Porokeratotic eccrine ostial and dermal duct nevus (PEODDN) is an uncommon, benign dermatosis that is characterized by asymptomatic grouped keratotic papules and plaques with a linear pattern on the extremities with distinct porokeratotic histopathological features. The lesions usually appear at birth or in childhood, although rare cases of late-onset adult PEODDN have been described. Herein we report a case of adult onset PEODDN with unilateral and segmental involvement.