Neurocutaneous melanosis: clinical features of large congenital melanocytic nevi in patients with manifest central nervous system melanosis

Primary Meningeal Melanocytic Tumors of the Central Nervous System: A Review from the Ultra-Rare Brain Tumors Task Force of the European Network for Rare Cancers (EURACAN)

BACKGROUND

Primary meningeal melanocytic tumors are ultra-rare entities with distinct histological and molecular features compared with other melanocytic or pigmented lesions, such as brain and leptomeningeal metastases from metastatic melanoma.

METHODS

The European Network for Rare Cancers (EURACAN) Task Force on Ultra-Rare Brain Tumors (domain 10, subdomain 10) performed a literature review from January 1985 to December 2023 regarding the epidemiologic and clinical characteristics, histological and molecular features, radiological findings, and efficacy of local treatments (surgery and radiotherapy) and systemic treatments for these entities.

RESULTS

Molecular analysis can detect specific mutations, including GNAQ, GNA11, SF3B1, EIF1AX, BAP1, that are typically found in circumscribed primary meningeal melanocytic tumors and not in other melanocytic lesions, whereas NRAS and BRAF mutations are typical for diffuse primary meningeal melanocytic tumors. The neuroimaging of the whole neuroaxis suggests a melanocytic nature of a lesion, depicts its circumscribed or diffuse nature, but cannot predict the tumor's aggressiveness. Gross-total resection is the first choice in the case of circumscribed meningeal melanocytoma and melanoma; conversely, meningeal biopsy may be reserved for patients with diffuse and multinodular leptomeningeal spread to achieve a definitive diagnosis. High-dose radiotherapy is rarely indicated in diffuse melanocytic tumors except as palliative treatment to alleviate symptoms. Last, a definitive advantage of a specific systemic treatment could not be concluded, as most of the data available derive from case reports or small cohorts.

CONCLUSIONS

As primary meningeal melanocytic tumors are extremely rare, the correlations between the clinical characteristics, molecular profile, radiological findings at diagnosis and progression are weak, and poor evidence on the best therapeutic approach is available. There is a need to develop shared platforms and registries to capture more knowledge regarding these ultra-rare entities.

Thickness of melanocytes in giant congenital melanocytic nevus for complete surgical excision: clinicopathological evaluation of 117 lesions according to the area and size

BACKGROUND

Giant congenital melanocytic nevi (GCMN) are usually defined as nevi that exceed 20 cm in maximal diameter or 15% of the total body surface area. There have been reports of life-long malignant change risks arising from GCMN, leading to surgical excision of GCMN. This study aims to evaluate the thickness of melanocytes based on clinical factors in order to provide objective information for the complete resection of the lesion.

METHODS

Overall, 75 patients diagnosed with GCMN between 2000 and 2021 were included, and their clinical records were collected retrospectively. 117 pathologic slides obtained during excision were reviewed to measure nevus thickness. Clinical factors were assessed with a generalized estimated equation model for association with nevus thickness.

RESULTS

The thickness of nevus was significantly associated with the location and size. Nevus thickness was more superficial in the distal extremity than in the head and trunk (P = 0.003 [head]; P < 0.001 [trunk]; P = 0.091 [Proximal extremity]). Nevi sized 60 cm or more were significantly deeper than those measuring 20-29.9 cm (P = 0.035). An interaction between size and location existed (P < 0.001). Trunk and distal extremity lesions consistently exhibited uniform thickness regardless of lesion size, whereas head and proximal extremity lesions showed variations in thickness based on lesion size.

CONCLUSION

GCMNs have differences in thickness according to location and size. Therefore, it is necessary to devise an approach optimized for each patient to treat GCMN. In the study, it was emphasized that the thickness of GCMN is correlated with clinical factors, specifically the location and size of the nevus. Consequently, these findings underscore the need for individualized treatment plans for effective surgical intervention.

A clinical and biologic review of congenital melanocytic nevi

Congenital melanocytic nevi (CMN) are the result of aberrations in the mitogen-activated protein kinase signal transduction pathway caused by postzygotic somatic mutations. The estimated incidence of newborns with CMN is 1%-2%. The main complications of CMN include proliferative nodules, melanomas, and neurocutaneous melanosis, and the latter two are the most troublesome issues to address. Treatments are primarily taken into account for aesthetic purposes and the reduction of melanoma risk. Due to the much lower incidence of malignant transformation observed in recent studies than in previous data, clinical management paradigms for CMN patients have gradually shifted towards conservative observation and close monitoring. Surgery and lasers are still the main treatments, and targeted therapy may be a promising strategy to help manage complications. With the increase in awareness of mental health, increasing focus has been placed on the quality of life (QoL) and psychological issues of both CMN patients and their parents. Recent studies have revealed that families coping with CMN might endure intense pressure, a major loss in QoL, and psychological problems after diagnosis and during treatment. Here, we sought to present an overview of genetic basis, complications, treatments, and psychological issues related to CMN and hope to provide better management for patients with CMN.

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.

SCALP syndrome with a germline heterozygous DOCK6 mutation and somatic mosaic NRAS Q61R mutation

We present a case of SCALP syndrome, which was diagnosed in a male infant with the characteristic findings of sebaceous nevi, central nervous system malformations, aplasia cutis congenita, limbal dermoid, and giant congenital melanocytic nevi, or pigmented nevi. We identified a germline compound heterozygous DOCK6 mutation and a somatic mosaic NRAS Q61R mutation in the giant congenital melanocytic nevus. This report will increase clinician awareness of SCALP syndrome and augment the literature in characterizing this rare syndrome, including its genetic background.

Central nervous system magnetic resonance imaging abnormalities and neurologic outcomes in pediatric patients with congenital nevi: A 10-year multi-institutional retrospective study

BACKGROUND

High-risk congenital melanocytic nevi (CMN) are associated with abnormalities of the central nervous system (CNS), prompting magnetic resonance imaging (MRI) screening guidelines.

OBJECTIVE

Describe MRI brain and spine abnormalities in children with CMN and report trends between nevus features, MRI findings, and neurologic outcomes.

METHODS

Retrospective review of individuals aged ≤18 years with an MRI of the brain and/or spine and at least 1 dermatologist-diagnosed CMN.

RESULTS

Three hundred fifty-two patients were identified. Forty-six children had CMN that prompted an MRI of the brain and/or spine (50% male, average age at first image, 354.8 days). In these children, 8 (17%) had melanin detected in the CNS, of whom all had >4 CMN. One developed brain melanoma (fatal). In patients without CNS melanin, 4 had concerning imaging. Concerning MRI patients had more neurodevelopmental problems, seizures, neurosurgery, and death than individuals with unremarkable imaging. Three hundred six patients received MRIs for other reasons; none detected melanin. No children with only multiple small CMN (n = 15) had concerning imaging.

LIMITATIONS

Lack of a control group, cohort size, and retrospective methods.

CONCLUSION

MRI of the brain and spine is useful for detecting intervenable abnormalities in high-risk children. Healthy infants with few small CMN may not require screening MRI.

Neurosurgical management of patients with neurocutaneous melanosis: a systematic review

OBJECTIVE

Neurocutaneous melanocytosis (NCM), also referred to as neurocutaneous melanosis, is a rare neurocutaneous disorder characterized by excess melanocytic proliferation in the skin, leptomeninges, and cranial parenchyma. NCM most often presents in pediatric patients within the first 2 years of life and is associated with high mortality due to proliferation of melanocytes in the brain. Prognosis is poor, as patients typically die within 3 years of symptom onset. Due to the rarity of NCM, there are no specific guidelines for management. The aims of this systematic review were to investigate approaches toward diagnosis and examine modern neurosurgical management of NCM.

METHODS

A systematic review was performed using the PubMed database between April and December 2021 to identify relevant articles using PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Search criteria were created and checked independently among the authors. Inclusion criteria specified unique studies and case reports of NCM patients in which relevant neurosurgical management was considered and/or applied. Exclusion criteria included studies that did not report associated neurological diagnoses and neuroimaging findings, clinical reports without novel observations, and those unavailable in the English language. All articles that met the study inclusion criteria were included and analyzed.

RESULTS

A total of 26 extracted articles met inclusion criteria and were used for quantitative analysis, yielding a cumulative of 74 patients with NCM. These included 21 case reports, 1 case series, 2 retrospective cohort studies, 1 prospective cohort study, and 1 review. The mean patient age was 16.66 years (range 0.25–67 years), and most were male (76%). Seizures were the most frequently reported symptom (55%, 41/74 cases). Neurological diagnoses associated with NCM included epilepsy (45%, 33/74 cases), hydrocephalus (24%, 18/74 cases), Dandy-Walker malformation (24%, 18/74 cases), and primary CNS melanocytic tumors (23%, 17/74 cases). The most common surgical technique was CSF shunting (43%, 24/56 operations), with tethered cord release (4%, 2/56 operations) being the least frequently performed.

CONCLUSIONS

Current management of NCM includes CSF shunting to reduce intracranial pressure, surgery, chemotherapy, radiotherapy, immunotherapy, and palliative care. Neurosurgical intervention can aid in the diagnosis of NCM through tissue biopsy and resection of lesions with surgical decompression. Further evidence is required to establish the clinical outcomes of this rare entity and to describe the diverse spectrum of intracranial and intraspinal abnormalities present.

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.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13023-022-02234-8.

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.

A Case of a Giant Congenital Melanocytic Nevus Treated by Curettage with the Application of Cultured Epidermal Autografts before 6 Months of Age

Curettage is common in the treatment of a giant congenital melanocytic nevus (GCMN) in infants and should generally be performed before 6 months of age. Post-curettage retarded epithelialization often interferes with the ability to perform multiple operations within a short interval, and thus, it is difficult to treat large lesions in the neonatal period. We herein report a case of a GCMN comprising 20% of the total body surface area, which required multi-stage curettage, in which a cultured epithelial autograft was used to promote epithelialization of the post-curettage wound. The patient was a 1-month-old boy with a GCMN in his head, neck, chest, back, buttock, left upper arm, and a few satellite lesions. A four-stage operation was performed between 3 and 6 months of age; the cultured epithelial autograft took well after each operation, and complete epithelialization was observed at postoperative days 20, 23, 27, and 12, respectively. Seven months after the last surgery, hypertrophic scar formation was only observed in a small area of the left upper arm without axillary contracture. The color of the treated area improved, except for slight partial re-pigmentation. A skin biopsy was obtained from the re-pigmented area. The results demonstrated that nevus cells remained in the basal layer of the epidermis, hair follicles, and deep layer of the remaining dermis, suggesting that the recurrent nevus cells in the regenerated epidermis migrated from hair follicles. We conclude that the combination of curettage and the application of a cultured epithelial autograft is a promising option for GCMN treatment.

Pigmented Lesions in Children: Update on Clinical, Histopathologic and Ancillary Testing

Patients are commonly referred to pediatric dermatology for the evaluation of pigmented lesions. For families, pediatricians, and dermatologists alike, malignancy is the main fear. In the past few decades, there has been evolving literature to inform diagnosis and management. This article provides an update on the clinical, histopathologic, and ancillary testing for 3 categories of particularly challenging pigmented lesions: congenital melanocytic nevi, spitzoid neoplasms, and pediatric melanoma.

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.

Giant cerebriform melanocytic nevus of the scalp: A case report

Giant melanocytic nevus is a rare condition caused by benign proliferation of melanocytes. There is a slight risk of malignancy in these lesions which should be noticed especially when they become larger. GCMN can be removed by plastic surgery.

Cerebellar amelanotic melanoma can mimic cerebellar abscess in a pediatric case of neurocutaneous melanosis

Neurocutaneous melanosis (NCM) is a rare phakomatosis that may be associated with intracerebral masses. The differential diagnosis of intracerebral masses in NCM is often challenging and should include pigmented and nonpigmented lesions.

Congenital melanocytic naevi: An up-to-date overview

Congenital melanocytic naevi are hamartomas of the neuroectoderm caused by genetic mosaicism. Congenital melanocytic naevi are seen in 1-6% of all live births and commonly classified based on the projected size in adults. Congenital melanocytic naevi appear in different colours, shapes, and sizes, and occasionally present with complications. In this review, we sought to evaluate congenital melanocytic naevi, their clinical, dermatoscopic, and reflectance confocal microscopic features, behavioural pattern over time, new trends in classification, underlying genetic factors and their influence on clinical manifestations and management, associated risks, complications, magnetic resonance imaging findings and their management in the light of recent literature.

Spastic quadriplegia following intradermal use of hydrogen peroxide in the tardive curettage procedure for the treatment of a giant congenital nevus

The possible transformation of a giant congenital melanocytic nevi (GCMN) in malignant melanoma estimated from 0.05% to 40% depend on the size of the lesions. Many are the surgical procedures proposed, including: full or partial-thickness excisions, dermabrasion, curettage in the first weeks of life and laser treatment. The curettage technique has been proposed in the literature for the treatment of GCMN in the first few weeks of life and defined as a relatively atraumatic surgery procedure without general complications. The authors report the first case in the literature of embolization due to use of subcutaneous peroxide infiltration before a tardive curettage procedure in a newborn case of GCMN resulting in spastic quadriplegia with dystonic reaction. Consequently, a lawsuit, due to this medical malpractice, has been opened.

Clinical Follow-Up of Patients with Neurocutaneous Melanosis in a Tertiary Center; Proposed Modification in Diagnostic Criteria

INTRODUCTION

Neurocutaneous melanosis (NCM) is a rare congenital syndrome. Except for some retrospective studies, information on clinical follow-up and management of these patients are limited. This study aimed to review our experience on diagnostic protocol and clinical follow-up of patients with NCM in a referral children's hospital in Iran.

METHODS

Between 2012 and 2019, eight patients with NCM were consecutively managed in our center. Brain magnetic resonance imaging and cutaneous biopsy were done in all patients at diagnosis. Follow-up surveillance and characteristics of the disease are described.

RESULTS

The mean follow-up period was 25.75 ± 13.81 months, and 75% of patients were male. Most magnetic resonance imaging findings were hypersignal lesions in the temporal lobe (75%), cerebellum (62.5%), brainstem (50%), and thalamus (12.5%). Dandy-Walker syndrome was found in 4 patients (50%), and shunt-dependent hydrocephalus was found in 3 patients (37.5%). Cutaneous malignant melanoma and malignant involvement of the central nervous system were found in 2 (25%) and 3 cases (37.5%), respectively. The mortality rate was 37.5%.

CONCLUSIONS

There are no specific guidelines for management of NCM due to the rarity of the disease. This study proposed modifications in diagnostic criteria, as well as recommendations for follow-up surveillance.

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).

A large-scale collection of giant congenital melanocytic nevi: Clinical and histopathological characteristics

Giant congenital melanocytic nevi (GCMN) place a heavy psychological burden on patients due to their poor cosmetic appearance. The histopathological characteristics of GCMN have remained largely elusive. The present study investigated the histopathological characteristics of GCMN in association with their clinical appearance. A total of 98 patients diagnosed with GCMN were included in the present study and their clinical features were collected from their records. Lesion specimens were obtained and stained for histopathological analysis. Regarding the microscopic appearance of GCMN, nevi cells in the whole dermis exhibited different patterns than those in healthy tissues. Most GCMN cases featured a sub-epidermal non-involvement zone, which implies an early occurrence in embryo development. Darker nevi exhibited a higher density of infiltrated nevi cells and more pigment deposition; this appears to induce a poor skin texture. Chemical peeling and laser therapy only partly removes pigment particles and nevi cells in the upper portion of the dermis. The clinical features of GCMN are associated with the histopathological characteristics, and non-surgical therapy cannot remove the nevus cells in the deep dermis.

Melanoma arising in a Giant congenital melanocytic nevus: two case reports

Background

A giant congenital melanocytic nevus (GCMN) is found in 0.1% of live-born infants. If present, the lesion has a chance of about 6% to develop into malignant melanoma. Both children and adults can be affected by malignant melanoma arising in a giant congenital nevus. Up to 95% of GCMNs harbor NRAS mutations, and mutations in the BRAF, MC1R, TP53, and GNAQ genes have also been described. The individualization of therapy is required, but diagnostic and prognostic criteria remain controversial.

Case presentations

We report two cases: 1) melanoma arising in a giant congenital nevus during the first month of life complicated with neurocutaneous melanosis (NCM), and 2) melanoma arising in a giant congenital nevus during the first 6 months of life. Pathology, immunohistochemistry, and genetic analyses of tumor tissue were performed. The first case revealed only a non-pathogenic P72R polymorphism of the TP53 gene in the homozygote condition. For the second case, a Q61K mutation was detected in the NRAS gene.

Conclusion

Malignant melanoma associated with GCMN is rare and therefore poorly understood. Outcomes have been linked to the stage at diagnosis, but no additional pathological prognostic factors have been identified. The most frequent genetic event in giant CMNs is NRAS mutations, which was discovered in one of our cases. To accumulate evidence to improve disease prognosis and outcomes, children with congenital melanocytic nevus should be included in a systemic follow-up study from birth.

Neurocutaneous Melanosis in Association With Large Congenital Melanocytic Nevi in Children: A Report of 2 Cases With Clinical, Radiological, and Pathogenetic Evaluation

Background: Melanocytic nevi present at birth, or within the first few months of life, are defined as congenital melanocytic nevi (CMN). Neurocutaneous melanosis (NCM) is a rare disorder, represents pigment cell tumors of the leptomeninges, and occurs in association with large or multiple CMN. NCM carries an extremely poor prognosis. NRAS and BRAF^V600E genetic mutations were reported in CMN. Our aim was to report 2 rare cases of NCM associated with large-sized CMN.

Materials and Methods: Two cases were enrolled, a 19-month-old boy with multiple satellite and giant CMN (GCMN); and a 57-month-old girl with large CMN (LCMN). Both patients had central nervous system (CNS) symptoms, and therefore, were studied from clinical, radiological, and immunohistopathological aspects. Cytogenetic study was done for one of them.

Results: Both patients had CMN located in the head/neck, with no cutaneous melanoma. MRI was the most reliable method for early detection of NCM. NCM was proved in the 2 studied cases by immunohistopathology performed after surgery. The boy with GCMN carried NRAS mutation at codon 61, in addition to the characteristic facial features relevant to RASopathies. Both patients died despite surgical intervention.

Conclusion: Our report highlights the need for pediatricians to be alert to the risk of NCM in association with CMN, especially when a CMN lesion is large, or there are multiple satellite lesions, or the nevus location is at the head or neck. Moreover, in the setting of CMN, the absence of skin melanoma does not exclude the presence of NCM.

Common Neonatal Skin Lesions: Melanocytic Nevi, Pigment Alterations, and Nonmelanocytic Nevi

Birthmarks are common in the healthy population and are generally harmless. Certain presentations, however, raise concern for associated syndromes or potential complications. It is important for pediatricians to be familiar with both harmless and potentially concerning birthmarks. This article discusses congenital melanocytic nevi, café-au-lait macules, hypomelanotic macules, nevus depigmentosus, nevus anemicus, epidermal nevi, and nevus sebaceous, including potential syndromes and complications. [Pediatr Ann. 2019;48(1):e23-e29.].

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.

A Practical Approach to the Diagnosis of Melanocytic Lesions

CONTEXT.—

Melanocytic lesions are common in routine surgical pathology. Although the majority of these lesions can be confidently diagnosed using well-established morphologic criteria, there is a significant subset of lesions that can be diagnostically difficult. These can be a source of anxiety for patients, clinicians, and pathologists, and the potential consequences of a missed diagnosis of melanoma are serious.

OBJECTIVE.—

To provide a practical approach to the diagnosis of melanocytic lesions, including classic problem areas as well as suggestions for common challenges and appropriate incorporation of ancillary molecular techniques.

DATA SOURCES.—

Literature search using PubMed and Google Scholar, incorporating numerous search terms relevant to the particular section, combined with contemporaneous texts and lessons from personal experience.

CONCLUSIONS.—

Although a subset of melanocytic lesions can be diagnostically challenging, the combination of a methodical approach to histologic assessment, knowledge of potential diagnostic pitfalls, opinions from trusted colleagues, and judicious use of ancillary techniques can help the pathologist navigate this difficult area.

Neurocutaneous Melanosis in an Adult Patient with Intracranial Primary Malignant Melanoma: Case Report and Review of the Literature

BACKGROUND

To explore the clinical characteristics of neurocutaneous melanosis (NCM) in adult patients to help improve diagnosis and treatment of this disease, we present a rare case of an adult patient suffering from NCM with malignant melanoma, as well as a review of the relevant Chinese and English literature.

CASE DESCRIPTION

The patient reported here plus the patients identified in our literature review total 30 adults with NCM (20 males [66.7%] and 10 females [33.3%]), age 19-65 years (average, 27.9 years). These include 24 cases of malignant melanoma (80.0%), 3 cases of melanocytoma (10.0%), 2 cases of diffuse melanocytosis (6.7%), and 1 case of unknown pathology (3.3%). Satellite nevi were reported in 25 cases (83.3%) and in 5 cases their presence was unknown (16.7%). Intracranial lesions were present in 28 cases (93.3%), and intraspinal lesions were present in 2 cases (6.7%). There are 4 cases of combined hydrocephalus (13.3%), and 2 cases of combined Dandy-Walker deformity (6.7%).

CONCLUSIONS

NCM is a rare disease, especially in adults. With the onset of symptoms, the diagnosis is generally confirmed. In children with congenital giant nevus, regular periodic surveys of the central nervous system (brain and spinal cord) with magnetic resonance imaging or cerebrospinal fluid analysis should be performed to diagnose NCM. Active treatment should be undertaken to improve the prognosis.

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.

Pathology and genomics of pediatric melanoma: A critical reexamination and new insights

The clinicopathologic features of pediatric melanoma are distinct from those of the adult counterpart. For example, most childhood melanomas exhibit a uniquely favorable biologic behavior, save for those arising in large/giant congenital nevi. Recent studies suggest that the characteristically favorable biologic behavior of childhood melanoma may be related to extreme telomere shortening and dysfunction in the cancer cells. Herein, we review the genomic profiles that have been defined for the different subtypes of pediatric melanoma and particularly emphasize the potential prognostic value of telomerase reverse transcriptase alterations for these tumors.

Update on Genetic Conditions Affecting the Skin and the Kidneys

Genetic conditions affecting the skin and kidney are clinically and genetically heterogeneous, and target molecular components present in both organs. The molecular pathology involves defects of cell-matrix adhesion, metabolic or signaling pathways, as well as tumor suppressor genes. This article gives a clinically oriented overview of this group of disorders, highlighting entities which have been recently described, as well as the progress made in understanding well-known entities. The genetic bases as well as molecular cell biological mechanisms are described, with therapeutic applications.

Late Onset Achromatic Melanoma Arising in a Giant Congenital Melanocytic Nevus

A 61-year-old woman, with a lifelong history of a giant congenital melanocytic nevus in the occipital region with secondary development of giant melanoma is presented. Surgical excision was performed, and the histopathological evaluation confirmed the diagnosis of Giant Malignant Melanoma (GMM) with a maximum tumour thickness of 16 mm. Nowadays, there is tremendous uncertainty regarding how giant congenital melanocytic nevi (GCMN) should be treated. The standard approach to patients with late onset giant congenital melanocytic nevi (GCMN is based on two main considerations: (1) obtain an acceptable cosmetic results with the purpose to decrease the psychosocial inconvenience to each patient, and (2) to attempt to minimise the risk of development of malignant transformation. Unfortunately complete surgical removal of the GCMN is usually difficult and very often impossible without subsequent functional or cosmetic mutilations.

A prospective study of patients with large congenital melanocytic nevi and the risk of melanoma

BACKGROUND:

Large congenital melanocytic nevus (LCMN) is considered a risk factor for melanoma, although the magnitude of this risk is controversial.

OBJECTIVE:

To evaluate the risk of melanoma development in patients with LCMN seen at a dermatology referral center in Brazil during a twelve-year period. To the best of our knowledge, there are no published similar studies on large congenital melanocytic nevus in South America.

METHODS:

Our prospective cohort included only patients with congenital nevi ≥20cm. The cumulative risk of developing melanoma and the standardized morbidity ratio were calculated for patients followed up prospectively for at least 1 month.

RESULTS:

Sixty-three patients were enrolled in this study. One patient who developed melanoma prior to enrollment was excluded, and five were eliminated because of insufficient follow-up time. Mean follow-up for the remaining 57 patients was 5.5 years (median 5.2 years). Median age of entry into the study was 2.6 years. Most patients (75.4%) underwent only clinical observation. Melanomas occurred in 2 (3.5%) patients. Five-year cumulative risk for melanoma was 4.8% (95% CI: 1.9-11.5%). Standardized morbidity ratio was 1584 (95% CI: 266-5232, p<0.001).

STUDY LIMITATIONS:

The small sample size reduces the accuracy of risk estimates.

CONCLUSIONS:

This study analyzed prospectively for the first time data from South America demonstrating that patients with LCMN have a higher risk of developing melanoma than the general population (p<0.001).

Dural Melanoma Associated with Ocular Melanosis and Multiple Blue Nevi

Background:

Primary meningeal melanomas of the central nervous system (CNS) are a rare malignant process with the majority originating from the leptomeninges. Primary dural melanomas have been reported to occur in isolation or in conjunction with Nevus of Ota. The association of primary dural melanoma with multiple cutaneous blue nevi has not been reported previously.

Objective:

To describe a case of a 41-year-old Asian woman patient with a primary dural melanoma that arose in association with ocular melanosis and multiple cutaneous blue nevi. The patient is alive almost more than 8 years after subtotal and subsequent total resection of her primary tumor. Primary dural melanomas, Nevus of Ota, and blue nevi are discussed in relation to their coexistence and potential for intracranial melanoma.

Conclusion:

CNS melanoma is regarded as an extremely aggressive disease with poor prognosis. This case and previous reports of dural melanomas occurring in isolation or with Nevus of Ota have demonstrated relatively prolonged survival after surgical intervention. We conclude that dural melanomas are less aggressive tumors requiring surgical extirpation only.

Metastatic melanoma in association with a giant congenital melanocytic nevus in an adult: controversial CGH findings

Giant congenital melanocytic nevi (GCMNs) represent a distress to patients for 2 reasons: one is disfigurement, and the other is the increased risk of developing secondary melanocytic tumors, such as benign proliferative nodules (BPNs) and malignant melanoma (MM). BPN present as a rapid growth nodule arising within a congenital melanocytic nevus (CMN) that often ulcerates, occurs in children younger than 2 years of age. BPNs arising within a CMN are exceedingly rare after childhood, and very few cases have been described in adults. Despite the worrisome clinical and histologic findings of BPN, most laboratory investigations seem to support their benignity. The distinction between MM and BPN is extremely important, but the histopathology of BPN of GCMN can be a challenge to differentiate from MM. In the recent years, molecular tests that investigate DNA copy number alterations such as fluorescence in situ hybridization and comparative genomic hybridization have shown promise to help guide the diagnosis of ambiguous melanocytic proliferations arising within CMNs. We report the case of a 22-year-old woman with a nodule arising in a GCMN and with an axillary mass suggesting a nodal metastasis of melanoma, and discuss the unusual clinical, histopathologic, and molecular findings that make this case particularly interesting.

Sonographic and magnetic resonance imaging findings of neurocutaneous melanosis

Neurocutaneous melanosis is a rare nonfamilial phakomatosis characterized by large or multiple congenital melanocytic nevi plus the presence of central nervous system melanosis or melanoma. We report a case of a male infant with a giant posteroaxial nevus and evidence of intracranial melanosis on ultrasound and magnetic resonance imaging.

Classification of neurological abnormalities in children with congenital melanocytic naevus syndrome identifies magnetic resonance imaging as the best predictor of clinical outcome

Background

The spectrum of central nervous system (CNS) abnormalities described in association with congenital melanocytic naevi (CMN) includes congenital, acquired, melanotic and nonmelanotic pathology. Historically, symptomatic CNS abnormalities were considered to carry a poor prognosis, although studies from large centres have suggested a much wider variation in outcome.

Objectives

To establish whether routine MRI of the CNS is a clinically relevant investigation in children with multiple CMN (more than one at birth), and to subclassify radiological abnormalities.

Methods

Of 376 patients seen between 1991 and 2013, 289 fulfilled our criterion for a single screening CNS MRI, which since 2008 has been more than one CMN at birth, independent of size and site of the largest naevus. Cutaneous phenotyping and radiological variables were combined in a multiple regression model of long‐term outcome measures (abnormal neurodevelopment, seizures, requirement for neurosurgery).

Results

Twenty‐one per cent of children with multiple CMN had an abnormal MRI. Abnormal MRI was the most significant predictor of all outcome measures. Abnormalities were subclassified into group 1 ‘intraparenchymal melanosis alone’ (n = 28) and group 2 ‘all other pathology’ (n = 18). Group 1 was not associated with malignancy or death during the study period, even when symptomatic with seizures or developmental delay, whereas group 2 showed a much more complex picture, requiring individual assessment.

Conclusions

For screening for congenital neurological lesions a single MRI in multiple CMN is a clinically relevant strategy. Any child with a stepwise change in neurological/developmental symptoms or signs should have an MRI with contrast of the brain and spine to look for new CNS melanoma.

What's already known about this topic?

Multiple congenital melanocytic naevi (CMN; more than one lesion at birth) can be associated with abnormalities of the central nervous system (CNS). The spectrum of these abnormalities includes congenital and acquired pathologies, melanotic and nonmelanotic lesions, rendering the term ‘CMN syndrome’ more appropriate than ‘neurocutaneous melanosis’.

Symptomatic CNS abnormalities were previously thought to carry a universally poor prognosis, although cohort data in the last decade have argued against this.

What does this study add?

A single CNS magnetic resonance imaging scan in multiple CMN, independent of projected adult size or site of the largest naevus, and ideally in the first 6 months of life, is currently an appropriate screening strategy.

An abnormal result is a better statistical predictor of clinical outcome than cutaneous phenotype.

Clinical management is altered as a result of the radiological result.

[The congenital melanocytic nevi of the face in child: What's new?]

Congenital melanocytic nevi of the face are a frequent reason for consultation in paediatric plastic surgery. Usually of small size, they raise a complex problem of reconstruction when they are large and giant. The indication of excision is generally stated on aesthetic criteria whereas the risk of melanoma is especially important in the giant nevi. Simple suture, full thickness skin graft and expanded skin flaps are the techniques of choice. The treatment must be carried out precociously, follow a surgical planning, respect the aesthetic units of the face and the periorificial areas, adapt to the age of the child and bring psychological benefit to the child.

Early sonographic diagnosis of neurocutaneous melanosis in a newborn

Neurocutaneous melanosis (NCM) is a rare, congenital non-hereditary syndrome, characterized by multiple pigmented nevi. We report the radiologic findings of a newborn who had extensive cutaneous melanotic nevus with satellite lesions in the brain. Ultrasound showed multiple echogenic foci in the cerebral parenchyma. Subsequent MRI confirmed these lesions as characteristic deposits of melanin. The infant was asymptomatic, but presence of risk factors such as malign transformation or neurological manifestations makes early diagnosis very important. We present this case to emphasize on the radiological findings of this syndrome in order to reach an early diagnosis.

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.

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.

NRAS mutation is the sole recurrent somatic mutation in large congenital melanocytic nevi

Congenital melanocytic nevus (CMN) is a particular melanocytic in utero proliferation characterized by an increased risk of melanoma transformation during infancy or adulthood. NRAS and BRAF mutations have consistently been reported in CMN samples, but until recently results have been contradictory. We therefore studied a series of large and giant CMNs and compared them with small and medium CMNs using Sanger sequencing, pyrosequencing, high-resolution melting analysis, and mutation enrichment by an enhanced version of ice-COLD-PCR. Large-giant CMNs displayed NRAS mutations in 94.7% of cases (18/19). At that point, the role of additional mutations in CMN pathogenesis had to be investigated. We therefore performed exome sequencing on five specimens of large-giant nevi. The results showed that NRAS mutation was the sole recurrent somatic event found in such melanocytic proliferations. The genetic profile of small-medium CMNs was significantly different, with 70% of cases bearing NRAS mutations and 30% showing BRAF mutations. These findings strongly suggest that NRAS mutations are sufficient to drive melanocytic benign proliferations in utero.

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.

Amygdalar neuromelanosis intractable epilepsy without leptomeningeal involvement

Neurocutaneous melanosis (NCM) is a rare, congenital neuroectodermal dysplasia generally resulting in early death from neurological decline due to leptomeningeal involvement. Nonmeningeal CNS epileptogenic lesions presenting in later childhood in the absence of leptomeningeal disease are rare. This report summarizes a rare presentation and curative epilepsy surgery. The authors discuss the case of a 14-year-old girl with NCM who originally presented with intractable partial-onset seizures. The MRI, PET, and SPECT studies subsequently revealed a focal epileptogenic source in the right temporal lobe. Results of video-electroencephalography monitoring concurred with the imaging findings, and a right temporal lobectomy was performed including the medial structures. Following surgery, histopathological features of the lesion included multiple scattered mononuclear cells with brown pigmentation in the amygdala specimen. The patient remains seizure free 2 years postresection, and no longer needs medication for seizure management. This patient presented with an atypical CNS manifestation of NCM that is curable by epilepsy surgery. Her intractable epilepsy developed secondary to amygdalar neuromelanosis, which had no associated leptomeningeal melanosis, an uncommon occurrence. As evidenced by the lack of seizure activity following resection, the patient's quality of life greatly improved after neurological surgery.

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.