Dohi Memorial Lecture. New aspects of cutaneous mosaicism

Case Report: A Novel MVK Missense Mutation in the Sporadic Porokeratosis Ptychotropica in China

Porokeratosis ptychotropica (PPt) is a rare type of porokeratosis (PK) characterized by pruritic, reddish-brownish verrucous papules, and plaques usually around genital area or buttocks. Here, a case of a 70-year-old woman who was diagnosed as PPt was reported. The patient suffered from severe pruritic papules and plaques in the buttock region and pubis for 4 years. The skin lesions were giant, well-defined brown plaques with many satellite papules scattered around. Both clinical manifestations and histopathological features supported the diagnosis of PPt. In review of the identified mutation was found in patients with disseminated superficial actinic porokeratosis (DSAP) combined with PPt, while its unclear in PPt. To investigate the hypothesis that the variant reported in the present case report may played as an independent "likely pathogenic factor" of PPt. Consequently, a de novo missense pathogenic mutation in the MVK gene was identified in this case. Unexpectedly, it is a first report of a novel MVK mutation in sporadic PPt. This rare case suggested an isogenetic background between PPt and DSAP, which may help to explore the underlying pathogenesis of PPt.

Acne Syndromes and Mosaicism

Abnormal mosaicism is the coexistence of cells with at least two genotypes, by the time of birth, in an individual derived from a single zygote, which leads to a disease phenotype. Somatic mosaicism can be further categorized into segmental mosaicism and nonsegmental somatic mosaicism. Acne is a chronic illness characterized by inflammatory changes around and in the pilosebaceous units, commonly due to hormone- and inflammatory signaling-mediated factors. Several systemic disorders, such as congenital adrenal hyperplasia, polycystic ovarian syndrome, and seborrhoea-acne-hirsutism-androgenetic alopecia syndrome have classically been associated with acne. Autoinflammatory syndromes, including PAPA, PASH, PAPASH, PsAPASH, PsaPSASH, PASS, and SAPHO syndromes include acneiform lesions as a key manifestation. Mosaic germline mutations in the FGFR2 gene have been associated with Apert syndrome and nevus comedonicus, two illnesses that are accompanied by acneiform lesions. In this review, we summarize the concept of cutaneous mosaicism and elaborate on acne syndromes, as well as acneiform mosaicism.

Outcomes of Management of Glaucoma in Phacomatosis Pigmentovascularis Over the Last Three Decades: A Single-Center Experience

PURPOSE

To report the clinical outcomes of glaucoma management in patients with phacomatosis pigmentovascularis (PPV) treated over a period of 3 decades.

DESIGN

Retrospective cohort study.

PARTICIPANTS

Fifty-five eyes of 38 patients (21 unilateral and 17 bilateral) with glaucoma in PPV managed at one institution between January 1990 and December 2019 with a minimum follow-up of 1 year.

METHODS

Medical records of children with glaucoma in PPV were reviewed, and demographic and clinical data were collected. Surgical interventions included primary combined trabeculotomy-trabeculectomy (CTT), trabeculectomy with mitomycin C (MMC), and transscleral cyclophotocoagulation (TSCPC). Complete success was defined as intraocular pressure (IOP) ≥ 6 and ≤ 16 mmHg without medications and qualified success as IOP ≤ 16 mmHg with the use of up to 2 medications.

MAIN OUTCOME MEASURES

Intraocular pressure, best-corrected visual acuity (BCVA), corneal clarity, antiglaucoma medications at preoperative and postoperative visits (last visit), and complications.

RESULTS

Median age was 4 months (range, 0.2-252 months) at the time of glaucoma surgery. Thirty-nine eyes (74%) had primary CTT, 10 eyes (19%) had trabeculectomy with MMC, and 4 eyes (7%) with advanced glaucoma had TSCPC. Two eyes (3.6%) received medical treatment. Preoperative IOP reduced from a mean of 25.7 ± 8.4 mmHg on 0.8 ± 0.6 medications to 14.6 ± 5.2 mmHg on 0.4 ± 0.5 medications (P < 0.0001) at last follow-up after surgery (77.7 ± 56.5 months). Thirty-seven eyes (67.3%) required medications preoperatively, and 22 eyes (40%) required medications at the last follow-up. Of 25 patients with available BCVA at last follow-up, 9 (36%) had ≥ 20/60; of these, 6 had > 20/40. Four of 10 eyes that underwent trabeculectomy with MMC developed retinal detachment and were managed surgically; however, all of these eyes had poor visual outcomes. There was no incidence of bleb leakage, bleb-related infection, or endophthalmitis.

CONCLUSIONS

Combined trabeculotomy-trabeculectomy is safe and effective as a primary procedure for management of glaucoma in PPV. Trabeculectomy augmented with MMC as a second procedure was associated with a higher rate of complications.

Cutis marmorata telangiectatica congenita: a literature review

Background

Cutis marmorata telangiectatica congenita (CMTC) is a rare capillary malformation characterised by persistent reticulated marbled erythema. It tends to be associated with cutaneous atrophy, ulcerations and body asymmetry. CMTC is usually reported to be a benign condition; however, associated anomalies are not rare. Here, we have compiled information on published CMTC patients with the aim to evaluate the proposed diagnostic criteria by Kienast et al. and address the clinical manifestations, associated anomalies, differential diagnoses, management and prognosis. Our review is based on a search of the PubMed database which retrieved studies between 1922 and April 2019. The search yielded 148 original articles with a total of 485 patients.

Results

Of the identified patients, 24.5% had generalised CMTC, 66.8% had localised and 8.7% had a non-specified distribution of CMTC. Associated anomalies were observed in 42.5% of patients, predominantly body asymmetry and neurological defects like seizure and developmental delay. Fewer patients (10.1%) had ophthalmological defects, usually glaucoma. The major criterium “absence of venectasia” was not met in 20.4% of patients.

Conclusion

We suggest that children with CMTC should be referred to an ophthalmologist for regular follow-up, and children with CMTC affecting the legs should be monitored for leg length discrepancy throughout the growth period. Furthermore, we suggest reconsideration of the major criterium “absence of venectasia” from the proposed diagnostic criteria, and instead include body asymmetry.

Clinical and Therapeutic Aspects of Linear Psoriasis: A Study of 30 Cases

BACKGROUND

Psoriasis affects 2-4% of the population, with the most common clinical type being plaque psoriasis. The linear form of psoriasis is very rare. The literature on linear psoriasis (LP) consists of only case reports, and data are few.

OBJECTIVE

This study aimed to better understand LP in a large-scale study.

PATIENTS AND METHODS

We retrospectively retrieved the medical records from 14 French medical centers of patients newly diagnosed clinically with LP, with or without the support of histology, between 1 February and 31 July 2015. For each case, we assessed the clinical features, treatments and treatment efficacy.

RESULTS

In total, 30 cases of LP (mean age 26.8 years, 13 males) were reported. Mean age at onset of LP was 20.0 years, with 18 developing LP in childhood. Ten patients had a family history of psoriasis, and two had psoriatic arthritis. A total of 19 cases were linear at onset, with concomitant classical psoriasis; these were termed "superimposed" LP. The remaining 11 cases were not associated with classical psoriasis and were termed "isolated" LP. In four of the superimposed cases, LP developed when the patient was receiving systemic treatment: methotrexate (n = 2), etanercept (n = 1) or infliximab (n = 1). Topical steroids were effective in 76% of cases in which they were used, and systemic treatment was effective in < 66%. Treatments were less effective in LP than in classical psoriasis.

DISCUSSION

We identified a wide range of LP, with two profiles: isolated LP and superimposed LP. Topical treatment usually evoked clinical response, with relative resistance to systemic therapy. Methotrexate and anti-tumor necrosis factor (TNF)-α therapies can possibly unmask LP.

Mixed vascular nevus syndrome: a report of four new cases and a literature review

BACKGROUND

Mixed vascular nevus (or nevus vascularis mixtus) represents an admixture of cutaneous vascular malformations of the telangiectatic type and angiospastic spots of nevus anemicus. It can occur as an purely cutaneous trait or as a hallmark of a neurocutaneous phenotype (mixed vascular nevus syndrome) characterised by the combination of: (I) paired vascular (telangiectatic and anemic) twin nevi and brain abnormalities of the Dyke-Davidoff-Masson type (i.e., crossed cerebral/cerebellar hemiatrophy with hypoplasia of the ipsilateral cerebral vessels and homolateral hypertrophy of the skull and sinuses (hyperpneumatisation) with contralateral hemispheric hypertrophy); or (II) paired vascular twin nevi and brain malformations of the Dyke-Davidoff-Masson type in association with systemic abnormalities consisting in facial asymmetry, skeletal anomalies (i.e., Legg-Calvé-Perthes-like disease) and disorders of autoimmunity (i.e., diabetes, thyroiditis). In 2014, Happle proposed to name the syndrome with the eponym Ruggieri-Leech syndrome.

METHODS

Review of the existing literature on nevus vascularis mixtus and information on our personal experience on new cases and follow-up of previously reported cases by some of us.

RESULTS

The existing literature revealed 4 previous studies including 33 cases with an inferred purely cutaneous trait and 3 cases with a combination of paired vascular twin nevi and brain malformation of the Dyke-Davidoff-Masson type. Our personal experience includes 4 unpublished patients (1 female and 3 males; currently aged 2 to 34 years) seen and followed-up at our Institutions in Italy who had: paired vascular nevi involving either the face (n=2) or the face and parts of the body (n=2); facial asymmetry (n=4); mild to moderate facial dysmorphic features (n=2); developmental delay (n=3); seizures/stroke-like episodes and associated hemiplegia (n=4); muscular hypotrophy (n=2); mild to moderate hemispheric atrophy (n=4); skull osseous hypertrophy (n=4); hyperpneumatisation of the sinuses (n=2); hypoplastic brain vessels (n=4); colpocephaly and malformation of cortical development (n=2). Follow-up data on our previous 2 cases revealed that the vascular abnormalities in the skin and nervous system were stable over years without neurological progression or deterioration.

CONCLUSIONS

Pathogenically, this complex phenotype suggests that embryonic pairing and somatic recombination of recessive (didymotic) alleles controlling the balance between constriction (i.e., nevus anemicus) and dilatation (i.e., nevus telangiectaticus) of blood vessels could be the primary event causing the phenomena of cutaneous and brain vascular twin spotting and the paired phenomena of skull hyperpneumatisation vs. hypertrophy and brain megalencephaly/colpocephaly vs. cortical dysplasia. This association is likely more frequent than previously thought and should be investigated by means of: (I) brain and spinal cord imaging (combination of CT and MRI studies); (II) skeletal X-ray studies (when dictated by clinical findings); (III) systemic ultrasound studies; (IV) neurophysiologic studies (EEG); (V) psychomotor testing; (VI) and laboratory investigation (including immune-mediated dysfunction).

Mosaic Neurocutaneous Disorders and Their Causes

Neurocutaneous disorders are a heterogeneous group of conditions (mainly) affecting the skin [with pigmentary/vascular abnormalities and/or cutaneous tumours] and the central and peripheral nervous system [with congenital abnormalities and/or tumours]. In a number of such disorders, the skin abnormalities can assume a mosaic patterning (usually arranged in archetypical patterns). Alternating segments of affected and unaffected skin or segmentally arranged patterns of abnormal skin often mirror similar phenomena occurring in extra-cutaneous organs/tissues [eg, eye, bone, heart/vessels, lung, kidney and gut]. In some neurocutaneous syndromes the abnormal mosaic patterning involve mainly the skin and the nervous system configuring a (true) mosaic neurocutaneous disorder; or an ordinary trait of a neurocutaneous disorder is sometimes superimposed by a pronounced linear or otherwise segmental involvement; or, lastly, a neurocutaneous disorder can occur solely in a mosaic pattern. Recently, the molecular genetic and cellular bases of an increasing number of neurocutaneous disorders have been unravelled, shedding light on the interplays between common intra- and extra-neuronal signalling pathways encompassing receptor-protein and protein-to-protein cascades (eg, RAS, MAPK, mTOR, PI3K/AKT and GNAQ pathways), which are often responsible of the mosaic distribution of cutaneous and extra-cutaneous features. In this article we will focus on the well known, and less defined mosaic neurocutaneous phenotypes and their related molecular/genetic bases, including the mosaic neurofibromatoses and their related forms (ie, spinal neurofibromatosis and schwannomatosis); Legius syndrome; segmental arrangements in tuberous sclerosis; Sturge-Weber and Klippel-Trenaunay syndromes; microcephaly/megalencephaly-capillary malformation; blue rubber bleb nevus syndrome; Wyburn-Mason syndrome; mixed vascular nevus syndrome; PHACE syndrome; Incontinentia pigmenti; pigmentary mosaicism of the Ito type; neurocutaneous melanosis; cutis tricolor; speckled lentiginous syndrome; epidermal nevus syndromes; Becker's nevus syndrome; phacomatosis pigmentovascularis and pigmentokeratotica; Proteus syndrome; and encephalocraniocutaneous lipomatosis.

Epidermal nevus syndromes

The term epidermal nevus syndrome (ENS) has been used to describe the association of epidermal hamartomas and extracutaneous abnormalities. Although many continue to use the term "ENS," it is now understood that this is not one disease, but rather a heterogeneous group with distinct genetic profiles defined by a common cutaneous phenotype: the presence of epidermal and adnexal hamartomas that are associated with other organ system involvement. One commonality is that epidermal nevi often follow the lines of Blaschko and it appears the more widespread the cutaneous manifestations, the greater the risk for extracutaneous manifestations. The majority of the extracutaneous manifestations involve the brain, eye, and skeletal systems. The CNS involvement is wide ranging and involves both clinical manifestations such as intellectual disability and seizures, as well as structural anomalies. Several subsets of ENS with characteristic features have been delineated including the nevus sebaceus syndrome, Proteus syndrome, CHILD syndrome, Becker's nevus syndrome, nevus comedonicus syndrome, and phakomatosis pigmentokeratotica. Advances in molecular biology have revealed that the manifestations of ENS are due to genomic mosaicism. It is likely that the varied clinical manifestations of ENS are due in great part to the functional effects of specific genetic defects. Optimal management of the patient with ENS involves an interdisciplinary approach given the potential for multisystem involvement. Of note, epidermal nevi have been associated with both benign and malignant neoplasms, and thus ongoing clinical follow-up is required.

Phakomatosis Pigmentovascularis Type IIB: A Case Report

Phakomatosis Pigmentovasularis (PPV) is a rare condition defined by the presence of both vascular and melanocytic nevi occurring in the same patient. We report the case of a 27-year-old Chinese female who presented with generalized port-wine stains over the left trigeminal region, trunk, and limbs, diffuse dermal melanosis on the back, nevus of Ota on the right cheek, and scleral melanosis. Her port-wine stain on the trunk was distributed in a checker-board pattern. She was otherwise well. She was diagnosed with phakomatosis pigmentovascularis (PPV) Type IIb. The 'twin spotting' phenomenon has been proposed in the pathogenesis of PPV, and PPV is an example of non-alleleic twin spotting. The checkerboard distribution of port-wine stain in our patient follows the type II pattern of distribution in cutaneous mosaics. This lends further credence to the proposed hypothesis of twin spotting and cutaneous mosaicism in the pathogenesis of PPV.

Klippel-Trenaunay syndrome in a boy with concomitant ipsilateral overgrowth and undergrowth

Klippel-Trenaunay syndrome comprises congenital vascular malformations of the capillary (nevus flammeus), venous (varicosities) or lymphatic systems and disturbed (usually over-) growth of one or more extremities and adjacent parts of the trunk. In some individuals the affected body area may show reduced rather than increased growth. Such patients have been described inverse Klippel-Trenaunay syndrome and included within the spectrum of the syndrome. We report on a 3-year-old boy with vascular malformation of the nevus flammeus type extending from the right buttock to the sole of the right foot with clinical and radiological evidence of leg varicosities and underlying deficiency of the soft tissues and bone. In addition, he had macrodactyly of the first, second, and third toes with small nails, and cutaneous syndactyly of the second and third toes of the ipsilateral foot. Cranial magnetic resonance imaging showed high signal lesions in the peritrigonal areas with normal spinal images. This mosaic phenotype demonstrates that decreased and increased growth can coexist in the same body area of an individual with Klippel-Trenaunay syndrome.

It's never too early to get it Right: A conserved role for the cytoskeleton in left-right asymmetry

For centuries, scientists and physicians have been captivated by the consistent left-right (LR) asymmetry of the heart, viscera, and brain. A recent study implicated tubulin proteins in establishing laterality in several experimental models, including asymmetric chemosensory receptor expression in C. elegans neurons, polarization of HL-60 human neutrophil-like cells in culture, and asymmetric organ placement in Xenopus. The same mutations that randomized asymmetry in these diverse systems also affect chirality in Arabidopsis, revealing a remarkable conservation of symmetry-breaking mechanisms among kingdoms. In Xenopus, tubulin mutants only affected LR patterning very early, suggesting that this axis is established shortly after fertilization. This addendum summarizes and extends the knowledge of the cytoskeleton's role in the patterning of the LR axis. Results from many species suggest a conserved role for the cytoskeleton as the initiator of asymmetry, and indicate that symmetry is first broken during early embryogenesis by an intracellular process.

Itchy lesions in pigmented skin

A 37-year-old woman with type VI skin presented with 1-year history of pruritic lesions affecting her arms, chest and legs. The lesions were approximately 5 mm in diameter, annular and with a raised border. A skin biopsy was performed which showed a diagnosis of disseminated superficial actinic porokeratosis. Porokeratosis is an unusual presentation in pigmented skin and there are very limited reports of this occurrence in the literature.

A unified model for left-right asymmetry? Comparison and synthesis of molecular models of embryonic laterality

Understanding how and when the left-right (LR) axis is first established is a fundamental question in developmental biology. A popular model is that the LR axis is established relatively late in embryogenesis, due to the movement of motile cilia and the resultant directed fluid flow during late gastrulation/early neurulation. Yet, a large body of evidence suggests that biophysical, molecular, and bioelectrical asymmetries exist much earlier in development, some as early as the first cell cleavage after fertilization. Alternative models of LR asymmetry have been proposed that accommodate these data, postulating that asymmetry is established due to a chiral cytoskeleton and/or the asymmetric segregation of chromatids. There are some similarities, and many differences, in how these various models postulate the origin and timing of symmetry breaking and amplification, and these events' linkage to the well-conserved subsequent asymmetric transcriptional cascades. This review examines experimental data that lend strong support to an early origin of LR asymmetry, yet are also consistent with later roles for cilia in the amplification of LR pathways. In this way, we propose that the various models of asymmetry can be unified: early events are needed to initiate LR asymmetry, and later events could be utilized by some species to maintain LR-biases. We also present an alternative hypothesis, which proposes that individual embryos stochastically choose one of several possible pathways with which to establish their LR axis. These two hypotheses are both tractable in appropriate model species; testing them to resolve open questions in the field of LR patterning will reveal interesting new biology of wide relevance to developmental, cell, and evolutionary biology.

Cutaneous clues for diagnosing X-chromosomal disorders

In a multidisciplinary outpatient clinic for hereditary skin diseases and/or syndromes involving the skin, 7% (30 of 409) of patients were found to have an abnormality involving the X chromosome, a mutation in a gene located on the X chromosome or a clinical diagnosis of an X-linked monogenetic condition. The collaboration of a dermatologist and a clinical geneticist proves to be very valuable in recognizing and diagnosing these conditions. By combining their specific expertize in counselling an individual patient, X-linked diagnoses were recognized and could be confirmed by molecular and/or cytogenetic studies in 24 of 30 cases. Mosaicism plays an important role in many X-linked hereditary skin disorders. From our experience, we extracted clinical clues for specialists working in the field of genetics and/or dermatology for considering X-linked disorders involving the skin.

Genodermatoses caused by genetic mosaicism

Genetic mosaicism is defined as the existence of at least two genetically distinct cell populations within one individual. Mosaic presentation of genetic disorders is common and is often particularly obvious in the skin, because there it will generate recognizable patterns. Recognizing those can frequently assist in establishing a diagnosis. In this review, we discuss the mechanisms that give rise to genetic mosaicism. We describe its most frequent cutaneous manifestations that are relevant to paediatric practice. While most mosaic genetic diseases are rare, it is important to recognize them so that patients and parents may receive appropriate genetic counselling. Moreover, recent developments are now resulting in novel, targeted treatments for such disorders that promise to considerably improve patients' lives.

Patterned disorders in dermatology

The skin gives us an opportunity to study pathologies unapparent in other systems such as patterned disorders. Among the best-identified patterns of skin disorders are the well-known lines of Blaschko, but other types of skin-patterned lesions have also been recognized. This short review will describe and discuss these different patterns and their pathophysiologic mechanisms, such as somatic mosaicism and X-chromosome associated mosaicism. Cutaneous patterned disorders are thought to be associated usually with inherited diseases per se, but in fact they are also reported in so-called acquired diseases. These cases suggest the existence of an underlying defect in a gene closely associated with the disease pathogenesis. The study of these acquired patterned disorders in the future may help us to understand the biologic foundations and pathogenesis of common human diseases.

Syndromic nevoid hypermelanosis: description of seven cases with a 10-year follow up

Skin lesions can often be the only sign of an underlying systemic abnormality which will require further investigation. Several syndromic conditions are diagnosed after their cutaneous marker, which is in most cases a nevus. We report a neurocutaneous condition which we named "syndromic nevoid hypermelanosis" (SNH). We studied seven patients who presented with hyperpigmented disseminated macules (melanotic or pigmented nevi) as a cardinal sign. Neurological abnormalities were detected in all cases and skeletal dysmorphism in four. In spite of the genetic alteration that may be the cause of this disease, dermatologists should be able to diagnose it based on its semiological features and distinguish it from other neurocutaneous conditions. We consider SNH to be a distinct clinical entity that has not been clearly defined until now.

Linear psoriasis - a case report

A 56-year-old woman presented with a 3-month history of erythematous plaques covered by scales and limited to the right side of her body. The plaques were arranged along Blaschko's lines with a marked mid-line cutoff. The histopathologic analysis of a skin biopsy in conjunction with the anamnesis allowed the diagnosis of linear psoriasis. Our patient showed a good clinical response to antipsoriatic treatment.

Far from solved: a perspective on what we know about early mechanisms of left-right asymmetry

Consistent laterality is a crucial aspect of embryonic development, physiology, and behavior. While strides have been made in understanding unilaterally expressed genes and the asymmetries of organogenesis, early mechanisms are still poorly understood. One popular model centers on the structure and function of motile cilia and subsequent chiral extracellular fluid flow during gastrulation. Alternative models focus on intracellular roles of the cytoskeleton in driving asymmetries of physiological signals or asymmetric chromatid segregation, at much earlier stages. All three models trace the origin of asymmetry back to the chirality of cytoskeletal organizing centers, but significant controversy exists about how this intracellular chirality is amplified onto cell fields. Analysis of specific predictions of each model and crucial recent data on new mutants suggest that ciliary function may not be a broadly conserved, initiating event in left-right patterning. Many questions about embryonic left-right asymmetry remain open, offering fascinating avenues for further research in cell, developmental, and evolutionary biology.

Genetic factors in non-syndromic congenital heart malformations

The genetic defect in most patients with non-syndromic congenital heart malformations (CHM) is unknown, although more than 40 different genes have already been implicated. Only a minority of CHM seems to be due to monogenetic mutations, and the majority occurs sporadically. The multifactorial inheritance hypothesis of common diseases suggesting that the cumulative effect of multiple genetic and environmental risk factors leads to disease, might also apply for CHM. We review here the monogenic disease genes with high-penetrance mutations, susceptibility genes with reduced-penetrance mutations, and somatic mutations implicated in non-syndromic CHM.

Mibelli revisited: a case of type 2 segmental porokeratosis from 1893

In autosomal dominant skin disorders, a pronounced mosaic involvement may sometimes be found to be superimposed on the ordinary nonsegmental lesions. Such "type 2 segmental manifestation" reflects loss of heterozygosity occurring at an early developmental stage, giving rise to a cell clone that lacks the corresponding wild-type allele. Here, this genetic concept is applied to an unusual case of plaque-type porokeratosis of Mibelli (PM) as published in 1893 by Vittorio Mibelli in the International Atlas of Rare Skin Diseases. The right forearm and hand of the 21-year-old patient showed a pronounced linear porokeratosis that had developed since the age of 2 years. Moreover, nonsegmental lesions of PM involved both hands and forearms as well as the face and the neck, having first been noticed at the age of 7 years. Two siblings and the father were likewise affected with PM. Hence, Mibelli's case from 1893 meets all of the criteria of a type 2 segmental manifestation of an autosomal dominant skin disorder. Recognizing such cases of superimposed segmental involvement may help elucidate the molecular basis of PM.

Phakomatosis cesioflammea with late-onset glaucoma and acquired nevus spilus-like lesion - 15 years of follow-up

Phakomatosis pigmentovascularis is a very rare disease characterized by coexistence of a capillary malformation with various melanocytic lesions, including dermal melanocytosis (Mongolian spots), nevus spilus, and nevus of Ota. As of now about 200 cases have been reported, most are of Japanese origin and about half of reported cases are associated with various systemic involvement. We present a 15-year-old Taiwanese male with phakomatosis cesioflammea who developed, during adolescence, a nevus spilus-like lesion and late-onset open angle glaucoma, suggesting that long-term ophthalmic follow-up is necessary in this type of patient.

Cutaneous mosaicism: a molecular and clinical review

Physicians have long been intrigued by the distinct patterns created by epidermal nevi and other mosaic cutaneous disorders. Although many of the molecular mechanisms underlying these disorders remain unrevealed, with the release of the results of the Human Genome Project our knowledge is rapidly increasing. The underlying genetic defects for many of the X-linked and mosaic disorders have recently been identified. Advances in technology, such as the array comparative genomic hybridization, will provide the tools for continued gene discovery and expanded understanding of the pathogenic mechanisms underlying mosaic skin conditions.

Mosaic manifestations of monogenic skin diseases

A genetic mosaic is defined as an organism which is composed of genetically different cell lines which originate from a homogeneous zygote. Etiologically, cutaneous mosaics can be divided into two large categories, epigenetic mosaicism and genomic mosaicism. Genomic mosaics which have two or more genetically different cell populations are not inherited with the exception of para-dominant inheritance pattern. Epigenetic mosaics have a structurally homogeneous cell population but there are functional differences induced by modifying factors in the form of gene-steering retroviral elements that can be inherited. We distinguish five different manifestation patterns of mosaicism, including the Blaschko lines pattern, patchy pattern without midline separation, checkerboard pattern, phylloid pattern and lateralization pattern. All forms of epigenetic mosaicism, including the various patterns of X-inactivation, appear to be caused by the action of retrotransposons. A new concept is functional autosomal mosaicism transmittable through the action of retrotransposons

A new indication of botulinum toxin: leiomyoma-related pain

Cutaneous leiomyomas are benign neoplasms with smooth muscle differentiation. They are painful tumors of the skin. Nearly 90% of patients report lesion-associated pain, characteristically precipitated by cold or trauma. In the published literature, surgical excision and pharmacologic agents such as analgesics, nifedipine, phenoxybenzamine hydrochloride, gabapentin, and doxazosin have been used in the treatment of leiomyomas with varying degrees of success. Herein we report the use of botulinum toxin for the relief of pain in leiomyomas. The use of botulinum toxin provided a decrease in the amount of analgesic use in our patient. Our experience showed that botulinum toxin might offer a new therapeutic approach for leiomyoma by reducing the intensity and the frequency of the pain. Botulinum toxin has no known systemic adverse effects, and can be combined with other treatments without concern for drug interactions. Like any other medication, aside from its actual pharmacologic effect, botulinum toxin may have had a placebo effect in our patient.

Perspectives and open problems in the early phases of left-right patterning

Embryonic left-right (LR) patterning is a fascinating aspect of embryogenesis. The field currently faces important questions about the origin of LR asymmetry, the mechanisms by which consistent asymmetry is imposed on the scale of the whole embryo, and the degree of conservation of early phases of LR patterning among model systems. Recent progress on planar cell polarity and cellular asymmetry in a variety of tissues and species provides a new perspective on the early phases of LR patterning. Despite the huge diversity in body-plans over which consistent LR asymmetry is imposed, and the apparent divergence in molecular pathways that underlie laterality, the data reveal conservation of physiological modules among phyla and a basic scheme of cellular chirality amplified by a planar cell polarity-like pathway over large cell fields.

Epidermodysplasia verruciformis-associated and genital-mucosal high-risk human papillomavirus DNA are prevalent in nevus sebaceus of Jadassohn

BACKGROUND

The hamartoma nevus sebaceus (NS) presents at birth or early childhood as a yellowish plaque characterized histologically by variable acanthosis, papillomatosis, sebaceus hyperplasia, and proliferations of adnexal structures. Clinically apparent human papillomavirus (HPV) infection is also recognized by acanthosis and papillomatosis.

OBJECTIVE

We sought to determine the prevalence and physical state of HPV DNA in NS.

METHODS

DNA was retrieved from 44 formalin-fixed, paraffin-embedded samples of NS (22 with secondary tumors [eg, trichoblastoma, verruca, syringocystadenoma papilliferum] and two epidermal nevi [EN]). Nested polymerase chain reaction with multiple degenerate consensus and type-specific primers and direct sequencing of polymerase chain reaction products was performed. For selected cases, in situ hybridization using probes specific for HPV 5 and 8 and for high-risk genital-mucosal HPV types was performed.

RESULTS

HPV DNA was detected in 82% of NS and both EN, and consisted of genital-mucosal HPV types in 52% (HPV 6, 16, and 33) and a diverse variety of epidermodysplasia verruciformis-associated HPV types in 61%, including well-known epidermodysplasia verruciformis HPV types (5, 8, 15, 20, 22, 24, 36, 37, 38, and 80) and putatively novel epidermodysplasia verruciformis HPV types (DL285, DL287, DL436, and alb-1, -2, -3, -5, -6, -7, -8, -10, -11, -12, and -13). HPV coinfection was frequent, found in 48% (two HPV genotypes in 35% and 3 in 13%). Of NS and EN, 42% had HPV genotypes associated with cancer (ie, HPV 5, 8, 16, 20, 33, and 38); the two most commonly identified HPV types where HPV 16 (39%) and HPV 38 (18%). No differences were detected comparing frequency of HPV DNA detected with respect to age or presence of a secondary tumor. Histologically, all NS and EN showed HPV-associated cytopathic effects (ie, perinuclear halos, altered keratohyaline granules). By in situ hybridization, 64% (18/28) were positive, showing a low-intensity, punctate nuclear signal in epidermal and adnexal keratinocytes, indicating viral integration and low viral genome copy number.

LIMITATIONS

Absence of adjacent, uninvolved normal-appearing skin control samples.

CONCLUSION

HPV DNA is prevalent in NS, and HPV 16, the most frequently detected genotype, appears to be integrated into the host genome. Whether HPV represents a commensal infection caused by localized cutaneous predisposition, or is an essential factor in the pathogenesis of NS is unknown. The high frequency of oncogenic HPV types implicates maternal transmission of HPV and infection of an ectodermal stem cell leading to an epigenetic mosaic and altered skin development manifested along Blaschko's lines.

Giant café-au-lait macule in neurofibromatosis 1: a type 2 segmental manifestation of neurofibromatosis 1?

Type 2 segmental manifestation of autosomal dominant dermatoses refers to pronounced segmental lesions superimposed on the ordinary nonsegmental phenotype, indicating loss of heterozygosity occurring at an early stage of embryogenesis. We describe a 20-year-old Taiwanese woman with typical lesions of neurofibromatosis type 1 (NF1) in the form of characteristic café-au-lait spots, neurofibromas, axillary freckling and Lisch nodules. In addition, a giant garment-like or "bathing-trunk" café-au-lait macule involved the lower half of the trunk, the buttocks, and parts of the thighs, being superimposed on the ordinary smaller spots of NF1. This large café-au-lait macule may be best explained as an example of type 2 segmental NF1. A novel mutation (3009delG) in exon 23 was also identified in this patient, which has not yet been described in sporadic and familial NF1.

Phakomatosis pigmentovascularis: Clinical findings in 15 patients and review of the literature

INTRODUCTION

Phakomatosis pigmentovascularis (PPV) is a rare syndrome characterized by the association of a vascular nevus with an extensive pigmentary nevus.

OBJECTIVE

We sought to study and evaluate clinical findings in patients with PPV referred to the laser department of our hospital.

METHODS

We revised the clinical findings of 15 patients with PPV and reclassified them according to Happle's new classification.

RESULTS

We studied 11 female patients and 4 male patients with a mean age of 21 years. Thirteen had phakomatosis cesioflammea, one cesiomarmorata, and one an unclassifiable form. Of 15 patients, 12 had nevus of Ota. The vascular involvement was extensive in our PPV population and 14 patients were affected in two or more areas. The mosaicism pattern in 13 patients was patchy and without a midline separation. The most frequent associations found were Sturge-Weber syndrome, Klippel-Trénaunay syndrome, and melanosis oculi.

LIMITATIONS

Limitations include the methods of case collection, that this is a retrospective study, and that there were a relatively small number of patients.

CONCLUSIONS

PPV are rare syndromes with a wide variability in their clinical expression. Most of the publications in the literature have only reported isolated cases.

Cutaneous mosaicism: right before our eyes

Autosomal recessive cutaneous disorders, including various types of epidermolysis bullosa (EB), usually manifest shortly after birth. The clinical course of these diseases is often characterized by severe complications, limited therapeutic options, and a poor prognosis. A study by Pasmooij et al. reported in this issue of the JCI unravels the molecular mechanisms by which germline mutations in non-Herlitz junctional EB can be corrected in vivo by multiple spontaneously occurring somatic mutational events, a phenomenon known as revertant mosaicism (see the related article beginning on page 1240). These insights open new avenues of thinking for the design of future gene therapy strategies for skin diseases.

Left-right patterning from the inside out: widespread evidence for intracellular control

The field of left-right (LR) patterning--the study of molecular mechanisms that yield directed morphological asymmetries in otherwise symmetrical organisms--is in disarray. On one hand is the undeniably elegant hypothesis that rotary beating of inclined cilia is the primary symmetry-breaking step: they create an asymmetric extracellular flow across the embryonic midline. On the other hand lurk many early symmetry-breaking steps that, even in some vertebrates, precede the onset of ciliary flow. We highlight an intracellular model of LR patterning where gene expression is initiated by physiological asymmetries that arise from subcellular asymmetries (e.g. motor-protein function along oriented cytoskeletal tracks). A survey of symmetry breaking in eukaryotes ranging from protists to vertebrates suggests that intracellular cytoskeletal elements are ancient and primary LR cues. Evolutionarily, quirky effectors like ciliary motion were likely added later in vertebrates. In some species (like mice), developmentally earlier cues may have been abandoned entirely. Late-developing asymmetries pose a challenge to the intracellular model, but early mid-plane determination in many groups increases its plausibility. Multiple experimental tests are possible.

Is the early left-right axis like a plant, a kidney, or a neuron? The integration of physiological signals in embryonic asymmetry

Embryonic morphogenesis occurs along three orthogonal axes. While the patterning of the anterior-posterior and dorsal-ventral axes has been increasingly well-characterized, the left-right (LR) axis has only relatively recently begun to be understood at the molecular level. The mechanisms that ensure invariant LR asymmetry of the heart, viscera, and brain involve fundamental aspects of cell biology, biophysics, and evolutionary biology, and are important not only for basic science but also for the biomedicine of a wide range of birth defects and human genetic syndromes. The LR axis links biomolecular chirality to embryonic development and ultimately to behavior and cognition, revealing feedback loops and conserved functional modules occurring as widely as plants and mammals. This review focuses on the unique and fascinating physiological aspects of LR patterning in a number of vertebrate and invertebrate species, discusses several profound mechanistic analogies between biological regulation in diverse systems (specifically proposing a nonciliary parallel between kidney cells and the LR axis based on subcellular regulation of ion transporter targeting), highlights the possible importance of early, highly-conserved intracellular events that are magnified to embryo-wide scales, and lays out the most important open questions about the function, evolutionary origin, and conservation of mechanisms underlying embryonic asymmetry.

Angiokeratoma circumscriptum arranged in a systematized band-like pattern suggesting mosaicism

A 10-year-old girl with vascular lesions that had been present since birth is reported. Initially, small red macules were limited to the legs, but later the lesions became more extensive. A hyperkeratotic aspect of the lesional skin surface had developed at the age of 2 years. On clinical examination, hyperkeratotic vascular lesions in a band-like distribution on the trunk, legs and face were observed. The type of lesion varied from discrete macules with no or slight hyperkeratosis to confluent, protruding verrucous plaques. The clinical and histopathological findings were consistent with a diagnosis of angiokeratoma circumscriptum. The systematized band-like arrangement observed in the present case strongly supports the concept that angiokeratoma circumscriptum reflects a mosaic state of a mutation that is so far unknown.