Large congenital melanocytic nevi and neurocutaneous melanocytosis: one pediatric center's experience

Metabolomic analysis reveals the biological characteristics of giant congenital melanocytic nevi

Giant congenital melanocytic nevi (GCMN) is a congenital cutaneous developmental deformity tumor that usually occurs at birth or in the first few weeks after birth, but its pathogenesis is still unclear. In this study, nuclear magnetic resonance-based metabolomics strategy was employed to evaluate the metabolic variations in serum and urine of the GCMN patients in order to understand its underlying biochemical mechanism and provide a potential intervention idea. Twenty-nine metabolites were observed to change significantly in serum and urine metabolomes, which are mainly involved in a variety of metabolic pathways including glyoxylate and dicarboxylate metabolism, TCA cycle and metabolisms of amino acids. The substantial cores of all the disturbed metabolic pathways are related to amino acid metabolism and carbohydrate metabolism and regulate the physiological state of the GCMN patients. Our results provide the physiological basis and physiological responses of GCMN and will be helpful for better understanding the molecular mechanisms of GCMN in future research.

Melanoma of the central nervous system based on neurocutaneous melanocytosis in childhood: A rare but fatal condition

BACKGROUND

Melanomas of the central nervous system (CNS) based on neurocutaneous melanocytosis (NCM) are exceptionally rare in childhood and have been described only sporadically. Rapidly progressive disease may represent a major challenge for treating physicians, especially given the limited knowledge about this condition. This analysis aimed to increase knowledge about the occurrence and treatment of these malignancies.

PROCEDURE

Data on diagnosis, treatment, and outcome of patients aged 0-18 years with CNS melanoma based on NCM recorded in the German Registry for Rare Pediatric Tumors (STEP registry) were analyzed. Additionally, published case reports on this condition were analyzed.

RESULTS

In STEP, five patients with leptomeningeal melanoma based on NCM were identified, with a median age at melanoma diagnosis of 3.7 years. Various multimodal treatments were performed: (partial) resection (n = 4), irradiation (n = 2), trametinib (n = 3), different cytostatics (n = 2), and anti-GD2 immunotherapy (n = 1). All patients died between 0.3 and 0.8 years after diagnosis. Including published case reports, 27 patients were identified with a median age of 2.8 years at melanoma diagnosis (range: 0.2-16.6). Fourteen of 16 cases with reported data had a NRAS alteration (88%), particularly NRAS p.Q61K (85%). In the expanded cohort, no patient survived longer than 1 year after diagnosis despite multimodal therapy (including trametinib; n = 9), with a median survival of 0.4 years (range 0.1-0.9).

CONCLUSIONS

CNS melanomas based on NCM in childhood are aggressive malignancies without curative treatment to date. Therapeutic approaches must be individualized. Genetic tumor sequencing is essential to improve understanding of tumorigenesis and potentially identify new therapeutic targets.

Melanoma on congenital melanocytic nevi

Among nevus-associated melanomas, which overall account for 20%-30% of all melanomas, those arising specifically in congenital melanocytic nevi are infrequent, but can be disproportionately frequent in childhood and adolescence. Congenital melanocytic nevi (CMNi) are common benign melanocytic tumors that are present at birth or become apparent in early childhood. They are classified based on the projected adult size. Small and medium-sized CMNi are frequent, whereas large/giant CMNi (over 20 cm in diameter) are rare, but can be associated with high morbidity due to marked aesthetic impairment and the risk of neurocutaneous syndrome or melanoma development. In this setting, melanomas can appear in early childhood and are very aggressive, while the risk of small-medium CMNi of developing melanoma is low and similar to non-congenital melanocytic nevi. Histologically, most melanomas on CMNi initiate their growth at the epidermal-dermal junction, but in large/giant CMNi they can develop entirely in the dermis, in deeper tissues, or in extracutaneous sites (especially in the central nervous system). Most CMNi harbour an NRAS mutation, but other genes are rarely involved, and gene translocations have recently been described. However, no prognostic implications have been associated with the CMN genotype. Melanomas developed on CMNi harbour additional molecular alterations to which the aggressive clinical course of these tumors has been attributed. This review covers the distinctive clinical and pathological aspects of melanomas on CMNi, and includes the epidemiology, etiopathogenesis, clinical and dermoscopic presentation, histological and molecular characteristics, as well as tumour behaviour.

Clinical Reasoning: A 30-Year-Old Woman Presenting With Rapidly Progressive Dementia and Extreme Hypoglycorrhachia

A 30-year-old woman presented with rapidly progressive dementia 1 month after the coronavirus disease 2019 infection. Repeated CSF analysis showed extreme hypoglycorrhachia, while cultures, metagenomic next-generation sequencing, and cytopathology testing of CSF were negative. Laboratory investigations for possible etiologies revealed elevated blood ammonia and cancer antigen 125. Brain MRI demonstrated bilateral symmetric diffuse cortical lesions with mild hyperintensity on T1-weighted image and postcontrast enhancement. A more thorough history and specific examinations subsequently indicated an underlying etiology. This case provides an approach for evaluating young patients with rapidly progressive dementia, extreme hypoglycorrhachia, and diffuse CNS lesions, highlighting the importance of considering a broad differential diagnosis.

Updates in the Management of Congenital Melanocytic Nevi

Congenital melanocytic nevi (CMN) carry an increased risk of melanoma and may be disfiguring, and consensus regarding treatment recommendations is lacking. While clinical monitoring is the standard of care, many caregivers are interested in its removal to prevent psychosocial burden or to decrease risk. Although melanoma can occur regardless of CMN removal, there are a variety of treatments that may offer improved cosmesis or local symptom control, including surgical excision, laser therapy, and other superficially destructive techniques. Regardless of the selected management, these patients are monitored for ongoing melanoma risk. An extensive discussion with families regarding the risks and benefits of observation versus active intervention is essential. To facilitate these discussions, we herein summarize current CMN management strategies and considerations.

Incidence of neurocutaneous melanosis in Japanese pediatric patients with congenital melanocytic nevi

Neurocutaneous melanosis (NCM) is a rare, non-hereditary neurocutaneous disorder characterized by excessive melanocytic proliferation in the skin and central nervous system. As no major studies have covered the incidence of NCM among Japanese patients with congenital melanocytic nevi (CMN), we prospectively investigated the incidence of NCM among Japanese patients who underwent initial treatment for CMN. The relationship of CMN and NCM was also investigated. Japanese pediatric patients with CMN under 1 year of age were included between January 2020 and November 2022, and all patients underwent brain MRI to check for NCM in this study. NCM lesions were most frequently seen in the amygdala, followed by the cerebellum, brainstem, and cerebral hemispheres. NCM was diagnosed on brain MRI in 31.6% of the 38 patients with CMN and in 25.0% of patients with no prior examination or treatment. Distribution and size of CMN, number of satellite nevi, rugosity and nodules were strongly associated with the existence of NCM, and these findings may guide a future registry study with a large cohort of CMN patients.

Neurological signs, symptoms and MRI abnormalities in patients with congenital melanocytic naevi and evaluation of routine MRI-screening: systematic review and meta-analysis

BACKGROUND

A congenital melanocytic naevus (CMN) is a rare skin condition that can be associated with abnormalities of the central nervous system (CNS). These anomalies can sometimes cause severe complications, and rarely death. Adequate information about aetiology and management is therefore crucial. To identify how to monitor patients with CMN, we aimed to estimate the prevalence of neurological involvement in patients with CMN and to summarize what specific neurological signs and symptoms and MRI abnormalities are reported in the medical literature. In addition, we summarized and evaluated the recommendations regarding MRI-screening reported in the medical literature.

METHODS

This review was registered in PROSPERO and reported according to the MOOSE checklist. A search was conducted in EMBASE (Ovid), PubMed, and the Cochrane Library. We included studies with 10 or more patients with CMN, reporting on neurological signs and symptoms or CNS MRI. Study selection, data extraction and methodological quality assessment were performed by two independent reviewers. A meta-analysis was used to assess the prevalence of neurological signs and symptoms.

RESULTS

Out of 1287 studies, fourteen studies were eligible for inclusion of which eight were included in the meta-analysis. Neurological signs and symptoms prevalence was 7.04% (CI 95% 4.47-10.93%) in the meta-analysis group and 6.26% (95% CI 3.85-10%) in a subgroup of patients with a CMN > 6 cm, evaluated in seven studies. Neurodevelopmental delay and seizures were the most frequently reported signs and symptoms. CNS melanocytosis and hydrocephalus were the most frequently reported MRI abnormalities. It was not possible to estimate the increased risk of neurological involvement in patients with CMN due to low quality of evidence and clinical heterogeneity.

CONCLUSION

Standardization in CMN studies and a multi-centre prospective study are needed to evaluate neurological involvement. Based on current literature, it is not possible to make strong recommendations on routine MRI-screening. For now, every clinical centre should decide on its own policy and weigh the advantages and disadvantages of routine MRI.

Genodermatoses associated with melanocytic nevi

Though melanocytic nevi are ubiquitous in the general population, they can also be key cutaneous manifestations of genetic syndromes. We describe genodermatoses associated with melanocytic nevi and discuss their clinical characteristics, cutaneous manifestations, underlying genetics, and, if applicable, guidelines for when genetic testing should be performed. We categorized these genodermatoses based on their association with congenital nevi, acquired nevi, or nevi whose first appearance is unknown. In many cases, the distinctive morphology or distribution of melanocytic nevi can be an important clue that an underlying genetic syndrome is present, allowing both the patient as well as family members to be screened for the more serious complications of their genetic disorder and receive education on potential preventative measures. As we continue to advance our understanding of how various genotypes give rise to the wide spectrum of phenotypes observed in these genodermatoses, we shall be able to better stratify risk and tailor our screening methods to clinically manage the heterogeneous manifestations of genodermatoses among these patients.

Care of Congenital Melanocytic Nevi in Newborns and Infants: Review and Management Recommendations

A pediatric dermatology expert working group performed a narrative review to describe care related to congenital melanocytic nevi (CMN) in neonates and infants. There are no published guidelines for most aspects of care, including routine skin care and visit intervals. Few guidelines exist for surgical management; newer recommendations favor conservative practice. Emerging evidence contributes to recommendations for screening MRI to evaluate for neural melanosis and related central nervous system complications, however, more research is needed. Risk for melanoma is generally low, but those with large, giant, or multiple CMN have a higher risk. Multidisciplinary care, with a focus on family and patient preferences, is of paramount importance. Without standardized screening and management guidelines, questions abound regarding appropriate physical examination intervals, potential treatment including full or partial excision, timing and frequency of imaging, melanoma risk, and assessment for neural melanosis. This review highlights the current state of knowledge concerning care of patients with CMN, reveals gaps in the literature surrounding skin care, and provides management recommendations. We additionally discuss cutaneous complications of CMN, such as pruritus, hypertrichosis, and wound healing. Resources and references for families and providers can help patients navigate this sometimes challenging diagnosis. Finally, we contribute expert care recommendations to the current body of literature as a foundation for the development of future, more comprehensive care guidelines.

Imaging and clinical features of neurocutaneous melanosis in the pediatric population

BACKGROUND

Neurocutaneous melanosis (NCM) is a rare nonfamilial phakomatosis characterized by the presence of congenital melanocytic nevi and abnormal melanocytes infiltration of the leptomeninges.

OBJECTIVE & METHODS

This paper shows the importance of early diagnosis and the most important imaging features of the disease on CT and MR scans. PubMed database was searched from January 1972 to September 2020. Papers including imaging findings of NCM, clinical, follow-up, and treatment features were collected, selecting only 89 studies.

DISCUSSION

NCM is a term used for the first time by van Bogaert in 1948. It refers to a condition caused by an error during morphogenesis and migration leading to leptomeningeal melanocytic accumulation. Although histological findings are the gold standard for diagnosis confirmation, neuroimaging and clinical features strongly support the suspect of NCM. Localization and extension of the lesions are predictive of neurological manifestations related to increased intracranial pressure, mass lesions, or spinal cord compression. CT demonstrates sites of increased density in the anterior temporal lobe - mainly the amygdala - thalami, cerebellum, and frontal lobes base. However, MRI is the best imaging method to diagnose central nervous system lesions, often appearing as T1-short signal areas of the cerebral parenchyma, indicative of central nervous system melanosis. MRI can also reveal associated intracranial and intraspinal abnormalities.

CONCLUSION

Early imaging, when available, is helpful if NCM suspect is raised and may be of guidance in comparing later studies. NCM requires a multidisciplinary approach since it is a multisystem disease with a genetic component.

Neurocutaneous Melanocytosis and Leptomeningeal Melanoma

Neurocutaneous melanocytosis (NCM) is a disorder characterized by multiple or large congenital nevi and excessive proliferation of melanocytes in the leptomeninges and brain parenchyma. The majority of NCM is a result of somatic mosaicism due to a single postzygotic mutation in codon 61 of NRAS. Patients with NCM are at high risk of developing leptomeningeal melanoma. The prognosis for leptomeningeal melanoma is poor with no known effective treatment options. We describe the clinical features, treatment, and outcome of 4 children with NCM and leptomeningeal melanoma and discuss the latest molecular findings and treatment options for this rare condition.

Distribution Patterns (7B Rule) and Characteristics of Large Congenital Melanocytic Nevi: A Retrospective Cohort Study in China

Large congenital melanocytic nevus has a high risk of malignancy. However, few studies have summarized its characteristics, treatments, outcomes and malignancy incidence in Chinese patients. This paper reviews a retrospective cohort study evaluating 1,171 patients from Shanghai Ninth People's Hospital between 1 January 1989 and 31 August 2019 using electronic medical records and phone calls to collect clinical and pathological data in which 133 patients were diagnosed with a large congenital melanocytic nevus. Three patients relapsed, and none developed melanoma among the qualified patients. Besides, a new “7B” rule for distribution patterns of large congenital melanocytic nevi was proposed, including bonce, bolero, back, bathing trunk, breast/belly, body extremity, and body. The most common distribution pattern of large congenital melanocytic nevi was bonce, and all blue nevi distributed as bonce. Statistical analysis showed a significant difference (P = 0.0249) in the “7B” patterns between the melanocytic nevus and the neuronevus. In conclusion, the malignancy rate of large congenital melanocytic nevi is much lower in China than in other regions and people of other races. The pathology of large congenital melanocytic nevus may decide its “7B” distribution pattern.

Neurocutaneous melanocytosis (melanosis)

Neurocutaneous melanosis (NCM; MIM # 249400; ORPHA: 2481], first reported by the Bohemian pathologist Rokitansky in 1861, and now more precisely defined as neurocutaneous melanocytosis, is a rare, congenital syndrome characterised by the association of (1) congenital melanocytic nevi (CMN) of the skin with overlying hypertrichosis, presenting as (a) large (LCMN) or giant and/or multiple (MCMN) melanocytic lesions (or both; sometimes associated with smaller "satellite" nevi) or (b) as proliferative melanocytic nodules; and (2) melanocytosis (with infiltration) of the brain parenchyma and/or leptomeninges. CMN of the skin and leptomeningeal/nervous system infiltration are usually benign, more rarely may progress to melanoma or non-malignant melanosis of the brain. Approximately 12% of individuals with LCMN will develop NCM: wide extension and/or dorsal axial distribution of LCMN increases the risk of NCM. The CMN are recognised at birth and are distributed over the skin according to 6 or more patterns (6B patterns) in line with the archetypical patterns of distribution of mosaic skin disorders. Neurological manifestations can appear acutely in infancy, or more frequently later in childhood or adult life, and include signs/symptoms of intracranial hypertension, seizures/epilepsy, cranial nerve palsies, motor/sensory deficits, cognitive/behavioural abnormalities, sleep cycle anomalies, and eventually neurological deterioration. NMC patients may be symptomatic or asymptomatic, with or without evidence of the typical nervous system changes at MRI. Associated brain and spinal cord malformations include the Dandy-Walker malformation (DWM) complex, hemimegalencephaly, cortical dysplasia, arachnoid cysts, Chiari I and II malformations, syringomyelia, meningoceles, occult spinal dysraphism, and CNS lipoma/lipomatosis. There is no systemic involvement, or only rarely. Pathogenically, single postzygotic mutations in the NRAS (neuroblastoma RAS viral oncogene homologue; MIM # 164790; at 1p13.2) proto-oncogene explain the occurrence of single/multiple CMNs and melanocytic and non-melanocytic nervous system lesions in NCM: these disrupt the RAS/ERK/mTOR/PI3K/akt pathways. Diagnostic/surveillance work-ups require physical examination, ophthalmoscopy, brain/spinal cord magnetic resonance imaging (MRI) and angiography (MRA), positron emission tomography (PET), and video-EEG and IQ testing. Treatment strategies include laser therapy, chemical peeling, dermabrasion, and surgical removal/grafting for CMNs and shunt surgery and surgical removal/chemo/radiotherapy for CNS lesions. Biologically targeted therapies tailored (a) BRAF/MEK in NCM mice (MEK162) and GCMN (trametinib); (b) PI3K/mTOR (omipalisib/GSK2126458) in NMC cells; (c) RAS/MEK (vemurafenib and trametinib) in LCMNs cells; or created experimental NMC cells (YP-MEL).

Surgical treatment of children and youth with congenital melanocytic nevi: self- and proxy-reported opinions

PURPOSE

The role of surgery in the management of congenital melanocytic nevi (CMN) is controversial. Data on surgical outcomes and predictors of satisfaction remain scarce.

METHODS

An online survey was employed following worldwide recruitment of youth aged 14-25 years (n = 44) and parents of children ≤ 18 years (n = 249) with CMN to query patterns of treatment and satisfaction with and opinions about the benefits of surgery.

RESULTS

In proxy-reports, 121 of 249 (49%) and in self-reports 30 of 44 (75%) participants underwent CMN excision. The most common reasons for surgery were psychosocial determinants, aesthetic improvement, and melanoma risk reduction. The overall satisfaction with surgical management was good, although no predictors for satisfaction could be identified. Higher current age of the child was found to predict decision regret in proxy-reports. Most participants indicated that having a scar is more socially acceptable than a CMN. Opinions differed on whether surgery should be deferred until the child is old enough to be involved in the decision-making process.

CONCLUSIONS

Whether and when to perform surgery in children with CMN is a multifaceted question. Awareness of common concerns as well as risks and benefits of surgery are essential to ensure critical reflection and balanced decision-making.

Skin-related quality of life in children and adolescents with congenital melanocytic naevi - an analysis of self- and parent reports

BACKGROUND

Congenital melanocytic naevi (CMN) may affect patient quality of life (QoL) due to medical complications (development of malignant melanoma or involvement of the central nervous system), skin-related discomfort or psychosocial sequelae.

OBJECTIVES

To analyse skin-related QoL in children and adolescents with CMN and to identify predictors of low QoL.

METHODS

Worldwide recruitment of participants through patient support groups. Data collection through a Web-based survey. QoL was assessed using the Children's Dermatology Life Quality Index© (CDLQI). Demographic and CMN-related characteristics were examined as possible predictors of impaired QoL.

RESULTS

A total of 135 proxy reports for children affected by CMN aged 4-18 years (M = 9.34 years, SD = 4.16 years) and 28 self-reports of adolescents aged 14-18 years (M = 16.3 years, SD = 1.2 years) were included. The mean CDLQI score was 4.00 (SD = 4.39) for proxy reports and 6.89 (SD = 5.85) for self-reports. Most parents (76%) reported 'no' or a 'small' impact, 19% a 'moderate' and 5% a 'very large' or 'extremely large' impact on their child's QoL. In self-reports, 46% of the adolescents reported 'no' or a 'small impact', 43% a 'moderate' and 11% a 'very large' or 'extremely large' impact. Visible CMN location, malignant melanoma and higher child's age were important predictors of QoL impairments.

CONCLUSIONS

Most CMN have a modest effect on QoL. However, there is large variability with a significant proportion of adolescents experiencing a moderate-to-large impact on QoL in contrast to children. Healthcare professionals should be aware of the predictors of QoL in children with CMN.

Giant melanocytic nevi and soft tissue undergrowth in the left leg: Pathogenetic hypothesis

Congenital melanocytic nevi (CMN) are observed frequently in children. The anomalous skin shows a widely variable clinical expression not only in the anatomic location, but also in color, morphology and superficial structure. According to the width CMN are distinguished in small, medium, large or giant. Aside the cosmetic problem and its psychological implications, CMN may present with severe complications consisting of malignant transformation and/or central nervous system involvement. We report on a 3-month old infant with an extensive CMN in the left leg, which extended from the lower portion of the knee to the foot, with satellite nevi. Concomitant with the extensive nevi in the same district a remarkable reduction in size was present, and involved the adipose and muscle tissues, contributing to a counterpart diameter difference of 5 cm, without bone involvement. Melanocytic nevi and soft tissue undergrowth in the leg is a usual association; a pathogenic explanation on the anomaly involving concomitantly the skin and the underneath soft tissues is advanced.

Paediatric melanoma: clinical update, genetic basis, and advances in diagnosis

Paediatric melanoma is rare and challenging to diagnose. The three subtypes are Spitzoid melanoma, melanoma arising in a congenital melanocytic nevus, and conventional (also known as adult-type) melanoma. Spitzoid melanomas have characteristic histopathological and genomic aberrations. Despite frequent involvement of the sentinel lymph nodes, most cases have an uneventful clinical course. Among congenital nevi, the risk of melanoma varies by projected size in adulthood, with the greatest risk in large or giant nevi. The clinical course is generally aggressive and accounts for most melanoma-related deaths in childhood. In conventional melanoma, superficial spreading and nodular melanoma account for most cases, with risk factors and presentation largely similar to adult disease. In this Review, we discuss advances in histological diagnosis using adjunctive molecular assays, and summarise the genetic basis of paediatric melanoma.

New insights into neurocutaneous melanosis

BACKGROUND

Neurocutaneous melanosis is a rare disorder in which children with large cutaneous melanotic nevi have associated melanosis in the brain. Although many affected children have structurally normal brains, some have associated developmental disorders or brain anomalies.

OBJECTIVES

To determine the range of extent of brain melanosis as assessed by magnetic resonance imaging (MRI) and to investigate the frequency and types of associated brain anomalies.

MATERIALS AND METHODS

We retrospectively reviewed brain and spine MRIs of 80 patients with congenital melanocytic nevi (range: 1 day to 22 years of age) affiliated with Nevus Outreach Inc. from 1998 to 2017. Central nervous system (CNS) melanosis was diagnosed when a mass with abnormal parenchymal T1 hyperintensity was seen. The locations of abnormal signal, associated malformations, the presence of contrast enhancement and, in patients with more than one MRI, changes over time were recorded. Associations among findings were analyzed using chi-square test or Fisher exact test.

RESULTS

Brain abnormalities were identified in 33 patients. The most common finding was melanosis in the amygdala, which was found in 31 patients (an isolated finding in 14 patients). Nineteen patients had melanosis in the brainstem, cerebellum, cerebral cortex or thalamus. Cerebral and/or spinal leptomeningeal enhancement was uncommon (five patients). Hindbrain melanosis was associated with cerebellar and pontine hypoplasia (P=0.012). Brain melanosis was most easily seen on T1 images prior to myelination; reduced/loss of visibility was noted as the CNS matured.

CONCLUSION

Brain melanosis is a common manifestation in children with large cutaneous melanotic nevi, most commonly found in the anterior temporal lobes (amygdala), brainstem, cerebellum and cerebral cortex. Hindbrain melanosis is associated with hypoplasia of the affected structures. Early imaging is optimal to provide the greatest sensitivity for diagnosis and to guide proper management.

Common and not so Common Melanocytic Lesions in Children and Adolescents

The acquired melanocytic nevus is the most common lesion encountered by pediatric pathologists and dermatopathologists in their daily practice. In most cases, there are few difficulties in histopathologic diagnosis. However, it is the acquired melanocytic lesion known as the Spitz nevus, with its intrinsic atypical features which becomes the challenge since it exists along a histopathologic and biologic continuum from the atypical Spitz tumor to spitzoid melanoma. The frustration with some of these spitzoid lesions is that even the "experts" cannot agree as to the differentiation of one from the other even at the level of molecular genetics. Other melanocytic lesions are discussed including the congenital melanocytic nevus with its proliferative nodule(s) and melanoma as the ultimate complication. Although uncommon, cutaneous melanoma in the first 2 decades is emerging as a clinical problem especially in young women in the second decade of life. These are ultraviolet-associated neoplasms whose histopathologic and prognostic features are identical to the adult experience. Considerable progress has been made over the past 15 to 20 years in our understanding of cutaneous melanocytic lesions, but gaps still exist in the important group of spitzoid lesions. It can also be anticipated that more cutaneous melanomas in children will be seen in the future based upon epidemiologic studies.

The High Multiplicity of Prenatal (Congenital Type) Nevi in Adolescents and Adults

In the absence of work on prenatal nevogenesis, it has long been necessary to define congenital melanocytic nevi by clinical detection on neonatal skin examination. They are seen in approximately 1% of newborns, with multiplicity in approximately 3% of cases. Melan-A staining of grossly normal fetal skin recently demonstrated fetal nevi, whose features validated certain traditional histologic criteria for "congenital type" nevi that may not have been detectable at birth. This suggested that many clinically acquired nevi actually formed in utero, like congenital nevi. Prenatal nevi has been suggested as a preferred synonym for "congenital type" nevi. Prenatal nevi were detected in 6 of 25 fetuses (24%), a strikingly higher incidence than congenital nevi in newborns. In this series of 354 patients with prenatal (congenital type) nevi encountered in routine practice at a community hospital, over 30% of both adolescents and adults had multiple prenatal nevi; a strikingly higher rate of multiplicity than congenital nevi in newborns. This high multiplicity may reflect origin beneath the epidermis, with many prenatal nevi working their way up to the surface of the skin decades after birth.

Common Pediatric Skin Lesions: A Comprehensive Review of the Current Literature

The timely diagnosis and treatment of dermatologic disease in the pediatric population can be challenging. A basic, yet comprehensive knowledge of common lesions is essential for a successful practice in plastic surgery. In this article, the authors describe vascular, cystic, and pigmented cutaneous lesions that are commonly encountered in the pediatric population. Epidemiology, pathogenesis, clinical course, and management options are discussed for each.

Melanocytic Nevi in Children: A Review

Common moles on the skin, known scientifically as melanocytic nevi, are seen frequently in the pediatric population. They are broadly grouped into two groups: congenital (generally present at birth or in infancy) or acquired. Congenital melanocytic nevi (CMN) are classified based on size and morphologic features. Neurocutaneous melanosis and melanoma represent two important complications, with overall risk affected by nevus size, location, appearance, and number of satellite lesions. Regular lifelong skin surveillance is required for high-risk CMN. Acquired melanocytic nevi (AMN) tend to appear in childhood and increase in number through adolescence. Risk factors for melanoma in children with moles include having more than 50 AMN, clinically atypical AMN, family history of melanoma, excessive ultraviolet light exposure, lightly pigmented skin, and immunosuppression. Children with risk factors should be monitored regularly. The periodic health examination presents an opportunity to perform total body skin examination to screen for concerning lesions and to provide anticipatory guidance about sun protection. [Pediatr Ann. 2016;45(8):e293-e298.].

Giant congenital melanocytic nevi and neurocutaneous melanosis

Introduction. The major medical concern with giant congenital melanocytic nevi CMN is high risk of developing cutaneous melanoma, leptomeningeal melanoma, and neurocutaneous melanocytosis. Case Report. A 30-year-old woman with a giant congenital melanocytic nevus covering nearly the entire right thoracodorsal region and multiple disseminated melanocytic nevi presented with neurological symptoms. Cerebral magnetic resonance imaging revealed a large expansive lesion in the left frontal region. Postsurgically pathological diagnosis revealed characteristics of melanoma. Immunohistochemical examination showed S100(+), HMB45(+), MelanA(+), and MiTF(+). She received radiotherapy with temozolomide followed by two more chemotherapy cycles with temozolomide. She followed a rapidly progressive course, reflecting widespread leptomeningeal infiltration, and she died of multiorgan failure seven months after diagnosis of cerebral melanoma. Discussion. This patient was diagnosed as having a neurocutaneous melanosis with malignant widespread leptomeningeal infiltration. Diffuse spinal involvement is unusual and is described in only another patient.

Update on melanocytic nevi in children

A new or changing melanocytic nevus in a child or adolescent often leads to concern in parents and physicians. To avoid undue alarm and unnecessary procedures, dermatologists should be aware of the natural history and clinical spectrum of nevi in pediatric patients, as well as findings that are potentially worrisome in this age group. This review provides an update on melanocytic nevi in children, focusing on their dynamic evolution over time, molecular insights into nevogenesis, and phenotypic markers for increased risk of melanoma in adolescence and adulthood. Special considerations for Spitz nevi and nevi located in particular sites (eg, scalp, acral, genital) are highlighted. Current understanding of the risks associated with congenital melanocytic nevi of different sizes and strategies for the management of children with numerous acquired nevi, Spitz nevi, and congenital nevi are also discussed.

Giant congenital melanocytic nevus

Giant congenital melanocytic nevus is usually defined as a melanocytic lesion present at birth that will reach a diameter ≥ 20 cm in adulthood. Its incidence is estimated in <1:20,000 newborns. Despite its rarity, this lesion is important because it may associate with severe complications such as malignant melanoma, affect the central nervous system (neurocutaneous melanosis), and have major psychosocial impact on the patient and his family due to its unsightly appearance. Giant congenital melanocytic nevus generally presents as a brown lesion, with flat or mammilated surface, well-demarcated borders and hypertrichosis. Congenital melanocytic nevus is primarily a clinical diagnosis. However, congenital nevi are histologically distinguished from acquired nevi mainly by their larger size, the spread of the nevus cells to the deep layers of the skin and by their more varied architecture and morphology. Although giant congenital melanocytic nevus is recognized as a risk factor for the development of melanoma, the precise magnitude of this risk is still controversial. The estimated lifetime risk of developing melanoma varies from 5 to 10%. On account of these uncertainties and the size of the lesions, the management of giant congenital melanocytic nevus needs individualization. Treatment may include surgical and non-surgical procedures, psychological intervention and/or clinical follow-up, with special attention to changes in color, texture or on the surface of the lesion. The only absolute indication for surgery in giant congenital melanocytic nevus is the development of a malignant neoplasm on the lesion.

Neurocutaneous melanocytosis

Neurocutaneous melanosis or neurocutaneous melanocytosis is a rare sporadic congenital disorder characterized by the presence of giant and/or multiple satellite congenital melanocytic nevi in the skin and benign melanocytic pigmentation of the leptomeninges. These two defining features were recognized more than a century ago. A third characteristic feature is proliferative nodules arising from giant nevi. The etiology is unknown, but neurocutaneous melanosis is considered a developmental disorder of melanocyte precursors from neural crest. The distinctive unique distribution of the congenital giant nevi that gives a "garment" appearance is also an expression of the neural crest. The neurological manifestations often appear in infancy.The special association of neurocutaneous melanosis with Dandy-Walker malformation complex may be explained by a common pathogenesis. Mortality in infancy and childhood is high.

Rapidly progressive and fatal neurocutaneous melanosis presenting as recurrent headache

Neurocutaneous melanosis is an extremely rare disease characterized by large or multiple congenital melanocytic nevi and benign or malignant proliferation of melanocytes in the central nervous system. Neurological manifestations usually develop during the first three years of life and the prognosis of patients with NCM who manifest neurological symptoms is very poor. Here we describe a 9-year-old girl who manifested neurological symptoms caused by communicating hydrocephalus and died of proliferation of melanocytes in the central nervous system 11 months after the initial symptoms. Serum and cerebrospinal fluid 5-S-CD levels could be a useful marker of disease progression, even in patients with NCM without apparent malignant findings at initial biopsy.

Congenital melanocytic nevi: where are we now? Part I. Clinical presentation, epidemiology, pathogenesis, histology, malignant transformation, and neurocutaneous melanosis

Congenital melanocytic nevi (CMN) are present at birth or arise during the first few weeks of life. They are quite common, may have a heritable component, and can present with marked differences in size, shape, color, and location. Histologic and dermatoscopic findings may help suggest the diagnosis, but they are not entirely specific. CMN are categorized based on size, and larger lesions can have a significant psychosocial impact and other complications. They are associated with a variety of dermatologic lesions, ranging from benign to malignant. The risk of malignant transformation varies, with larger CMN carrying a significantly higher risk of malignant melanoma (MM), although with an absolute risk that is lower than is commonly believed. They may also be associated with neuromelanosis, which may be of greater concern than cutaneous MM. The information presented herein aims to help dermatologists determine when it is prudent to obtain a biopsy specimen or excise these lesions, to obtain radiographic imaging, and to involve other specialists (eg, psychiatrists and neurologists) in the patient's care.

[Asymptomatic neonatal neurocutaneous melanosis]

Giant congenital nevi in 1% of cases are associated with anomalies of the central nervous system, which are characteristic of neurocutaneous melanosis. When neurocutaneous melanosis becomes symptomatic, it is associated with a poor prognosis. With recommended neonatal screening, asymptomatic neonatal cases are being discovered more frequently. On the basis of this observation, we consider various aspects of this association.

Spectrum of central nervous system abnormalities in neurocutaneous melanocytosis

AIM

Neurocutaneous melanocytosis is a rare neurocutaneous syndrome defined by the presence of large and/or multiple congenital cutaneous nevi and melanocytic deposits in the central nervous system. We sought to define the spectrum of central nervous system abnormalities in children with neurocutaneous melanocytosis.

METHOD

We retrospectively reviewed cases of neurocutaneous melanocytosis referred to the pediatric neuro-oncology service at our center from 2003 to 2010.

RESULTS

Of 14 patients (11 males, 3 females) identified, eight were living. Median age of survivors was 31 months (range 12mo-6y 10mo) while median age of death was 81 months (19mo-28y). Of the six patients who died, all had diffuse leptomeningeal melanocytic deposits and four had leptomeningeal melanoma. All patients had neuroimaging: six had findings suggestive of diffuse leptomeningeal melanocytosis; seven had multifocal melanocytic deposits; and one patient had normal neuroimaging but focal seizures. Spinal abnormalities were common: three patients had extensive dorsal spinal arachnoid cysts and one had a benign cervical spindle cell tumor. Seven patients had epilepsy. Three patients had profound developmental delay; the other 11 patients had no or mild delay.

INTERPRETATION

Children with neurocutaneous melanocytosis exhibit a wide range of intracranial and intraspinal abnormalities and variable clinical outcomes.

Fatal leptomeningeal melanoma in neurocutaneous melanosis

We report an unusual occurrence of a primary dural-based malignant melanoma in a 13-year-old boy with neurocutaneous melanosis. The lesion presented with rapid-onset symptoms characterized by raised intracranial pressure and seizures, had an aggressive clinical course, and proved to be fatal despite two surgeries and adjuvant therapy. There should be a high index of suspicion for the occurrence of such a malignant leptomeningeal tumor in patients with congenital melanocytic nevi presenting with neurological symptoms of recent onset.

The risk of melanoma and neurocutaneous melanosis associated with congenital melanocytic nevi

Congenital melanocytic nevi are commonly encountered in clinical practice. Although the development of malignant melanoma arising in small and intermediate congenital melanocytic nevi is rare, there is a significant risk of malignant degeneration associated with large congenital melanocytic nevi, in particular those that arise on the torso in the so-called "bathing trunk" distribution, where the risk is estimated to be about 2.5% to 5%. The risk of malignant melanoma arising within a large congenital melanocytic nevus is highest in the first 5 to 10 years of life and carries a significant mortality. Large congenital melanocytic nevi, in particular those overlying the posterior axis and occurring in the context of multiple satellite melanocytic nevi, are also associated with the development of neurocutaneous melanosis, which may result in neurologic and neurodevelopmental sequelae and is associated with a significant risk of primary central nervous system melanoma and death.