Porokeratotic Adnexal Ostial Nevus: A Paradigm of Cutaneous Mosaicism

Porokeratotic adnexal ostial nevus (PAON) is a rare skin condition characterized by small, scaly papules that can form plaques, typically appearing unilaterally on the palms or soles. Histopathology reveals parakeratotic columns and dyskeratotic keratinocytes, with somatic mutations in the GJB2 gene identified as causative, linking PAON to keratosis ichthyosis deafness (KID) syndrome. The condition is usually asymptomatic and resistant to treatment, though therapies like topical corticosteroids and retinoids have been tried. This case underscores the subtlety of PAON's clinical features and its potential genetic implications, including a theoretical risk of systemic disease transmission to offspring.