Papular epidermal nevus with skyline basal cell layer
While most cases of PENS develop sporadically, familial occurrence has been described and a genetic basis suspected.
PENS syndrome (PENSS) refers to a rare neurocutaneous syndrome characterized by the presence of typical PENS lesions in association with extracutaneous findings, mainly neurologic. PENSS has been reported to occur in up to 50% of PENS cases. It has been postulated that individuals with more than 4 PENS lesions are at greater risk of also having extracutaneous manifestations. Neurological signs are of varying severity and may include psychomotor delay, learning difficulties, dyslexia, hyperactivity, attention deficit disorder, autism spectrum disorder, and epilepsy. Neurologic manifestations may occur within the first 1-2 years of age. Some neurologic manifestations have been noted to improve and/or resolve during infancy and adolescence. Other extracutaneous manifestations such as dysmorphic facies, Achilles tendon shortening, hypospadias, and curved penis have also been described.
D22.9 – Melanocytic nevi, unspecified
771473004 – Papular epidermal nevi with skyline basal cell layers syndrome
Differential Diagnosis & Pitfalls
- Epidermal nevi – Clinically, these lesions may be linear or small, verrucous papules. On pathology, acanthosis and hyperkeratosis are usually evident. The strikingly palisaded basal cells seen in PENS are absent.
- Waxy keratoses of childhood (also known as kerinokeratosis papulosa) – Several skin-colored papules, most commonly located on the trunk, arms, and thighs. Histopathologic examination reveals marked orthokeratotic hyperkeratosis, papillomatosis of the epidermis, and focal acanthosis.
- Common warts
- Flat warts