Porokeratotic eccrine ostial and dermal duct nevus: A rare case report

Porokeratotic eccrine ostial and dermal duct nevus (PEODDN) is an uncommon benign disorder that clinically mimicks comedo nevus but usually favors the palms and soles, where pilosebaceous follicles are absent. It also can present with widespread involvement along Blaschko's lines. It is a disorder of keratinisation involving the intraepidermal eccrine duct (acrosyringium) with classical histopathological examination findings (eccrine hamartoma and cornoid lamellation). The patient is a 32-year-old woman with a 12-year history of pruritic skin lesions on her right palm and index finger. Histopathological examination revealed multiple small epidermal invaginations with overlying parakeratotic cornoid lamellation and loss of granular layer. Few dyskeratotic cells are seen at the base of epidermal invagination. After clinic-pathologic correlation, the diagnosis of PEODDN was made. Late-onset and rare clinical presentation as pruritic lesion are the characteristic features that make this patient an extraordinary presentation of PEODDN.