Primary melanocytic neoplasms of the central nervous system

A rare case report of primary malignant melanocytoma of foramen magnum and literature review

Background

Primary malignant melanoma is an extremely rare pathology that can occur anywhere in the brain and spinal cord. Patients often present with symptoms like that of brain tumors. This similarity and inability to make a definitive diagnosis from radiological imaging alone make it a challenging diagnosis. Gross total resection is the accepted mainstay of treatment, while histopathological biopsy can confirm the diagnosis.

Case Description

A young gentleman who was otherwise healthy presented with neck pain and right-sided weakness. Magnetic resonance imaging revealed an extra-axial mass at the level of the foramen magnum. The patient underwent lateral sub-occipital craniotomy with C1 laminectomy and maximum safe resection of the lesion. Intra-operatively, a firm, moderately vascular black-colored dura-based lesion was found. The frozen section revealed highly pigmented spindle cell neoplasm, and histopathology confirmed that it was malignant melanoma. Postoperative recovery was unremarkable.

Conclusion

Primary malignant melanoma is rare and very challenging to diagnose. It demands an early diagnosis and meticulous surgical management for a favorable prognosis.

Primary intracranial malignant melanoma in an adolescent: case report and literature review

Primary intracranial malignant melanoma (PIMM) is an exceedingly rare central nervous system tumor, accounting for only 1% of melanoma cases and 0.07% of primary CNS tumors, with limited documentation in adolescents. This case report describes an 18-year-old male who presented with a seizure, marking the onset of his symptoms. Following an emergency assessment, MRI identified a heterogeneous mass in the right parasagittal frontal region, initially misdiagnosed as a cystic meningioma. A craniotomy allowed for total tumor resection, and histopathological analysis revealed a malignant melanoma characterized by neoplastic cells with pronounced nuclear pleomorphism and significant mitotic activity. Postoperative evaluations, including a PET scan, confirmed no extracranial melanoma, affirming the diagnosis of primary CNS melanoma. The patient demonstrated no neurological deficits or seizures one year post-surgery and was managed with adjuvant radiotherapy. This report emphasizes the necessity of considering PIMM in differential diagnoses for seizures in young patients and highlights the importance of comprehensive diagnostic evaluations, including MRI and histopathology, in rare cases. Additionally, the findings underscore the critical role of complete surgical resection in improving outcomes, with adjuvant therapies potentially enhancing long-term management and surveillance. As PIMM presents with nonspecific symptoms, awareness among clinicians is essential for early detection and appropriate intervention, warranting further research to develop standardized treatment protocols and enhance understanding of this rare tumor's pathophysiology.

Primary Diffuse Leptomeningeal Melanomatosis Leading to Raised Intracranial Pressure in a Pediatric Patient

A critical clinical consideration, in addition to other common risk factors predisposing individuals to idiopathic intracranial hypertension (IIH), involves the potential co-occurrence of increased intracranial pressure and elevated cerebrospinal fluid protein levels in the presence of underlying malignancies. Primary diffuse leptomeningeal melanomatosis, an exceptionally rare condition with few reported cases in the pediatric population, illustrates this scenario. Timely decision-making based on clinical suspicion to perform a biopsy and involving a skilled pathologist for accurate reporting are essential steps toward achieving a definitive diagnosis.

Primary intracranial malignant melanomas: A case series with literature review

RATIONALE

There is a high chance of misdiagnosis and limited knowledge regarding therapeutic strategies owing to the rarity of primary intracranial malignant melanoma (PIMM). The objective of the present study was to evaluate the clinical features, treatment modalities, and outcomes of patients with histologically proven PIMM.

PATIENT CONCERNS

Data of 15 patients with PIMM admitted to the Chinese People's Liberation Army General Hospital in a 14-year period between January 2005 and January 2019 were collected. Clinical presentations, pathology, surgical strategies, adjuvant treatment, and prognosis were retrospectively analyzed.

DIAGNOSES

CT showed iso- or high-density lesions in 12 cases (80%). MRI revealed short T1 and slightly short T2 in 14 cases (93.3%).The tumors showed mild or no enhancement on enhanced MRI. The patients were eventually diagnosed with PIMM through pathological examination.

INTERVENTIONS

The treatment modalities included radical resection followed by conventional radiotherapy (RT, n = 12) and subtotal resection followed by stereotactic radiosurgery (n = 3).

OUTCOMES

All 15 patients had either recurrence or metastasis at an average of 14.7 months (range, 6-23 months) after surgery. In total, 14 patients (93.3%) succumbed to disease, with a mean overall survival of 22 months (range, 6-36 months). The median survival time was 23 months. The overall survival rates at 1, 2, and 3 years were 80, 47, and 13%, respectively. Radical resection with RT was associated with longer overall survival (log-rank, P < .05) than subtotal resection followed by stereotactic radiosurgery.

LESSONS

PIMM is an extremely rare tumor with a poor prognosis. Radical resection with RT may result in a longer overall survival rate. Targeted immunotherapy may be a promising treatment option for PIMM.

GNAQ/GNA11-Related Benign and Malignant Entities-A Common Histoembriologic Origin or a Tissue-Dependent Coincidence

Uveal melanoma (UM), recognized as the most prevalent primary intraocular malignancy in adults, is primarily driven by mutations in the GNAQ and GNA11 genes. These genetic alterations are also implicated in other conditions, which exhibit distinct morphological characteristics. In this article, we investigate the role of GNAQ and GNA11 mutations across varied disorders (e.g., UM, skin blue nevi, and hemangiomas), emphasizing the shared pathogenic mechanisms that connect them despite their differing clinical manifestations. By investigating the molecular pathways affected by these mutations, we provide insights into the potential for targeted therapies that could address not only UM but also other disorders associated with GNAQ/GNA11 mutations. Moreover, we discuss the role of SOX10-positive perivascular cells that may be implicated in the complex pathophysiology of GNAQ/GNA11-related entities. Understanding the common molecular foundation of these conditions opens new ways for research and treatment opportunities, potentially leading to more effective, personalized therapeutic strategies.

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 leptomeningeal melanocytic neoplasms: A clinicopathologic, immunohistochemical, and molecular study of 12 cases

This study investigated the clinicopathological, immunohistochemical, and molecular features of primary leptomeningeal melanocytic neoplasms (LMNs). Twelve LMN cases were retrospectively reviewed. We performed Fluorescence in-situ hybridization (including a 4-probe FISH assay with CDKN2A and MYC assay) and Next-Generation sequencing analyses on available cases. Histologically, 2 tumours were classified as melanocytomas (MC), 2 as intermediate-grade melanocytomas (IMC), and 8 as leptomeningeal melanomas (LMM). Two rare cases of LMM were associated with large plaque-like blue nevus. One MC case was associated with Ota. Ten cases (83.3%) showed melanocytic cells with benign features diffusely proliferating within the meninges. The Ki-67 in three categories differed (MC 0-1%, IMC 0-3%, LMM 3-10%). 57.1% of LMM cases (4/7) were positive for FISH. Nine of 10 tumours harboured activating hotspot mutations in GNAQ, GNA11, or PLCB4. Additional mutations of EIF1AX, SF3B1, or BAP1 were found in 40%, 30%, and 10% of tumours, respectively. During the follow-up (median = 43 months), 5 LMM patients experienced recurrence and/or metastasis, 3 of them died of the disease and the other 2 are alive with the tumour. Our study is by far the first cohort of LMN cases tested by FISH. In addition to morphological indicators including necrosis and mitotic figures, using a combination of Ki-67 and FISH helps to differentiate between IMC and LMM, especially in LMM cases with less pleomorphic features. SF3B1 mutation is first described in 2 cases of plaque-type blue nevus associated with LMM. Patients with SF3B1 mutation might be related to poor prognosis in LMN.

A case report and literature review on primary intracranial malignant melanoma: Challenges and insights

INTRODUCTION AND IMPORTANCE

Primary central nervous system (CNS) melanoma is a rare entity. Primary CNS malignant melanomas account for 1 % of melanomas and 0.07 % of intracranial tumours. These are highly aggressive and are associated with poor prognosis. Herein, we have discussed one such rare case of PIMM.

CASE PRESENTATION

62-year-old man with primary CNS melanoma underwent craniotomy and resection of left temporal lesion. Postoperative MRI showed no evidence of residual disease. He received 28 fractions of radiation. Follow-up MRI showed no evidence of disease. However, he later developed worsening symptoms and repeat imaging revealed disease progression with hydrocephalus and drop metastasis to spine. He underwent VP shunting and was started on Temozolomide. He progressively declined functionally and eventually died from his disease.

CLINICAL DISCUSSION

Primary CNS melanoma is characterized by its rarity, challenging diagnosis, and aggressive behaviour. Current literature suggests limited treatment options, which depend on complete resection of the primary tumour. Molecular analysis may play a key role in deciding future treatment options, including immune checkpoint inhibitors and targeted therapies targeting the BRAFV600E mutation.

CONCLUSION

Primary intracranial malignant melanoma (PIMM) is an extremely rare tumour of CNS, and its treatment paradigm is very limited based on available literature. Currently any long-term survival depends on the complete resection of tumour. Our case is unique as it talks about the limited therapeutic options in case of rapidly declining performance status in a resource constraint setting.

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.

Surgical Management of Primary Thoracic Epidural Melanoma

In this study, we reported one of the first cases where a rare robotic-assisted platform with neuronavigation technology and carbon-fiber-polyetheretherketone (CF/PEEK) screws is employed to surgically treat multilevel thoracic primary spinal epidural melanoma. A 67-year-old male presented with left upper thoracic pain. His magnetic resonance imaging (MRI) of the thoracic spine revealed a dumbbell-shaped left epidural mass at the T2-3 level. Partial resection was performed due to tumor growth into the vertebral bodies and patient discretion for minimal surgery. The patient's neurological conditions improved postoperatively, with reduced reported symptoms of pain and numbness. Postoperative imaging showed evidence of appropriate spinal stabilization. Patient underwent stereotactic body radiation therapy (SBRT), and no adverse events were reported. This case reflects one of the first examples of treating thoracic epidural melanoma with the use of robotic-assisted navigation. Further prospective studies are needed to determine the efficacy of robot-assisted navigation for patients with primary spinal malignant melanoma which may open the possibility of surgery to once presumed non-operative patients.

Supratentorial meningeal melanocytoma mimicking meningioma: case report and literature review

Introduction: Primary melanocytic tumors originating from CNS melanocytes are rare, with a low incidence of 0.7 cases per 10 million annually. This study focuses on primary leptomeningeal melanocytomas, emphasizing their epidemiology, clinical characteristics, and diagnostic challenges. Despite their infrequency, these tumors warrant attention due to their unique features and potential for local recurrence. Case Report: A 32-year-old female presented with syncope and seizures, leading to the discovery of two left-sided supratentorial lesions initially misidentified as convexity meningiomas. Detailed imaging suggested meningioma-like features, but intraoperative findings revealed unexpected hyperpigmented lesions. Histopathological examination, supported by immunohistochemistry, confirmed primary leptomeningeal melanocytoma. The surgical approach and subsequent management are discussed. Discussion: The discussion emphasizes challenges in diagnosing primary leptomeningeal melanocytomas. Treatment debates, especially regarding adjuvant radiotherapy, are explored. Recurrence risks stress the importance of vigilant follow-up, advocating for complete surgical resection as the primary approach. The rarity of supratentorial cases adds complexity to diagnosis, necessitating a multidisciplinary approach. Insights from this case contribute to understanding and managing primary leptomeningeal melanocytomas, addressing challenges in differentiation from more common tumors and prompting ongoing research for refined diagnostics and optimized treatments. Conclusion: This study contributes insights into primary leptomeningeal melanocytomas, highlighting their rarity in supratentorial regions. The case underscores the importance of a multidisciplinary approach, incorporating clinical, radiological, and histopathological expertise for accurate diagnosis and tailored management. Ongoing research is crucial to refine treatment strategies, enhance prognostic precision, and improve outcomes for individuals with this uncommon CNS neoplasm.

Atypical primary malignant melanoma originating in the spinal canal: A case report and literature review

Central nervous system (CNS) malignant melanomas are rare tumors of the CNS that are thought to arise from aberrant changes in melanocytes of the neural crest or melanocytic elements of the pia mater during early embryonic development. As a rare type of CNS malignant melanoma, only a few cases of primary malignant melanoma in the spinal canal have been reported thus far. The majority of these studies have reported on the diagnosis, radiographic features and gross total resection of primary spinal canal malignant melanoma; however, the prognosis and ideal treatment of patients with residual tumors remain elusive. The current study presented the rare case of a patient with primary malignant melanoma originating from the thoracic spinal canal, without any history of irradiation exposure and with an incompletely resected tumor. Disease-free survival of >2.5 years was observed in this patient who was treated with concurrent chemoradiotherapy followed by adjuvant chemotherapy with temozolomide and bevacizumab.

Multifocal primary amelanotic meningeal melanomas mimicking lymphoma: a case report and literature review

Primary meningeal melanoma is a rare type of melanocytic cancer originating from the melanocytes of the leptomeninges. It commonly presents as a solitary mass, and multifocal amelanotic lesions were scarcely reported. Diagnosis of multifocal melanoma is particularly challenging, clinically and diagnostically, especially in the absence of cutaneous nevi and melanin pigment. Surgical biopsy result is the gold standard. In this case study, we present an uncommon case of multifocal primary amelanotic meningeal melanomas mimicking lymphomas in the skull base and near the Sylvian fissure, which serves to provide reference value to the clinical diagnosis. Physicians should be aware of the existence of this special type in the clinical work.

Pearls & Oy-sters: Primary Diffuse Leptomeningeal Melanocytosis: A Diagnostic Conundrum

Primary diffuse leptomeningeal melanocytosis (PDLM) is an extremely rare CNS tumor with nonspecific clinicoradiologic features that overlap considerably with aseptic meningitis posing significant diagnostic and therapeutic challenges. We present one such case report of a patient treated empirically at first presentation as aseptic viral meningitis based on MRI and CSF analysis. Diagnosis of PDLM was established subsequently through meningeal biopsy that demonstrated a melanocytic tumor with fine granular melanin pigment without significant mitoses. Her systemic and ocular examination was unremarkable. Whole-body 18F-fluorodeoxyglucose PET/CT (FDG-PET/CT) did not identify any other primary site. Following ventriculoperitoneal shunt to relieve hydrocephalus, she was treated with definitive craniospinal irradiation plus whole-brain boost and remains stable on periodic clinicoradiologic surveillance. Optimal management of PDLM lacks consensus with role of radiotherapy, chemotherapy, targeted therapy and immunotherapy being controversial.

Pediatric Primary Intracranial Malignant Melanoma: Case Report and Literature Review

INTRODUCTION

Primary intracranial malignant melanoma (PIMM) is an extremely rare primary brain tumor with most cases diagnosed in adults. To date, there are only a few cases reported in the pediatric population. Owing to its infrequency, there are no established guidelines to treat this aggressive neoplasm. Recent insights suggest that PIMM are molecularly different between adults and children, whereby NRAS mutations drive tumor growth in the latter group. We present a unique case of PIMM in a pediatric patient and discuss the case in corroboration with current literature.

CASE PRESENTATION

A previously well 15-year-old male presented with progressive symptoms of raised intracranial pressure. Neuroimaging reported a large solid-cystic lesion with significant mass effect. He underwent gross total resection of the lesion that was reported to be a PIMM with pathogenic single nucleotide variant NRAS p.Gln61Lys. Further workup for cutaneous, uveal, and visceral malignant melanoma was negative. A trial of whole-brain radiotherapy followed by dual immune checkpoint inhibitors was commenced. Despite concerted efforts, the patient had aggressive tumor progression and eventually demised from his disease.

CONCLUSION

We therein report a case of pediatric PIMM, in the context of the patient's clinical, radiological, histopathological, and molecular findings. This case highlights the therapeutic difficulties faced in disease management and contributes to the very limited pool of medical literature for this devastating primary brain tumor.

Malignant Melanoma Presenting as Spinal Cord and Pleural Lesions

Primary spinal cord melanoma (PSCM) and primary pleural melanoma (PPM) are extremely rare entities with scarce cases reported in the literature. We present a case of a 54-year-old male diagnosed with possible primary pleural melanoma and primary spinal melanoma, managed with partial surgical resection, postoperative radiotherapy, and chemotherapy consisting of Ipilimumab, nivolumab, and temozolomide. This leads to decreased symptoms and improved quality of life of the patient. In this case report, we review the literature on PSCM and PPM in detail, addressing the pertinent clinical aspects as well as current and upcoming therapeutic options.

Intracranial Granular Cell Tumours in Three Dogs: Atypical Magnetic Resonance Imaging Features and Immunohistochemical Study

Intracranial granular cell tumours (GCT) are uncommon neoplasms of uncertain cellular origin that are rarely reported in dogs. This case series describes three aged dogs that presented with neurological signs in which magnetic resonance (MR) imaging revealed plaquelike extra-axial lesions that were hypointense on T2-weighted (T2w) images. The surgical biopsy of the lesions and necropsies were followed by histochemical characterisation with periodic acid-Schiff (PAS) staining and immunohistochemistry with ubiquitin, S-100, and SOX-10 to elucidate the cellular origin. The immunohistochemical study indicated that these intracranial GCTs were not of Schwann cell origin. In conclusion, GCTs should be considered a differential diagnosis of intracranial, extra-axial hypointense brain lesions on T2w MR images.

Primary intracranial melanoma, amelanotic variant: Case report

Primary brain melanoma is a very rare tumour (only 0.07% of primary CNS neoplasms) which usually shows with abundant melanin content; whereas hypo/melanotic variants have been scarcely described. We introduce the case of a female patient with headache, left brachial paresis and frontallobar syndrome. The MRI image showed a right frontal mass with homogeneous contrast uptake. As treatment, a complete surgical resection was performed. Pathology was diagnostic for melanoma, with very low melanin content and a high proliferative index. A thorough extension study was performed to rule out an extracranial primary origin. Due to several intercurrent complications, the patient evolved unfavorably, not being able to receive further treatment. The amelanotic variant of primary intracranial malignant melanomas has not been described in detail previously. We will review the literature, focusing on the particularities of management and diagnosis of this clinical entity.

Clinical Reasoning: A 67-Year-Old Woman With Abdominal Pain, Constipation, and Urinary Retention

Meningeal melanocytomas are extremely rare, pigmented tumors of the CNS. They generally carry a favorable prognosis, although recurrence and transformation into the more aggressive malignant melanoma have been reported. We present a case of a patient who reported constipation and abdominal pain around the umbilicus, which progressed into cord compression with lower extremity weakness and gait instability. Spinal MRI revealed a tumor at the level of T11, and she underwent gross total resection of the mass. Pathology demonstrated a meningeal melanocytoma with intermediate features. She received postoperative radiation therapy and had stable disease for 3 years, at which time she developed new weakness and drop metastases. This case represents a rare presentation of a rare disease, in which a spinal cord tumor presented with constipation and abdominal distress. Intradural extramedullary tumors of the thoracic spine are most commonly nerve sheath tumors or meningiomas, but rare entities such as melanocytomas can present in this location; even more rarely, these tumors can have an aggressive course with delayed recurrence.

Stereotactic radiosurgery for intracranial primary melanocytomas

OBJECTIVE

The role of stereotactic radiosurgery (SRS) in the management of recurrent and residual intracranial primary melanocytomas (PMC) remains unclear. The aim of this study is to evaluate the safety and efficacy of SRS in the management of these rare tumors.

METHODS

One patient treated with SRS in our institution for an intracranial PMC was retrospectively identified. Additionally, a systematic review of English articles using MEDLINE was performed to identify studies reporting on treatment and tumor characteristics and patient outcomes following SRS-management of intracranial PMC.

RESULTS

Including our institution's patient, a total of 13 patients (11 males and 2 females) met the inclusion criteria and were analyzed. The median age at SRS treatment was 49 years [Interquartile range (IQR) 27]. At a median follow-up of 24 (IQR 48) months, the aggregate local tumor-control rate was 76.9%. Progression occurred in three patients and was managed with repeat SRS (1/13) or salvage resection (2/13). One case of malignant transformation to melanoma leading to leptomeningeal dissemination and death was noted.

CONCLUSION

SRS appears to be a reasonable treatment option for recurrent and residual melanocytomas. A higher prescription dose might be reasonable in the treatment of intermediate grade or recurring PMC. Close longitudinal follow up for recurrence or malignant transformation of melanocytomas after SRS is recommended.

Primary intracranial malignant melanomas in solitary type: a tertiary center experience

PURPOSE

Solitary type primary intracranial malignant melanoma (PIMM) is extremely rare but fatal. The optimal treatment algorithm according to clinical relevance of symptoms and outcomes is unclear. This series emphasized the prognostic factors of solitary PIMM and established the treatment algorithm for this rare disease.

METHODS

Patients with solitary PIMMs were pathologically verified and treated with neurosurgical tumor resection. All solitary PIMMs recruited at our institute received multidisciplinary team care. We analyzed the clinical findings and prognostic factors.

RESULTS

The study cohort included 10 patients. PIMMs in solitary type impacted middle-aged populations with male predominance in Taiwan. Most patients (80%) presented a single tumor initially. Six patients had progressed to multiplicity after the initial treatment. Rates of tumor bleeding and leptomeningeal metastasis seeding (LS) are high in solitary PIMMs. Patients who had gross-total resection (GTR) had better survival than those who had incomplete resection, with median overall survival (OS) rates of 170.4 months vs. 5.23 months (p = 0.004). Multiplicity, eloquent area involvement, initial tumor bleeding, LS, hydrocephalus, and Karnofsky Performance Score < 80 at diagnosis were associated with negative outcomes in progression-free survival and OS. Adjuvant radiotherapy for patients who had LS and for those who cannot undergo grossly total tumor removal resulted in a good outcome.

CONCLUSIONS

GTR demonstrated better outcomes for solitary PIMM. For recurrent tumors, aggressively repeated surgical resection remained beneficial for selected cases. Adjuvant radiotherapy was a treatment option for LS following operation. We proposed a possible treatment algorithm for solitary PIMM.

Malignant Transformation and Metastatic Spread of Dumbbell-Shaped Meningeal Melanocytoma of the Cervical Spine: A Case Report and Literature Review

Background

Meningeal melanocytoma is a rare disease that originates from leptomeningeal melanocytes in the central nervous system. Meningeal melanocytoma is generally considered benign, and has a good prognosis following complete surgical resection. Reports of the malignant transformation and spread of these tumors are scarce.

Case Presentation

A 19 year old female presented with headache, progressive limb weakness, and dyspnea. Magnetic resonance imaging showed a dumbbell-shaped lesion at C1–C2 that was hyperintense on T1 weighted images and showed strong contrast enhancement. Total resection was achieved using a posterior midline approach. Post-operative pathology showed meningeal melanocytoma. The tumor recurred 9 months later with intracranial spread. Resection of the lesion revealed malignant transformation to meningeal melanoma.

Conclusion

Meningeal melanocytoma harbors malignant potential even with total resection. Radiotherapy could be considered to prevent disease recurrence and progression.

Primary Meningeal Melanocytoma Located in the Craniovertebral Junction: A Case Report and Literature Review

Primary meningeal melanocytoma is a rare benign tumor in the central nervous system (CNS), comprising less than 0.1% of all intracranial tumors. A 44-year-old man presented with occipital headache, nausea, and vomiting. Computed tomography (CT) and magnetic resonance imaging (MRI) showed a well-defined intradural extramedullary mass lesion at the craniovertebral junction (CVJ). Gross total removal was achieved, and the patient improved symptomatically. The pathologic findings were consistent with meningeal melanocytoma. No tumor recurrence was seen on follow-up MRI two years after surgery. Cases of primary meningeal melanocytoma located at the CVJ are rare. The preoperative differential diagnosis of meningeal melanocytoma from meningioma is sometimes difficult because of their similar appearance on CT and MRI. Complete surgical removal is curative for most cases. We present a case of gross total removal of a meningeal melanocytoma located in the CVJ with references to the literature.

Primary meningeal melanoma masquerading as neurofibromatosis type 2: illustrative case

BACKGROUND

Primary meningeal melanocytic neoplasms are exceedingly rare tumors, representing only 0.06% to 0.1% of all primary brain tumors and ranging in spectrum from benign localized tumors to highly aggressive malignant lesions. The diagnosis of these tumors is often challenging from clinical, radiological, and pathologic standpoints. Equally challenging is the distinction between primary meningeal melanocytic neoplasm and metastatic melanoma.

OBSERVATIONS

The authors reported the case of a 41-year-old man with imaging findings diagnostic of neurofibromatosis type 2: bilateral internal auditory canal lesions (most consistent with bilateral vestibular schwannomas), two dura-based lesions presumed to be meningiomas, multiple spinal lesions consistent with peripheral nerve sheath tumors, and one intramedullary spinal lesion consistent with an ependymoma. Biopsy of these lesions revealed melanocytic neoplasms with mild to moderate atypia and a mildly elevated proliferation index, which made the distinction between benign and malignant challenging. In addition, the disseminated nature of these tumors made it difficult to determinate whether they arose from the meninges or represented metastases from an occult primary melanoma.

LESSONS

This case illustrated the challenges presented by the diagnosis of meningeal melanocytic neoplasms and highlighted the importance of integrating the clinical and radiographic findings with histologic appearance and molecular studies.

Malignant spindle cell tumors of the posterior fossa in children: case series and review of management

OBJECTIVE

The WHO Classification of Tumours of the Central Nervous System (2016) classifies nonmeningothelial malignant spindle cell tumors involving the extraaxial tissues of the posterior fossa as melanocytic tumors and malignant mesenchymal tumors (sarcomas). The objective of this study was to conduct a review of the literature pertaining to the management strategies of posterior fossa malignant spindle cell tumors in the pediatric population.

METHODS

The authors performed an institutional search of their pathology database for patients younger than 18 years of age who presented with posterior fossa malignant spindle cell tumors. A literature review was also performed using the PubMed database, with "posterior fossa" or "spindle cell tumors" or "Ewing sarcoma" or "high-grade" or "spindle cell sarcoma" or "leptomeningeal melanocytoma" as keywords. The database search was restricted to pediatric patients (age ≤ 18 years). Parameters reported from the literature review included patient age, tumor location, presenting symptoms, treatment modalities (resection, chemotherapy, and/or radiotherapy), leptomeningeal spread at or after the time of treatment, and follow-up length and resulting outcome.

RESULTS

The authors report 3 rare cases of posterior fossa malignant spindle cell tumors, including Ewing sarcoma in a 13-year-old male; high-grade spindle cell sarcoma, not otherwise specified in a 10-year-old male; and primary leptomeningeal melanocytoma in a 16-year-old female. All 3 patients underwent resection and radiotherapy and either chemotherapy or targeted immunotherapy. At the last follow-up, all patients were alive with either resolution or stable disease.

CONCLUSIONS

A review of these 3 cases and the existing literature support managing patients with intracranial malignant spindle cell tumors with multimodal therapy that can include a combination of resection, radiotherapy, and chemotherapy or immunotherapy to prolong progression-free and overall survival.

Suprasellar Melanocytoma with Leptomeningeal Seeding: An Aggressive Clinical Course for a Histologically Benign Tumor

Introduction

Meningeal melanocytoma (MM) is a very rare neuroectodermal neoplasm arising from the leptomeninges. Primary suprasellar melanocytomas are exceedingly rare, with only a handful of cases reported. The systemic spread of a nontransformed meningeal melanocytoma is an unusual occurrence. Herein, we report the first case of a primary sellar melanocytoma with cerebral and spinal meningeal seeding. Case Report. A 30-year-old male with no previous medical history presented to the endocrinology department with a loss of body hair. The endocrine workup concluded with isolated hypogonadotropic hypogonadism. The Magnetic Resonance Imaging (MRI) of the brain and sella revealed a large suprasellar mass continuous with the infundibulum of the pituitary gland. It was heterogeneously hyperintense on T1-, T2-, and FLAIR-weighted images and was enhanced with contrast, along with cerebral and spinal leptomeningeal spread. The patient was referred to the neurosurgery department, and a lumbar spine biopsy was indicated. The histopathological examination was suggestive of a grade I meningeal pigmented melanocytoma.

Conclusion

Thus, primary sellar melanocytomas with leptomeningeal spread are an extremely rare phenomenon. Metastatic malignant melanoma should be ruled out. Being aware of differential diagnosis and the unusual behavior of meningeal melanocytoma will be necessary to manage the patient appropriately. Complete tumor resection is the best treatment whenever possible, and radiotherapy should be considered in case of unresectability or partial resection.

Primary intramedullary melanocytoma presenting with lower limbs, defecation, and erectile dysfunction: A case report and review of the literature

BACKGROUND

Primary intramedullary melanocytoma is an exceedingly rare type of primary melanocytic tumor in the central nervous system. Unfortunately, primary intramedullary melanocytoma lacks specificity in clinical symptoms and imaging features and there is currently no standard strategy for diagnosis or treatment.

CASE SUMMARY

A 52-year-old male patient suffered from weakness and numbness involving the bilateral lower limbs for 18 mo, and defecation and erectile dysfunction for 6 mo. Furthermore, these symptoms started to worsen for the last 3 mo. Preoperative magnetic resonance imaging (MRI) revealed an intramedullary tumor located at the T9-T10 level. In subsequently surgery, the maximal safe resection extent approached to 98%. The lesion was confirmed to be melanocytoma by pathological examination. In addition, the possibility of original melanocytoma outside the spinal cord was excluded after the examination of the whole body. Therefore, a diagnosis of primary intramedullary melanocytoma was established. The patient refused to accept radiotherapy or Gamma Knife, but MRI examination on July 28, 2020 showed no sign of development. In addition, on April 10, 2021, the recent review showed that the disorder of defecation and lower limbs improved further but erectile dysfunction benefited a little from the surgery.

CONCLUSION

After diagnosing intramedullary melanocytoma by postoperative pathology, the inspection of the whole body contributed to excluding the possibility of metastasis from other regions and further suggested a diagnosis of primary intramedullary melanocytoma. Complete resection, adjuvant radiation, and regular review are critical. In addition, maximal safe resection also benefits prognosis while the tumor is difficult to be resected totally.

Primary Intramedullary Spinal Melanoma: A Rare Disease of the Spinal Cord

Primary malignant melanoma of the intramedullary region of the spinal cord has rarely been reported in the literature. These tumors can have variable appearance on magnetic resonance imaging (MRI) due to different extents of melanin and hemorrhage. Histopathologic confirmation and a comprehensive workup to rule out extra-spinal melanoma are required to make definitive diagnosis. We present a case of a patient diagnosed with primary intramedullary spinal melanoma in his lower thoracic spinal cord who was effectively treated with surgical resection, adjuvant radiation, and adjuvant immunotherapy. Gross total resection (GTR) is most vital in the management of this spinal tumor. Although several studies have established the efficacy of immunotherapy agents in advanced malignant melanoma, the use of these agents has not been studied in primary central nervous system melanomas. This case provides insight into the diagnostic approach and treatment options for this unique malignancy.

A CHALLENGING CASE OF SPORADIC MELANOCYTOMA OF THE JUGULAR FORAMEN

BACKGROUND

The jugular foramen (JF) can be the site of several tumours. Paragangliomas, schwannomas and meningiomas are the most commonly reported. We describe a case of melanocytoma originating from the JF and presenting with an accessory nerve palsy. Illustrative case: A 48-year-old woman presented with a 6-month history of cervical and left shoulder pain with wasting and weakness of the left trapezius. A Magnetic Resonance Imaging (MRI) showed a T1-hyperintense, T2-isointense, heterogeneously enhancing lesion involving the left JF and extending into the cerebello-medullary and cerebello-pontine cisterns. A retrosigmoid craniotomy was performed and a near total removal achieved. The accessory nerve was involved by tumour and could not be preserved. Given the diagnostic uncertainty between melanotic schwannoma, metastatic melanoma and meningeal melanocytoma, next generation sequencing and genome-wide DNA methylation arrays were performed, documenting a mutation in GNA11 (c.6226A>T, p. Gln209Leu) and a methylation profile consistent with melanocytoma. The patient underwent adjuvant fractionated radiotherapy of the tumour remnant. A follow-up MRI 4 years after surgery did not show any tumour recurrence.

CONCLUSIONS

The differential diagnosis of skull base pigmented tumours can be challenging, particularly when they occur in unusual locations such as the JF. They can be misdiagnosed given their similar clinical, neuroradiological and pathological features if anatomy of the site of origin is not carefully considered and molecular tests are not performed, leading to erroneous treatment and follow up planning.

Nivolumab as adjuvant treatment for a spinal melanocytoma: A case report

RATIONALE

Meningeal melanocytoma is a rare benign melanocytic tumor of the central nervous system. We report for the first time a case of meningeal melanocytoma treated with immunotherapy.

PATIENT CONCERNS

A 70-year-old man with no medical history was admitted to the Emergency Room. He suffered from a motor and sensory deficit in his left lower limb and a bilateral upper arm neuralgia.

DIAGNOSES

A contrast-enhanced magnetic resonance imaging (MRI) was performed. It showed a C7-T1 bleeding intramedullary tumor. Laminectomy was decided and performed. The results of the pathologic examination showed a melanocytic tumor harboring GNAQ mutation. Meningeal melanocytoma was the final diagnosis.

INTERVENTIONS

The patient was treated with 10 radiotherapy sessions and 6 cycles of nivolumab. A year later, the patient experienced neuralgia again with severe pain and an increasing sensory motor deficit. He underwent a second surgery that was incomplete. As the tumor kept growing, he received temozolomide. But the 6th cycle had to be interrupted due to bedsore infection in the hip area.

OUTCOMES

Disease progression finally led to the patient's death 3 years after diagnosis.

LESSONS

This case report is the first about a patient with meningeal melanocytoma treated with immunotherapy. Treatment based on biomolecular mutations will probably change spinal melanocytoma therapeutic approach in the next few years.

Primary intramedullary melanoma of lumbar spinal cord: A case report

BACKGROUND

Primary intramedullary melanoma is a very rare tumor, most frequently occurring in the cervical and thoracic spinal cord.

CASE SUMMARY

We present a rare case in which the primary intramedullary melanoma was located in the lumbar spine. A 56-year-old man complained of progressive intermittent pain in the lumbar area. Thoracic magnetic resonance imaging showed a spinal intramedullary tumor between the L3 and S1 levels. The tumor was resected entirely, and the diagnosis of malignant melanoma was confirmed by histopathology.

CONCLUSION

Primary melanoma of the spinal cord, particularly intramedullary localization, has rarely been reported in the previous literature. We describe a primary malignant melanoma of the lumbar spinal cord and discuss the challenges associated with the diagnosis.

Recurrent Meningeal Melanocytoma of Cervical Spine: A Rare Case

Melanocytomas of the central nervous system are rare benign or intermediate grade localized melanocytic tumors. Despite its benign nature, it can follow a locally aggressive course with propensity to recur. We present the case of a 29 years old female who presented with a recurrent lesion in cervical spine and rapidly progressing quadriparesis. On examination, there was loss of power in right-sided extremities and reduction in sensations in left-sided extremities. Magnetic resonance imaging spine revealed a homogeneously enhancing intradural extramedullary dumbbell-shaped mass lesion at C4/5 level with extension through right C4 neural foramina to the extraforamina space, causing severe spinal cord compression. Intraoperatively, bluish-colored tumor was identified along with underlying hematoma. Gross total excision of the tumor was done. Tumor was received in the histopathology department in multiple black-colored fragments. Microscopically, a heavily pigmented tumor was seen with the sheets and nodules of polygonal cells with large nuclei and prominent nucleoli. Differentials considered were meningeal melanocytoma and malignant melanoma. On immunohistochemistry, the tumor cells showed diffuse positivity for HMB 45 and S100. Ki 67 index was around 1%. On radiological review, the tumor was fairly well circumscribed and did not infiltrate the adjacent tissues. There was no evidence of any lesions elsewhere in the body. Considering these features, the tumor was diagnosed with meningeal melanocytoma. Postoperatively, there was significant immediate improvement in quadriparesis and patient could walk with minimal support.

Sudden Death from Primary Cerebral Melanoma: Clinical Signs and Pathological Observations

Primary cerebral tumors rarely provoke sudden death. The incidence is often underestimated with reported frequencies in the range of 0.02 to 2.1% in medicolegal autopsy series. Furthermore, primary cerebral melanoma is an uncommon neoplasm. It represents approximately 1% of all melanoma cases and 0.07% of all brain tumors. This neoplasm is very aggressive, and its annual incidence is about 1 in 10 million people. In the present study, a 20-year-old male was admitted to hospital with vomiting, headache, paresthesia and aggressive behavior. A computed tomography (CT) scan of the head was performed showing a hyperdense nodule in the right parietal lobe with inflammation of the Silvian fissure. A complete autopsy was performed 48 h after death. A blackish material was displayed on the skull base, and posterior fossa. Microscopic examination diagnosed primary brain melanoma. A systematic review of the literature was also performed where no previous analogous cases were found. The forensic pathologist rarely encounters primary cerebral melanoma, and for these reasons, it seemed appropriate to describe this case as presenting aspecific clinical symptoms and leading to sudden unexpected death. Histopathological observations are reported and discussed to explain this surprising sudden death caused by a primary cerebral melanoma.

Diagnosis of meningeal melanomatosis in a dog using magnetic resonance imaging and cerebrospinal fluid findings

A 13-year-old spayed female Labrador Retriever was presented with severe progressive tetraparesis. The neuroanatomic localization was the C1-C5 spinal cord segments with brainstem or cranial nerve involvement. Magnetic resonance imaging revealed diffuse T1-weighted and T2-weighted hyperintense lesions with strong contrast enhancement spreading through meninges of the cervical spinal cord and the brain. Few small round areas showing T1-weighted hyperintensity and T2-weighted hypointensity were scattered within the lesions. Cerebrospinal fluid analysis revealed neoplastic round cells and possible melanocytes. Malignant melanoma was suspected. At necropsy, the brain and the entire spinal cord were covered with thick, dark membranous tissue. Based on histopathologic findings, a positive response against Melan-A, and no melanoma identified outside the central nervous system, primary meningeal melanomatosis was diagnosed.

A Rare Case of Primary Malignant Melanoma Presenting with Lower Extremity Weakness

The authors report a pathologically confirmed case of primary malignant melanoma located in the intradural lumbosacral area, which is extremely rare due to its atypical location and manifestation. However rare, primary malignant melanoma could present as an intradural tumor and cause neurological deficit.

Nevus of Ota with midface tumors and a vanishing orbital mass

Nevus of Ota, also known as oculodermal melanocytosis, is a benign melanocytic lesion that develops along the distribution of the V1 and V2 branches of the trigeminal nerve. Prior reports have described the typical imaging and clinical features of nevus of Ota. We present a rare case of a 31 year-old female with midface tumors and presumed hemorrhage into an orbital lesion in the setting of nevus of Ota resulting in acute loss of vision.

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.

Primary intramedullary malignant melanoma: can imaging lead to the correct diagnosis?

Melanoma is a malignant neoplasm of melanin-producing cells. Melanoma usually occurs in the skin, but can also arise in any anatomical site that contains melanocytes, such as mucous membranes, the eyes, and the central nervous system (CNS). Primary CNS malignant melanoma most often develops in the leptomeninges. We report a case of a rare intramedullary melanoma of the thoracic spinal cord. A 78-year-old man was treated with surgery, radiotherapy, and immunotherapy for leptomeningeal spread. We also discuss the role of imaging methods in diagnosis and follow-up. Medullary melanoma occurs more frequently in adults. The most common presenting symptoms are the insidious onset of lower extremity weakness and paresthesia. Magnetic resonance imaging is the method of choice for evaluation. Although there are no imaging features to accurately distinguish primary malignant melanoma from other melanocytic or hemorrhagic tumors, hyperintensity on T1-weighted magnetic resonance imaging should lead to inclusion of this neoplasm in differential diagnosis of spinal cord tumors. Positron emission tomography-computed tomography is a useful auxiliary examination to evaluate the extent of local and metastatic disease. Surgical resection is the primary treatment for intramedullary melanoma. However, the efficacy of adjunctive radiotherapy and chemotherapy for primary spinal cord malignant melanoma is still controversial.

Clinical characteristics and treatment outcomes of pigmented tumors in central nervous system: Focusing on melanocytic tumors

Pigmented tumors are rare neoplasm of central nervous system. Melanocytic tumor, including primary and metastatic lesions, is the most common type. Owing to the rarity, the differential diagnosis of pigmented tumors and clinical management of melanocytic tumor remain challenge. Therefore, focusing on melanocytic tumors, the clinical, radiological, histopathological features and treatment outcomes were presented and analyzed in this study. We identified 22 melanocytic tumors, 2 melanotic medulloblastomas, 2 melanotic ependymomas and 1 melanotic schwannoma. Compared with metastatic melanocytic tumors (MMTs), primary melanocytic tumors (PMTs) were characterized by younger age (36.11 ± 17.96 vs. 51.69 ± 12.58 years, p = 0.0262), lower possibility to be multiple lesions (11.1%vs. 61.5%, p = 0.0306), higher proportion of hypointensity on T2-weighted images (66.7% vs. 15.4%, p = 0.0260) and higher frequency in black appearance (77.8% vs. 23.1%, p = 0.0247). During the follow-up, 4 PMTs and 11 MMTs (71.4%) experienced tumor progression. PMTs had better prognosis than MMTs that progression-free survival (PFS) rate of PMT was 50.0% but decreased to 23.1% for MMTs at 12 months (p = 0.0123). Cox proportional hazards regression revealed that multiplicity of tumor was an independent predictor for PFS. None of patient with multiple tumors was in PFS after 12 months' follow-up whereas PFS rate was 40.5% for single tumor (p = 0.0002). In conclusion, radiological appearances, especially hypointensity on T2-weighted images, might be an indication for PMT. MMTs are more likely to be multiple intraparenchymal masses in elder patients located in supratentorial region. Current treatments included operation, radiotherapy and chemotherapy are not competent to control tumor progression and other therapeutic modalities are urgently needed.

[A case of meningeal melanomatosis diagnosed by immunostaining of cerebrospinal fluid]

A 49-year-old woman was admitted to our hospital with suspected hypertensive encephalopathy. On the basis of MRI showing leptomeningeal enhancement and Class V cytology of the CSF, she was diagnosed as having leptomeningeal carcinomatosis. Although no primary site was detected, a few melanin granules were observed at the third CSF examination. The atypical cells in the CSF demonstrated immunoreactivity for HMB-45 and S-100, which are specific markers of malignant melanoma. There have been few reports of meningeal melanomatosis in Japan. This case illustrates that immunostaining is diagnostically useful in patients with leptomeningeal carcinomatosis from neoplasms with unknown primary sites.

C6-T1 Intradural Extramedullary Ventral Meningeal Melanocytoma Resected Via Anterior Corpectomy with Reconstruction

BACKGROUND

Melanocytic lesions of the nervous system are thought to arise from leptomeningeal melanocytes, which are derived from neural crest and include diffuse melanocytosis, melanocytomas, and malignant melanomas. Meningeal melanocytomas are extremely rare benign lesions. The usual treatment of intradural extramedullary melanocytomas involves surgical removal through a posterior approach using a laminectomy or laminotomy.

CASE DESCRIPTION

We present a 30-year-old female harboring a C6-T1 ventrally located intradural extramedullary lesion compressing the cord anteriorly. The lesion was totally resected via an anterior approach with oblique corpectomy even if the usual treatment involves surgical removal through a posterior approach using a laminectomy or laminotomy.

CONCLUSIONS

There is no evidence of recurrence at 4-year follow-up records of the patient. We discuss the surgical approach of these rare lesions.

CT and MRI findings in leptomeningeal melanocytosis

Leptomeningeal melanocytosis is a rare cause of seizure in the pediatric population. Shown here is a case of this disease in a 9-year-old male who presented with seizures and minor trauma. Imaging showed progression of leptomeningeal enhancement in the setting of increased seizure activity, and biopsy confirmed the diagnosis. The patient received immunotherapy but eventually succumbed to the disease. This case serves as an educational tool to improve awareness of melanocytic proliferation as a differential consideration for leptomeningeal enhancement.

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.