Neoplastic meningitis

Individual survival prediction model for patients with leptomeningeal metastasis

BACKGROUND

Survival prediction for patients with leptomeningeal metastasis (LM) is crucial for making proper management plans and counseling patients. Prognostic models in this patient domain have been limited, and existing models often include predictors that are not available in resource-limited settings. Our aim was to develop a practical, individualized survival prediction model for patients diagnosed with LM.

METHODS

We collected a retrospective cohort of patients diagnosed with LM from cerebrospinal fluid at Chiang Mai University Hospital from January 2015 to July 2021. Nine candidate predictors included male gender, age > 60 years, presence of extracranial involvement, types of primary cancer, the time between primary cancer and LM diagnosis, presence of cerebral symptoms, cranial symptoms, spinal symptoms, and abnormal CSF profiles. Flexible parametric survival analysis was used to develop the survival prognostic model for predicting survival at 3, 6, and 12 months after diagnosis. The model was evaluated for discrimination and calibration.

RESULTS

161 patients with 133 events were included. The derived individual survival prediction model for patients with LM, or the LMsurv model, consists of three final predictors: types of primary cancer, presence of cerebral symptoms, and presence of spinal symptoms. The model showed acceptable discrimination (Harrell's C-statistics: 0.72; 95% confidence interval 0.68-0.76) and was well calibrated at 3, 6, and 12 months.

CONCLUSIONS

The LMsurv model, incorporating three practical predictors, demonstrated acceptable discrimination and calibration for predicting survival in LM patients. This model could serve as an assisting tool during clinical decision-making. External validation is suggested to confirm the generalizability of the model.

Application of metabolomics in diagnostics and differentiation of meningitis: A narrative review with a critical approach to the literature

Due to its high mortality rate associated with various life-threatening sequelae, meningitis poses a vital problem in contemporary medicine. Numerous algorithms, many of which were derived with the aid of artificial intelligence, were brought up in a strive for perfection in predicting the status of sepsis-related survival or exacerbation. This review aims to provide key insights on the contextual utilization of metabolomics. The aim of this the metabolomic approach set of methods can be used to investigate both bacterial and host metabolite sets from both the host and its microbes in several types of specimens - even in one's breath, mainly with use of two methods - Mass Spectrometry (MS) and Nuclear Magnetic Resonance (NMR). Metabolomics, and has been used to elucidate the mechanisms underlying disease development and metabolic identification changes in a wide range of metabolite contents, leading to improved methods of diagnosis, treatment, and prognosis of meningitis. Mass spectrometry (MS) and Nuclear Magnetic Resonance (NMR) are the main analytical platforms used in metabolomics. Its high sensitivity accounts for the usefulness of metabolomics in studies into meningitis, its sequelae, and concomitant comorbidities. Metabolomics approaches are a double-edged sword, due to not only their flexibility, but also - high complexity, as even minor changes in the multi-step methods can have a massive impact on the results. Information on the differential diagnosis of meningitis act as a background in presenting the merits and drawbacks of the use of metabolomics in context of meningeal infections.

Leptomeningeal dissemination in pediatric brain tumors

Leptomeningeal disease (LMD) in pediatric brain tumors (PBTs) is a poorly understood and categorized phenomenon. LMD incidence rates, as well as diagnosis, treatment, and screening practices, vary greatly depending on the primary tumor pathology. While LMD is encountered most frequently in medulloblastoma, reports of LMD have been described across a wide variety of PBT pathologies. LMD may be diagnosed simultaneously with the primary tumor, at time of recurrence, or as primary LMD without a primary intraparenchymal lesion. Dissemination and seeding of the cerebrospinal fluid (CSF) involves a modified invasion-metastasis cascade and is often the result of direct deposition of tumor cells into the CSF. Cells develop select environmental advantages to survive the harsh, nutrient poor and turbulent environment of the CSF and leptomeninges. Improved understanding of the molecular mechanisms that underlie LMD, along with improved diagnostic and treatment approaches, will help the prognosis of children affected by primary brain tumors.

The diagnostic significance of cerebrospinal fluid cytology and circulating tumor DNA in meningeal carcinomatosis

Objective

The objective of this research is to investigate the clinical application value of cerebrospinal fluid (CSF) cytology and circulating tumor DNA (ctDNA) in lung adenocarcinoma (LUAD) meningeal metastasis-meningeal carcinomatosis (MC), and to further explore the possible molecular mechanisms and drug treatment targets of LUAD meningeal metastasis by next-generation sequencing (NGS).

Methods

We retrospectively analyzed LUAD with MC in 52 patients. CSF cytology was carried out using the slide centrifugation precipitation method and May-Grüwald-Giemsa (MGG) staining. Tumor tissue, plasma and CSF ctDNA of some MC patients were detected by NGS.

Results

Of the 52 MC patients, 46 (88.46%) were positive for CSF cytology and 34 (65.38%) were positive for imaging, with statistically significant differences in diagnostic positivity (P < 0.05). In 32 of these patients, CSF cytology, cerebrospinal fluid ctDNA, plasma ctDNA and MRI examination were performed simultaneously, and the positive rates were 84.38, 100, 56.25, and 62.50% respectively, the difference was statistically significant (P < 0.001). Analysis of the NGS profiles of tumor tissues, plasma and CSF of 12 MC patients: the mutated gene with the highest detection rate was epidermal growth factor receptor (EGFR) and the detection rate were 100, 58.33, and 100% respectively in tumor tissues, plasma and CSF, and there were 6 cases of concordance between plasma and tissue EGFR mutation sites, with a concordance rate of 50.00%, and 12 cases of concordance between CSF and tissue EGFR mutation sites, with a concordance rate of 100%. In addition, mutations not found in tissue or plasma were detected in CSF: FH mutation, SETD2 mutation, WT1 mutation, CDKN2A mutation, CDKN2B mutation, and multiple copy number variants (CNV), with the most detected being CDKN2A mutation and MET amplification.

Conclusion

CSF cytology is more sensitive than traditional imaging in the diagnosis of meningeal carcinomatosis and has significant advantages in the early screening and diagnosis of MC patients. CSF ctDNA can be used as a complementary diagnostic method to negative results of CSF cytology and MRI, and CSF ctDNA can be used as an important method for liquid biopsy of patients with MC, which has important clinical significance in revealing the possible molecular mechanisms and drug treatment targets of meningeal metastasis of LUAD.

Investigation of white blood cell characteristics in cerebrospinal fluid samples at pediatric brain tumor diagnosis

PURPOSE

The role of white blood cells (WBC) in the pediatric central nervous system (CNS) tumor microenvironment is incompletely defined. We hypothesized that the WBC profile in cerebrospinal fluid (CSF) correlates with the presence of tumor cells and prognosis in pediatric CNS tumors, as well as other patient and disease characteristics, and differs by tumor type, thus giving insight into the tumor immune response.

METHODS

We conducted a retrospective analysis of CSF WBC profiles at CNS tumor diagnosis in 269 patients at our institution. We examined total nucleated cell count, absolute counts, and percentages by WBC subtype. We compared CSF WBC values by tumor cell presence, patient vital status, tumor location, and the most common tumor types.

RESULTS

Patients who died of their tumor had a lower CSF lymphocyte percentage and a higher absolute monocyte count in CSF at diagnosis. The presence of tumor cells in CSF was associated with fewer lymphocytes and monocytes. Ventricular tumors had higher CSF lymphocyte, monocyte, macrophage, and total nucleated cell counts than extraventricular tumors. Germ cell tumors, low-grade glioma, high-grade glioma, and ependymoma had lower macrophage counts or percentages compared to other tumor types.

CONCLUSIONS

WBC profile in CSF at pediatric CNS tumor diagnosis correlates with patient prognosis and presence of metastatic cells, along with tumor type and other tumor characteristics like relationship to the ventricles. Prospective CSF profiling and study may be useful to future immunotherapy and other pediatric CNS tumor clinical trials.

Ovarian Adenocarcinoma With Leptomeningeal Metastases

Leptomeningeal carcinomatosis (LMC) is an uncommon disease that unfortunately has a rapid deterioration and a very poor prognosis with a devastating outcome. There has been an associated increase in the incidence of the leptomeningeal disease recently. There is a low percentage of LMC, around five percent of patients with metastatic disease. LMC has been presented in solid tumors such as breast cancer, lung cancer, melanoma, and GI malignancies. LMC is less likely reported in ovarian cancers. The clinical presentation of LMC is variable and will express according to where the cancer cells infiltrate. The malignant cells can travel with the cerebrospinal fluid (CSF) and deposit on the brain, cerebellum, spinal cord, cranial nerves, and spinal roots. We report this case as a clinical anatomical exercise for healthcare professionals.

Chronic meningitis, seizures and myoclonus

A 70-year-old retired male plumber was admitted with reduced consciousness following a recent onset of confusion and headache. He developed encephalopathy, seizures and myoclonus. He died despite treatment 10 weeks later. This article reports the clinicopathological conference presented at the Edinburgh Clinical Neurology Course 2021.

A case report of endometrial adenocarcinoma with leptomeningeal metastases

In patients with a history of solid tumors, any new onset of neurological symptoms should be assessed for central nervous system involvement even in rare cases such as gynecological malignancies that nervous system involvement is a rare event.

Leptomeningeal Carcinomatosis in Urothelial Carcinoma of the Urinary Bladder: A Report of a Patient with a Fulminant Course Who Died of Cancer after Definitive Therapies

A 45-year-old Japanese man visited a community hospital with the chief complaint of asymptomatic macrohematuria. He was diagnosed with muscle-invasive bladder cancer (MIBC), and he received intra-arterial chemotherapy followed by radiation therapy at another institution. Twenty-eight months after chemoradiotherapy, magnetic resonance imaging (MRI) revealed MIBC recurrence. After neoadjuvant chemotherapy, robot-assisted radical cystectomy was performed. Pathological examination indicated high-grade urothelial carcinoma with lymphovascular invasion, a positive surgical margin, and skip lesions of cancer cells in the perivesical adipose tissue. Three months after surgery, he was brought to our hospital in an ambulance with the chief complaint of rotatory vertigo and was speaking inarticulately. Head and whole spine MRI revealed meningeal metastasis along both the vestibulocochlear nerves and cauda equina. Analysis of the cerebrospinal fluid revealed malignant cells. The patient was diagnosed with leptomeningeal carcinomatosis originating from the MIBC. He received whole-brain radiotherapy followed by the administration of pembrolizumab. Unfortunately, the patient's condition quickly deteriorated, and he died of cancer 4 months after surgery.

Leptomeningeal disease in pancreas ductal adenocarcinoma: A manifestation of longevity

BACKGROUND

/Objectives: Pancreatic adenocarcinoma (PDAC) metastatic to the leptomeninges is a rare and lethal event. Leptomeningeal disease (LMD) research is limited in PDAC, and insights into clinical descriptors, possible disease predictors, and treatment strategies is necessitated.

METHODS

Memorial Sloan Kettering databases were queried with Institutional Review Board approval to identify patients with LMD and PDAC treated between January 2000 and June 2020. Medical record review was used to abstract clinical, genomic, pathologic, and radiographic data. Overall survival was calculated from date of PDAC diagnosis to date of death. Previously published literature on LMD from PDAC was reviewed.

RESULTS

Four patients with LMD from PDAC were identified, two males and two females. Age at diagnosis ranged from 57 to 68 years. All four patients had predominant lung metastasis and a relatively low burden of intra-abdominal disease. Somatic testing indicated alterations typical of PDAC and no PDAC defining pathogenic germline mutations were identified. An extended clinical course prior to LMD diagnosis was observed in all patients, ranging from 16 to 148 months. Upon diagnosis of LMD, three patients elected for supportive care and one patient received a limited course of craniospinal radiation. The median survival following diagnosis of LMD was 1.6 months (range 0.5-2.8 months).

CONCLUSIONS

LMD from PDAC is a rare occurrence that may be more frequent in patients with lung metastasis and/or a more indolent clinical course. Following diagnosis of LMD, prognosis is poor, and survival is short. New treatment strategies for this manifestation of PDAC are needed.

Leptomeningeal Carcinomatosis of a Poorly Differentiated Cervical Carcinoma Caused by Human Papillomavirus Type 18

Cervical cancer is caused by a persistent infection with high-risk types of Papillomaviruses (hrHPV); HPV16 and HPV18 are associated with about 70% of the cases. In the last decades the introduction of a cervical cancer screening has allowed a decrease in cervical cancer incidence and mortality; regular adhesion to the screening procedures, by pap test or HPV test, and colposcopy, according to the international guidelines, prevents cancer development and allows for diagnosis at the early stages. Nowadays, in industrialized countries, it is not common to diagnose this pathology in advanced stages, and this occurrence is frequently associated with patient’s unattendance of cervical screening programs. We describe a case of delayed diagnosis of cervical cancer, posed only after the onset of the neurological symptoms caused by leptomeningeal metastases, despite a two-year history of abnormal cytology. The endocervical mass was analyzed by immunohistochemistry, and search and typing of HPV sequences was performed by PCR in the meningeal carcinomatous cells. A poorly differentiated squamous cell carcinoma was diagnosed, and HPV18 sequences were detected. This rapidly fatal case highlights the importance of following the evidence-based recommended protocols and the preventive role of the population-based cervical cancer screening programs.

Detection of genes mutations in cerebrospinal fluid circulating tumor DNA from neoplastic meningitis patients using next generation sequencing

Background

This study profiled the somatic genes mutations and the copy number variations (CNVs) in cerebrospinal fluid (CSF)-circulating tumor DNA (ctDNA) from patients with neoplastic meningitis (NM).

Methods

A total of 62 CSF ctDNA samples were collected from 58 NM patients for the next generation sequencing. The data were bioinformatically analyzed by (Database for Annotation, Visualization and Integrated Discovery) DAVID software.

Results

The most common mutated gene was TP53 (54/62; 87.10%), followed by EGFR (44/62; 70.97%), PTEN (39/62; 62.90%), CDKN2A (32/62; 51.61%), APC (27/62: 43.55%), TET2 (27/62; 43.55%), GNAQ (18/62; 29.03%), NOTCH1 (17/62; 27.42%), VHL (17/62; 27.42%), FLT3 (16/62; 25.81%), PTCH1 (15/62; 24.19%), BRCA2 (13/62; 20.97%), KDR (10/62; 16.13%), KIT (9/62; 14.52%), MLH1 (9/62; 14.52%), ATM (8/62; 12.90%), CBL (8/62; 12.90%), and DNMT3A (7/62; 11.29%). The mutated genes were enriched in the PI3K-Akt signaling pathway by the KEGG pathway analysis. Furthermore, the CNVs of these genes were also identified in these 62 samples. The mutated genes in CSF samples receiving intrathecal chemotherapy and systemic therapy were enriched in the ERK1/2 signaling pathway.

Conclusions

This study identified genes mutations in all CSF ctDNA samples, indicating that these mutated genes may be acted as a kind of biomarker for diagnosis of NM, and these mutated genes may affect meningeal metastasis through PI3K-Akt signaling pathway.

Nivolumab efficacy in leptomeningeal metastasis of renal cell carcinoma: a case report

BACKGROUND

Meningeal carcinomatosis is rare in patients with kidney cancer and treatment options are limited. Few patients treated with systemic approaches have been reported. We describe a case of complete remission of leptomeningeal metastasis in a patient with renal cell carcinoma treated with nivolumab. To our knowledge, this is the first report of nivolumab safety and efficacy in this particular site of metastasis.

CASE PRESENTATION

Our patient was a 60-year-old Caucasian man with bone and lung metastases from renal cell carcinoma. He developed leptomeningeal metastasis and progression of bone and lung lesions after only 2 months of his first-line treatment. He was then treated with nivolumab in second-line setting and experienced a rapid improvement of cancer-related symptoms, complete remission of leptomeningeal and lung lesions, and increased bone mineral density in bone metastasis. The patient did not experience any drug-related toxicity.

CONCLUSIONS

Meningeal carcinomatosis metastasis from renal cancer is a rare condition. Diagnosis is often challenging: the onset of nonspecific presenting symptoms could be initially attributed to bone involvement, side effects of oncologic therapy, or paraneoplastic syndromes. Our case suggests that nivolumab could be an effective and safe treatment option in patients with pretreated renal cancer with leptomeningeal metastasis.

Leptomeningeal Carcinomatosis in a Patient with Pancreatic Cancer Responding to Nab-Paclitaxel plus Gemcitabine

Leptomeningeal carcinomatosis is an extremely rare, but devastating complication in pancreatic cancer patients with a poor prognosis despite multimodal treatment. We present a 51-year-old male patient with the very rare condition of leptomeningeal carcinomatosis originating from pancreatic cancer. He presented to our hospital with severe headache and neck stiffness 30 months after systemic chemotherapy. Cerebral and spinal MRI as well as cerebrospinal fluid examination confirmed the diagnosis of leptomeningeal carcinomatosis. The patient responded to gemcitabine plus nab-paclitaxel in terms of elimination of tumor cells from the CSF and concurrent clinical improvement for 3 months. The observed findings suggest that the combination of gemcitabine plus nab-paclitaxel is potentially effective in affected cerebrospinal fluid of pancreatic carcinoma patients.

Evaluating the cerebrospinal fluid ctDNA detection by next-generation sequencing in the diagnosis of meningeal Carcinomatosis

Background

Meningeal carcinomatosis (MC) is the most severe form of brain metastasis and causes significant morbidity and mortality. Currently, the diagnosis of MC is routinely confirmed on the basis of clinical manifestation, positive cerebrospinal fluid (CSF) cytology, and/or neuroimaging features. However, negative rate of CSF cytology and neuroimaging findings often result in a failure to diagnose MC from the patients who actually have the disease. Here we evaluate the CSF circulating tumor DNA (ctDNA) in the diagnosis of MC.

Methods

A total of 35 CSF samples were collected from 35 patients with MC for CSF cytology examination, CSF ctDNA extraction and cancer-associated gene mutations detection by next-generation sequencing (NGS) at the same time.

Results

The most frequent primary tumor in this study was lung cancer (26/35, 74%), followed by gastric cancer (2/35, 6%), breast cancer (2/35, 6%), prostatic cancer (1/35, 3%), parotid gland carcinoma (1/35, 3%) and lymphoma (1/35, 3%) while no primary tumor could be found in the remaining 2 patients in spite of using various inspection methods. Twenty-five CSF samples (25/35; 71%) were found neoplastic cells in CSF cytology examination while all of the 35 CSF samples (35/35; 100%) were revealed having detectable ctDNA in which cancer-associated gene mutations were detected. All of 35 patients with MC in the study underwent contrast-enhanced brain MRI and/or CT and 22 neuroimaging features (22/35; 63%) were consistent with MC. The sensitivity of the neuroimaging was 88% (95% confidence intervals [95% CI], 75 to 100) (p = 22/25) and 63% (95% CI, 47 to 79) (p = 22/35) compared to those of CSF cytology and CSF ctDNA, respectively. The sensitivity of the CSF cytology was 71% (95% CI, 56 to 86) (n = 25/35) compared to that of CSF ctDNA.

Conclusions

This study suggests a higher sensitivity of CSF ctDNA than those of CSF cytology and neuroimaging findings. We find cancer-associated gene mutations in ctDNA from CSF of patients with MC at 100% of our cohort, and utilizing CSF ctDNA as liquid biopsy technology based on the detection of cancer-associated gene mutations may give additional information to diagnose MC with negative CSF cytology and/or negative neuroimaging findings.

Leptomeningeal metastases arising from gynecological cancers

BACKGROUND

Most cases of leptomeningeal metastasis (LM) arise from solid tumors, such as breast cancer, lung cancer, or malignant melanoma. LM arising from gynecological cancers are extremely rare. Longer survival owing to recent advances in chemotherapy and other treatments has contributed to the increased frequency of gynecological cancers metastasizing to the central nervous system (CNS). Detailed information regarding LM is scarce; therefore, we conducted a study concerning LM arising from primary gynecological cancers.

METHODS

Among 24 patients with CNS metastases from gynecological cancer treated at our hospital between January 2011 and August 2018, those who were eventually diagnosed with LM were included in this retrospective study.

RESULTS

Among 24 patients with CNS metastases, five patients (20.8%) were diagnosed with LM. The primary cancer was endometrial in two, cervical in one, and peritoneal in two patients. Of these five patients, three developed LM as a complication 1-11 months after the treatment of brain metastases; one patient had multiple brain metastases diagnosed at the same time as LM, and one had LM alone, without accompanying brain metastases. The median survival after the diagnosis of LM was 23 (12-69) days, while the median survival of 24 patients after the initial diagnosis of CNS metastases was 106 (13-959) days.

CONCLUSION

Although LM arising from gynecological cancers is considered rare, identification of LM may be important to predict prognosis and develop new therapeutic strategies.

Breast cancer and leptomeningeal disease (LMD): hormone receptor status influences time to development of LMD and survival from LMD diagnosis

Leptomeningeal disease (LMD) occurs in 5 % of breast cancer patients. The aim of this study was to identify risk factors related to survival and time to development of LMD in breast cancer patients. A retrospective analysis of breast cancer patients with LMD, evaluated in MDACC between 1995 and 2011. 103 patients with diagnosis of breast cancer and LMD were identified (one male). The median age at LMD diagnosis was 49.2 years. 78.2 % had invasive ductal carcinoma. Hormone receptors (HRs) were positive in 55.3 % of patients, 47.4 % were human epidermal growth factor receptor 2-positive and 22.8 % were triple negative. 52 % of the patients were treated with WBRT, 19 % with spinal radiation, 36 % with systemic chemotherapy and 55 % with intrathecal chemotherapy. Estimated median overall survival from time of breast cancer diagnosis was 3.66 years. Median survival from time of LMD diagnosis was 4.2 months. Time from breast cancer diagnosis to LMD was 2.48 years. In multivariate analysis, HR status and stage at diagnosis were significantly associated with time to LMD diagnosis (p < 0.05). In triple negative patients, time to LMD was shorter. In patients who were HR positive, time to LMD was longer. Survival from LMD diagnosis was significantly associated with both treatment, as well as positive HR status (multivariate analysis p < 0.05). In conclusion LMD has dismal prognosis in breast cancer patients. HR status contributes to time to LMD diagnosis and survival from LMD diagnosis. The impact of treatment aimed at LMD cannot be ascertained in our retrospective study due to the inherent bias associated with the decision to treat.

Meningeal carcinomatosis in solid tumors

The involvement of the leptomeninges by metastatic tumors can be observed in solid tumors, in which case it is termed meningeal carcinomatosis (MC), and in lymphoproliferative malignant disease. It is more common in breast and lung cancer, as well as melanoma, with adenocarcinoma being the most frequent histological type. MC is usually a late event, with disseminated and progressive disease already present and, it is characterized by multifocal neurological signs and symptoms. Diagnosis is based on the evaluation of clinical presentation, cerebrospinal fluid and neuroimaging studies. The better systemic disease control is observed with new therapeutic agents, and the development of neuroimaging methods is responsible for the increasing incidence of such metastatic evolution. Intrathecal chemotherapy is generally the treatment of choice, although frequently palliative. Prognosis is guarded, although a higher performance status may indicate a subgroup of patients with a more favorable outcome.

Neoplastic meningitis resulting from hematological malignancies: pharmacokinetic considerations and maximizing outcome

Neoplastic meningitis, also known as leptomeningeal metastases, is a complication of various types of cancer that occurs when tumor cells enter the cerebrospinal fluid (CSF), travel along CSF pathways and grow. Treatment options include drug delivery directly into the CNS or systemic administration for targeted action in the CNS. CNS drug delivery is limited by the blood-brain barrier and the blood-CSF barrier. It may be possible to partially overcome this by using high-dose systemic therapy; however, this is done at the possible expense of increased systemic toxicity. Intra-CSF drug delivery bypasses the blood-brain barrier and allows direct access of the chemotherapeutic agent to the CSF. Because neoplastic meningitis occurs in an increasingly large percentage of all cancer patients, it is imperative to optimize drug delivery to the CSF and meninges. Both the pharmacokinetic profile of the chemotherapeutic agent and the site of administration influence therapeutic efficacy. Achieving prolonged therapeutic cytotoxic drug concentrations and even distribution in the CSF will improve efficacy. In this article we summarize data on the efficacy, safety and outcome of high-dose systemic and intra-CSF treatments.

Novel approaches to treating leptomeningeal metastases

Leptomeningeal metastasis is a devastating complication of the central nervous system in patients with late-stage solid or hematological cancers. Leptomeningeal metastasis results from the multifocal seeding of the leptomeninges by malignant cancer cells. Although central nervous system metastasis usually presents in patients with widely disseminated and progressive late-stage cancer, malignant cells may spread to the cerebrospinal fluid during earlier disease stages in particularly aggressive cancers. Treatment of leptomeningeal metastasis is largely palliative but will often provide stabilization and protection from further neurological deterioration and improve quality of life. There is a need to raise awareness of the impact of leptomeningeal metastases on cancer patients and its known and putative biological basis. Novel diagnostic approaches include identification of biomarkers that may stratify the risk for developing leptomeningeal metastasis. Current therapies can be used more effectively while waiting for advanced treatments to be developed.

Tuberculous meningitis

Tuberculous meningitis is a severe form of extrapulmonary tuberculosis. The exact incidence and prevalence are not known. In countries with high burden of pulmonary tuberculosis, the incidence is expected to be proportionately high. Children are much more vulnerable. Human immunodeficiency virus-infected patients have a high incidence of tuberculous meningitis. The hallmark pathological processes are meningeal inflammation, basal exudates, vasculitis and hydrocephalus. Headache, vomiting, meningeal signs, focal deficits, vision loss, cranial nerve palsies and raised intracranial pressure are dominant clinical features. Diagnosis is based on the characteristic clinical picture, neuroimaging abnormalities and cerebrospinal fluid changes (increased protein, low glucose and mononuclear cell pleocytosis). Cerebrospinal fluid smear examination, mycobacterial culture or polymerase chain reaction is mandatory for bacteriological confirmation. The mortality and morbidity of tuberculous meningitis are exceptionally high. Prompt diagnosis and early treatment are crucial. Decision to start antituberculous treatment is often empirical. WHO guidelines recommend a 6 months course of antituberculous treatment; however, other guidelines recommend a prolonged treatment extended to 9 or 12 months. Corticosteroids reduce the number of deaths. Resistance to antituberculous drugs is associated with a high mortality. Patients with hydrocephalus may need ventriculo-peritoneal shunting. Bacillus Calmette-Guérin vaccination protects to some degree against tuberculous meningitis in children.

Biology and therapy of neoplastic meningitis

Neoplastic meningitis (NM) occurs in 5% to 8% of cancer patients, commonly as an end-stage process in previously metastatic disease. As newer therapeutics extend patient survival by maintaining long-term control of systemic malignancies, the incidence of NM is likely to rise. This can be expected both because of a change in the natural history of the underlying disease and the generally poor penetrance of many newer anticancer drugs into the central nervous system, thereby creating a sanctuary site for malignant cells. Currently available treatments have provided limited benefit in overall survival in NM, although long-term survival does occur. Because of the morbidity occasionally associated with treatment, prognostic indicators are being analyzed to identify patients who may benefit from systemic and/or intrathecal therapy before making the decision to initiate treatment. Additionally, because of the relative insensitivity of traditional cerebrospinal fluid analysis, new markers of NM are being investigated. This endeavor is being aided by ongoing research into the underlying biology of the metastatic process.