Neurocutaneous melanosis

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.

Imaging and clinical features of neurocutaneous melanosis in the pediatric population

BACKGROUND

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

OBJECTIVE & METHODS

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

DISCUSSION

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

CONCLUSION

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

Neurocutaneous Melanocytosis and Leptomeningeal Melanoma

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

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.

Symptomatic neurocutaneous melanosis: mild clinical onset in a teenager

Neurocutaneous melanosis (NCM) is a rare disorder characterised by giant or multiple melanocytic nevi and meningeal melanosis or melanoma. Onset of neurological symptoms is typically in children younger than 2 years and can be rapidly fatal. We present the case of a 13-year-old adopted girl presenting with numerous congenital melanocytic nevi and a seizure. She had no significant previous neurological history. Electroencephalogram showed epileptiform discharges over the right frontal region. MRI of the brain showed T1 hyperintensity in the bilateral amygdala and anterior temporal lobes with corresponding hyperintensity on T2 and fluid attenuated inversion recovery. There was no hydrocephalus. Along with the history of nevi, these imaging findings were concerning for NCM. The patient is being managed with levetiracetam and trametinib and shows no further neurological decline at 1-year follow-up, providing prognostic hope in this case of NCM.

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).

Primary Diffuse Leptomeningeal Melanomatosis: Case Report and Review of the Literature

BACKGROUND

Primary diffuse leptomeningeal melanomatosis (PDLM) is an extremely rare pathologic condition that can mimic several other neurologic disease states.

METHODS

We report a rare case of PDLM without evidence of a primary focus. In addition, we performed a comprehensive review of the literature to describe all previously reported cases of PDLM.

RESULTS

In the reported case, making the diagnosis of PDLM was difficult. A brain and frontal dural biopsy was nondiagnostic. Computed tomography of the chest, abdomen, and pelvis did not show any distinct solitary mass. After a positron emission tomography scan was performed that showed lumbar sacral enhancement, lumbar dorsal rootlet biopsy was initiated, which was diagnostic of PDLM. Our literature review found 32 previously reported cases of PDLM. Sixteen cases (48.5%) had a distinct focus or mass discovered on imaging workup. The reported case was the seventeenth reported case of PDLM without a distinct focus or mass found on imaging workup.

CONCLUSIONS

PDLM is an extremely rare disease, and diagnosis is difficult because of nonspecific clinical, radiographic, and laboratory findings. In approximately half of cases, no distinct mass is shown on imaging workup, which may further complicate diagnosis. PDLM should be on the differential diagnosis for cases of diffuse dural enhancement. Neurosurgical intervention is often limited to ventriculoperitoneal shunting for increased intracranial pressure and dural and cranial biopsy to obtain diagnosis. If the initial biopsy is nondiagnostic, hypermetabolic activity as seen on positron emission tomography may be helpful to find an alternative biopsy site.

Epilepsy surgery for a patient with neurofibromatosis type 1 concomitant with moyamoya syndrome

BACKGROUND

Epilepsy associated with neurocutaneous disorders is well known, and the prevalence of epilepsy among patients with neurofibromatosis type 1 (NF1) ranges from 4% to 13%. However, epilepsy surgery for patients with NF1 is not commonly performed.

CASE DESCRIPTION

We report the case of a patient with medically intractable mesial temporal lobe epilepsy (mTLE) concomitant NF1 and moyamoya syndrome (MMS) who had already undergone bilateral superficial temporal artery-middle cerebral artery anastomosis at 17 years old. As the standard temporal approach was unavailable, we evaluated the patient with neurologists, radiologists, neurosurgeons and neuropsychologists to identify the safest trajectory for epilepsy surgery. The patient underwent the right selective amygdala hippocampectomy from the posterior auricle part at 32 years old and obtained freedom from seizures.

CONCLUSION

To the best of our knowledge, this represents the first surgical case report for mTLE concomitant with NF1 and MMS.

Neurocutaneous melanosis presenting with hydrocephalus and malignant transformation: case-based update

INTRODUCTION

Neurocutaneous melanosis (NCM) is a sporadic condition characterised by congenital melanocytic nevi and melanocytic thickening of the leptomeninges. It is believed to result from congenital dysplasia of melanin-producing cells within the skin and leptomeninges. The management of cutaneous manifestations remains controversial; for neurological manifestations, outcome remains poor even with the use of radiotherapy and chemotherapy.

PATIENTS AND METHODS

We describe the case of a 5-month-old boy who presented with giant congenital melanocytic nevus and hydrocephalus. MR imaging and CSF immunohistochemistry confirmed leptomeningeal melanosis. We discuss the diagnosis, treatment and prognosis of this rare disorder in the light of recent published literature.

RESULTS

Patient required placement of right-sided ventriculoperitoneal shunt to control hydrocephalus. The patient tolerated the procedure well and was discharged home with normal neurological function. A presumptive diagnosis of NCM was made based on the MR characteristics, CSF cytology and clinical presentation. He received trametinib, a MAPK/Erk kinase inhibitor for 7 months. At 30 months of age, he developed left-sided weakness and status epilepticus requiring paediatric intensive care unit admission and ventilator support. The patient eventually succumbed to malignant transformation of leptomeningeal disease.

CONCLUSION

Cutaneous manifestations of NCM are usually congenital, and neurological manifestations develop early in life. Patients with large or multiple congenital nevi should therefore be investigated early to facilitate treatment. MR imaging is the investigation of choice which can further assist in performing biopsy. Symptomatic NCM is refractory to radiotherapy and chemotherapy and has a poor prognosis. A multidisciplinary approach is necessary in the management of NCM patients.

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.

Pigmented Lesions of the Nervous System and the Neural Crest: Lessons From Embryology

Neurosurgeons encounter a number of pigmented tumors of the central nervous system in a variety of locations, including primary central nervous system melanoma, blue nevus of the spinal cord, and melanotic schwannoma. When examined through the lens of embryology, pigmented lesions share a unifying connection: They occur in structures that are neural crest cell derivatives. Here, we review the important progress made in the embryology of neural crest cells, present 3 cases of pigmented tumors of the nervous system, and discuss these clinical entities in the context of the development of melanoblasts. Pigmented lesions of the nervous system arise along neural crest cell migration routes and from neural crest-derived precursors. Awareness of the evolutionary clues of vertebrate pigmentation by the neurosurgical and neuro-oncological community at large is valuable for identifying pathogenic or therapeutic targets and for designing future research on nervous system pigmented lesions. When encountering such a lesion, clinicians should be aware of the embryological basis to direct additional evaluation, including genetic testing, and to work with the scientific community in better understanding these lesions and their relationship to neural crest developmental biology.

Primary Amelanotic Leptomeningeal Melanomatosis in a Child: A Rare but Severe Disease

BACKGROUND

Primary leptomeningeal melanomatosis (PLM) is a rare and aggressive form of nonmetastatic invasion of leptomeninges by malignant melanocytic cells. Clinical presentation includes nonspecific meningism with various forms of cerebrospinal fluid circulation or absorption disorders leading to hydrocephalus.

CASE DESCRIPTION

A 5-year-old child with PLM without neurocutaneous melanosis presented with cystic enlargement of the brainstem surrounding cisterns and hydrocephalus requiring occipitoaxial decompression and endoscopic cystostomy. Initial cerebrospinal fluid cytology screening and frontal meningeal and brain biopsy specimens showed negative results. The diagnosis of unpigmented (amelanotic) malignant melanocytic cells was made after a biopsy specimen of the bulbar leptomeninges was obtained. Despite continuous management of hydrocephalus and chemotherapy, the disease progressed, and the patient died 11 months after diagnosis.

CONCLUSIONS

To the best of our knowledge, this is the first report of an amelanotic form of PLM without association of neurocutaneous melanosis in a child. This case report illustrates the difficulty of diagnosis in the absence of cutaneous lesions and lack of melanin.

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.

Neurocutaneous melanosis in association with dandy-walker complex with extensive intracerebral and spinal cord involvement

Neurocutaneous melanosis (NCM) is a rare congenital syndrome consisting of benign or malignant melanotic tumors of the central nervous system with large or numerous cutaneous melanocytic nevi. The Dandy-Walker complex (DWC) is characterized by an enlarged posterior fossa with high insertion of the tentorium, hypoplasia or aplasia of the cerebellar vermis, and cystic dilatation of the fourth ventricle. These each two conditions are rare, but NCM associated with DWC is even more rare. Most patients of NCM with DWC present neurological symptoms early in life such as intracranial hemorrhage, hydrocephalus, and malignant transformation of the melanocytes. We report a 14-year-old male patient who was finally diagnosed as NCM in association with DWC with extensive intracerebral and spinal cord involvement.

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.

A newborn with neurocutaneous melanocytosis and Dandy-Walker malformation

BACKGROUND

Neurocutaneous melanocytosis is a rare congenital dysplasia of the neuroectodermal melanocyte precursor cells that leads to proliferation of melanin-producing cells in the skin and leptomeninges.

PATIENT

We describe a newborn with a giant congenital melanocytic nevus on his back, buttocks, and thighs. His brain magnetic resonance imaging study revealed bilateral T1 hyperintense lesions in the cerebellum and in the amygdala, hydrocephalus, and a Blake's pouch cyst, consistent with neurocutaneous melanocytosis and Dandy-Walker malformation.

CONCLUSION

Neurocutaneous melanocytosis has a wide clinical spectrum that includes hydrocephalus, epilepsy, cranial nerve palsy, increased intracranial pressure, and sensorimotor deficits.

[Asymptomatic neonatal neurocutaneous melanosis]

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

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.

Dandy-walker malformation associated with neurocutaneous melanosis

Neurocutaneous melanosis associated with Dandy-Walker malformation is a rare dysmorphogenesis that is associated with single or multiple giant pigmented cutaneous nevi and diffuse involvement of the central nervous system. In this article, we present a 2-month-old patient with neurocutaneous melanosis associated with Dandy-Walker malformation. In addition, we reviewed the literature and discussed the pathogenesis based on the preferred hypotheses.

Primary leptomeningeal melanocytosis in a 10-year-old girl: a challenging diagnosis with a poor prognosis

Primary leptomeningeal melanocytosis is rarely encountered in the pediatric population. Despite being considered a nonmalignant condition, it uniformly carries a poor prognosis given the ineluctable progression of meningeal infiltration. The case of a previously healthy 10-year-old girl who was first thought to suffer from recurrent hemiplegic migraine is reported. She later developed insidious subacute hydrocephalus. Meningeal biopsy performed during shunt insertion demonstrated an unexpectedly large number of melanocytes consistent with meningeal melanocytosis. Subsequently, the child developed recurrent shunt dysfunction and showed evidence of malignant transformation. The steps to reaching the proper diagnosis are discussed, and the current literature on this rare clinical entity as well as on related central nervous system melanocytic lesions that can occur in the pediatric population is reviewed.

Neurocutaneous Melanosis: A Case Report and Review of the Literature

This report concerns a case in which suicide by self-immolation occurred in an adolescent with neurocutaneous melanosis (NCM). A rare neurocutaneous syndrome, NCM has often been reported to occur concomitantly with psychiatric and neurologic disorders. While symptomatic disease is most often encountered in children, symptomatic disease at any age typically results in rapid morbidity and mortality. The gross and microscopic findings of NCM, the potential relevance of NCM to the case scenario, and a literature review of NCM will be presented. NCM may have a large influence on antemortem behavior and determination of cause of death, and for this reason it is important to be aware of its morphology and potential significance when encountered at autopsy.

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.

Primary melanocytic neoplasms of the central nervous system

Primary melanocytic neoplasms of the central nervous system (CNS) are rare lesions arising from melanocytes of the leptomeninges. They include diffuse leptomeningeal melanocytosis or melanomatosis, melanocytoma and primary malignant melanoma. We have reviewed the English literature regarding these lesions, which consists of case reports and a small number of larger case series. The presenting features, radiological, surgical and histological findings are reviewed, as are current management options and prognosis. We also present illustrative case reports of diffuse leptomeningeal melanocytosis and primary melanoma of the CNS.

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.

Pigmented lesions of the central nervous system: radiologic-pathologic correlation

Pigmented lesions of the central nervous system (CNS) are a diverse group of entities that run the gamut from benign to malignant. These lesions may be well circumscribed or diffuse, and their imaging appearances are influenced by the degree of melanin content as well as the presence or absence of hemorrhage. Pigmented lesions include primary melanocytic lesions of the CNS and metastatic melanoma, as well as other CNS neoplasms that may undergo melanization, including schwannoma, medulloblastoma, and some gliomas. Primary melanocytic lesions of the CNS arise from melanocytes located within the leptomeninges, and this group includes diffuse melanocytosis and meningeal melanomatosis (seen in neurocutaneous melanosis), melanocytoma, and malignant melanoma. Primary melanin-containing lesions of the CNS must be differentiated from metastatic melanoma because these lesions require different patient workup and therapy. Absence of a known primary malignant melanoma helps in the differential diagnosis, but an occult primary lesion outside the CNS must be sought and excluded. Pigmented lesions of the CNS are uncommon, and knowledge of their imaging characteristics and pathologic features is essential for their identification.

Large congenital melanocytic nevi presenting with lissencephaly with an absent corpus callosum

A neonatal case of provisional neurocutaneous melanosis presenting with lissencephaly is reported. Several congenital nevi were observed on the trunk and extremities of the infant, including a giant congenital hairy nevus over the skull. Brain magnetic resonance imaging revealed a marked ventricular dilatation with pachygyria and an absent corpus callosum; however, an injection of gadolinium did not demonstrate any enhanced lesions. Histopathological investigations by a brain biopsy showed a disorganized and anomalous embryonic cerebral architecture, suggesting lissencephaly. The detailed mechanism of this combined pathology is difficult to explain; however, a developmental disturbance was suggested to be present in both the neural crest cells and the neuroepithelial cells, resulting in the development of neurocutaneous melanosis accompanied with lissencephaly.

Progressive brainstem compression in an infant with neurocutaneous melanosis and Dandy-Walker complex following ventriculoperitoneal shunt placement for hydrocephalus. Case report

Neurocutaneous melanosis (NM) coexisting with the Dandy-Walker complex (DWC) is a rare condition, with fewer than 15 cases reported in the literature. The authors present a case of an infant with NM and DWC suffering from progressive brainstem compression following ventriculoperitoneal (VP) shunt placement for hydrocephalus. This 1-year-old boy with congenital melanocytic nevi had met normal developmental milestones until the age of 11 months, when he began regressing in ambulation and language function. Intractable vomiting had developed 1 week later. Magnetic resonance (MR) imaging of the brain revealed DWC with hydrocephalus, and spinal MR images demonstrated a proliferative process within the meninges, consistent with NM. The patient underwent right frontal VP shunt placement resulting in immediate symptom relief, but 3 weeks later became irritable, increasingly lethargic, unable to pull to stand, and unable to tolerate solid food without choking. Due to these symptoms and intractable vomiting, the patient presented to the authors' institution. Brain MR imaging revealed a new-onset diffuse cystic process with anterior and posterior brainstem compression, marked kinking of the cervicomedullary junction, melanocyte pigmentation of the left temporal lobe, diffuse leptomeningeal enhancement, and no evidence of hydrocephalus. Consistent with these imaging findings, the degree of brainstem involvement upon gross visualization predictably deterred resection attempts beyond those necessary for biopsy. Pathological examination revealed diffuse melanocytosis, and the family decided not to pursue aggressive measures postoperatively. This report indicates the potential for rapid intracranial manifestation of diffuse melanocytosis in NM patients. Although the prognosis is poor, early neurosurgical involvement in these patients may provide tissue diagnosis and the potential for decompression if the process is caught early in its course.

Large primary meningeal melanoma in an adult patient with neurocutaneous melanosis

Neurocutaneous melanosis is often associated with melanoma of the central nervous system. Due to the inconspicuously looking cutaneous melanosis additional examinations are often not performed. We describe a patient with cutaneous melanosis who presented with neurological symptoms due to a large primary meningeal melanoma. The diagnosis of neurocutaneous melanosis was made. This case is an illustration of melanoma development in the central nervous system in a patient with cutaneous melanosis. This phenomenon should be kept in mind when observing patients with such skin lesions, even if they are of minor extent.

Sudden Change of a Large Congenital Melanocytic Nevus to Neurocutaneous Melanosis

Neurocutaneous melanosis (NCM) is a congenital phakomatosis in which large congenital melanocytic nevi are associated with a benign or malignant melanocytic tumor of the leptomeninges. Because the prognosis of patients with symptomatic NCM is poor, it is essential to monitor the large congenital melanocytic patient regularly for a neurological evaluation. However, it has not been reported how quickly the lesion could appear. We observed a case of NCM suddenly developing in a large congenital melanocytic nevi patient. With this case, the NCM had developed within six months and was aggravated during the subsequent six months.

Neurocutaneous melanosis associated with Dandy-Walker malformation

Neurocutaneous melanosis is an uncommon congenital disorder consisting of benign or malignant melanocytic tumors of the leptomeninges with large or numerous cutaneous congenital melanocytic nevi. The Dandy-Walker malformation occurs as an enlarged posterior fossa with high insertion of the tentorium, hypoplasia or aplasia of the cerebellar vermis, and cystic dilatation of the fourth ventricle. To our knowledge, the association of these two conditions has been reported only 14 times. In this article, we present a newborn patient with neurocutaneous melanosis associated with Dandy-Walker malformation, which was diagnosed by magnetic resonance imaging.

Neurocutaneous melanosis with associated Dandy-Walker complex

CASE REPORT

The authors report the case of a child with neurocutaneous melanosis associated with a Dandy-Walker complex. Magnetic resonance (MR) images showed shortened T1-weighted images in areas involving the amygdala, mesencephalon, rostral brain stem, and superior cerebellar surface compatible with melanin deposits. There was also partial agenesis of the cerebellar vermis with an enlarged fourth ventricle cyst along with a high-lying torcular and ventricular enlargement. Endoscopic fenestration and biopsy of the cyst wall was performed without evidence of abnormal melanin deposits in the meninges.

OUTCOME

The patient eventually required ventriculoperitoneal shunting and at 1-year follow-up did not develop evidence of primary CNS melanoma. ILLUSTRATION: Computed tomography and MR images consistent with neurocutaneous melanosis and the Dandy-Walker complex are presented along with photographs of the cutaneous nevi.

DISCUSSION

The major clinical and radiological features of this rare association, with only 11 previously reported cases, are discussed in detail.

Asymptomatic neurocutaneous melanocytosis in patients with large congenital melanocytic nevi: A study of cases from an Internet-based registry

BACKGROUND

Recent retrospective studies using magnetic resonance imaging (MRI) to screen for neurocutaneous melanocytosis (NCM) among neurologically asymptomatic children with large congenital melanocytic nevi (LCMN) report high prevalence (23-30%) of asymptomatic NCM. We sought to determine prevalence of asymptomatic NCM, and current application of MRI as a screening tool.

METHODS

Patients with LCMN from an Internet-based registry answered a questionnaire regarding NCM status.

RESULTS

Of 379 patients with LCMN, 26 reportedly had NCM, with 17 reporting neurologic symptoms. Of 186 patients undergoing MRI, 9 reported abnormal findings without neurologic symptoms (4.8%); 80% had LCMN on the posterior axis, whereas 55% had more than 20 satellite nevi.

LIMITATIONS

Study data rely on the registry members' self-reported findings and are limited by lack of independent data verification.

CONCLUSION

Asymptomatic NCM (determined by MRI) may not be common, with much lower prevalence (4.8%) than previously reported. MRI is widely used for screening patients at risk for NCM, such as patients with LCMN involving the posterior axis and greater than 20 satellite nevi.

[Neurocutaneous melanosis and malignant melanoma]

A 36-year-old man presented with a giant congenital melanocytic nevus and multiple disseminated melanocytic nevi. After he had developed neurological symptoms (grand mal seizures), a cerebral metastasis of a malignant melanoma without a primary melanoma was found. The patient was diagnosed as having a neurocutaneous melanosis with a cerebral metastasis. In spite of a variety of therapeutic attempts (surgery, radiation therapy and chemotherapy) he followed a rapidly progressive, lethal course with increased intracranial pressure, hydrocephalus and spinal metastases.