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

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 cervicothoracic melanoma of spinal cord: a case report and literature review

A 53-year-old male patient presented progressive numbness and weakness in the right limbs for a 2-year duration. Magnetic resonance imaging scans revealed an intramedullary lesion crossed over cervical and thoracic levels accompanied by syringomyelia at the proximal end of the lesion. The patient underwent subtotal resection of the neoplasm. The histological findings of the tumor were consistent with primary intramedullary malignant melanoma and not initial ependymoma after careful dermatologic and ophthalmologic re-examination. Primary melanoma of the spinal cord, particularly cervicothoracic localization with syringomyelia, is seldom reported in the literature. We report a case of this uncommon tumor and also discuss the clinical course, diagnosis, and treatment.

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.

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.

Case Report: Differential Genomics and Evolution of a Meningeal Melanoma Treated With Ipilimumab and Nivolumab

Primary melanocytic tumors of the CNS are extremely rare conditions, encompassing different disease processes including meningeal melanoma and meningeal melanocytosis. Its incidence range between 3-5%, with approximately 0.005 cases per 100,000 people. Tumor biological behavior is commonly aggressive, with poor prognosis and very low survivability, and a high recurrence rate, even after disease remission with multimodal treatments. Specific genetic alterations involving gene transcription, alternative splicing, RNA translation, and cell proliferation are usually seen, affecting genes like BRAF, TERT, GNAQ, SF3B1, and EIF1AX. Here we present an interesting case of a 59-year-old male presenting with neurologic symptoms and a further confirmed diagnosis of primary meningeal melanoma. Multiple therapy lines were used, including radiosurgery, immunotherapy, and chemotherapy. The patient developed two relapses and an evolving genetic makeup that confirmed the disease’s clonal origin. We also provide a review of the literature on the genetic basis of primary melanocytic tumors of the CNS.

A case report of a patient with inoperable primary diffuse leptomeningeal melanomatosis treated with whole-brain radiotherapy and pembrolizumab

RATIONALE

Primary diffuse leptomeningeal melanomatosis (PDLM) is a rare disease that affects melanocytes in the leptomeninges. There is very limited data on the efficacy of immunotherapy in this setting.

PATIENT CONCERNS

A patient (23 years old) was diagnosed with PDLM. Histologically, atypical melanocytic cells were also observed.

DIAGNOSIS

Immunohistochemistry showed positivity for S100 protein, NKiC3, and vimentin, and negativity for Melan-A and HMB-45, with a proliferation index of 30%. Extracranial disease was excluded using dermatological and other examinations, including positron emission tomography/computed tomography with 18F-fluorodeoxyglucose.

INTERVENTIONS

The patient was treated with whole-brain radiotherapy (10 fractions to a total dose of 30 Gy) concomitantly with pembrolizumab and then continued with immunotherapy until disease progression with a maximum effect of partial remission on magnetic resonance imaging scans.

OUTCOMES

Progression-free survival was 6.0 months and overall survival 6.5 months.

LESSONS

This is one of the few case reports of an adult patient with this rare malignancy being treated with a programmed death-1 inhibitor with partial response. Immunotherapy in metastatic PDLM may be a reasonable therapeutic option.

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.

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.

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 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.

NRASQ61K mutated diffuse leptomeningeal melanomatosis in an adult patient with a brief review of the so-called "forme fruste" of neurocutaneous melanosis

Primary melanocytic tumors of central nervous system represent rare tumors arising from melanocytes of the leptomeninges. These neoplasms include focal forms like melanocytoma and primary malignant melanoma and diffuse forms like leptomeningeal melanocytosis and primary leptomeningeal melanomatosis. The clinical diagnosis remains challenging, with clinical and radiologic features overlapping with other more common diseases. Here we present a case of a 38 years old male with primary diffuse leptomeningeal melanomatosis with presence of a NRAS^Q61K mutation without features of neurocutaneous melanosis.

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.