Porokeratotic eccrine ostial and dermal duct nevus with extensive linear distribution: a case report

Porokeratotic eccrine ostial and dermal duct nevus (PEODDN) is known as an uncommon disorder of keratinization in which acrosyringium is involved; however, its causes have yet remained unknown. It is presented clinically by discrete keratotic papules on distal extremities arranged in a linear pattern along Blaschko lines. Histopathologically, it is characterized by cornoid lamella, which is almost always located overlying an acrosyringium. We present a case with an unusual presentation of extensive PEODDN lesions along the lower extremity. Our case was a young woman presented with multiple keratotic elevated papules on her left sole since her birth. In continuity with the lesions on her sole, a linear plaque was extended up to her buttock. Histopathology showed hyperkeratosis with cornoid lamella overlying the acrosyringium. The rarity of PEODDN and interesting presentation of the lesions on the sole of our patient with extension in a linear Blaschko pattern up to her buttock resembling verrucous linear epidermal nevus encouraged us to present this case.