F7Ch14bP6b (H9505): In this small, “young,” lesion, the basic features of a tricholemmoma are represented. Columns of squamous cells extend from the epidermis into a tumor stroma. The lesion is confined to the tumor stroma (a widened, richly vascularized papillary dermis). At a certain depth, the epithelial component becomes confluent. There are irregular clusters of vacuolated cells in the confluent portion. In areas, where the vacuolated cells extend to the margin of the epithelial component, the basal layer shows prominent palisading of nuclei. Two small follicles (blue arrows) have been distorted by the expansile tumor. As is often the case, small follicles appear to increased in number, at the margins, or beneath, a tricholemmoma.
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