Sessile serrated adenomas with dysplasia: morphological patterns and correlations with MLH1 immunohistochemistry

Liu, Cheng, Walker, Neal I., Leggett, Barbara A., Whitehall, Vicki L. J., Bettington, Mark L. and Rosty, Christophe (2017) Sessile serrated adenomas with dysplasia: morphological patterns and correlations with MLH1 immunohistochemistry. Modern Pathology, 30 12: 1728-1738. doi:10.1038/modpathol.2017.92


Author Liu, Cheng
Walker, Neal I.
Leggett, Barbara A.
Whitehall, Vicki L. J.
Bettington, Mark L.
Rosty, Christophe
Title Sessile serrated adenomas with dysplasia: morphological patterns and correlations with MLH1 immunohistochemistry
Journal name Modern Pathology   Check publisher's open access policy
ISSN 0893-3952
1530-0285
Publication date 2017-07-28
Year available 2017
Sub-type Article (original research)
DOI 10.1038/modpathol.2017.92
Open Access Status DOI
Volume 30
Issue 12
Start page 1728
End page 1738
Total pages 11
Place of publication London, United Kingdom
Publisher NATURE PUBLISHING GROUP
Language eng
Subject 2734 Pathology and Forensic Medicine
Abstract Sessile serrated adenomas are the precursor polyp of approximately 20% of colorectal carcinomas. Sessile serrated adenomas with dysplasia are rarely encountered and represent an intermediate step to malignant progression, frequently associated with loss of MLH1 expression. Accurate diagnosis of these lesions is important to facilitate appropriate surveillance, particularly because progression from dysplasia to carcinoma can be rapid. The current World Health Organization classification describes two main patterns of dysplasia occurring in sessile serrated adenomas, namely, serrated and conventional. However, this may not adequately reflect the spectrum of changes seen by pathologists in routine practice. Furthermore, subtle patterns of dysplasia that are nevertheless associated with loss of MLH1 expression are not encompassed in this classification. We performed a morphological analysis of 266 sessile serrated adenomas with dysplasia with concurrent MLH1 immunohistochemistry with the aims of better defining the spectrum of dysplasia occurring in these lesions and correlating dysplasia patterns with MLH1 expression. We found that dysplasia can be divided morphologically into four major patterns, comprising minimal deviation (19%), serrated (12%), adenomatous (8%) and not otherwise specified (79%) groups. Minimal deviation dysplasia is defined by minor architectural and cytological changes that typically requires loss of MLH1 immunohistochemical expression to support the diagnosis. Serrated dysplasia and adenomatous dysplasia have distinctive histological features and are less frequently associated with loss of MLH1 expression (13 and 5%, respectively). Finally, dysplasia not otherwise specified encompasses most cases and shows a diverse range of morphological changes that do not fall into the other subgroups and are frequently associated with loss of MLH1 expression (83%). This morphological classification of sessile serrated adenomas with dysplasia may represent an improvement on the current description as it correlates with the underlying mismatch repair protein status of the polyps and better highlights the range of morphologies seen by pathologists.
Keyword Hyperplastic Polyps
Colorectal-Carcinoma
Cytologic Dysplasia
Pathway
Cancers
Lesions
Caught
Colon
Grade
Act
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: HERDC Pre-Audit
Faculty of Medicine
 
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Created: Sat, 16 Dec 2017, 23:08:47 EST