TRICHOEPITHELIOMA WITH AN ADJACENT BASAL-CELL CARCINOMA, TRANSFORMATION OR COLLISION

Trichoepitheliomas (TEs) are benign follicular neoplasms that can be d ifficult to separate histologically from basal cell carcinomas (BCCs). It is important to make this distinction, because the treatments and prognoses differ for the two lesions. Previous reports have employed b oth histologic and immunohistochemical data in order to separate these two lesions. It is believed that transformation from a TE to a BCC is a rare event. We describe a case in which a single lesion with featur es of TE and BCC is present in a patient with multiple lesions of BCC.