title: Are metaplasias in colorectal adenomas truly metaplasias?
abstract: 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.
mesh_terms: D000236:Adenoma / Q000473:pathology*; D000328:Adult; D000367:Age Factors; D000368:Aged; D002454:Cell Differentiation; D003110:Colonic Neoplasms / Q000473:pathology*; D005260:Female; D006651:Histocytochemistry; D006801:Humans; D007417:Intestinal Polyps / Q000473:pathology; D007420:Intestine, Large / Q000473:pathology*; D007633:Keratins / Q000032:analysis; D008297:Male; D008544:Melanocytes / Q000473:pathology; D008679:Metaplasia / Q000473:pathology*; D008875:Middle Aged; D009113:Muramidase / Q000032:analysis; D012004:Rectal Neoplasms / Q000473:pathology*; D012189:Retrospective Studies; D012737:Sex Factors
chemical_list: D007633:Keratins; D009113:Muramidase