Trichilemmal pilar tumors.

We report 16 cases of trichilemmal pilar tumors. All of the patients were women of older ages. These unusual tumors are located chiefly on the scalp and consists of areas of squamous epithelium with non-epidermal keratinization and moderate cellular polymorphism. The origin of the tumor appears to be the outer root sheath of hair. Two of our cases were cystic. In order to avoid an erroneous diagnosis of squamous cell carcinoma, an adequate knowledge of these tumors is necessary.