Adult-onset porokeratotic eccrine ostial and dermal duct nevus:dermatoscopic findings and treatment with tazarotene.

Porokeratotic eccrine ostial and dermal duct nevus (PEODDN) is a rare dermatosis initially described as 'comedo nevus' and renamed 'PEODDN'; it has also been referred to as linear eccrine nevus with comedones, porokeratotic eccrine ostial and hair follicle nevus, and porokeratotic adnexal ostial nevus. PEODDN is usually present at birth or develops early in life. Rarely, PEODDN can develop in adults. The treatment of this puzzling condition is not standardized. We report herein a new case of adultonset PEODDN with dermatoscopic images. Our patient responded favorably to topical tazarotene.