Pilomatricoma with apocrine poroma: A novel cutaneous collision tumor

Abstract

The term “collision tumor” implies the occurrence of two or more neoplasms in a single biopsy specimen. This is a rare feature in skin biopsies, with most of the reported combinations involving melanocytic lesions or basal cell carcinomas. Combinations of adnexal tumors are found very sporadically. We report a 67-year-old woman with a scalp nodule, clinically suspected to be verrucous carcinoma, who underwent a wide excision. Histopathology showed apocrine poroma with adjacent regressing pilomatricoma.