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Case Reports

Abstract

Porokeratotic eccrine and hair follicle nevus (PEHFN) is an extremely rare variant of porokeratosis with fewer than 10 reported cases in the literature. A related and slightly more common condition is porokeratotic eccrine ostial and dermal duct nevus (PEODDN), which involves eccrine structures, but lacks the follicular involvement seen in PEHFN. Both lesions are associated with mutations in the GJB2 gene, and can be considered a mosaic form of keratitis–ichthyosis–deafness (KID) syndrome. Classically, lesions of PEHFN appear at birth or early in life; however, later onset cases have been observed. Here, we present a 1 day old male infant who was born with widespread Blaschkolinear hypopigmented verrucous plaques affecting the trunk and bilateral upper and lower extremities. The lesions were bilateral, while the lesions of PEODDN are more commonly unilateral. Clinically, the differential diagnosis included incontinentia pigmenti and epidermal nevus. On histology, the epidermis was papillated, and cornoid lamellae were present overlying dilated eccrine glands and follicular units, consistent with PEHFN. Dermatopathologists should be aware of this rare entity with a unique histopathological presentation. While there have been no cases with associated extracutaneous findings, there is a theoretical increased risk of conceiving children with KID syndrome in patients with more widespread involvement.