Clinicopathological Study of Serrated Polyps of the Colorectum,with Special Reference to Maspin Expression

Abstract

: Aims : We compared the clinicopathologic features of three types of colorectal serrated polyps, namely, hyperplastic polyps HPs , sessile serrated adenomas/polyps SSA/Ps , and traditional serrated adenomas TSAs , and analyzed the expression pattern of maspin in these serrated lesions. We retrospectively examined 173 polypoid lesions that were endoscopically excised from 136 patients and diagnosed as hyperplastic or adenomatous serrated lesions, and histologically classi ed as HPs, SSA/Ps, or TSAs. Maspin expression was immunohistochemically examined in all lesions. Overall, 59 lesions 34% were classi ed as HPs, 70 40% as SSA/Ps and 44 25% as TSAs. There were no significant differences in mean age or gender of patients between types, but SSA/Ps frequently developed on the right colon and showed a super cial/ at elevation, whereas HPs and TSAs frequently developed on the left colon and showed protruded lesions. The average diameters of HPs, SSA/ Ps, and TSAs were 7.2, 9.9, and 12.9 mm, respectively, showing significant differences. Diffuse cytoplasmic expression of maspin was observed in the serrated glands of all three types. In addition, focal or diffuse intranuclear localization of maspin was observed in 15% of HPs, 13% of SSA/Ps, and 84% of TSAs, showing signi cant differences between TSAs and the other two types. The three types of serrated polyp examined in this study showed distinct clinicopathological features. The presence of maspin expression in these polyps, regardless of whether they were hyperplastic or neoplastic, indicates that maspin might be commonly associated with cell proliferation, although the underlying mechanism might be different between types.