We performed a histologic and immunohistochemical assessment of 53 noninvasive appendiceal epithelial proliferations, appropriating terminology and using markers shown useful in differentiating serrated colorectal polyps. These were classified as hyperplastic polyp (HP), sessile serrated adenoma (SSA), mixed serrated and adenomatous lesion (MSAL), mucinous cystadenoma (MCA), or conventional adenoma (CAD). Immunohistochemical analysis for cytokeratin (CK) 20, Ki-67, MUC6, and beta-catenin was performed. Diagnoses were as follows: HP, 6; SSA, 12; HP vs SSA, 3; MSAL, 16; MCA, 14; and CAD, 2. All HPs showed expanded (beyond surface) CK20 and expanded or normal (base) Ki-67; 1 was MUC6+. Most SSAs and MSALs were CK20-expanded or expanded with random expression in deep crypts (Ex/I) and Ki-67-expanded, Ex/I (expanded with asymmetry), or normal. All SSAs and 8 of 16 MSALs were MUC6+. CADs were CK20-Ex/I, Ki-67-Ex, and MUC6-; 1 showed nuclear beta-catenin expression. Serrated appendiceal lesions can be categorized using colorectal terminology. MUC6 is associated with SSA morphologic features. Similar immunohistochemical patterns in SSA and MSAL suggest a link between these lesions.
"Regarding the IHC profile of SSL found in colon, the loss of hMLH-1 and MGMT was reported to play an important role in the serrated neoplasia carcinogenesis pathway , and colon carcinomas with high-level microsatellite instability (MSI) have been estimated to be in at least 20% of the right-sided colon carcinomas. On the other hand, although some IHC analysis of appendiceal adenocarcinoma has been reported [14, 17, 18], very few were investigating lesions containing SSL. "
[Show abstract][Hide abstract] ABSTRACT: Although the definition of sessile serrated lesion (SSL) of colon is controversial and the risk of progression to malignancy is also under investigation at present, SSL is generally described as a polyp characterized by a serrated architecture. It is estimated to represent a feature of a new cancerization pathway, coined "serrated neoplasia pathway," particularly in right-sided colon adenocarcinomas. On the other hand, in appendix, the role of this pathway remains uncertain, probably because very few cases of appendiceal adenocarcinoma associated with SSL were reported, and furthermore, immunohistochemical examination was rarely carried out. We herein report an interesting case of invasive appendiceal mucinous adenocarcinoma exhibiting SSL, which was pathologically estimated as a potential precursor lesion, and performed representative immunohistochemistry for both the mucinous adenocarcinoma and SSL in the same specimen. To further elucidate the progression of the appendiceal carcinoma from SSL, both an adequate sectioning of the lesion and systematic immunohistochemical examination of a large number of appendiceal carcinoma cases containing adjacent SSL would be required.
[Show abstract][Hide abstract] ABSTRACT: Background/aims:
Serrated adenomas of the colon show mixed characteristics of both hyperplastic and adenomatous polyps. Serrated adenomas are known to progress via the serrated pathway than the adenoma-carcinoma pathway. The aim of this study was to evaluate the characteristics of traditional serrated adenomas compared to hyperplastic polyps and tubular adenomas by using immunohistochemical staining for p53, Bcl-2, and Ki-67.
Age, sex, location, size and the immunoexpression of p53, Bcl-2, and Ki-67 were retrospectively analyzed in 20 traditional serrated adenomas, 20 hyperplastic polyps, and 20 tubular adenomas from January 2007 to December 2012 at The Catholic University of Korea, Yeouido St. Mary's Hospital.
There was no difference in Bcl-2 and p53 expression between traditional serrated adenomas and hyperplastic polyps. Ki-67 Expression of traditional serrated adenomas was higher than that of hyperplastic polyps (p=0.001). Ki-67 and p53 expression was similar between traditional serrated and tubular adenomas. Bcl-2 expression of traditional serrated adenomas was lower than that of tubular adenomas (p=0.001). Regarding the expression of p53, Bcl-2, and Ki-67 in traditional serrated adenomas, there were no statistical differences among age, sex, location, and size.
Our study suggested that Ki-67 may be helpful in distinguishing traditional serrated adenomas from hyperplastic polyps, and p53 expression may be ineffective in distinguishing between traditional serrated and tubular adenomas. From Bcl-2 expression, it is suggested that the tumorigenesis of traditional serrated adenomas is lower than that of tubular adenomas.
The Korean journal of gastroenterology = Taehan Sohwagi Hakhoe chi 12/2013; 62(6):336-43. DOI:10.4166/kjg.2013.62.6.336
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