[634] Morphologic Reappraisal of Traditional Serrated Adenoma in 43 Cases

Sara Hafezi-Bakhtiari, Keneth P Batts, Dale Snover, Emina Torlakovic. University Health Network, University of Toronto, Toronto, ON, Canada; Hospital Pathology Associates, Minneapolis, MN; Fairview Southdale Hospital, Edina, MN

Background: In 2003 the traditional serrated adenoma (TSA) was for the first time distinguished as a separate lesion from other serrated polyps and in 2008 further diagnostic criteria was proposed to facilitate its diagnosis. However, the field of serrated polyps of the colorectum remains diagnostically challenging. The current study was performed to evaluate characteristics of different histologic subtypes of TSA.
Design: The archives of Hospital Pathology Associated, Minneapolis, MN were searched for polyps diagnosed as TSA. 43 most recent cases were selected based on the quality of histologic sections. TSA cellular composition in all cases included eosinophilic cells (EOC) as well as variable mucinous compartment (MUC). In all cases the EOC compartment contained variable number of goblet cells (GC). Following variables were evaluated: content of eosinophilic cells, content of non-eosinophilic/mucinous cells, and the GC content admixed with EOC compartment, which were scored from 1 (rare GC) to 4 (abundant GC). Furthermore, the presence of putative precursor lesion as well as the presence of conventional dysplasia were also recorded.
Results: EOC compartment accounted from 5 to 100% of the polyps with the remaining represented by MUC compartment. MUC uniformly failed to show microvesicular mucin except in one polyp (8% of MUC lesions or 2% of all TSAs). Conventional dysplasia was significantly more frequent in TSAs with MUC (Spearman Correlation, r=-0.403, p=0.007). Putative precursor lesions were detected in 32% cases; there was no association of precursor type with dysplasia or extent of MUC.
Conclusions: Although the majority of TSAs exhibit a major component of EOC, lesions with a significant component of mucinous differentiation exist and when they account for >20% of the lesion, they are more likely to be associated with conventional dysplasia than pure EOC TSAs.
Category: Gastrointestinal

Tuesday, March 5, 2013 1:00 PM

Poster Session IV # 131, Tuesday Afternoon


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