrated adenoma''', abbreviated ''SSA'', is a premalignant [[GI polyps|polyp]] of the large bowel. | ||
It is also known as '''sessile serrated polyp''' (abbreviated ''SSP''), '''sessile serrated lesion''' and '''sessile serrated adenoma/polyp''' (abbreviated ''SSA/P''). | It is also known as '''sessile serrated polyp''' (abbreviated ''SSP''), '''sessile serrated lesion''' and '''sessile serrated adenoma/polyp''' (abbreviated ''SSA/P''). In the United Kingdom, this entity and is known as a sessile serrated lesion, a terminology that is likely to be adopted in the 2019/5th edition WHO Blue Book. | ||
This lesion should not be confused with the ''[[traditional serrated adenoma]]'', previously known as ''[[serrated adenoma]]''. | This lesion should not be confused with the ''[[traditional serrated adenoma]]'', previously known as ''[[serrated adenoma]]''. | ||
==General== | ==General== | ||
*Colonic lesion. | *Colonic lesion. | ||
*May be seen in the context of ''[[serrated polyposis syndrome]]''. | *May be seen in the context of ''[[serrated polyposis syndrome]]''. | ||
*Approximately 5% of SSAs have dysplasia.<ref name=pmid25724036>{{Cite journal | last1 = Yang | first1 = JF. | last2 = Tang | first2 = SJ. | last3 = Lash | first3 = RH. | last4 = Wu | first4 = R. | last5 = Yang | first5 = Q. | title = Anatomic distribution of sessile serrated adenoma/polyp with and without cytologic dysplasia. | journal = Arch Pathol Lab Med | volume = 139 | issue = 3 | pages = 388-93 | month = Mar | year = 2015 | doi = 10.5858/arpa.2013-0523-OA | PMID = 25724036 }}</ref> | |||
Epidemiology: | Epidemiology: | ||
| Line 65: | Line 67: | ||
*Horizontal crypts = crypt long axis parallel to the muscularis mucosae. | *Horizontal crypts = crypt long axis parallel to the muscularis mucosae. | ||
*Crypt branching. | *Crypt branching. | ||
*Submucosal [[lipoma]] or pseudolipoma is often seen in associated with SSA.{{fact}} | |||
*Perineuriomas are also seen in a small proportion of cases | |||
Minimal extent criteria - number of abnormal crypts with the above features: | Minimal extent criteria - number of abnormal crypts with the above features: | ||
*''German Society of Pathology'' proposal: at least two abnormal crypts -- crypts do not have to be adjacent.<ref name=pmid23052370>{{Cite journal | last1 = Ensari | first1 = A. | last2 = Bilezikçi | first2 = B. | last3 = Carneiro | first3 = F. | last4 = Doğusoy | first4 = GB. | last5 = Driessen | first5 = A. | last6 = Dursun | first6 = A. | last7 = Flejou | first7 = JF. | last8 = Geboes | first8 = K. | last9 = de Hertogh | first9 = G. | title = Serrated polyps of the colon: how reproducible is their classification? | journal = Virchows Arch | volume = 461 | issue = 5 | pages = 495-504 | month = Nov | year = 2012 | doi = 10.1007/s00428-012-1319-7 | PMID = 23052370 }}</ref><ref name=pmid20617338>{{Cite journal | last1 = Aust | first1 = DE. | last2 = Baretton | first2 = GB. | title = Serrated polyps of the colon and rectum (hyperplastic polyps, sessile serrated adenomas, traditional serrated adenomas, and mixed polyps)-proposal for diagnostic criteria. | journal = Virchows Arch | volume = 457 | issue = 3 | pages = 291-7 | month = Sep | year = 2010 | doi = 10.1007/s00428-010-0945-1 | PMID = 20617338 }}</ref> | *''German Society of Pathology'' proposal: at least two abnormal crypts -- crypts do not have to be adjacent.<ref name=pmid23052370>{{Cite journal | last1 = Ensari | first1 = A. | last2 = Bilezikçi | first2 = B. | last3 = Carneiro | first3 = F. | last4 = Doğusoy | first4 = GB. | last5 = Driessen | first5 = A. | last6 = Dursun | first6 = A. | last7 = Flejou | first7 = JF. | last8 = Geboes | first8 = K. | last9 = de Hertogh | first9 = G. | title = Serrated polyps of the colon: how reproducible is their classification? | journal = Virchows Arch | volume = 461 | issue = 5 | pages = 495-504 | month = Nov | year = 2012 | doi = 10.1007/s00428-012-1319-7 | PMID = 23052370 }}</ref><ref name=pmid20617338>{{Cite journal | last1 = Aust | first1 = DE. | last2 = Baretton | first2 = GB. | title = Serrated polyps of the colon and rectum (hyperplastic polyps, sessile serrated adenomas, traditional serrated adenomas, and mixed polyps)-proposal for diagnostic criteria. | journal = Virchows Arch | volume = 457 | issue = 3 | pages = 291-7 | month = Sep | year = 2010 | doi = 10.1007/s00428-010-0945-1 | PMID = 20617338 }}</ref> | ||
*An expert panel lead by ''Rex'' states that one unequivocally altered crypt should prompt calling SSA.<ref name=pmid22710576>{{Cite journal | last1 = Rex | first1 = DK. | last2 = Ahnen | first2 = DJ. | last3 = Baron | first3 = JA. | last4 = Batts | first4 = KP. | last5 = Burke | first5 = CA. | last6 = Burt | first6 = RW. | last7 = Goldblum | first7 = JR. | last8 = Guillem | first8 = JG. | last9 = Kahi | first9 = CJ. | title = Serrated lesions of the colorectum: review and recommendations from an expert panel. | journal = Am J Gastroenterol | volume = 107 | issue = 9 | pages = 1315-29; quiz 1314, 1330 | month = Sep | year = 2012 | doi = 10.1038/ajg.2012.161 | PMID = 22710576 }}</ref> | *An expert panel lead by ''Rex'' states that one unequivocally altered crypt should prompt calling SSA.<ref name=pmid22710576>{{Cite journal | last1 = Rex | first1 = DK. | last2 = Ahnen | first2 = DJ. | last3 = Baron | first3 = JA. | last4 = Batts | first4 = KP. | last5 = Burke | first5 = CA. | last6 = Burt | first6 = RW. | last7 = Goldblum | first7 = JR. | last8 = Guillem | first8 = JG. | last9 = Kahi | first9 = CJ. | title = Serrated lesions of the colorectum: review and recommendations from an expert panel. | journal = Am J Gastroenterol | volume = 107 | issue = 9 | pages = 1315-29; quiz 1314, 1330 | month = Sep | year = 2012 | doi = 10.1038/ajg.2012.161 | PMID = 22710576 }}</ref> | ||
*The WHO requires - depending on what you read: | *The 4th edition of the WHO blue book requires - depending on what you read: | ||
**Three adjacent crypts to be abnormal.<ref>URL: [http://surgpathcriteria.stanford.edu/gitumors/sessile-serrated-polyp-adenoma/ http://surgpathcriteria.stanford.edu/gitumors/sessile-serrated-polyp-adenoma/]. Accessed on: 26 September 2012.</ref> | **Three adjacent crypts to be abnormal.<ref>URL: [http://surgpathcriteria.stanford.edu/gitumors/sessile-serrated-polyp-adenoma/ http://surgpathcriteria.stanford.edu/gitumors/sessile-serrated-polyp-adenoma/]. Accessed on: 26 September 2012.</ref> | ||
**Two or three adjacent crypts to be abnormal.<ref name=pmid23052370/> | **Two or three adjacent crypts to be abnormal.<ref name=pmid23052370/> | ||
**The 5th edition is likely to make a single crypt sufficient for diagnosis. | |||
===Dysplasia=== | |||
Sessile serrated adenomas typically lack "conventional" nuclear atypia, as seen in adenomata in the tubulovillous spectrum. They are nonetheless neoplastic lesions on account of architectural "dysplasia". Additionally, dysplasia may manifest in more than one way: | |||
;Intestinal or "cytological" dysplasia: As seen in conventional adenomata, i.e. nuclear hyperchromasia and crowding. SSAs with nuclear atypia may be referred to as ''advanced sessile serrated adenomas'' | |||
;Serrated dysplasia: Round nuclei, prominent nucleoli and eosinophilic cytoplasm | |||
;Minimal deviation dysplasia: As the name suggests, there is only minor architectural and cytological changes. These areas are associated with loss of MLH1 immunostaining.<ref name=pmid28752838>{{Cite journal | last1 = Liu | first1 = C. | last2 = Walker | first2 = NI. | last3 = Leggett | first3 = BA. | last4 = Whitehall | first4 = VL. | last5 = Bettington | first5 = ML. | last6 = Rosty | first6 = C. | title = Sessile serrated adenomas with dysplasia: morphological patterns and correlations with MLH1 immunohistochemistry. | journal = Mod Pathol | volume = 30 | issue = 12 | pages = 1728-1738 | month = 12 | year = 2017 | doi = 10.1038/modpathol.2017.92 | PMID = 28752838 }}</ref> | |||
===DDx=== | ===DDx=== | ||
*[[Hyperplastic polyp]]. | *[[Hyperplastic polyp]]. | ||
*[[Tubular adenoma of the gastrointestinal tract|Tubular adenoma]] - for ''SSA with dysplasia'', TAs often less than 1 cm (uncommon for SSAs). | *[[Tubular adenoma of the gastrointestinal tract|Tubular adenoma]] - for ''SSA with dysplasia'', TAs often less than 1 cm (uncommon for SSAs). | ||
*[[Mucosal prolapse]] - especially for left sided lesions and a background of [[diverticulosis]].<ref name=pmid23069257>{{Cite journal | last1 = Huang | first1 = CC. | last2 = Frankel | first2 = WL. | last3 = Doukides | first3 = T. | last4 = Zhou | first4 = XP. | last5 = Zhao | first5 = W. | last6 = Yearsley | first6 = MM. | title = Prolapse-related changes are a confounding factor in misdiagnosis of sessile serrated adenomas in the rectum. | journal = Hum Pathol | volume = 44 | issue = 4 | pages = 480-6 | month = Apr | year = 2013 | doi = 10.1016/j.humpath.2012.06.011 | PMID = 23069257 }}</ref> | |||
===Images=== | ===Images=== | ||
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Image:Sessile_serrated_adenoma_3_very_high_mag.jpg | SSA - very high mag. (WC/Nephron) | Image:Sessile_serrated_adenoma_3_very_high_mag.jpg | SSA - very high mag. (WC/Nephron) | ||
</gallery> | </gallery> | ||
==IHC== | |||
*[[Chromogranin A]] -ve; complete loss of staining.<ref>Vitkovski T, Jawale R, Goldblum J ''et al.'' Density of neuroendocrine cells can distinguish hyperplastic polyps from small sessile serrated polyps. Modern Pathology (USCAP Annual Meeting 2018, Abstract Number 865), URL: [https://www.nature.com/articles/modpathol20189.pdf https://www.nature.com/articles/modpathol20189.pdf]. Accessed on: 10 May 2018.</ref> | |||
**Normal colorectal mucosa has scattered Chromogranin A-positive cells. | |||
**[[Hyperplastic polyp]] has increased scattered Chromogranin A-positive cells. | |||
==Sign out== | ==Sign out== | ||
<pre> | |||
Polyp, Hepatic Flexure of Colon, Polypectomy or Biopsy: | |||
- Sessile serrated adenoma, NEGATIVE for conventional adenomatous dysplasia. | |||
</pre> | |||
====Block letters==== | |||
<pre> | <pre> | ||
POLYP, CECUM, POLYPECTOMY: | POLYP, CECUM, POLYPECTOMY: | ||
| Line 113: | Line 130: | ||
===Dysplasia present=== | ===Dysplasia present=== | ||
<pre> | |||
Polyp, Ascending Colon, Polypectomy or Biopsy: | |||
- Sessile serrated adenoma with low-grade dysplasia, see comment. | |||
Comment: | |||
Sessile serrated adenomas with dysplasia are considered to be advanced lesions that | |||
have an increased propensity to transform to adenocarcinoma. Complete endoscopic removal is recommended. If complete endoscopic removal cannot be achieved, short-term re-endoscopy and biopsy, or surgical resection should be considered. | |||
</pre> | |||
===Block letters=== | |||
<pre> | <pre> | ||
POLYP, ASCENDING COLON, POLYPECTOMY: | POLYP, ASCENDING COLON, POLYPECTOMY: | ||
| Line 118: | Line 145: | ||
</pre> | </pre> | ||
The above mirrors the Canadian consensus.<ref name=driman>{{cite journal | last1 = Driman | first1 = DK. | last2 = Marcus | first2 = VA. | last3 = Hilsden | first3 = RJ | last4 = Owen | first4 = DA |title=Pathologic reporting of colorectal polyps: pan-Canadian consensus guidelines |journal=Canadian Journal of Pathology |volume=4 |issue=3 |pages=81-90 |year=2012 |month= |pmid= |doi= |url=http://andrewjohnpublishing.com/images/cjp%204-3.pdf }}</ref> | |||
====Sign out comment==== | |||
The Canadian consensus<ref name=driman/> also advocates use of a comment, like the following statement: | |||
<pre> | |||
Sessile serrated adenomas with dysplasia are considered to be advanced lesions that | |||
have an increased propensity to transform to adenocarcinoma. Complete endoscopic removal | |||
is recommended. If complete endoscopic removal cannot be achieved, short-term re-endoscopy | |||
and biopsy, or surgical resection should be considered. | |||
</pre> | |||
===Micro=== | ===Micro=== | ||
The section shows a small polypoid fragment of colonic mucosa with a serrated epithelium that focally extends to the crypt base. Several dilated crypt bases are seen. One horizontal crypt and one boot-shaped crypt are present. The epithelium matures to the surface. A small amount of submucosa is present and contains a benign lymphoid aggregate. | The section shows a small polypoid fragment of colonic mucosa with a serrated epithelium that focally extends to the crypt base. Several dilated crypt bases are seen. One horizontal crypt and one boot-shaped crypt are present. The epithelium matures to the surface. A small amount of submucosa is present and contains a benign lymphoid aggregate. | ||
==See also== | |||
*[[Colorectal polyps]]. | |||
==References== | ==References== | ||