Neurocutaneous melanosis in children with giant congenital melanocytic nevi

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.

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.

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.

The retrospective molecular analysis of large or giant congenital melanocytic nevi in a group of Polish children

Background

Large and giant congenital melanocytic nevi (CMN), benign naevomelanocytic proliferations derived from neural crests, with a projected adult size (PAS) ≥ 20 cm, are connected to a high risk of melanoma and neurocutaneous melanosis. Among several factors, genetic alterations seem to be involved in tumorigenesis. The aim of the present study was to analyse the mutation status of NRAS and BRAF genes in resection specimens from large or giant CMN in a group of Polish patients.

Material and methods

The formalin-fixed, paraffin-embedded resection specimens from 18 patients, fixed in the years of 2006 to 2017, were included in the study. The regions containing the highest load of melanocytes were macrodissected prior to DNA isolation. The NRAS and BRAF mutation status was evaluated using qPCR.

Results

We detected activating mutations in NRAS gene (codons: 12 and 61) in 7 out of the 18 (38.9%) patients. No BRAF mutations were found.

Conclusion

Our study, the first molecular analysis of large/giant CMN in Polish patients, supports the hypothesis that NRAS mutation in codon 61 are frequent, recurrent mutations in large/giant CMN. Moreover, we show, for the first time, that NRAS mutations in codon 12 (p.Gly12Asp) can be also detected in giant CMN. The exact role of these genetic alterations in CMN formation remains to be elucidated.

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.

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.

Epilepsy in isolated parenchymal neurocutaneous melanosis: A systematic review

PURPOSE

Neurocutaneous melanosis (NCM) is a rare congenital syndrome characterized by giant melanocytic cutaneous nevi and melanosis within the central nervous system (CNS), often sparing leptomeninges and concentrated in the brain parenchyma. Epilepsy and neurodevelopmental abnormalities are the only complications reported in children with isolated parenchymal melanosis. A minority of patients experience drug-resistant epilepsy, and up to now, no predictors of epilepsy prognosis have been identified.

METHODS

In this systematic review, according to preferred reporting items for systematic review and meta-analysis (PRISMA) guidelines, we aggregated clinical cases of patients with isolated parenchymal melanosis affected by epilepsy, in order to recognize predictors of clinical outcome and to clarify indications of available therapeutic approaches.

RESULTS

Sixteen articles (19 patients) were included in the final analysis from initial database research; 4 articles (4 patients) were selected from reference lists and 1 from conference abstracts (1 patient). In our series, distribution of parenchymal melanosis was the best predictor of epilepsy outcome: frequencies of seizure-free patients were different between cases of isolated/bilateral amygdale melanosis and those of multiple localizations (p = 0.037). Failure of antiepileptic drugs (AEDs) and/or surgical epilepsy therapy were associated with poor cognitive outcome (p = 0.03).

CONCLUSION

Antiepileptic drugs were effective in the majority of patients with epilepsy with parenchymal melanosis. In case of multifocal distribution, more than one-third of patients presented a drug-resistant epilepsy. Epilepsy surgery is the best choice in patients with isolated amygdala localization. We propose the recognition of a multifactorial nature of cognitive impairment in neuromelanosis, emphasizing the role of drug-resistant epilepsy.

Neurocutaneous Melanosis Presenting as Cavernous Hemangioma Persistent Abdominal Pain

Neurocutaneous melanosis (NCM) is a rare congenital syndrome characterized by the presence of multiple congenital melanocytic nevi and the proliferation of melanocytes in the central nervous system. The authors present a 9-year-old Chinese boy whose clinical manifestations are intermittent headache for 2 months and persistent abdominal pain for 10 days. 3D-reconstruction computed tomography angiography image, digital subtraction angiography, and magnetic resonance imaging plus angiography (MRI+MRA) examinations results suggested that cavernoma at left frontal lobe potentially associated with hemorrhage. In addition, miliary abnormal signals were widely scattered on MRA image so that other malignant metastatic diseases cannot be ruled out. GI physical examination had not any abnormal findings, antispasmodic drugs were ineffective but antiepilepsy drugs were effective to abdominal pain. In surgery, no cavernoma was noticed but an accumulation of densely melanocytic mass located at the lesion on radiology images. The lesions spread along with perivascular of sylvian veins and leptomeningeal. Pathology investigation demonstrated brain metastatic malignant melanoma associated with hemosiderosis. The lesion of brain parenchyma was totally removed but the spread lesions could not be treated with surgery. Adjuvant radiotherapy was performed but failed to control the malignant development, still the patient died in 3 months postinitial operation. The authors conclude that abdominal pain was a manifestation of epilepsy related to the frontal lobe lesion. Neurocutaneous melanosis is a rare disease, brain metastases result in abdominal pain is rare even more, and it is worth the attention of clinicians.

Mosaic Neurocutaneous Disorders and Their Causes

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

Cutaneous and ocular manifestations of neurocutaneous syndromes

Neurocutaneous syndromes are a heterogeneous group of congenital and hereditary disorders with manifestations in the skin and the nervous system, usually together with ocular features that represent diagnostic clues and potential sources of morbidity. Dermatologists and ophthalmologists often need to work together in identifying and managing patients with these conditions; herein, we focus on classic and under-recognized neurocutaneous syndromes. We begin with autosomal dominant genodermatoses characterized by hamartomas and tumors in the skin, eyes, and central nervous system: neurofibromatosis type 1, tuberous sclerosis complex, and PTEN hamartoma-tumor syndrome. This is followed by a discussion of two mosaic disorders, Sturge-Weber syndrome and neurocutaneous melanocytosis. In addition to providing an update on clinical presentations and evaluation of patients with these conditions, we review recent insights into their pathogenesis, drawing attention to relationships among the diseases on a molecular level and implications regarding treatment. We also highlight the major features of other neurocutaneous syndromes that have ocular findings plus pigmentary, vascular, hyperkeratotic, adnexal, connective tissue, photosensitive, and inflammatory manifestations in the skin.

Neurocutaneous melanocytosis, hemimegalencephaly and large ovarian cyst in a newborn

We report a case of a newborn girl with neurocutaneous melanocytosis, hemimegalencephaly and a large ovarian cyst. She also had melanocyte deposition in the filum terminale. The ultrasound and the magnetic resonance imaging findings are discussed.

Giant congenital melanocytic nevi: selected aspects of diagnostics and treatment

Background

Treatment of giant melanocytic nevi (GMN) remains a multidisciplinary challenge. We present analysis of diagnostics, treatment, and follow-up in children with GMN to establish obligatory procedures in these patients.

Material/Methods

In 24 children with GMN, we analyzed: localization, main nevus diameter, satellite nevi, brain MRI, catecholamines concentrations in 24-h urine collection, surgery stages number, and histological examinations. The t test was used to compare catecholamines concentrations in patient subgroups.

Results

Nine children had “bathing trunk” nevus, 7 had main nevus on the back, 6 on head/neck, and 2 on neck/shoulder and neck/thorax. Brain MRI revealed neurocutaneous melanosis (NCM) in 7/24 children (29.2%), symptomatic in 1. Among urine catecholamines levels from 20 patients (33 samples), dopamine concentration was elevated in 28/33, noradrenaline in 15, adrenaline in 11, and vanillylmandelic acid in 4. In 6 NCM children, all catecholamines concentrations were higher than in patients without NCM (statistically insignificant). In all patients, histological examination of excised nevi revealed compound nevus, with neurofibromatic component in 15 and melanoma in 2. They remain without recurrence/metastases at 8- and 3-year-follow-up. There were 4/7 NCM patients with more than 1 follow-up MRI; in 1 a new melanin deposit was found and in 3 there was no progression.

Conclusions

Early excision with histological examination speeds the diagnosis of melanoma. Brain MRI is necessary to confirm/rule-out NCM. High urine dopamine concentration in GMN children, especially with NCM, is an unpublished finding that can indicate patients with more serious neurological disease. Treatment of GMN children should be tailored individually for each case with respect to all medical/psychological aspects.

BRAF mutations are also associated with neurocutaneous melanocytosis and large/giant congenital melanocytic nevi

NRAS and BRAF mutations occur in congenital melanocytic nevi (CMN), but results are contradictory. Sixty-six prospectively collected CMN patients were analyzed for NRAS Q61 mutations using Sanger sequencing. Negative cases were evaluated for BRAF V600E mutation. NRAS Q61 mutations affected 51 patients (77.3%), and BRAF V600E was found in 5 (7.6%). NRAS Q61 mutation affected 29 (80.6%) of 36 giant, 16 (80.0%) of 20 large, and 5 (62.5%) of 8 medium-size CMN; BRAF mutation affected 1 (5%) of 20 large and 4 (11.4%) of 36 giant CMN. Compared to NRAS, BRAF-mutated nevi show scattered/extensive dermal and subcutaneous nodules (100% BRAF+ vs 34.8% NRAS+) (P=0.002). Neurocutaneous melanocytosis (NCM) affected 16 (24.2%) of 66 patients, with NRAS Q61 mutation in 12 (75.0%), and BRAF V600E in 2 (12.5%), P=0.009. Two patients were negative for both mutations (12.5%). In conclusion, although NRAS Q61 mutations predominate, BRAF V600E mutation also affects patients with large/giant CMN (L/GCMN), and with NCM, a novel finding. BRAF V600E is also associated with increased dermal/subcutaneous nodules. These findings open the possibility of BRAF-targeted therapy in some L/GCMN and NCM cases.

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.

Oncogenic codon 13 NRAS mutation in a primary mesenchymal brain neoplasm and nevus of a child with neurocutaneous melanosis

A 28-month female with a clinical diagnosis of neurocutaneous melanosis and numerous intracranial abnormalities (including a right choroid plexus tumor and left hemimegalencephaly) presented with a rapidly expanding tumor in the left occipital cerebrum. Microscopic examination of the resected specimen revealed a myxoid mesenchymal neoplasm consisting of fusiform cells that were immunoreactive for vimentin, CD34, and P53 but no melanocyte markers. Focused amplicon deep sequencing on DNA extracted from the brain tumor and a cutaneous nevus revealed a heterozygous (c.37G > C; p.G13R) substitution in the NRAS gene. DNA sequencing of “normal” skin and buccal swab showed the identical NRAS change albeit at lower allelic frequency. Her parents did not harbor the NRAS mutation. The skin lesion, but not the brain tumor, had a BRAF mutation (c.1397G > T; p.G466V). A germline single nucleotide polymorphism in MET was found in the child and her father (c.3209C > T; p.T1010I). The findings suggest NRAS mosaicism that occurred sometime after conception and imply an oncogenic role of the activating NRAS mutation in both the brain and skin lesions in this child.