BRAF V600E mutation in two distinct meningeal melanocytomas associated with a nevus of Ota

Meningeal melanocytoma of the central nervous system in children

PURPOSE

This study aimed to summarize the existing English-language literature on central nervous system (CNS) meningeal melanocytomas in children, and additionally describe our institutional case report.

METHODS

PubMed database was screened on September 2, 2024, for English-language papers reporting on pediatric patients with CNS meningeal melanocytoma.

RESULTS

A total of 17 papers reporting on 18 patients with 19 CNS meningeal melanocytomas were found in the literature. Additionally, we reported on a 15-year-old male patient with C2-C6 meningeal melanocytoma. Pediatric cohort analysis showed nearly equal sex distribution and a mean age at diagnosis of 11.9 years. There were fifteen intracranial (75%) and five spinal tumors (25%). Four lesions (20%) were diagnosed as intermediate-grade melanocytomas, while the remaining sixteen (80%) were benign meningeal melanocytomas. Most tumors were hyperintense on T1-weighted imaging (85%) and hypointense on T2-weighted imaging (73%). All tumors showed positivity for S100 and Melan-A. Most tumors were characterized by a lack of CNS invasion (91%). Gross-total resection (GTR) was performed in 61% of tumors. Adjuvant radiotherapy (RT) was applied in 50% of patients with incomplete tumor resection. Postoperatively, 62% of patients achieved a favorable outcome. We found 1, 2, 3, and 4-year overall survival of 80%, 71%, 71%, and 50%, respectively. The recurrence rate was 15% after a mean time of 10 months.

CONCLUSIONS

Meningeal melanocytomas constitute a rare subgroup of CNS tumors. Surgical tumor removal aiming at maximally safe GTR remains a standard approach, resulting in favorable postoperative outcomes. Considering high recurrence rate, long-term follow-up is needed.

Intracranial meningeal melanocytoma: a case report and literature review

Primary intracranial melanocytoma is an uncommon benign pigmented tumor arising from leptomeningeal melanocytes. Neuroimaging characteristics of central nervous system melanocytoma are distinct from similarly presenting intracranial neoplasms and can aid in diagnosis prior to histopathological examination. In rare cases, there may be more than one lesion present. We report a case of a 19-year-old woman presenting with progressively worsening headaches, nausea, emesis, and generalized weakness of 2 months. Imaging revealed tumors in the parietal and ipsilateral medial temporal lobe. The patient underwent gross total resection of the parietal lesion which histopathological assessment revealed to be primary intracranial meningeal melanocytoma. This case highlights the utility of specific imaging criteria such as diffusely increased T1 signal without enhancement in the initial diagnostic evaluation of intracranial melanocytoma. We also describe the clinical characteristics, management strategy, and histopathological features of a rare case of a patient with multiple primary intracranial melanocytoma lesions.

How Should We Treat Meningeal Melanocytoma? A Retrospective Analysis of Potential Treatment Strategies

BACKGROUND

Meningeal melanocytomas (MM) are rare primary melanocytic tumors of the leptomeninges with an incidence of 1:10,000,000. Until now, there has been only sparse information about this tumor entity. Here, we provide a meta-analysis of all cases published in the English language since 1972.

METHODS

A literature review was performed using PubMed and Web of Science. All published cases were evaluated for location, sex, age, therapeutic approach, and outcome. In total, we included 201 patient cases in our meta-analysis.

RESULTS

The majority of MM was diagnosed more frequently in men between the third and fifth decade of life. Surgery is the preferred therapeutic approach, and total resection is associated with the best outcome. Patients with partial resection or tumor recurrence benefit from adjuvant radiotherapy, whereas chemo- or immunotherapies do not improve the disease course. Malignant transformation was described in 18 patients. Of these, 11 patients developed metastasis.

CONCLUSIONS

We present the first retrospective meta-analysis of all MM cases published in the English language, including an evaluation of different treatment strategies allowing us to suggest a novel treatment guideline highlighting the importance of total resection for recurrence-free survival and characterizing those cases which benefit from adjuvant radiotherapy.

Intracranial meningeal melanocytomas: Clinico-radiological characteristics and outcomes. A Literature review

OBJECTIVES

Melanocytes are neural crest derivatives. Intracranial meningeal melanocytomas (MM) are rare tumors and the available literature is sparse for these neoplasms. This present review aims to provide a detailed and comprehensive literature review of these tumors.

MATERIALS AND METHODS

By searching online databases, literature review was performed to include and analyze all cases of cranial MM reported till date. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed for the review process.

RESULTS

A total of 109 cases were analyzed. Male:female ratio was 1.2:1. The mean age was 40.3 years. The mean duration of symptoms was 23.9 months (range 2days-15 years). Cerebellopontine (CP) angle, suprasellar and Meckel cave were the most common locations. Sixty-four cases (58%) underwent GTR. Twenty-eight patients (26%) received some form of adjuvant radiation. There were 29(26%) recurrences and mean time to recurrence was 50.2 months. The recurrence rates (RR) for GTR and STR were 20% and 42% respectively. Extent of resection (STR) and tumor locations (CP angle and Meckel cave) were significantly associated with higher RR. Six (6.5%) cases had higher-grade transformations.

CONCLUSIONS

Complete surgical resection is the ideal treatment and adjuvant radiation is to be considered for residual/recurrent tumors. Adjuvant radiotherapy may also be prescribed despite GTR, in locations with higher RR such as CP angle and Meckel's cave. Because of higher-grade transformations and delayed recurrences, long-term follow-up is required.

GNA11 Mutation in an Intracranial Melanocytoma with Orbital Involvement and Nevus of Ota

The prognostic value of mutations in G-protein genes GNAQ and GNA11 in patients with intracranial and orbital melanocytomas is unknown. The authors present a case of GNA11 mutation (GNA11Q209L) in a 32-year-old male suffering from a meningeal melanocytoma with orbital involvement and ipsilateral Nevus of Ota. The patient underwent gamma knife stereotactic radiosurgery without biopsy and later partial transcranial resection of the melanocytic tumor that was subject to immunohistochemical and molecular analysis. A 50-gene next-generation sequencing panel revealed a 626A>T mutation in the GNA11 gene. One year later, intracranial extension of the melanocytoma necessitated a ventriculoperitoneal shunt and immunotherapy. Future work is needed to determine how GNA11 mutations in melanocytomas influence prognosis and monitoring strategies.

Identification of a Novel BRCA1 Alteration in Recurrent Melanocytoma Resulting in Increased Proliferation

Primary meningeal melanocytomas are rare tumors of the central nervous system. Although they are considered benign neoplasms, some reports describe recurrent rates up to 45%. Little is known about their genetic and epigenetic landscape because of their infrequency. Even less has been described about markers with prognostic value. Here we describe a patient who developed a primary meningeal melanocytoma, suffered 3 recurrences in a period of 6 years and died of the tumor. The genetic and epigenetic changes explored confirmed GNAQ mutation as an initiating event. We found an epigenetic alteration of GSTP1, a feature that has recently been described in meningiomas, from the beginning of the disease. In addition, there was loss of heterozygosity in BRCA1 beginning in the second recurrence that was linked to an increase in the proliferation index; this suggested a progression pathway similar to the one described in uveal melanomas. These findings underscore the necessity of further research focused on these tumors.

Meningeal Melanocytoma Associated with Nevus of Ota: Analysis of Twelve Reported Cases

BACKGROUND

Primary melanocytic neoplasms (PMNs) are rare neoplasms, especially within the central nervous system. Meningeal melanocytomas, a subtype of PMN, are even rarer. Nevus of Ota results from the incomplete migration of melanocytes from the neural crest. Synchronous nevus of Ota and meningeal melanocytoma are infrequently encountered in clinical practice.

OBJECTIVE

To evaluate and elucidate 12 cases of synchronous meningeal melanocytoma and nevus of Ota, thereby improving the understanding of the relationship between these 2 diseases.

METHODS

We reviewed cases and searched the English-language literature from the PubMed database and collected clinical parameters of 12 cases of synchronously occurring nevus of Ota and meningeal melanocytoma.

RESULTS

Among the 12 cases, 90.90% and 91.66% of the lesions were located ipsilaterally and supratentorially, respectively.

CONCLUSIONS

Our findings indicated a trend for both types of lesion to be located ipsilaterally and supratentorially. When a patient with nevus of Ota is found to harbor an intracranial neoplasm, the most likely diagnosis is PMN.

Orbital meningeal melanocytoma: Histological, immunohistochemical and molecular characterization of a case and review of the literature

AIMS

We provide morphological, immunohistochemical and molecular characterization of the 3rd "intermediate-grade" orbital meningeal melanocytoma, testing for the first time Vysis Melanoma FISH Probe Kit. We reviewed the literature in order to discuss the main differential diagnoses and to provide a better molecular description of these unusual tumors of difficult diagnosis and controversial management.

METHODS

Histochemical stains (Haematoxylin and Eosin, Perls, reticulin), immunohistochemistry (HMB45, p16, Melan-A, S100, EMA, Ki67, CD68), polymerase chain reaction amplification and sequence analysis (BRAF, exon 15; NRAS exons 2 and 3; c-KIT, exons 11, 13, 17, 18; GNAQ, exons 4 and 5; GNA11, exons 4 and 5) and fluorescent in situ hybridization (RREB1, 6p25; MYB, 6q23; CCND1, 11q13; CEP 6, 6p11.1-q11.1) were performed on paraffin-embedded, formalin-fixed material.

RESULTS

Histological diagnosis of "intermediate-grade" melanocytoma was supported by zonal necrosis and increased Ki67-index (12%). Immunophenotype: HMB45+(strong, >75%), Melan-A+(strong, >75%), p16+(∼20%), S100 -/+ (<5%), EMA -/+ (<5%), CD68 - (positive histiocytes). No gene mutations nor copy-number alterations were identified. The patient was asymptomatic and disease-free 3 years after total surgical excision.

CONCLUSIONS

Adequate sampling and accurate immunohistochemical characterization are important for a correct diagnosis. Molecular analysis could provide important additional information (especially for "intermediate-grade" tumors), but further data are needed.

Primary melanocytic tumors of the central nervous system: a review with focus on molecular aspects

Primary melanocytic tumors of the central nervous system (CNS) represent a spectrum of rare tumors. They can be benign or malignant and occur in adults as well as in children, the latter often in the context of neurocutaneous melanosis. Until recently, the genetic alterations in these tumors were largely unknown. This is in contrast with cutaneous and uveal melanomas, which are known to harbor distinct oncogenic mutations that can be used as targets for treatment with small-molecule inhibitors in the advanced setting. Recently, novel insights in the molecular alterations underlying primary melanocytic tumors of the CNS were obtained, including different oncogenic mutations in tumors in adult patients (especially GNAQ, GNA11) vs. children (especially NRAS). In this review, the focus is on molecular characteristics of primary melanocytic tumors of the CNS. We summarize what is known about their genetic alterations and discuss implications for pathogenesis and differential diagnosis with other pigmented tumors in or around the CNS. Finally, new therapeutic options with targeted therapy are discussed.

BRAF mutations are also associated with neurocutaneous melanocytosis and large/giant congenital melanocytic nevi

NRAS and BRAF mutations occur in congenital melanocytic nevi (CMN), but results are contradictory. Sixty-six prospectively collected CMN patients were analyzed for NRAS Q61 mutations using Sanger sequencing. Negative cases were evaluated for BRAF V600E mutation. NRAS Q61 mutations affected 51 patients (77.3%), and BRAF V600E was found in 5 (7.6%). NRAS Q61 mutation affected 29 (80.6%) of 36 giant, 16 (80.0%) of 20 large, and 5 (62.5%) of 8 medium-size CMN; BRAF mutation affected 1 (5%) of 20 large and 4 (11.4%) of 36 giant CMN. Compared to NRAS, BRAF-mutated nevi show scattered/extensive dermal and subcutaneous nodules (100% BRAF+ vs 34.8% NRAS+) (P=0.002). Neurocutaneous melanocytosis (NCM) affected 16 (24.2%) of 66 patients, with NRAS Q61 mutation in 12 (75.0%), and BRAF V600E in 2 (12.5%), P=0.009. Two patients were negative for both mutations (12.5%). In conclusion, although NRAS Q61 mutations predominate, BRAF V600E mutation also affects patients with large/giant CMN (L/GCMN), and with NCM, a novel finding. BRAF V600E is also associated with increased dermal/subcutaneous nodules. These findings open the possibility of BRAF-targeted therapy in some L/GCMN and NCM cases.