Cerebral mass due to neurocutaneous melanosis: eight years later

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).

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.

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.

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.

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.

Stable Neurocutaneous Melanosis in a Ten-Year-Old Boy with Controlled Partial-Complex Seizures

Neurocutaneous melanosis (NCM) is a rare neuroectodermal dysplasia that includes both central nervous system (CNS) and integumentary melanocytic abnormalities. NCM can present with varied clinical and imaging findings, classically presenting with large melanocytic nevi involving the posterior axial trunk region. We describe a case with predominant small non-scalp and non posterior axial-trunk nevi, which nevertheless demonstrated typical CNS imaging findings. Our case clinically presented with epilepsy that was controlled by medical treatment. The patient also demonstrated motor developmental delay, and an otherwise stable course.

An unusual case of congenital melanocytic nevus presenting as neurocutaneous melanoma coexisting with Tuberous Sclerosis complex: A case report

Introduction

Congenital melanocytic nevi are among the several known risk factors for the development of melanoma. Neurocutaneous melanosis is a rare, congenital, non-hereditary disorder characterized by the presence of multiple and/or giant congenital melanocytic nevi. It is a rare condition, with fewer than 200 cases reported in the literature. Its association with tuberous sclerosis complex, a form of the neurocutaneous syndrome, is an unusual finding which, to the best of our knowledge, has not been documented in the English literature so far. Herein we present the first case documenting such an association in a 16-year-old post-pubertal Indian girl.

Case presentation

In this report, we describe the case of a 16-year-old Indian girl who presented to our hospital with swelling on the scalp which had progressed from the hairline to just above the left brow, causing mechanical ptosis. She was born with a black-pigmented triangular patch covered with hair over the scalp which had increased in size over a period of eight years after birth. An X-ray of her skull and ultrasonography revealed soft tissue swelling in the left temporofrontoparietal region. Magnetic resonance imaging of her brain showed the presence of 8.99 cm × 2.26 cm abnormal signal intensity involving the scalp, a few small tubers with cortical dysplasia in the left frontoparietal region with asymmetric dilatation, and the presence of calcified subependymal nodules within the left lateral ventricle. These findings were suggestive of tuberous sclerosis. A histopathological examination of the swelling was suggestive of congenital melanocytic nevi. The patient underwent surgery. Excision of the tumor with primary skin grafting was done, with the graft being taken from the medial aspect of the right thigh.

Conclusion

This case warrants further research to provide concrete evidence of an association of neurocutaneous melanoma with tuberous sclerosis complex. Research should be conducted to prove whether this is an unusual association or a new syndrome. Also, similar cases in other parts of the globe should be documented, as they would provide substantial support for such an association.

Congenital melanocytic nevi-when to worry and how to treat: Facts and controversies

Congenital melanocytic nevi (CMN) are evident in 1% to 6% of neonates. In some studies, nevi with clinical, dermatoscopic, and histologic features identical to CMN have had a prevalence of more than 15% in older children and adults, possibly reflecting the "tardive" appearance of nevi programmed from birth. There is ongoing debate about the magnitude of the risk of melanoma and other complications associated with CMN of various sizes and the best approach to management of these lesions. We review the natural history of CMN, including proliferative nodules and erosions during infancy, neurotization, and spontaneous regression, and features of variants such as speckled lentiginous and congenital blue nevi. The risk of melanoma arising within small-sized (<1.5 cm) and medium-sized CMN is low (likely <1% over a lifetime) and virtually nonexistent before puberty. Recent data suggest that melanoma (cutaneous or extracutaneous) develops in approximately 5% of patients with a large (>20 cm) CMN, with about half of this risk in the first few years of life. Melanoma and neurocutaneous melanocytosis (NCM) are most likely in patients with CMN that have a final size of >40 cm in diameter, numerous satellite nevi, and a truncal location. One-third of individuals with NCM have multiple medium-sized (but no large) CMN. In patients at risk for NCM, a screening gadolinium-enhanced magnetic resonance imaging, preferably before age 6 months, and longitudinal neurologic assessment are recommended. Management of CMN depends on such factors as the ease of monitoring (more difficult for large, dark, thick nevi) and cosmetic and psychologic benefits of excision or other procedures. CMN require lifelong follow-up. Periodic total body skin examinations are necessary for all patients with large CMN, even when complete resection (often impossible) has been attempted.

Neurocutaneous melanosis and the Dandy-Walker complex: an uncommon but not so insignificant association

BACKGROUND

Neurocutaneous melanosis represents a rare congenital but nonheritable phakomatosis defined as the association of giant or multiple congenital nonmalignant melanocytic nevi with leptomeningeal melanosis or melanoma of the central nervous system.

METHODS

We describe the case of an adolescent with a giant congenital bathing trunk melanocytic nevus who developed progressive intracranial hypertension due to leptomeningeal melanosis confirmed by surgical biopsy. Brain and spine magnetic resonance images showed posterior fossa malformation compatible with the Dandy-Walker complex, hydrocephalus, and extensive enhancement of posterior fossa then spine. Shunt placement, corticotherapy, and chemotherapy were attempted leading to transient relief but the boy died 12 months after the onset of primary neurological symptoms.

DISCUSSION

We discuss diagnosis, pathogenesis, management, and prognosis in the light of data from the recent literature.

CONCLUSION

Neurocutaneous melanosis is considered to follow from neurulation disorders which could account for associated developmental malformations as the so-called Dandy-Walker complex. Cutaneous lesions are usually recognized at birth whereas neurological manifestations develop later. Numerous neurological symptoms have been reported according to extent of leptomeningeal and parenchymal infiltration. Whether magnetic resonance imaging of the neuroaxis represents the choice radiological exam, definite diagnosis relies upon the histological data obtained by mean of biopsy. Once symptomatic, surgical and medical measures remain palliative since death occurs within 3 years.

Neurocutaneous melanosis: report of three cases and up-to-date review

Neurocutaneous melanosis is a rare noninherited embryonic neuroectodermal dysplasia, which is observed sporadically and never affects the entire integument. The hallmark of neurocutaneous melanosis in the neonatal period is the presence of a large bilateral hairy dark nevus with satellite nevi over the trunk and neck. The diagnosis should be considered in neonates with large pigmented nevi and in those with more than 3 hairy dark nevi regardless of their size. Neonates with neurocutaneous melanosis are at risk of developing neurological problems. The most common neurological complications are hydrocephalus, seizures, cranial nerve dysfunction, and signs of spinal cord and root involvement. The authors report 3 cases of histologically confirmed neurocutaneous melanosis and describe the course of neurological symptoms and clinical findings including cognitive tests and neuroimaging. The case reports are complemented by an up-to date review on this clinical entity.

Neurocutaneous melanosis presenting as chronic partial epilepsy

Background

Neurocutaneous melanosis (NCM) is a rare neurocutaneous syndrome characterized by the presence of multiple congenital melanocytic nevi (CMN) and the proliferation of melanocytes in the central nervous system, usually involving the leptomeninges. Chronic partial epilepsy as a sole manifestation is rare in NCM.

Case Report

A 32-year-old man suffering from chronic partial epilepsy presented with multiple CMN on his trunk and scalp. Brain MRI demonstrated a focal lesion in the right amygdala that was consistent with interictal epileptiform discharges in the right temporal region on electroencephalography (EEG). An anterior temporal lobectomy was performed, and the pathology investigation revealed numerous melanophages in the amygdala. The patient was seizure-free after surgery.

Conclusions

We report a patient with NCM presenting as chronic partial epilepsy who was successfully treated by anterior temporal lobectomy.

Neurocutaneous melanosis

Neurocutaneous melanosis (NCM) is a rare congenital disorder characterized by the presence of large or multiple congenital melanocytic nevi in association with benign or malignant proliferation of melanocytes in the leptomeninges. NCM is believed to occur as a consequence of an error in morphogenesis in neural ectoderm in the developing embryo. Animal models suggest that aberrant expression of the hepatocyte growth factor/scatter factor (HGF/SF) may be involved in the pathogenesis in the NCM. While the majority of patients with NCM have large congenital melanocytic nevi in a posterior axial distribution, a significant proportion of patients present with multiple smaller nevi in the absence of a single larger lesion. Neurologic manifestations generally occur within the first two years of life, and are often related to increased intracranial pressure. Associated structural anomalies of the CNS have been reported in NCM, particularly the Dandy-Walker complex. The long-term clinical significance of characteristic magnetic resonance findings in neurologically asymptomatic patients is unclear. Approximately half of NCM patients develop CNS melanoma. The prognosis of symptomatic patients remains poor.

The rare phakomatoses

This article outlines the clinical, central nervous system, and neuropathologic features,pathogenesis, genetics, molecular biology, and neuroimaging characteristics of the rare vascular phakomatoses, melanophakomatoses, and organoid phakomatoses.