Differentiation of the basal cell epithelioma-like changes overlying dermatofibroma

Epidermis overlying dermatofibroma rarely displays basal cell epithelioma-like changes (BCE-like changes). Based on the histopathological findings, whether BCE-like changes are induced by dermal lesion or adnexal regression secondary to the solid fibrotic growth remains to be explored. From the standpoint of differentiation, we examined the BCE-like changes overlying dermatofibroma, normal epidermis, and hair follicles. PNA and two kinds of anti-keratin monoclonal antibodies were used to detect markers for epidermal differentiation. When PNA and anti-keratin monoclonal antibody (34betaB4) were used, no difference was observed in the staining patterns among BCE-like changes, hair follicles or normal basal cells. With the other anti-keratin antibody (34betaE12), BCE-like changes and normal basal cells were recognized, though the hair matrix was not. Thus the results obtained indicate that normal basal cells show the most similar differentiation to BCE-like changes.