NRAS(Q61K) mutated primary leptomeningeal melanoma in a child: case presentation and discussion on clinical and diagnostic implications.

BACKGROUND: Primary melanocytic neoplasms are rare in the pediatric age. Among them, the pattern of neoplastic meningitis represents a peculiar diagnostic challenge since neuroradiological features may be subtle and cerebrospinal fluid analysis may not be informative. Clinical misdiagnosis of neoplastic meningitis with tuberculous meningitis has been described in few pediatric cases, leading to a significant delay in appropriate management of patients. We describe the case of a child with primary leptomeningeal melanoma (LMM) that was initially misdiagnosed with tuberculous meningitis. We review the clinical and molecular aspects of LMM and discuss on clinical and diagnostic implications. CASE PRESENTATION: A 27-month-old girl with a 1-week history of vomiting with mild intermittent strabismus underwent Magnetic Resonance Imaging, showing diffuse brainstem and spinal leptomeningeal enhancement. Cerebrospinal fluid analysis was unremarkable. Antitubercular treatment was started without any improvement. A spinal intradural biopsy was suggestive for primary leptomeningeal melanomatosis. Chemotherapy was started, but general clinical conditions progressively worsened and patient died 11 months after diagnosis. Molecular investigations were performed post-mortem on tumor tissue and revealed absence of BRAF(V600E), GNAQ(Q209) and GNA11(Q209) mutations but the presence of a NRAS(Q61K) mutation. CONCLUSIONS: Our case adds some information to the limited experience of the literature, confirming the presence of the NRAS(Q61K) mutation in children with melanomatosis. To our knowledge, this is the first case of leptomeningeal melanocytic neoplasms (LMN) without associated skin lesions to harbor this mutation. Isolated LMN presentation might be insidious, mimicking tuberculous meningitis, and should be suspected if no definite diagnosis is possible or if antitubercular treatment does not result in dramatic clinical improvement. Leptomeningeal biopsy should be considered, not only to confirm diagnosis of LMN but also to study molecular profile. Further molecular profiling and preclinical models will be pivotal in testing combination of target therapy to treat this challenging disease.

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.

Primary Malignant Meningeal Melanoma Complicated by Cerebral Venous Sinus Thrombosis: An Illustrative Case With a Systematic Review of the Literature.

Melanocytic tumors of the central nervous system (CNS) such as meningeal melanoma are exceedingly rare tumours derived from leptomeningeal melanocytes. We report an illustrative case of a previously healthy 47-year-old male who presented with tonic-clonic seizure. Magnetic resonance imaging (MRI) with contrast demonstrated a homogenously enhancing right temporal extra-axial lesion. The patient was stabilized on anti-epileptic medications and dexamethasone prior to proceeding with complete surgical resection of the lesion. Intraoperatively, the lesion was heavily pigmented with invasion of the surrounding dura and skull. Histopathology revealed a poorly differentiated neoplasm with nuclear atypia and melanin-containing cells with strong SOX10 and variable S100 positivity. Computed tomography (CT) of the chest, abdomen, and pelvis showed no metastatic disease, and molecular profiling was negative including absent BRAF mutation. He began checkpoint inhibitor therapy and subsequently developed cerebral venous sinus thrombosis managed with anticoagulation. Sixteen months post-operatively, he was neurologically intact, working full-time, and had resumed immunotherapy. We systematically reviewed the literature on primary intracranial malignant melanoma (PIMM) with the goal of understanding the prognosis and best treatment options for this disease. Our systematic review produced 82 articles (118 unique cases) of PIMM. The average age at diagnosis was 45.9 years (95% CI:42.9-48.9), and headache (54.2%) was the most common initial presentation. Eighty-nine percent of patients had primary surgical resection, and 41.0% of these individuals experienced a recurrence with a mean time to recurrence of 19.6 months (95% CI:6.95-32.23). Adjuvant therapy was administered in 65.7% of surgically resected patients; including radiotherapy, chemotherapy, immunotherapy, or a combination. In summary, PIMM is a rare tumour that can appear radiographically similar to meningioma. The results of our systematic review demonstrate that surgical resection remains the mainstay of therapy for best long-term prognosis.

Leptomeningeal Disease and Hydrocephalus as the First Presentation of Melanoma.

We present a case of an 83-year-old man who developed acute hydrocephalus as the first presentation of leptomeningeal disease secondary to melanoma of unknown primary, which is an exceedingly rare subtype of melanoma, in addition to a very rare complication of malignancy in general, which was diagnosed with imaging as well as cytology modalities. This presentation is rare and highlights the importance of recognizing this condition.

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. NRASQ16K 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.

Primary leptomeningeal melanoma in association with neurocutaneous melanosis: A case report.

Background: Primary melanocytic tumors of the central nervous system accounts for approximately 1% of all melanoma with a peak incidence in the fourth decade. The tumor originates from leptomeningeal melanocytes with a variable degree of belligerence. The proliferation of these melanocytes in large amounts in the dermis and nervous system can raise suspicion of neurocutaneous melanosis (NCM), which is an association between malignant melanoma and the presence of a giant intradermal nevus. Case Description: We present a case of a 62-year-old South Asian male with a large congenital melanocytic nevus (>20 cm in size) in the left hemifacial, and head region who presented with complaints of a single episode of grand-mal seizure followed by neuropsychiatric symptoms. The patient was thoroughly evaluated both clinically and surgically leading to a rare diagnosis of primary leptomeningeal melanoma of the left temporal lobe. The patient subsequently underwent a neuronavigation guided left temporal craniotomy with gross total resection of the lesion. Conclusion: Primary leptomeningeal melanoma with a clinical association with NCM is rarely ever reported within the literature. To date, our case is one of the very few instances where such an association is being reported in this age group along with rare neuropsychiatric symptoms.

An Uncommon Case of Primary Leptomeningeal Melanoma in a 66-Year-Old White Caucasian Male.

Primary melanocytic tumors of the central nervous system (CNS) arise from leptomeningeal melanocytes and possess a variable degree of aggressiveness. They have been classified into melanomatosis, melanocytoma, malignant melanoma, and diffuse melanocytosis. Melanocytic lesions of the CNS include both benign (leptomeningeal melanocytosis, melanocytoma) and malignant (leptomeningeal melanomatosis, melanoma) pathologies and the extent of anatomical site involvement dictates their clinical features. Primary CNS melanoma accounts for approximately 1% of all melanoma cases with a peak incidence in the fourth decade. Though the most common location of occurrence is in the lumbar region, our patient presented with a thoracolumbar lesion. We present a case of a 66-year-old white Caucasian male who presented with complaints of headache for six months and was thoroughly evaluated leading to a rare diagnosis of primary leptomeningeal melanoma.

Impact of New Systemic Treatment and Radiotherapy in Melanoma Patients with Leptomeningeal Metastases.

IMPORTANCE: Few data are available on patients with leptomeningeal disease (LM) from melanoma treated with new systemic therapies. OBJECTIVE: To gain a better understanding of patients, disease characteristics, and therapeutic interventions in melanoma patients with LM in the era of new systemic treatment. DESIGN: Clinical characteristics, treatments, and survival of melanoma patients diagnosed with LM, isolated or associated with brain metastases, were collected. The Cox regression model assessed the influence of patient and melanoma characteristics on survival. SETTING: Monocentric, retrospective, real-life cohort of patients with LM from melanoma. PARTICIPANTS: All patients followed up at Saint-Louis University Hospital and diagnosed with LM between December 2013 and February 2020 were included. For each patient identified, a central review by dermato-oncologist and neuro-oncologist experts was performed to confirm the diagnosis of LM. EXPOSURE: Impact of new systemic therapies and radiotherapy. RESULTS: Among the 452 advanced melanoma patients followed at St Louis Hospital between 2013 and 2020, 41 patients with LM from melanoma were identified. Among them, 29 patients with a diagnosis of LM "confirmed" or "probable" after central neuro-oncologists reviewing were included. Nineteen patients had known melanoma brain metastases at LM diagnosis. Among the 27 patients treated with systemic therapy, 17 patients were treated with immunotherapy, 5 patients received targeted therapy, 1 was treated with chemotherapy, and 4 patients were treated with anti-PD-1 in combination with BRAF inhibitor. The median overall survival (OS) from LM diagnosis was 5.1 months. Median OS was 7.1 months for the 9 patients receiving systemic therapy combined with radiotherapy, and 3.2 months for the 20 patients not receiving combined radiotherapy. Elevated serum lactate dehydrogenase (LDH) (HR 1.44, 95% CI 1.09-1.90, p < 0.01) and presence of neurological symptoms at LM diagnosis (HR 2.96, 95% CI 1.25-6.99, p = 0.01) were associated with poor survival. At the time of data analysis, five patients were still alive with a median follow-up of 47.4 months and had persistent complete response. CONCLUSION: Targeted therapy and immunotherapy are promising new treatment options in LM from melanoma that can increase overall survival, and may induce long lasting remission in some patients.

Genomic analysis reveals low tumor mutation burden which may be associated with GNAQ/11 alteration in a series of primary leptomeningeal melanomas.

Primary central nervous system melanoma is rare and characterized by a variable prognosis, and no current treatment guidelines exist. We describe the clinical course of a 70-year-old female patient diagnosed with primary leptomeningeal melanoma (LMN) whose case represents the diagnostic and management challenges of this tumor. Targeted genomic sequencing of 315 genes from this tumor revealed GNAQ Q209L mutation and low (4 mutations/Megabase) tumor mutation burden (TMB). Wild-type NRAS, KIT, and BRAF were also observed. A cohort of 4,787 melanomas was subsequently analyzed to identify additional primary central nervous system melanomas, of which 10 additional tumors met pathologic criteria (0.21% of total melanoma cohort). These tumors were genomically assessed according to the same targeted sequencing panel, and 6 of the tumors were also found to harbor a GNAQ mutation. All 10 tumors had low (less than or equal to 2 mutations/Megabase) TMB indicating a potential trend between G-protein-coupled receptor (GPCR) alterations and low TMB in LMNs. GPCR alterations were found to significantly correlate with TMB across the cohort of 4,787 melanomas, supporting this potential finding in the limited LMN subset.

Primary Leptomeningeal Melanocytic Tumors of the Spine: Report of Two Cases and Review of the Literature.

BACKGROUND: Primary leptomeningeal melanocytic tumors of the central nervous system are rare and, especially in the spine, less frequent compared with other entities. There is no consensus regarding the best care of these tumors. CASE DESCRIPTION: We report 2 cases of primary leptomeningeal melanocytic tumors, 1 primary leptomeningeal melanoma (PLM) and 1 primary leptomeningeal melanocytoma (PLMC) of the upper cervical spine, and emphasize different surgical findings and clinical courses of these patients. A review of the literature according to primary leptomeningeal melanocytic tumors of the spine was done, especially to compare different treatment modalities in the younger history. CONCLUSIONS: Primary melanocytic tumors of the spine are exceedingly rare. Before surgery it is difficult to make a correct diagnosis. Usually an unexpected intraoperative finding with consecutive histopathologic analyses leads to the final diagnosis. An accurate search for melanocytic tumors outside the central nervous system as a primary source is mandatory. PLMC has a better prognosis than PLM. There is no consensus regarding the adjuvant therapy, but patients with PLM should be given radiotherapy, chemotherapy, and immunotherapeutic approaches as immune checkpoint blockade after surgery. Communicating hydrocephalus is highly associated with PLM, but may occur in PLMC as well.

Neurocutaneous Melanosis in Association With Large Congenital Melanocytic Nevi in Children: A Report of 2 Cases With Clinical, Radiological, and Pathogenetic Evaluation.

Background: Melanocytic nevi present at birth, or within the first few months of life, are defined as congenital melanocytic nevi (CMN). Neurocutaneous melanosis (NCM) is a rare disorder, represents pigment cell tumors of the leptomeninges, and occurs in association with large or multiple CMN. NCM carries an extremely poor prognosis. NRAS and BRAF V600E genetic mutations were reported in CMN. Our aim was to report 2 rare cases of NCM associated with large-sized CMN. Materials and Methods: Two cases were enrolled, a 19-month-old boy with multiple satellite and giant CMN (GCMN); and a 57-month-old girl with large CMN (LCMN). Both patients had central nervous system (CNS) symptoms, and therefore, were studied from clinical, radiological, and immunohistopathological aspects. Cytogenetic study was done for one of them. Results: Both patients had CMN located in the head/neck, with no cutaneous melanoma. MRI was the most reliable method for early detection of NCM. NCM was proved in the 2 studied cases by immunohistopathology performed after surgery. The boy with GCMN carried NRAS mutation at codon 61, in addition to the characteristic facial features relevant to RASopathies. Both patients died despite surgical intervention. Conclusion: Our report highlights the need for pediatricians to be alert to the risk of NCM in association with CMN, especially when a CMN lesion is large, or there are multiple satellite lesions, or the nevus location is at the head or neck. Moreover, in the setting of CMN, the absence of skin melanoma does not exclude the presence of NCM.

Implementation of cell-free tumor DNA sequencing from the cerebrospinal fluid to guide treatment in a patient with primary leptomeningeal melanoma: A case report.

Primary leptomeningeal melanoma (PLM) is a rare type of cancer that represents a major clinical and molecular diagnostic challenge. A definitive diagnosis requires consistent magnetic resonance imaging findings and cerebrospinal fluid (CSF) cytology. Due to the small number of malignant cells in the CSF, routine testing for mutations in the BRAF gene is difficult, which prevents the stratification of these patients to potentially beneficial therapies. We herein present the case of a 62-year old man with CSF cytology indicating PLM, where BRAF mutation testing, from cell-free (cf) tumor DNA isolated from the CSF and plasma was implemented to guide clinical decision making. Testing for BRAFV600E mutation from the CSF and plasma was technically feasible, yielded concordant results, and guided the treatment for this patient. This case suggests that mutation testing of cfDNA isolated from the CSF is technically feasible and may guide therapy in cases where a tissue diagnosis is not possible for PLM and other malignancies with defined oncogenic driver mutations.

Primary leptomeningeal melanoma.

Primary melanoma of the central nervous system is a rare melanocytic tumor typically located in the leptomeninges. We report a 57-year-old woman with an intracranial leptomeningeal melanoma who presented with myoclonic seizures. Brain CT scan and MRI revealed a hemorrhagic intracranial tumor. The tumor was completely removed and leptomeningeal melanoma was proven pathologically. Follow-up imaging studies up to 19 months showed no recurrence of the disease. Here we present radiological, gross, and pathological images of leptomeningeal melanoma, discuss its characteristics, and review the relevant literature.

Primary leptomeningeal melanoma of the cervical spine mimicking a meningioma-a case report.

Background and Importance Primary leptomeningeal melanoma (PLM) is highly malignant and exceedingly rare. Due to its rarity, diagnostic and treatment paradigms have been slow to evolve. We report the first case of a PLM that mimics a cervical spine meningioma and then discuss the current clinical, radiologic, and pathologic diagnostic methodologies as well as expected outcomes related to this disease. Clinical Presentation A 54-year-old woman presented a dural-based extramedullary solid mass ventral to the C2-C3 spinal cord causing spinal cord compression without cord signal changes, characteristic of meningioma. Intraoperative microscopic inspection revealed numerous black spots littering the surface of the dura; the tumor itself was yellow in appearance and had a soft consistency. Pathologic analysis of the specimen revealed a malignant melanin-containing tumor. No primary site was found, so a diagnosis of primary leptomeningeal melanoma was made, and the patient subsequently received interferon therapy. To date (2 years postoperatively), no local or systemic recurrence of the tumor has been identified. Conclusion As with most rare tumors, case reports constitute the vast majority of references to PLM. Only an increased awareness and an extensive report of each individual case can help diagnose and clarify the nature of PLM. Clinicians need to be aware of such malignant conditions when diagnosing benign tumoral lesions of the spine such as meningiomas.