Automated volumetry of meningiomas in contrast-enhanced T1-Weighted MRI using deep learning.

BACKGROUND: Meningiomas are among the most common intracranial tumors. In these tumors, volumetric assessment is not only important for planning therapeutic intervention but also for follow-up examination.However, a highly accurate automated volumetric method for meningiomas using single-modality magnetic resonance imaging (MRI) has not yet been reported. Here, we aimed to develop a deep learning-based automated volumetry method for meningiomas in MRI and investigate its accuracy and potential clinical applications. METHODS: For deep learning, we used MRI images of patients with meningioma who were referred to Osaka University Hospital between January 2007 and October 2020. Imaging data of eligible patients were divided into three non-overlapping groups: training, validation, and testing. The model was trained and tested using the leave-oneout cross-validation method. Dice index (DI) and root mean squared percentage error (RMSPE) were measured to evaluate the model accuracy. Result: A total of 178 patients (64.6 ± 12.3 years [standard deviation]; 147 women) were evaluated. Comparison of the deep learning model and manual segmentation revealed a mean DI of 0.923 ± 0.051 for tumor lesions. For total tumor volume, RMSPE was 9.5 ± 1.2%, and Mann-Whitney U test did not show a significant difference between manual and algorithm-based measurement of the tumor volume (p = 0.96). CONCLUSION: The automatic tumor volumetry algorithm developed in this study provides a potential volume-based imaging biomarker for tumor evaluation in the field of neuroradiological imaging, which will contribute to the optimization and personalization of treatment for central nervous system tumors in the near future.

A rare case of breast carcinoma metastasis into a meningioma in a 64-year-old female patient.

This report discusses the occurrence of tumor-to-tumor metastasis-an atypical phenomenon in oncology where a secondary malignancy develops within an existing primary tumor. The case of a 64-year-old woman is presented, who, with a history of stage II invasive ductal carcinoma of the breast treated with mastectomy and chemoradiotherapy, developed neurological symptoms indicative of a secondary brain tumor. MRI and subsequent histopathological analysis post-craniotomy confirmed a meningioma with a metastatic breast carcinoma, demonstrating the clinical importance of considering tumor-to-tumor metastasis in similar patient histories.

Diffuse Leptomeningeal Glioneuronal Tumor with FGFR1 Mutation in a 29-Year-Old Male.

This study reports on diffuse leptomeningeal glioneuronal tumor (DL-GNT) in a 29-year-old male. DL-GNT is a rare central nervous system (CNS) tumor mostly seen in children and only few cases have been reported in adult patients. Our patient presented with a chronic headache that lasted for five months. MR imaging showed mild hydrocephalus, multiple rim-enhancing nodular lesions in the suprasellar cistern, diffuse leptomeningeal enhancement in the lumbosacral area, and multiple small non-enhancing cyst-appearing lesions not suppressed on fluid attenuated inversion recovery (FLAIR) images in the bilateral basal ganglia, thalami, and cerebral hemispheres. Under the impression of germ cell tumor with leptomeningeal seeding, the patient underwent trans-sphenoidal tumor removal. DL-GNT was pathologically confirmed and FGFR1 mutation was detected through a next-generation sequencing test. In conclusion, a combination of leptomeningeal enhancement and multiple parenchymal non-enhancing cyst-appearing lesions not suppressed on FLAIR images may be helpful for differential diagnosis despite overlapping imaging features with many other CNS diseases that have leptomeningeal enhancement.

The Role of Pharmacotherapy in Treatment of Meningioma: A Systematic Review.

The safety and efficacy of various pharmacotherapeutic regimens on refractory meningiomas have been the focus of investigations. We present a comprehensive review of the previous efforts and the current state of ongoing clinical trials. A PRISMA-compliant review of the MEDLINE and ClinicalTrial.gov databases of the National Library of Medicine were performed. The primary outcomes of interest for included articles were radiographic response, overall survival, progression-free survival, six-month progression-free survival, and adverse events. Overall, 34 completed trials and 27 ongoing clinical trials were eligible. Six-month progression-free survival was reported in 6-100% of patients in the completed studies. Hematological disorders were the most common adverse events. Of the ongoing clinical trials identified, nine studies are phase I clinical trials, eleven are phase II trials, two are phase I and II trials, one is phase II and III, and two trials do not have a designated phase. Currently, there is no effective chemotherapy for refractory or recurrent meningiomas. Several promising targeted agents have been developed and are currently being investigated in the hope of identifying novel therapeutic strategies for the treatment of this pathology.

Detection of meningeal carcinomatosis by metagenomic next-generation sequencing and copy number variation analysis of cerebrospinal fluid / 中华神经科杂志

Objective:To evaluate the significance of copy number variation (CNV) and metagenomic next-generation sequencing (mNGS) of cerebrospinal fluid (CSF) in the diagnosis of meningeal carcinomatosis (MC).Methods:Ten patients with MC diagnosed in the Department of Neurology of Peking Union Medical College Hospital from March 2022 to June 2022 were consecutively enrolled in this study. The patients were diagnosed according to the criteria of the Chinese expert consensus on the diagnosis of MC by the Chinese Society of Infectious Diseases and Cerebrospinal Fluid Cytology, and the diagnosis of MC was confirmed by CSF cytology. The control group included 10 patients who were diagnosed as autoimmune encephalitis or viral encephalitis. CSF mNGS and CNV analysis were performed simultaneously in all the patients.Results:Of the 10 patients with MC, 6 had lung adenocarcinoma, 4 had breast cancer. CSF mNGS and CNV analysis detected large CNV in 8 of 10 patients with MC, including 4 patients with breast cancer and 4 patients with lung cancer. The results of pathogenic microorganism analysis of CSF mNGS in all the patients were negative. Meanwhile, large CNV was not detected in the control group.Conclusions:CSF CNV can serve as a diagnostic marker for MC. The combination of mNGS and CNV analysis has demonstrated a high positive rate in the diagnosis of MC. The dual-omics analysis of pathogenic microorganisms and CNV has been proposed as a potential strategy to further expand the clinical utility of CSF mNGS in the realm of auxiliary diagnosis.

A Rare Case of Xanthomatous Meningioma.

Xanthomatous meningioma is an extremely rare subtype of metaplastic meningiomas with few cases reported in the literature. Histopathologically, it is composed of oval-shaped cells that have central nuclei and cytoplasm with lipid-filled vacuoles, resembling macrophages. Here, the authors present a case of xanthomatous meningioma and discuss the hypotheses related to its origin and the differential diagnosis. A 40-year-old woman presented with an increased headache complaint over the past month. A computed tomography scan revealed a heterogeneous mass on the right parietal lobe, following which a right craniotomy was done. Microscopic examination showed neoplastic meningothelial cells with whorl formation and areas of xanthomatous changes. Both meningothelial and xanthomatous cells were positive with vimentin, progesterone, and epithelial membrane antigen. CD68 and lysozyme were expressed only in the xanthomatous component, and there was no expression with periodic acid-Schiff (PAS) stain and PAS-diastase. As the diagnostic criteria of atypical meningioma were not observed, a diagnosis of xanthomatous meningioma, WHO grade I, was made. Owing to the characteristic xanthomatous changes, its differential diagnosis includes grade II clear cell meningioma, Rosai-Dorfman disease, and hemangioblastoma. To avoid misidentifying these cells as macrophages, a high degree of awareness of this unique subtype of meningioma is required.

Primary Leptomeningeal B-cell Lymphoma in an Immunocompetent Adult: Case Report.

Primary leptomeningeal lymphoma (PLML) is a rare disease, comprising less than 1% of all lymphomas. Clinical manifestations include headache, encephalopathy, ataxia, cranial nerve palsy, and myelitis. Diagnosis requires a combination of magnetic resonance images (MRI), cytology, flow cytometry of cerebrospinal fluid (CSF), and an extensive workup to rule out systemic lymphoma. We describe the case of a 49-year-old man who developed subacute onset headache, encephalopathy, and blindness. Whole-body examinations, including a bone marrow trephine biopsy, excluded systemic lymphoma. Brain MRI showed leptomeningeal enhancement. Cytology and flow cytometry of CSF found a clonal B-cell population making a diagnosis of PLML. He began treatment with rituximab and high-dose methotrexate (HD-MTX), with progressive clinical improvement. CSF analysis after two cycles and one intrathecal methotrexate dose was normal. Brain and spinal MRI images plus CSF analysis, along with an extensive workup to exclude systemic lymphoma, are necessary to diagnose PLM. Early treatment with HD-MTX alone or in combination with rituximab improves clinical outcomes.

Primary extraosseous dural chondrosarcoma: a case report.

BACKGROUND: Dural chondrosarcoma is a very rare intracranial tumor, given that meninges do not normally contain cartilaginous tissue from which it can originate. We present a case of primary extraosseous dural chondrosarcoma. CASE PRESENTATION: A 48-year-old woman presented to our tertiary center neurosurgery consultation with progressive headache, vomiting, vertigo, and gait instability of 5 months' duration. An initial brain CT revealed a large parietal mass with gross calcifications and subtle hyperostosis of the inner table. Subsequent brain MRI showed a heterogeneous expansive lesion with a honey-comb enhancement. Discussion of intra- or extra-axial location was warranted, and finally, initial presurgical suspicion of meningioma arose although some atypical imaging features were detected. The differential diagnosis included solitary fibrous tumor-hemangiopericytoma and dural metastasis. Total resection of the lesion was performed, extra-axial origin was confirmed, and pathology resulted in a primary dural chondrosarcoma. CONCLUSION: The importance of this case presentation lies in the unusual nature of the final diagnosis, the brief literature review and differential diagnosis with emphasis on imaging pearls, as well as the useful reminder for physicians to consider less frequent diseases when key findings do not unambiguously lead to the usual suspects.

Intracranial Inflammatory Myofibroblastic Tumor: A Review of 49 cases.

Inflammatory Myofibroblastic Tumor (IMT) is a rare pathologic entity that was first described in 1973. This lesion is most commonly found in the lungs, but other organs' involvement has also been reported. Intracranial location of Inflammatory Myofibroblastic Tumor is rare, and the first case was reported in 1980. An intriguing fact about the intracranial IMT is its resemblance with meningioma on clinical presentation and neuroimaging. We came across a case of intracranial Inflammatory Myofibroblastic Tumor (IIMT) in a 27-year-old male who presented with recurrent episodes of seizures and was diagnosed as meningioma on neuroimaging. The lesion did not subside with medical management and kept on progressing in size. The patient had to undergo surgery, and diagnosis of Inflammatory Myofibroblastic Tumor was ascertained on histopathology. This 'surprise' diagnosis prompted us to review the literature on all cases of IIMTs reported to date to better understand the entity and its implications. In this review article, we present our observations regarding various studied parameters, including patient profile, clinical presentation, site of involvement, focality of the lesion, special associations, and lines of management of the 49 published cases of IIMTs.

Intracranial Inflammatory Myofibroblastic Tumor: A Review of 49 cases

Inflammatory Myofibroblastic Tumor (IMT) is a rare pathologic entity that was first described in 1973. This lesion is most commonly found in the lungs, but other organs' involvement has also been reported. Intracranial location of Inflammatory Myofibroblastic Tumor is rare, and the first case was reported in 1980. An intriguing fact about the intracranial IMT is its resemblance with meningioma on clinical presentation and neuroimaging. We came across a case of intracranial Inflammatory Myofibroblastic Tumor (IIMT) in a 27-year-old male who presented with recurrent episodes of seizures and was diagnosed as meningioma on neuroimaging. The lesion did not subside with medical management and kept on progressing in size. The patient had to undergo surgery, and diagnosis of Inflammatory Myofibroblastic Tumor was ascertained on histopathology. This 'surprise' diagnosis prompted us to review the literature on all cases of IIMTs reported to date to better understand the entity and its implications. In this review article, we present our observations regarding various studied parameters, including patient profile, clinical presentation, site of involvement, focality of the lesion, special associations, and lines of management of the 49 published cases of IIMTs.

Early Onset Epilepsy Caused by Low-Grade Epilepsy-Associated Tumors and Focal Meningeal Involvement.

Background: Low-grade epilepsy-associated neuroepithelial tumors (LEATs) are a frequent etiology in pediatric patients with epilepsy undergoing surgery. Objective: To identify differences in clinical and post-surgical follow-up between patients with focal meningeal involvement (MI) and those without MI within our cohort of pediatric patients with LEATs. Methods: We retrospectively reviewed all pediatric patients (<18 y) who underwent epilepsy surgery between 2011 and 2017 at our hospital. Cohort inclusion required histological diagnosis of LEATs and post-surgical follow-up of ≥2 y. We subsequently stratified patients according to presence of neuroradiological MI. Results: We identified 37 patients: five with MI and 32 without. Half of patients (19) were drug sensitive at surgery; similar between groups. The group with MI differed mainly for age of epilepsy-onset (0.6 vs. 7.0 y) but not for epilepsy duration (0.9 vs. 1.5 y). Post-surgery radiological follow-up (median 4.0 y; IQR 2.8-5.0 y) did not indicate disease progression. Seizure outcome was excellent in both groups, with 34 patients overall being both drug- and seizure-free. Conclusions: Our study identified a new subgroup of LEATs with focal MI and excellent post-surgical outcome. Moreover, this highlights the effectiveness of early surgery in pediatric LEATs.

Meningioma primario intraóseo esfenotemporal: presentación de caso / Primary spheno-temporal intra-osseous meningioma: a case report

RESUMEN Fundamento: los meningiomas ectópicos, definidos como aquellos que no tienen ninguna conexión con la duramadre, poco frecuentes. Son una variante rara y representan cerca del uno por ciento de todos los meningiomas intracraneales. Objetivo: presentar una variante poco frecuente de un meningioma ectópico como causa de proptosis y oftalmoparesia encontrado en una paciente joven. Presentación del caso: paciente de 40 años de edad, que hace seis meses comenzó con dolor en el ojo derecho de moderada intensidad, aumento de volumen de la región frontorbitaria, disminución de la agudeza visual y visión doble. Los estudios de tomografía axial computarizada y resonancia magnética de cráneo y órbita mostraron lesión extraaxial a nivel de la pared lateral de la órbita con extensión extra e intraorbitaria con compresión de estructuras adyacentes que provocó desplazamiento anterior del globo ocular. Se realizó tratamiento quirúrgico con excéresis y el estudio histológico concluyó un meningioma meningotelial ectópico del hueso grado I. Conclusiones: los meningiomas ectópicos resultan poco frecuentes, el tratamiento quirúrgico con la resección total de la lesión es la elección para evitar recurrencias y pueden tener indicación de tratamiento oncológico complementario.

ABSTRACT Background: ectopic meningioma, defined as those that have no connection with the dura mater, are rare. They are a rare variant and represent approximately 1 % of all intracranial meningioma. Objective: to present a rare variant of an ectopic meningioma as a cause of proptosis and ophthalmoparesis found in a young patient. Case report: patient of 40 years of age, who 6 months ago began with pain in the right eye of moderate intensity, increased volume of the front-orbital region, decreased visual acuity and double vision. Computed tomography and MRI of the skull and orbit showed extra-axial lesion at the level of the lateral wall of the orbit with extra and intra-orbital extension with compression of adjacent structures that caused anterior displacement of the eyeball. Surgical treatment was performed with resection and the histological study concluded an ectopic meningotial meningioma of bone grade I. Conclusions: ectopic meningioma are infrequent, surgical treatment with total resection of the lesion is the choice to avoid recurrences and may have an indication of complementary oncological treatment.

Clinicopathological observation and literature review of cystic meningioangiomatosis / 中华神经科杂志

Objective To summarize the clinicopathological features of cystic meningioangiomatosis.Methods The clinical manifestations,imaging characteristics and pathological features of a case of cystic meningioangiomatosis were analysed,and the relevant literature was reviewed.Results A 16-year-old male patient from Xuanwu Hospital,Capital Medical University had a history of epileptic seizures for more than three months.Magnetic resonance imaging (MRI) demonstrated a cystic mass in the left frontal lobe with long T1 and long T2 signals.Extensive resection of the upper frontal gyms was performed.The excised lesion presented with a cystic shape after incision and contained colorless translucent liquid.Microscopic examination of the lesion showed that the number of blood vessels in the local cortex of the brain tissue was increased and the vessels appeared to be branching.The blood vessel walls were surrounded by proliferative spindle cells,which were arranged in concentric circles.Immunohistochemical study revealed that those spindle cells and the cyst wall were vimentin positive.These cells had a rich reticular fibers.Ten months after the operation,the general condition of the patient was good,no epileptic seizure was observed,and the follow-up MRI did not reveal any residual lesion.Conclusions MRI of cystic meningioangiomatosis shows cystic space occupying.Pathological findings show typical features of meningioangiomatosis and cystic space formation.Cystic meningioangiomatosis has good prognosis after surgical resection.

Clinicopathological observation and literature review of cystic meningioangiomatosis / 中华神经科杂志

Objective@#To summarize the clinicopathological features of cystic meningioangiomatosis.@*Methods@#The clinical manifestations, imaging characteristics and pathological features of a case of cystic meningioangiomatosis were analysed, and the relevant literature was reviewed.@*Results@#A 16-year-old male patient from Xuanwu Hospital, Capital Medical University had a history of epileptic seizures for more than three months. Magnetic resonance imaging (MRI) demonstrated a cystic mass in the left frontal lobe with long T1 and long T2 signals. Extensive resection of the upper frontal gyrus was performed. The excised lesion presented with a cystic shape after incision and contained colorless translucent liquid. Microscopic examination of the lesion showed that the number of blood vessels in the local cortex of the brain tissue was increased and the vessels appeared to be branching. The blood vessel walls were surrounded by proliferative spindle cells, which were arranged in concentric circles. Immunohistochemical study revealed that those spindle cells and the cyst wall were vimentin positive. These cells had a rich reticular fibers. Ten months after the operation, the general condition of the patient was good, no epileptic seiƶure was observed, and the follow-up MRI did not reveal any residual lesion.@*Conclusions@#MRI of cystic meningioangiomatosis shows cystic space occupying. Pathological findings show typical features of meningioangiomatosis and cystic space formation. Cystic meningioangiomatosis has good prognosis after surgical resection.

CORRELATION OF PERITUMORAL BRAIN EDEMA WITH MORPHOLOGICAL CHARACTERISTICS AND KI67 PROLIFERATIVE INDEX IN RESECTED INTRACRANIAL MENINGIOMAS.

The aim of the study was to analyze correlation between morphological characteristics of intracranial meningiomas and Ki67 labeling index (Ki67 LI), and their influence on peritumoral brain edema (PTBE). There were 41 consecutive patients with intracranial meningiomas surgically treated at the Department of Neurosurgery, Zenica Cantonal Hospital, Zenica, Bosnia and Herzegovina, during the period from January 2010 to December 2015. We reviewed clinical data including patient age, gender, magnetic resonance imaging (MRI) characteristics of the tumor and peritumoral edema, tumor margins, intraoperative characteristics, histopathologic grade and Ki67 LI. In all cases, follow up MRI was obtained at about three months after resection and PTBE was analyzed. Our research showed the tumor volume, tumor margins, and intraoperative signs of arachnoidal and pial invasion to be associated with PTBE in intracranial meningiomas. Ki67 LI expression correlated with PTBE. This study showed the resolution of PTBE to depend on invasive behavior of meningioma and KI67 LI. PTBE, pial/cortical and arachnoidal invasion significantly influence the extent of surgical resection.

Subjective cognitive functioning in patients with a meningioma: Its course and association with objective cognitive functioning and psychological symptoms.

OBJECTIVE: Although meningioma patients show deficits in objective cognitive functioning (OCF) measured with neuropsychological tests, subjective cognitive functioning (SCF) has received little attention. We investigate SCF from pre- to postsurgery and its associations with OCF, psychological, sociodemographic, and clinical characteristics. METHODS: SCF was measured using the Cognitive Failures Questionnaire (CFQ) 1 day before (T0) and 3 (T3) and 12 months (T12) after surgery. Patients' scores were compared with normative data and changes over time were assessed. The neuropsychological battery CNS Vital Signs and the Hospital Anxiety and Depression Scale were administered. Correlations of SCF with OCF, psychological, sociodemographic, and clinical characteristics were explored. RESULTS: Patients reported significantly better SCF as compared with controls at T0 (N = 54) and T3 (N = 242), but not at T12 (N = 50). A significant decrease in group level SCF was observed from T0 to T12 (n = 24, P < .001). SCF was associated with anxiety at all time points (rs = -0.543 to -0.352) and with depression at T3 and T12 (r = -0.338 and -0.574), but not with OCF, sociodemographic, or clinical characteristics (rs = -0.202 to 0.288). CONCLUSIONS: Meningioma patients experienced better SCF as compared with controls before and 3 months after surgery, which might be the result of phenomena related to disease and recovery. As the findings suggest that cognitive symptoms might increase later on, future studies should further investigate the course of SCF in meningioma patients. In clinical practice, measurements of SCF should be combined with those of OCF and psychological distress in order to determine whether and which interventions are needed.

Dural masses: meningiomas and their mimics.

Meningiomas are the most common dural tumour. They are regularly being seen as an incidental finding on brain imaging and treated conservatively. However, there are many other dural masses which mimic their appearances, including primary neoplastic processes, metastases, granulomatous diseases and infection. While some of these are rare, others such as metastases and tuberculosis arise relatively frequently in practice. Although not pathognomonic, key features which increase the probability of a lesion being a meningioma include intralesional calcifications, skull hyperostosis, local dural enhancement and increased perfusion. It is important to have an awareness of these entities as well as their main imaging findings, as they have a wide range of prognoses and differing management strategies. This review outlines several of the most important mimics along with their imaging findings on both standard and advanced techniques with key features which may be used to help differentiate them from meningiomas.

Hemorrhagic and Cystic Brain Metastases Are Associated With an Increased Risk of Leptomeningeal Dissemination After Surgical Resection and Adjuvant Stereotactic Radiosurgery.

BACKGROUND: Brain metastases (BM) treated with surgical resection and focal postoperative radiotherapy have been associated with an increased risk of subsequent leptomeningeal dissemination (LMD). BMs with hemorrhagic and/or cystic features contain less solid components and may therefore be at higher risk for tumor spillage during resection. OBJECTIVE: To investigate the association between hemorrhagic and cystic BMs treated with surgical resection and stereotactic radiosurgery and the risk of LMD. METHODS: One hundred thirty-four consecutive patients with a single resected BM treated with adjuvant stereotactic radiosurgery from 2008 to 2016 were identified. Intracranial outcomes including LMD were calculated using the cumulative incidence model with death as a competing risk. Univariable analysis and multivariable analysis were assessed using the Fine & Gray model. Overall survival was analyzed using the Kaplan-Meier method. RESULTS: Median imaging follow-up was 14.2 mo (range 2.5-132 mo). Hemorrhagic and cystic features were present in 46 (34%) and 32 (24%) patients, respectively. The overall 12- and 24-mo cumulative incidence of LMD with death as a competing risk was 11.0 and 22.4%, respectively. On multivariable analysis, hemorrhagic features (hazard ratio [HR] 2.34, P = .015), cystic features (HR 2.34, P = .013), breast histology (HR 3.23, P = .016), and number of brain metastases >1 (HR 2.09, P = .032) were independently associated with increased risk of LMD. CONCLUSION: Hemorrhagic and cystic features were independently associated with increased risk for postoperative LMD. Patients with BMs containing these intralesion features may benefit from alternative treatment strategies to mitigate this risk.

Application of cerebrospinal fluid circulating cell-free DNA in the diagnosis and treatment of leptomeningeal metastases from non-small-cell lung cancer / 中华检验医学杂志

Objective To investigate the application value of cerebrospinal fluid circulating cell-free DNA (cfDNA) in the diagnosis and treatment of leptomeningeal metastases in non-small-cell lung cancer (NSCLC). Methods Twenty-five patients with leptomeningeal metastases of NCSLC from Fudan University Huashan Hospital North during the period from September 2017 to November 2018 were enrolled. All 25 patients were confirmed leptomeningeal metastases by cerebrospinal fluid cytology and immunocytochemical staining of cytokeratin(CK7), carcinoembryonic antigen(CEA), thyroid transcription factor-1(TTF-1) and Ki67. The cerebrospinal fluid cfDNA was extracted and genetic variation of 12 genes including epidermal growth factor receptor(EGFR), TP53 and anaplastic lymphoma kinase(ALK) was detected by next-generation sequencing [PlasAim TM gene non-invasive detection of lung cancer (12 gene) kit, Singlera Genomics].The application value of cerebrospinal fluid cfDNA in the diagnosis and treatment of leptomeningeal metastases of NSCLC was analyzed with the cfDNA mutation data and the clinical follow-ups. Results Morphologically typical lung cancer tumor cells with tumor immunochemistry marker CK, CK7 and CEA were found in the cerebrospinal fluid of all 25 patients. Next generation sequencing of cerebrospinal fluid showed that 96％(24/25) patients had at least one single nucleotide variation (SNV) or copy number variation (CNV). The EGFR and TP53 mutations were identified in 80％(20/25) and 48％(12/25) of the patients, respectively. In addition, patients with bone metastases had a higher rate of EGFR mutations than those without bone metastases (100％ vs 64％, P<0.05). Changes in the mutant allele frequency of EGFR and TP53 in cerebrospinal fluid were consistent with patients' disease progression parameters including neurological symptoms, imaging, and tumor biomarkers. The results indicate that genetic alteration of EGFR in cerebrospinal fluid cfDNA is an actionable biomarker for targeted therapy of leptomeningeal metastases of lung cancer. Conclusion Cerebrospinal fluid cfDNA accurately reveals the unique genetic background of leptomeningeal metastasis in NSCLC, showing great application value in the diagnosis and treatment of the leptomeningeal metastasis of NSCLC.