Papular Epidermal Nevus with Skyline Basal Cell Layer (PENS): Three New Cases and Review of the Literature

Background/Objective Papular epidermal nevus with skyline basal cell layer (PENS) is a recently described type of epidermal nevus with characteristic histopathologic findings, mainly regular, rectangular acanthosis and a well-demarcated basal cell layer with clear palisading and separation between basal cell nuclei and the first row of Malpighian cell nuclei. Although the first reports described randomly distributed lesions appearing sporadically in otherwise healthy patients, cases of Blaschkoid distribution, lesions associated with extracutaneous manifestations, and familial cases have been reported. Methods We performed a review of the clinical charts of all patients with histologic diagnosis of PENS in our hospital. We evaluated epidemiologic, clinical, and histologic features. We then reviewed the literature with a particular emphasis on the presence or absence of extra-cutaneous associations. Results Three patients with PENS are described. One had a single lesion, one had three lesions, and one, a patient with mild developmental delay, a curved penis, and hypospadias, had multiple lesions. Conclusion The probability of having extracutaneous manifestations is 6.3 times as great in individuals with more than four lesions. Therefore these patients may need closer follow-up.