Multiple tumors of the follicular infundibulum: a cutaneous reaction pattern?

The etiology of tumor of the follicular infundibulum (TFI) is unknown. Eruptive forms of TFI are rare. We present the case of a 49-year-old woman with multiple lesions on the arms, shoulders, trunk, buttocks, and legs of more than 3 years' duration. On clinical and histologic examination, a diagnosis of multiple TFI was made. Additionally, the patient presented with other rare remarkable features including severe pruritus, the Köbner phenomenon, and underlying inflammatory cell infiltration of the tumors. These findings strongly suggest that eruptive TFI may represent a kind of cutaneous reaction.