Lectin-binding histochemistry of verruca vulgaris and seborrheic keratosis

Sugar residues in the epithelial cells of verruca vulgaris and seborrheic keratosis were demonstrated by the horseradish peroxidase-conjugated lectin methods. The lectins, Con A, RCA-1, UEA-1, DBA, PNA, SBA, and WGA were used to bind specifically to the sugars, Man, Glc, Gal, Fuc, GalNAc, GlcNAc and NANA. The cytochemical distribution of lectin bindings were limited to the cell surface, intercellular materials and basement membrane in the epithelial structures of the lesions. The lectin bindings in the basal layer cells were negative or weak, but increased gradually in upper spinous cells from moderate to strong levels. Vacuolated cells in verruca vulgaris showed positive lectin stainings. The intercellular materials of parakeratinized cells bound lectins differently, but orthokeratinized cells failed to bind lectins. The regional distribution of lectin bindings in stratified squamous epithelia may indicate an expression of keratinocytic stratification as well as in keratinized benign lesions.