Metastatic Peritoneal Neurocutaneous Melanocytosis

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.

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.

Neurocutaneous melanocytosis-associated malignant melanoma presenting with peritoneal seeding

Neurocutaneous melanocytosis (NCM) is characterized by melanocyte deposition in the leptomeninges and brain parenchyma, primarily occurring in children with large or giant congenital melanocytic nevi (LCMN) or multiple congenital melanocytic nevi. Patients with NCM may develop hydrocephalus and increased intracranial pressure, which can be managed with ventriculoperitoneal (VP) shunting. We present the case of a 16-month-old girl who developed peritoneal carcinomatosis and malignant ascites following VP shunting for hydrocephalus secondary to NCM to increase awareness of this rare, but serious, complication of cerebrospinal fluid diversion.

Cutaneous Melanomas Arising during Childhood: An Overview of the Main Entities

Cutaneous melanomas are exceptional in children and represent a variety of clinical situations, each with a different prognosis. In congenital nevi, the risk of transformation is correlated with the size of the nevus. The most frequent type is lateral transformation, extremely rare before puberty, reminiscent of a superficial spreading melanoma (SSM) ex-nevus. Deep nodular transformation is much rarer, can occur before puberty, and must be distinguished from benign proliferative nodules. Superficial spreading melanoma can also arise within small nevi, which were not visible at birth, usually after puberty, and can reveal a cancer predisposition syndrome (CDKN2A or CDK4 germline mutations). Prognosis is correlated with classical histoprognostic features (mainly Breslow thickness). Spitz tumors are frequent in adolescents and encompass benign (Spitz nevus), intermediate (atypical Spitz tumor), and malignant forms (malignant Spitz tumor). The whole spectrum is characterized by specific morphology with spindled and epithelioid cells, genetic features, and an overall favorable outcome even if a regional lymph node is involved. Nevoid melanomas are rare and difficult to diagnose clinically and histologically. They can arise in late adolescence. Their prognosis is currently not very well ascertained. A small group of melanomas remains unclassified after histological and molecular assessment.

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).

Widespread Intra-abdominal Carcinomatosis from a Rhabdoid Meningioma after Placement of a Ventriculoperitoneal Shunt: A Case Report and Review of the Literature

Intra-abdominal metastasis (IAM) of central nervous system (CNS) tumors via ventriculoperitoneal shunt (VPS) is rare but has been previously reported (e.g., germinomas and medulloblastomas). However, there has been no previous report in the literature involving meningiomas. A case of primary rhabdoid meningioma with widespread intra-abdominal carcinomatosis after placement of a VPS in a 36-year-old man is described. The patient underwent preoperative angioembolization of the tumor, craniotomy, and surgical excision, followed by postoperative gamma knife radiosurgery. Five months later, he underwent a decompressive craniectomy and surgical excision for tumor recurrence causing raised intracranial pressure and communicating hydrocephalus, necessitating placement of a VPS. One month after placement of the VPS, the patient developed abdominal distension and confusion. He was treated for a VPS infection, and the shunt was explanted. He continued to deteriorate with high output from the peritoneal drain placed at the time of shunt explantation. An exploratory laparotomy revealed multiple diffuse peritoneal and omental nodules which had the same histopathological and immunohistochemical morphology as the primary tumor. We reviewed the current literature on IAM of primary CNS tumors via VPS, which revealed that patients belonging in the pediatric age group, of the male gender, and with a primary intracranial germinoma or medulloblastoma have a higher incidence of IAM. Majority of IAM occurred within 2 years of VPS placement, and patients most commonly present with abdominal distension and ascites. Treatment after diagnosis is varied and the prognosis is poor, with more than half of the patients dying within a year. It is vital for clinicians to maintain a high index of suspicion for similar patients, as early intervention could potentially improve patient outcomes and patient expectations managed more effectively.

Widespread Intra-abdominal Carcinomatosis from a Rhabdoid Meningioma after Placement of a Ventriculoperitoneal Shunt: A Case Report and Review of the Literature

Intra-abdominal metastasis (IAM) of central nervous system (CNS) tumors through ventriculoperitoneal shunt (VPS) is rare but has been previously reported (e.g., germinomas and medulloblastomas). However, there has been no previous reports in literature involving meningiomas. A case of primary rhabdoid meningioma with widespread intra-abdominal carcinomatosis after placement of a VPS in a 36-year-old man is described. The patient underwent preoperative angioembolization of the tumor, craniotomy, and surgical excision, followed by postoperative gamma knife radiosurgery. Five months later, he underwent a decompressive craniectomy and surgical excision for tumor recurrence causing raised intracranial pressure and communicating hydrocephalus, necessitating placement of a VPS. One month after placement of the VPS, the patient developed abdominal distension and confusion. He was treated for a VPS infection and the shunt was explanted. He continued to deteriorate with high output from the peritoneal drain placed at the time of shunt explantation. An exploratory laparotomy revealed multiple diffuse peritoneal and omental nodules which had the same histopathological and immunohistochemical morphology as the primary tumor. We reviewed the current literature on IAM of primary CNS tumors through VPS, which revealed that patients belonging to the pediatric age group of the male gender and with a primary intracranial germinoma or medulloblastoma have a higher incidence of IAM. The majority of IAM occurred within 2 years of VPS placement, and patients most commonly present with abdominal distension and ascites. Treatment after diagnosis is varied, and the prognosis is poor, with more than half of the patients dying within a year. It is vital for clinicians to maintain a high index of suspicion for similar patients as early intervention could potentially improve patient outcomes and patient expectations managed more effectively.

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.

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.

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.

The pathologic features of neurocutaneous melanosis in a cynomolgus macaque

Neurocutaneous melanosis (NCM) is a rare phakomatosis characterized by proliferation of melanin-producing cells in both the skin and the brain. In this study, we describe the clinical and pathologic features of NCM in a 4.5-year-old female cynomolgus macaque. Histopathologically, skin lesions showed foci of nests and cords of pigmented cells in the dermis similar to blue nevi in humans. In the brain, focal pigmented cell infiltration was observed in the connective tissue under the leptomeninges and in the brain parenchyma. The pigmented cell was moderately reactive with a pan-melanoma antibody (melanoma(pan)) in the skin. In the brain, the pigmented cell was moderately to strongly positive for melanoma(pan) in subleptomeningeal areas and in the cerebral cortex. Melanosomes were observed in pigmented cells in the brain by electron microscopic examination. Based on the histologic, immunohistochemical, and electron microscopic results, the diagnosis of NCM was made. This case is possibly the first report of the condition in animals.

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.