Two histologic compartments in nonpolypoid conventional colon adenomas

Abstract

Two intertwined compartments coexisting in nonpolypoid conventional (i.e. tubular or villous) adenomas are highlighted in this review: one built of dysplastic tissue on top and the other portraying crypts with irregular, corrupted shapes, albeit lined with normal epithelium, below. The latter compartment has remained unattended in the literature. Recently, however, the histologic characteristics of the nondysplastic compartment in nonpolypoid conventional adenomas were closely examined, and some of its biological attributes were unveiled. Studies with the proliferation marker ki67 showed that the crypts with irregular, corrupted shapes in the nondysplastic compartment displayed haphazardly distributed proliferating cell-domains. Given that the proliferating cells are generated by stem cells, the relocation of proliferating cell-domains in those crypts seems to be the result of a reorganization of the stem cells within the crypts. The abnormal distribution of proliferating cells, the finding of p53-upregulated cells, and of crypts in asymmetric fission suggest that the crypts in that compartment are histo-biologically altered, probably somatically mutated. This new information might contribute to unravel the riddle of crypto-histogenesis of nonpolypoid conventional adenomas of the colon. More research along these lines is necessary, before the biology of the crypts in the nondysplastic compartment can be fully translated into molecular terms.

Nondysplastic Crypts in Fission in Nonpolypoid Adenomas and in the Adjacent Mucosa Support Field Cancerization in the Colon

“…The results of this survey indicate that nonpolypoid adenomas often exhibit NDCSAF, either sandwhiched amongst dysplastic crypts, beneath the neoplastic canopy of nonpolypoid adenomas (40) or are partially replaced by downward-growing dysplastic cells (41,42). Importantly, NDCSAF were ofen seen in the adjacent, apparently normal mucosa surrounding NPA.…”

“…Recently, while reviewing sections from endoscopicallyresected small nonpolypoid adenomas, we observed in the non-dysplastic mucosa adjacent to nonpolypoid adenomas, crypts in symmetric and in asymmetric fission (40).…”