Differential diagnosis of traditional serrated adenomas and tubulovillous adenomas: a compartmental morphologic and immunohistochemical analysis

Traditional serrated adenomas are the rarest member of the serrated polyps, that have endoscopic and morphologic similarities with conventional adenomas, tubulovillous adenomas, in particular. We aimed to compare the histopathologic and immunohistochemical features of TSAs showing overt dysplasia with conventional TVAs in a compartmental manner using digitalized images. For 25 TSAs and 25 TVAs, extent of the morphologic features including cytoplasmic eosinophilia, mid-zonal nuclei, ECFs, slit-like serration, brush border, gastric foveolar-like epithelium and goblet cells were evaluated. Immunohistochemistry was perfomed using primary antibodies including CK7, CK20, MUC2, MUC5AC, MUC6, B-catenin, Ki67, p53, p16, MLH1, MSH2, MSH6 and PMS2. Eosinophilic cells, mid-zonal nuclei, slit-like serration and ECF were significantly more extensive in TSAs compared to TVAs (p