Mosaic EGFR exon 20 in-frame insertion pathogenic variants are associated with papular epidermal naevus with 'skyline' basal cell layer (PENS)

Papular epidermal naevus with ‘skyline’ basal cell layer (PENS) is a type of keratinocytic epidermal naevus for which the molecular genetic mechanism has not yet been identified. EGFR ex20ins could represent a new and specific genetic somatic marker of PENS.

Familial Cases of PENS: A Review of the Literature

Papular epidermal nevus with "skyline" basal cell layer (PENS) is a keratinocytic nevus that can occur sporadically or has a familial transmission. There are 5 families reported with PENS, in which there are 2 family members affected with each case. We present the sixth familial case, with the peculiarity of being the first time in which there are 3 family members with PENS, while reviewing the other cases described until now. In addition, we present a new histopathological finding, an inflammatory lichenoid infiltrate on the upper dermis in PENS lesions. This finding could be the result of trauma to the biopsied lesion, or it may represent a new inflammatory histological variant.

Epidermal Nevi and Related Syndromes -- Part 1: Keratinocytic Nevi

Epidermal nevi are hamartomatous lesions derived from the epidermis and/or adnexal structures of the skin; they have traditionally been classified according to their morphology. New variants have been described in recent years and advances in genetics have contributed to better characterization of these lesions and an improved understanding of their relationship with certain extracutaneous manifestations. In the first part of this review article, we will look at nevi derived specifically from the epidermis and associated syndromes.

Familial papular epidermal nevus with "skyline" basal cell layer

Papular epidermal nevus with "skyline" basal cell layer is a variant of keratinocytic nevus that usually occurs sporadically but may affect different family members. We report on the fourth family with papular epidermal nevus with "skyline" basal cell layer affecting a 3-month-old girl and her father.

Familial papular epidermal nevus with "skyline" basal cell layer and multiple pilomatricomas: A new association?

Papular epidermal nevus with "skyline" basal cell layer is a newly described keratinocytic nevus. Recently, papular epidermal nevus with "skyline" basal cell layer has been reported in association with extracutaneous involvement, and the term papular epidermal nevus with "skyline" basal cell layer syndrome is used to indicate a neurocutaneous syndrome characterized by the presence of papular epidermal nevus with "skyline" basal cell layer and different neurologic symptoms that seem to improve during infancy and adolescence. Multiple pilomatricomas have been reported in association with various syndromes. We report herein papular epidermal nevus with "skyline" basal cell layer associated with multiple pilomatricomas in two members of a family with the aim of drawing attention to this peculiar epidermal nevus to improve our knowledge of the syndrome.

Papular Epidermal Nevus with "Skyline" Basal Cell Layer Syndrome - Natural Course: Case Report and Literature Review

Papular epidermal nevus with “skyline” basal cell layer (PENS) is a very rare type of keratinocytic nevus and is associated with extracutaneous findings such as neurological symptoms in about 50% of the cases. Therefore, it is also referred to as PENS syndrome. Clinically visible hyperkeratotic papules and plaques already appear at birth or shortly thereafter, while neurological symptoms such as epilepsy and mental retardation manifest themselves during childhood. Genetics suggests gonadal mosaicism as a possible cause for the disease. Another hypothesis is that genetic mutation can occur in a mendelian trait or through a paradominant inheritance.

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.

Familial papular epidermal nevus with "skyline" basal cell layer

Papular epidermal nevus with "skyline" basal cell layer (PENS), a novel keratinocytic nevus, has recently been described as a mosaic condition with varying presentations. We herein describe typical PENS lesions, which usually occur sporadically, affecting two members of the same family. The concept of paradominant inheritance is proposed to explain the paradox of occasional transmission of normally sporadically occurring traits.

Papular epidermal nevus with "skyline" basal cell layer (PENS) following a Blaschko linear pattern

Papular epidermal nevus with "skyline" basal cell layer (PENS), a variant of epidermal nevi, has recently been described as a small, round or polygonal papule, visible at birth or shortly thereafter, with characteristic histopathologic features. It has been considered a separate entity from keratinocytic nevi because no lesion observed thus far has followed any of the known archetypical mosaic patterns. Here we describe for the first time a PENS lesion following a linear distribution pattern along Blaschko's lines.

Nevus anemicus in neurofibromatosis type 1: a potential new diagnostic criterion

BACKGROUND

Children with multiple café-au-lait macules (CALMs) may be followed for years before a second National Institutes of Health clinical criterion of neurofibromatosis type 1 (NF1) develops to confirm the diagnosis.

OBJECTIVE

We sought to assess the prevalence of nevus anemicus (NA) in NF1 and its association with neuro-ophthalmologic complications.

METHODS

This was a prospective multicenter case-control study of 210 consecutive patients with multiple CALMs. Patients with NF1 were matched for age, sex, and center with control subjects. We documented the number, location, and morphologic appearance of NA; dermatologic features of NF1; magnetic resonance imaging results; and family history.

RESULTS

In all, 77 (51%) patients with NF1 had NA compared with 6 (2%) control subjects. NA was not detected in 26 patients with other genodermatoses associated with CALMs. Patients with NF1 and NA were younger than those without NA (median age: 17 years) (P = .002). NA was mostly localized to the upper anterior aspect of the chest. NA was not significantly linked with other clinical manifestations of NF1, including optic glioma and unidentified bright objects.

LIMITATIONS

A potential referral bias associated with tertiary care centers is a limitation.

CONCLUSIONS

NA appears to have a high prevalence and specificity in NF1 and might serve as a marker for NF1 in children with multiple CALMs.

Papular epidermal nevus with "skyline" basal cell layer (PENS) with extracutaneous findings

Papular epidermal nevus with "skyline" basal cell layer (PENS), a variant of epidermal nevus, was recently described in otherwise normal children. We describe herein a patient with multiple, typical PENS lesions associated with peculiar facies, bilateral Achilles tendon shortening, and mild psychomotor delay. The association of PENS with extracutaneous manifestations suggests the possibility of a new type of epidermal nevus syndrome, for which we propose the term PENS syndrome.

[What's new in pediatric dermatology?]

This paper is based on a review of the literature focused on pediatric dermatology, from October 2011 to september 2012. Our objective was to highlight the main advances in fields such as atopic dermatitis, infantile hemangiomas, infectious diseases, inflammatory disorders, and genodermatoses.