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

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.

Primary Diffuse Leptomeningeal Melanomatosis in an Indian Child With Review of Literature

BACKGROUND

Primary diffuse leptomeningeal melanomatosis (PDLM) is an extremely rare, aggressive malignant neoplasia of the central nervous system. We report the first case of pediatric PDLM from India.

METHODS

A review of literature was done to describe the 15 pediatric cases reported so far.

RESULTS

A 12-year-old male child presented with fever, vomiting, and headache for 2 months. Cerebrospinal fluid examination was normal. An MRI of the brain revealed hydrocephalus, for which antitubercular therapy was started and external ventricular drainage followed by ventriculoperitoneal shunt was done. Repeat MRI revealed a suprasellar lesion, nodular enhancement of cranial nerves along with dural enhancement of spinal cord with arachnoiditis, and long-segment myelomalacia. Repeat cerebrospinal fluid examination was negative for malignant cells. During biopsy, blackish dura with diffuse blackish deposits in ventricle were noted. Histopathological examination revealed tumor cells with intracytoplasmic coarse brown pigment melanoma, frequent mitotic figures, and immunohistochemistry testing was positive for human melanoma black-45 and MelanA, suggestive of PDLM. He expired 4 months after the diagnosis.

CONCLUSION

Diagnosing PDLM can be daunting in light of its slow but malignant progression mimicking TBM leading to improper management. However, the absence of any supportive microbiological evidence and failure to respond to the standard antitubercular therapy with subsequent progression of the symptoms should prompt the need for finding an alternative diagnosis. A targeted molecular diagnosis and precision medicine may provide a favorable outcome in children with PDLM.

Clinicopathological features, current status, and progress of primary central nervous system melanoma diagnosis and treatment

Primary central nervous system (CNS) melanoma is an extremely rare condition, with an incidence rate of 0.01 per 100,000 individuals per year. Despite its rarity, the etiology and pathogenesis of this disease are not yet fully understood. Primary CNS melanoma exhibits highly aggressive biological behavior and presents clinically in a distinct manner from other types of melanomas. It can develop at any age, predominantly affecting the meninges as the primary site, with clinical symptoms varying depending on the neoplasm's location. Due to the lack of specificity in its presentation and the challenging nature of imaging diagnosis, distinguishing primary CNS melanoma from other CNS diseases. The combination of challenges in early detection, heightened tumor aggressiveness, and the obscured location of its origin contribute to an unfavorable prognostic outcome. Furthermore, there has been currently no consensus on a standardized treatment approach for primary CNS melanoma. Despite recent advancements in targeted therapy and immunotherapy for CNS melanoma, patients with primary CNS melanoma have limited treatment options due to their inadequate response to these therapies. Here, we provided a comprehensive summary of the epidemiology, clinical features, molecular pathological manifestations, and available diagnostic and therapeutic approaches of primary CNS melanoma. Additionally, we proposed potential therapeutic strategies for it.

Missense mutation of NRAS is associated with malignant progression in neurocutaneous melanosis

Neurocutaneous melanosis (NCM) is a rare congenital neurocutaneous syndrome characterized by congenital melanocytic nevus of skin and abnormal proliferation of leptomeningeal melanocytes. Early acquisition of post-zygotic somatic mutations has been postulated to underlie the pathogenesis of NCM. The pathogenesis of NCM remains to be fully elucidated, and treatment options have not been established. Here, we report for the first time, multiregional genomic analyses in a 3-year-old autopsied girl with leptomeningeal melanomatosis associated with NCM, in which a ventriculo-peritoneal (VP) shunt was inserted for the treatment of hydrocephalus. The patient expired six months after the onset due to respiratory failure caused by abdominal dissemination via VP shunt. We performed multiregional exome sequencing to identify genomic differences among brain and abdominal tumors, nevus, and normal tissues. A total of 87 somatic mutations were found in 71 genes, with a significantly large number of gene mutations found in the tumor site. The genetic alterations detected in the nevus were only few and not shared with other sites. Three mutations, namely GNAQ R183Q, S1PR3 G89S and NRAS G12V, considered pathogenic, were found, although S1PR3 mutations have not been previously reported in melanocytic tumors. GNAQ and S1PR3 mutations were shared in both tumor and normal sites. Moreover, the mutant allele frequencies of the two mutations were markedly higher in tumor sites than in normal sites, with copy-neutral loss-of-heterozygosity (CN-LOH) occurring in tumor. NRAS mutation was found only in the abdominal tumor and was thought to be responsible for malignant progression in the present case. Multiregional comprehensive genetic analysis may lead to discovering novel driver mutations associated with tumorigenesis and targeted therapy.

Primary Diffuse Leptomeningeal Melanomatosis in a Child with Extracranial Metastasis: Case Report

Primary meningeal melanomatosis is an extremely rare tumor with very few documented responses to treatment. A 3-year-old male with a complex past medical history, including prematurity and shunted hydrocephalus, was diagnosed with primary meningeal melanomatosis with peritoneal implants. Molecular testing revealed an NRAS Q61R mutation. The patient received proton craniospinal radiation followed by immunotherapy with nivolumab (1 mg/kg) and ipilimumab (3 mg/kg) IV every 3 weeks and, upon progression, he was switched to a higher dose of nivolumab (3 mg/kg IV every 2 weeks) and binimetinib (24 mg/m2/dose, twice a day). The patient had significant improvement of CNS disease with radiation therapy and initial immunotherapy but progression of extracranial metastatic peritoneal and abdominal disease. Radiation was not administered to the whole abdomen. After two cycles of nivolumab and treatment with the MEK inhibitor binimetinib, he had radiographic and clinical improvement in abdominal metastasis and ascitis. He ultimately died from RSV infection, Klebsiella sepsis, and subdural hemorrhage without evidence of tumor progression. This is the first report of a child with primary meningeal melanomatosis with extracranial metastatic disease with response to a combination of radiation, immunotherapy and MEK inhibitor therapy.

Liquid Biopsy with Detection of NRASQ61K Mutation in Cerebrospinal Fluid: An Alternative Tool for the Diagnosis of Primary Pediatric Leptomeningeal Melanoma

Primary leptomeningeal melanoma (PLMM) is a very rare disease in childhood with a poor prognosis. NRAS^Q16K mutation frequently drives malignant transformation in this population, so its evaluation should be considered in childhood PLMM diagnosis. In the presented case, the mutation was detected by Sanger sequencing performed on DNA extracted from cerebrospinal fluid neoplastic cells. Liquid biopsy has been shown to be a safe and reliable technique for the diagnosis of PLMM. Its use can potentially be extended to other neoplasms of the central nervous system bearing well-defined molecular mutations, sparing the patient invasive surgery and finally allowing a more rapid diagnosis and early initiation of targeted therapies.

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.

Novel Insights into Diagnosis, Biology and Treatment of Primary Diffuse Leptomeningeal Melanomatosis

Primary diffuse leptomeningeal melanomatosis (PDLMM) is an extremely rare and aggressive cancer type for which best treatment strategies remain to be elucidated. Herein, we present current and prospective diagnostic strategies and treatment management of PDLMM. Against the background of an extensive literature review of published PDLMM cases and currently employed therapeutic strategies, we present an illustrative case of a pediatric patient suffering from PDLMM. We report the first case of a pediatric patient with PDLMM who received combination treatment including trametinib and everolimus, followed by intravenous nivolumab and ipilimumab with concomitant intensive intraventricular chemotherapy, resulting in temporary significant clinical improvement and overall survival of 7 months. Following this clinical experience, we performed a comprehensive literature review, identifying 26 additional cases. By these means, we provide insight into current knowledge on clinical and molecular characteristics of PDLMM. Analysis of these cases revealed that the unspecific clinical presentation, such as unrecognized increased intracranial pressure (present in 67%), is a frequent reason for the delay in diagnosis. Mortality remains substantial despite diverse therapeutic approaches with a median overall survival of 4 months from diagnosis. On the molecular level, to date, the only oncogenic driver reported so far is mutation of NRAS (n = 3), underlining a close biological relation to malignant melanoma and neurocutaneous melanosis. We further show, for the first time, that this somatic mutation can be exploited for cerebrospinal fluid liquid biopsy detection, revealing a novel potential biomarker for diagnosis and monitoring of PDLMM. Last, we use a unique patient derived PDLMM cell model to provide first insights into in vitro drug sensitivities. In summary, we provide future diagnostic and therapeutic guidance for PDLMM and first insights into the use of liquid biopsy and in vitro models for this orphan cancer type.

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

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

Pediatric primary diffuse leptomeningeal melanomatosis: Case report and review of the literature

RATIONALE

Primary melanocytic tumors of central nerve system (CNS) are rare, primary diffuse leptomeningeal melanomatosis (PDLM), a subtype of malignant melanomas of CNS, is extremely rare,especially in pediatrics. As the clinical manifestation of PDLM is not characteristic, It is often misdiagnosed as tubercular meningitis and hemorrhage.

PATIENT CONCERNS

A 13-year-old boy was admitted to our department with symptoms of recurrent headache and vomiting twice. As the brain imaging revealed a lesion located in the left temporal lobe mimicked hemorrhage, so there was a misdiagnosis of hemorrhage in first hospitalization. He was admitted again for the recurrence of the headache and vomiting. Detailed physical examination showed multiple melanin changes in the skin of the whole body which were ignored in last hospitalization. Brain imaging showed the significantly enlarged lesion in the left temporal lobe and several smaller lesions in the left parietal lobe and cerebellum which indicated metastasis.

DIAGNOSIS

According to the history,physical examination and the radiological finding, the patient was diagnosed with malignant melanoma of central never system possibly.

INTERVENTIONS

The patient underwent left temporal and parietal lesions total resection with a craniotomy.

OUTCOMES

The diagnosis of PDLM was established according to pathological characteristics and the negative finding of positron emission tomography (PET)-computed tomography (CT) outside CNS. The patient got no further treatment for economic reasons and experienced the progression and died 5 months after operation.

LESSONS

PDLM is extremely rare in CNS, as the clinical manifestation, radiological changes are not special, early diagnosis is difficult. The confirmed diagnosis is established by leptomeningeal biospy or surgical tissue. PET-CT can help differential diagnosis with metastastic leptomeningeal melanomas. The prognosis is dismal due to the inefficiency of chemotherapy or radiotherapy.

Primary diffuse meningeal melanomatosis - a rare form of meningeal melanoma: case report

Background

Meningeal melanomatosis is a rare type of central nervous system neoplasm (with incidence ranging between 3 and 5%) that develops in the course of malignant melanoma. In a small percentage of cases, meningeal melanomatosis may develop without a primary focus. It affects the leptomeninx. The clinical activity of the disease is uncharacteristic, with a number of neurological symptoms developing over weeks or months.

Case presentation

A 45-year-old male patient presented with consciousness disturbance, cognitive dysfunctions, seizures and progressive paresis. None of the examinations performed, including cerebrospinal fluid examination, neuroimaging and biopsy of the leptomeninges, permitted us to establish a diagnosis during the patient’s hospital stay. The diagnosis of meningeal melanomatosis was established after an autopsy had been carried out.

Conclusions

In the absence of unequivocal test results, it is also worth taking into account the primary changes in the leptomeninx, including those caused by melanoma.

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.

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.

Primary central nervous system malignant melanoma with leptomeningeal melanomatosis: a case report and review of the literature

Leptomeningeal melanomatosis is an extremely rare variant of primary central nervous system (CNS) melanoma and has a poor prognosis and no standard treatment. Primary CNS melanoma is derived from the melanocytes of the leptomeninges. Here, we describe a case of a 37-year-old male who visited our hospital due to worsening headaches. Characteristic imaging findings of this tumor type include hyper-dense lesions that are enhanced by contrast medium on computed tomography and hyper-intensity on T1-weighted magnetic resonance images and iso- to hypo-intensity on T2-weighted magnetic resonance images. Imaging of the CNS in our patient showed several lesions of this type. Pathological diagnosis and exclusion of systemic melanoma are required to confirm primary CNS malignant melanoma. Partial resection of the mass in the left temporal lobe of this patient was performed, and histological analysis showed pigmentation, melanin black-45 positivity, and BRAF mutation. Because no lesions were found outside the CNS following a thorough whole-body search, he was diagnosed with primary CNS malignant melanoma with leptomeningeal melanomatosis. He was treated with whole-brain radiation and the BRAF kinase inhibitor vemurafenib. His condition worsened, and he was given the anti-programmed cell death-1 antibody nivolumab as second-line therapy. This was also unsuccessful, and he died 5 months after treatment initiation. Further studies are needed to improve treatment and prognosis of this rare but serious disease.

Two cases of primary leptomeningeal melanomatosis mimicking subacute meningitis

Primary involvement of leptomeninges with melanocytic tumours is rarely seen and its diagnosis is challenging. Here we summarise two cases of primary leptomeningeal melanomatosis presenting as subacute meningitis. Both cases have pleocytosis and high protein on cerebrospinal fluid analysis, and demonstrated atypical cells on cytology. On magnetic resonance imaging, there is diffuse leptomeningal thickening and avid enhancement of intracranial and intraspinal leptomeninges. One of them demonstrates T1 shortening due to magnetic effects of melanin, the other case is amelanotic and shows hypointensity on precontrast T1-weighted images. Both cases can be diagnosed with biopsy. In conclusion, these cases highlight the importance of the correct interpretation of cytological and magnetic resonance imaging findings in patients with atypical findings.

MEK inhibition appears to improve symptom control in primary NRAS-driven CNS melanoma in children

BACKGROUND

Primary melanoma of the CNS in children is extremely rare, and usually linked to congenital melanocytic naevus syndrome, caused by mosaicism for oncogenic NRAS mutations. Outcome is fatal in all cases. Data from murine and in vitro studies suggest that MEK inhibition is a possible therapeutic option.

METHODS

Four children with NRAS-mutated CNS melanoma were treated with Trametinib on a compassionate basis.

RESULTS

All four had an improvement in symptoms and objectively in signs. These varied from mild improvement for 1 month, to a sustained symptom-free period of 9 months in one case. In all cases there was eventual disease progression through treatment, followed by rapid death after discontinuation. There were no clinically-significant side effects.

CONCLUSIONS

Trametinib is the first therapy to show any objective or measurable effect in NRAS-mutated primary CNS melanoma, with few side effects in this small series. The role of this therapy should be explored further in this rare paediatric tumour.