Pilomatrix carcinoma: a report of a case arising from a previously excised pilomatrixoma and a review of the literature.

A 63-year-old woman was evaluated in 1995 for a nodule on the left parietal scalp. Biopsy revealed pilomatrixoma. The lesion was treated by curettage. The patient returned to the clinic in March of 1998 with a 2-month history of a rapidly growing nodule at the surgical site. Histology showed changes consistent with pilomatrix carcinoma. We will discuss the malignant transformation of a common hair matrix tumor and review the literature.