Are metaplasias in colorectal adenomas truly metaplasias?

Five thousand seven hundred seventy-eight adenomas or adenomas containing carcinoma from 3215 patients were examined by routine histologic methods for the presence of epithelial metaplasias. Three forms of epithelial metaplasia were encountered: squamous cell metaplasia (0.44%), Paneth cell metaplasia (0.20%), and melanocytic metaplasia (0.017%). In several instances multiple forms of metaplasia were encountered in the same polyp. In those cases in which the paraffin blocks were available, a Grimelius stain was performed. Grimelius-positive cells were present in 63% of the adenomas containing a metaplastic cell type. All cases with Paneth cell differentiation were immunoreactive for lysozyme; all lesions containing areas of squamous differentiation were immunoreactive for keratin except 2. The histopathologic features of these cases are discussed, and it is concluded that rather than representing a true metaplastic process, Paneth cell, squamous cell, and melanocyte differentiation represent the full range of cellular differentiation that endodermally derived tissues can exhibit, particularly when they undergo neoplastic alterations.

Duke Scholars

Author Stanley J. Robboy Pathology