Cytokeratin Expression in Trichoblastic Fibroma, Trichoepithelioma, and Basal Cell Carcinoma

The study investigated the immunostaining patterns of 10 anticytokeratin antibodies in trichoblastic fibroma, trichoepithelioma, and basal cell carcinoma (BCC), comparing them with normal skin. It found that trichoblastic fibroma and BCC shared similar cytokeratin expression patterns, making them indistinguishable by these markers alone. However, the presence of CK7 in trichoblastic fibroma and BCC, but not in trichoepithelioma, suggested that trichoblastic fibroma and BCC might retain fetal phenotypic characteristics, differentiating them from trichoepithelioma. This supported the idea that trichoepithelioma and trichoblastic fibroma are distinct entities, despite being previously considered a single tumor group. The study included 3 cases of trichoblastic fibroma, 7 cases of trichoepithelioma, and 29 cases of BCC.