Association of trichilemmal and basal cell carcinomas: a case report.

Proliferating trichilemmal tumor (PTT) is a benign tumor arising from the isthmic portion of the hair follicle. Malignant transformation in PPT is very rare and unusual. Indeed, only about sixty well-documented cases have been found in the English literature. We present here the case of a 72-year-old patient with an exceptional combination of malignant trichilemmal carcinoma and basal cell carcinoma, occurring on actinic keratosis lesions. The aim of this work is to describe the diagnostic and therapeutic modalities of this association which is exceptional.