FGFR2 signaling and the pathogenesis of acne

Acne in Apert syndrome and unilateral segmental acneiform nevus are associated with mutations of fibroblast growth factor receptor 2 (FGFR2), which are likely to be involved in the pathogenesis of acne. Translational animal and cellular models, developmental biology studies and clinical observations have contributed to our understanding of FGF‐FGFR2 signaling in the pilosebaceous follicle. The importance of FGF‐FGFR2 signaling in mesenchymal‐epithelial interaction for skin appendage formation, pilosebaceous follicle homeostasis, come‐dogenesis and sebaceous gland proliferation is explored. Overstimulation of FGFR2 signaling with increased expression of interleukin‐1α explains acne in Apert syndrome und nevus comedonicus. Androgen‐mediated up‐regulation of FGFR2 signaling could be the initiating signal in the pathogenesis of acne. The gain of function FGFR2 mutations in Apert syndrome and unilateral acneiform nevus are most helpful model diseases for uncovering the fundamental process of androgen‐dependent mesenchymal‐epithelial FGF‐FGFR2 signaling in acne in Apert syndrome, nevus comedonicus and acne vulgaris.     

Segmental acne versus mosaic conditions with acne lesions

Acne rarely presents in segmental patterns, which are encountered only in cutaneous mosaicism. We report herein two cases of segmentally arranged acne and systematically review the literature on the topic. Beside already known mosaic conditions which may show primary lesions typical of acne, i.e. nevus comedonicus, Happle-Tinschert syndrome, acne superimposed on epidermal nevi and mosaic Apert syndrome, we introduce the possibility that acne itself may present in a mosaic form. As from the extremely small casuistics retrieved, segmental acne is not present at birth, follows Blaschko lines, is polymorphous in nature and occurs on locations typical of common acne.     

Epidermal nevus syndromes: New insights into whorls and swirls

Knowledge of the molecular underpinnings of many epidermal nevi and epidermal nevus syndrome has expanded rapidly in recent years. In this review and update on epidermal nevus syndrome, we will cover recent genetic discoveries involving epidermal nevi, including nevus sebaceus, keratinocytic epidermal nevus, nevus comedonicus, congenital hemidysplasia with ichthyosiform nevus and limb defects syndrome, phakomatosis pigmentokeratotica, Becker's nevus, porokeratotic adnexal ostial nevus, inflammatory linear verrucous epidermal nevi, and cutaneous‐skeletal hypophosphatemia syndrome. We will discuss how newly defined mutations relate to the biology reflected in the cutaneous patterns seen in these mosaic disorders and how new molecular data has informed our understanding of these diseases and shaped management decisions.     

Congenital nevus comedonicus complicated by a hidradenitis suppurativa‐like lesion: Report of a childhood case

Nevus comedonicus is a rare, benign hamartoma of the pilosebaceous unit that may be isolated or part of the nevus comedonicus syndrome. Although rare in children, complication by hidradenitis suppurativa‐like lesions has been described. We present a report of a 9‐year‐old girl in whom surgical excision was curative, with a review of the relevant literature.     

Acneiform eruptions

Is it acne or is it not? When this question arises, we can presume that we have crossed the boundaries of “acneiform eruptions” of the face. Although acne may be considered a condition fairly easy to diagnose, it is not rare for the practicing dermatologist or the general physician to wonder when faced with an acneiform eruption before establishing a diagnosis. In this review, we address facial acneiform eruptions in children and in adults, including perioral dermatitis, granulomatous periorificial dermatitis, nevus comedonicus, acne cosmetica, rosacea, demodicosis, folliculitis, acneiform presentation of cutaneous lymphomas, and drug-induced [epidermal growth factor receptor (EGFR) inhibitors, steroids, etc] acneiform eruptions, along with their diagnosis and therapeutic approaches. The major distinguishing factor in acneiform eruptions is that, in contrast to acne, there are no comedones (whiteheads or blackheads).     

Nevus Comedonicus Syndrome—Nevus Comedonicus Associated with Ipsilateral Polysyndactyly and Bilateral Oligodontia

Abstract: A 7‐year‐old boy diagnosed as a case of nevus comedonicus syndrome is presented because of the rarity of the condition and the association of the previously unreported features oligodontia and unilateral polysyndactyly restricted to the same side as the nevus comedonicus.     

Extensive inflammatory nevus comedonicus involving half of the body

Nevus comedonicus is an uncommon variant of adnexal hamartoma without known cause. It usually occurs on the face, neck and chest and appears as groups of closely arranged dilated follicular openings with keratin plugs. We report extensive inflammatory nevus comedonicus in a 14-year-old boy involving half of his body, limited by the midline, with suppuration and residual scarring. The lesions first appeared at 3 years of age and worsened at the start of puberty. The clinical features, etiopathology, histopathology and treatment options of nevus comedonicus are briefly reviewed in the light of the literature.     

Nevus Comedonicus in Oral‐Facial‐Digital Syndrome Type 1: A New Finding or Overlapping Syndromes?

We report a patient with oral‐facial‐digital syndrome type 1 (OFDS1) who exhibited features overlapping those of nevus comedonicus syndrome, an unusual presentation that may potentially represent a new variant of OFDS1. OFDS1 and nevus comedonicus syndrome represent two rare syndromes with numerous overlapping features that have yet to be described in relation to one another. The features present in our patient led us to propose the possibility of a new variant of OFDS1 in which nevus comedonicus represents a cutaneous manifestation of the syndrome. Knowledge of this potential relationship is important for identification and management of the syndromes' accompanying manifestations in affected patients and may offer further insight into crossroads of pathogenesis.     

Linear Morhpea,Nevus Comedonicus,and Lichen Striatus in a 5‐Year‐Old Girl

Abstract: Linear morphea, lichen striatus, and nevus comedonicus are rare conditions. We describe a five‐year‐old girl in whom all three of these dermatoses are present.     

Nevus comedonicus with hidradenoma papilliferum and syringocystadenoma papilliferum in the female genital area

Background Nevus comedonicus is an uncommon malformation of the pilosebaceous unit. Association of nevus comedonicus with tumors originating from the apocrine gland has not previously been reported. Method We present a case of nevus comedonicus associated with hidradenoma papilliferum (HAP) and syringocystadenoma papilliferum (SCAP) in the female genital area. Results Histological features strongly suggested nevus comedonicus associated with HAP and SCAP. Conclusion Although the association of nevus comedonicus with HAP and SCAP is very rare, the possibility of coexistence cannot be excluded.     

The Nevus Comedonicus Syndrome: A case Report with Emphasis on Associated Internal Manifestations

A 14-year-old boy with nevus comedonicus, multiple congenital abnormalities of the spine, and a central nervous system disorder is described. The associated abnormalities previously reported with nevus comedonicus are summarized. Thorough evaluation of patients with nevus comedonicus may disclose the occurrence of certain internal abnormalities in syndromic association.     

Successful treatment of late‐onset nevus comedonicus with Er:YAG laser

Nevus comedonicus, a rare congenital hamartoma of the pilosebaceous unit, is characterized by keratotic plugging. It usually occurs after birth and during early childhood. It rarely appears in adulthood. Despite the benign nature of the condition, it usually requires treatment due to aesthetic reasons. Several treatments have been reported in nevus comedonicus, most of them resulting with recurrences. Here, we report a case of nevus comedonicus with adult onset, successfully treated with erbium‐doped yttrium aluminum garnet (Er:YAG) laser therapy.     

Unilateral linear basal cell nevus

Clinical, histopathological, electron-microscopical and cytophotometrical features of a case of linear unilateral basal cell nevus are reported. Several publications exist on basaliomas originating in a nevus verrucosus or nevus comedonicus. Our case, however, is regarded as an abortive form of the basal cell nevus syndrome due to somatic mutation. Only some few comparable cases are documented in the literature.     

Nevus comedonicus syndrome

BACKGROUND: Nevus comedonicus is a rare disease and diagnosis is made chiefly on clinical grounds. It may occur in isolation, or in rare cases, it may be combined with other congenital malformations to constitute nevus comedonicus syndrome. We report a case of this disease herein. PATIENTS AND METHODS: A young woman aged 20 years presented with cribriform plaques since birth resulting from the juxtaposition of depressed pigmented scars and comedonic lesions. These lesions were found on the entire face, the left hemithorax and the left upper limb, with well delineated distribution stopping at the median line. The patient's history revealed congenital cataract of the left eye operated at the age of 10 years. Clinical diagnosis of nevus comedonicus was confirmed by histological examination of the skin. Laboratory screening for other associated malformations revealed no abnormalities. Oral retinoids were proposed but the patient refused all treatments. DISCUSSION: Nevus comedonicus is one of the rarest forms of cutaneous nevus. This case is original as regards the extent and topography of the nevus covering the left side of the patient's body and its association with congenital cataract potentially indicating nevus comedonicus syndrome. This syndrome is extremely rare and belongs to a large group of epidermal nevus syndromes characterised by association of nevus and extracutaneous malformations, particularly ocular, skeletal and neurological.     

Nevus comedonicus with epidermolytic hyperkeratosis

A 7-year-old girl had a linear nevus comedonicus affecting the right upper limb. Histologic examination of two biopsies specimens showed both the common changes of nevus comedonicus and the presence of epidermolytic hyperkeratosis. Therefore, nevus comedonicus should be included in the list of dermatoses having the distinctive histologic pattern of epidermolytic hyperkeratosis.     

Keratoacanthoma arising in nevus comedonicus

Nevus comedonicus is a benign hamartoma of the pilosebaceous unit and is considered as a rare subtype of epidermal nevus. It was first described in 1895. It manifests as a group of closely dilated follicular openings with dark keratin plugs resembling comedones. Malignant degeneration of a nevus comedonicus is exceptional; we report a case of keratoacanthoma arising in extensive nevus comedonicus.     

Cytokeratin and filaggrin expression in nevus comedonicus

To elucidate the pathogenesis of abnormal keratinization in nevus comedonicus, we performed an immunohistochemical study using antikeratin and antifilaggrin (filament-aggregating protein) antibodies. There were no significant differences between nevus comedonicus and normal skin in cytokeratin expression. Although filaggrin was only detected in the granular layer in open comedones, filaggrin was detected in both superficial cells and also intermediate cells in closed comedones, suggesting that filaggrin is involved in the formation of closed comedones. The disorder of terminal differentiation related to filaggrin may play a role in the pathogenesis of abnormal keratinization in nevus comedonicus.     

Epidermal nevus syndrome and didymosis aplasticosebacea

Abstract:  The epidermal nevus syndrome is a disease complex consisting of the association of an epidermal nevus with various developmental abnormalities of the skin, eyes, nervous, skeletal, cardiovascular, and urogenital systems. The epidermal nevi are classified according to their predominant component; nevus sebaceus (sebaceous glands), nevus comedonicus (hair follicles), and nevus verrucosus (keratinocytes). We report a neonate who presented with a nevus sebaceus on the scalp and face as well as a coloboma and dermoid on his left eye. Within the sebaceous nevus on the scalp, circumscribed lesions of aplasia cutis congenita were detected, which is consistent with the recently proposed term in the literature didymosis aplasticosebacea.     

Nevus Comedonicus: Case Report and Brief Review of the Literature

Abstract: We report extensive nevus comedonicus in a female patient that involved half of her body entirely, with infected cystic lesions as well as typical scars, limited by the midline. The lesions worsened at the beginning of puberty. A brief review of the literature highlights the histopathologic, etiopathogenic, and therapeutic aspects.     

Nevus Comedonicus: A Case Series

Twelve previously unreported cases of nevus comedonicus are presented. Characteristic closely grouped dilated follicular openings with horny plugs that mimic comedones led to the diagnosis. One patient had nevus comedonicus syndrome and there were cases with atypical locations and unusual complications of this condition. We also highlight clinical associations and therapeutic options.