Leukemic and lymphomatous meningitis: incidence, prognosis and treatment

Cauda equina thickening: an approach to MRI findings

There are many causes of cauda equina (CE) thickening on neuroimaging of the lumbar spine. The imaging features of CE thickening for the various conditions often overlap and are non-specific to clinch a definite diagnosis. Hence, the imaging findings have to be discerned in accordance with the patient's presenting history, clinical examination findings, and results from electrophysiology and laboratory studies. In this review, the authors aim to supplement the existing literature on imaging findings of CE thickening with a diagnostic framework for clinical workup. The authors also aim to familiarise readers with the interpretation of CE thickening on magnetic resonance imaging (MRI) and would like to illustrate the normal variants and pitfalls that could be mistaken for abnormal results.

A narrative review of central nervous system involvement in acute leukemias

Acute leukemias (both myeloid and lymphoblastic) are a group of diseases for which each year more successful therapies are implemented. However, in a subset of cases the overall survival (OS) is still exceptionally low due to the infiltration of leukemic cells in the central nervous system (CNS) and the subsequent formation of brain tumors. The CNS involvement is more common in acute lymphocytic leukemia (ALL), than in adult acute myeloid leukemia (AML), although the rates for the second case might be underestimated. The main reasons for CNS invasion are related to the expression of specific adhesion molecules (VLA-4, ICAM-1, VCAM, L-selectin, PECAM-1, CD18, LFA-1, CD58, CD44, CXCL12) by a subpopulation of leukemic cells, called “sticky cells” which have the ability to interact and adhere to endothelial cells. Moreover, the microenvironment becomes hypoxic and together with secretion of VEGF-A by ALL or AML cells the permeability of vasculature in the bone marrow increases, coupled with the disruption of blood brain barrier. There is a single subpopulation of leukemia cells, called leukemia stem cells (LSCs) that is able to resist in the new microenvironment due to its high adaptability. The LCSs enter into the arachnoid, migrate, and intensively proliferate in cerebrospinal fluid (CSF) and consequently infiltrate perivascular spaces and brain parenchyma. Moreover, the CNS is an immune privileged site that also protects leukemic cells from chemotherapy. CD56/NCAM is the most important surface molecule often overexpressed by leukemic stem cells that offers them the ability to infiltrate in the CNS. Although asymptomatic or with unspecific symptoms, CNS leukemia should be assessed in both AML/ALL patients, through a combination of flow cytometry and cytological analysis of CSF. Intrathecal therapy (ITT) is a preventive measure for CNS involvement in AML and ALL, still much research is needed in finding the appropriate target that would dramatically lower CNS involvement in acute leukemia.

Neoplastic meningitis due to colorectal cancer

Herein, we describe a rare case of neoplastic meningitis in a 54-year-old male with a history of colorectal cancer. He first noticed a loss of sensation in his left thigh along with back pain. Magnetic resonance imaging showed a tumor lesion in the cauda equina. The tumor was surgically resected and pathologically diagnosed as a metastatic tumor of the descending colon cancer for which he had undergone resection a year earlier. The patient was treated with chemotherapy using capecitabine, oxaliplatin, and cetuximab. During chemotherapy, his tumor markers decreased and magnetic resonance imaging showed tumor shrinkage, but he became aware of neurological symptoms such as hearing loss, tinnitus, and headache. The patient's condition suddenly worsened during the 5th course of chemotherapy and he died 5 months after the diagnosis. Neoplastic meningitis occurs in 4-15% of patients with solid tumors, but it is rarely seen in colorectal cancer. It should be considered when a patient with a history of cancer has back pain or neurological symptoms. The progression of neoplastic meningitis is fast and it has a poor prognosis. Diagnosis in the early stages is important to prevent progression of neurological symptoms and to provide the most effective treatment.

[Central nervous system lymphoma revealed by lymphocytic meningitis in a patient with systemic lupus erythematosus: An unusual association]

INTRODUCTION

We report an unusual observation of central nervous system (CNS) lymphoma in a 60-year-old woman with systemic lupus erythematosus and fatal outcome.

OBSERVATION

The patient had systemic erythematosus lupus for 7 years, treated with mycophenolate mofetil and developed lymphocytic meningitis in 2015 associated to the presence of EBV in the cerebrospinal fluid and a necrotic vermis' lesion. Diagnosis of large B-cell lymphoma was histologically confirmed from stereotaxic biopsy, shortly before she died from neurological complications.

CONCLUSION

Even though the current association is unusual, lymphocytic meningitis with hypoglycorrachia in patients with systemic lupus erythematosus may reveal CNS lymphoma and diagnosis confirmation requires stereotaxic biopsy in order not to delay specific therapeutic management.

Central nervous system involvement in adult acute lymphoblastic leukemia: diagnostic tools, prophylaxis, and therapy

In adult patients with acute lymphoblastic leukemia (ALL), Central Nervous System (CNS) involvement is associated with a very poor prognosis. The diagnostic assessment of this condition relies on the use of neuroradiology, conventional cytology (CC) and flow cytometry (FCM). Among these approaches, which is the gold standard it is still a matter of debate. Neuroradiology and CC have a limited sensitivity with a higher rate of false negative results. FCM demonstrated a superior sensitivity over CC, particularly when low levels of CNS infiltrating cells are present. Although prospective studies of a large series of patients are still awaited, a positive finding by FCM appears to anticipate an adverse outcome even if CC shows no infiltration. Current strategies for adult ALL CNS-directed prophylaxis or therapy involve systemic and intrathecal chemotherapy and radiation therapy. An early and frequent intrathecal injection of cytostatic combined with systemic chemotherapy is the most effective strategy to reduce the frequency of CNS involvement. In patients with CNS overt ALL, at diagnosis or upon relapse, allogeneic hematopoietic stem cell transplantation might be considered. This review discusses risk factors, diagnostic techniques for identification of CNS infiltration and modalities of prophylaxis and therapy to manage it.

Neurologic aspects of lymphoma and leukemias

The lymphomas and leukemias are a heterogenous group of hematologic malignancies with protean manifestations. Neurologic sequelae of the diseases have been recognized since the time the conditions were first described in the mid-1800s. Although our understanding of the various presentations of these blood disorders evolved along with our knowledge of malignancies, accurate diagnosis can still be difficult. It is critical for neurologists to have a high index of clinical suspicion to appropriately recognize their heralding features. This review's focus is the relevant clinical neurologic features and diagnostic studies that identify leukemias and lymphomas affecting the nervous system.

Central nervous system infections in cancer patients and hematopoietic stem cell transplant recipients

Central nervous system (CNS) infections in cancer patients present a diagnostic and therapeutic challenge for clinicians. While CNS infections are not frequent complications of cancer, its therapies, or hematopoietic stem cell transplantation, the importance of CNS infections lies in their propensity to result in profound morbidity and substantial mortality in this vulnerable patient population. With an expanding population of patients with malignant disease undergoing more potent and aggressive therapies and with the advent of newer immunomodulatory agents, the incidence of CNS infectious complications is likely to rise. This chapter will summarize the clinical and diagnostic evaluation of potential infections of the CNS in these patients and will discuss particular pathogens of interest with regard to this at-risk patient population.

Utility of Flow Cytometry of Cerebrospinal Fluid as a Screening Tool in the Diagnosis of Central Nervous System Lymphoma

Context.—Experiences at our institution show that flow cytometry analysis (FCA) has become routine clinical practice in the workup of patients with altered mental status, even if risk factors are low.

Objective.—To assess diagnostic accuracy of combined FCA and cytology in the diagnosis of central nervous system lymphoma in an unselected patient population with neurologic symptoms, including patients with no history of lymphoma or suspicious radiology.

Design.—Between 2001 and 2011, cerebrospinal fluid was submitted from 373 patients for lymphoma screening by FCA. The medical records were reviewed for patient symptomatology, history of malignancy, brain imaging, FCA results, cytology results, brain biopsy, and clinical follow-up.

Results.—A lymphoid malignancy was detected by FCA in 4% of cases. A positive diagnosis was more likely in patients with either a history of hematologic malignancy and/or a suspicious radiology result (P = .009). All patients with no history of lymphoma and no suspicious radiology (n = 102) had negative cytology, and none had a correspondingly positive FCA result. The positive and negative predictive values of combined cytology and FCA in the patients with history of lymphoma and/or abnormal imaging results were 92% and 89%, respectively, when compared with open brain tissue biopsy, and 89% and 86%, respectively, when compared with clinical follow-up. When low-risk patients were included, the positive predictive value remained at 92%, but the negative predictive value dropped to 52% with the open brain biopsy as the reference, and values did not change significantly for the group with clinical follow-up.

Conclusions.—Concurrent FCA and cytology are most useful in the appropriate clinical setting, and we propose a triage algorithm for how FCA on cerebrospinal fluid is best used.

Flow cytometric detection of liposomal cytarabine in cerebrospinal fluid of patients treated with intrathecal chemotherapy

We report the unusual flow cytometric detection of liposomes in the cerebrospinal fluid of patients with aggressive non-Hodgkin's lymphoma and acute myeloid leukemia, treated with intrathecal liposomal cytarabine.

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.

B-cell lymphoma infiltration of cerebrospinal fluid with minimal symptoms and benign course

We report a patient diagnosed with a B-cell lymphoma after detecting monoclonal B-cells in the cerebrospinal fluid (CSF) and who had only minimal symptoms and a benign course. A 46-year-old man experienced three transitory episodes with neurological symptoms. On examination papilledema in both eyes was found. Flow cytometry (FACS)-analysis detected monoclonal B-cells in the CSF as well as in the peripheral blood and the bone marrow. Results were consistent with a low-risk lymphoma, most probably a marginal zone B-cell lymphoma. Interestingly, our patient had no progressive clinical symptoms and remained without specific therapy during 36 months of follow-up. Nevertheless, CSF-analysis led to the diagnosis of the B-cell lymphoma.

Use of magnetic resonance imaging to detect neoplastic meningitis: limited use in leukemia and lymphoma but convincing results in solid tumors

BACKGROUND

An early diagnosis of meningitis is important to improve patients' survival. Data about a direct comparison of cerebrospinal fluid cytology (CSF-cytology) and MRI are very limited. Therefore, the aim of this study was to compare these two diagnostic modalities in diagnosing meningitis in patients with hematopoietic and solid malignancies.

METHODS

In 68 patients suspicious for neoplastic meningitis, cytology and MRI (1.5 T) was performed. The meningeal, pial or intraparenchymal hyperintense signal or contrast enhancement was correlated to the final CNS diagnosis and to cytology.

RESULTS

44 patients (64.7%) had neoplastic meningitis, 21 patients (30.9%) had non-neoplastic meningitis. The sensitivity to diagnose meningeal disease was 49.2% for MRI and 95.4% for cytology (p<0.001). In patients with neoplastic meningitis, sensitivity was 45.5% for MRI and 93.2% for cytology (p<0.001). In patients with infectious meningitis, sensitivity was 57.1% for MRI and 100% for cytology (p=0.0013). In patients with solid tumors, the sensitivity was 84.6% for both diagnostic methods. The sensitivity for MRI was low in patients with leukemia (20.0%) and lymphoma (37.5%). The positive predictive value (PPV) for MRI to differentiate infectious from neoplastic meningitis was high in patients with infectious meningitis (75.0%), in patients with lymphoma (83.3%), and in patients with solid tumors (72.7%). Ppv was low in patients with leukemia (33.3%).

CONCLUSION

Diagnostic value of MRI for diagnosing meningitis is especially limited in patients with hematopoietic malignancies. MRI better detected leptomeningeal involvement caused by solid tumors than by leukemia or lymphoma. The ppv to specify neoplastic meningitis depends on tumor subtype.

Neurologic aspects of lymphoma and leukemias

The leukemias and lymphomas represent a heterogenous group of hematologic malignancies with protean manifestations. Neurologic sequelae of the diseases have been recognized almost since the time the conditions were first described in the mid-1800s. Although our understanding of the various presentations of these blood disorders has evolved along with our knowledge of the malignancies, accurate diagnosis can still be difficult. It is critical for neurologists to have a high index of clinical suspicion to appropriately recognize the heralding features. This review focuses on the relevant clinical neurologic features and diagnostic studies to identify leukemias and lymphomas affecting the nervous system.

Cerebrospinal fluid pleocytosis: pitfalls and benefits of combined analysis using cytomorphology and flow cytometry

BACKGROUND

Cerebrospinal fluid samples with doubtful morphologic interpretation are a common problem in the workup of patients with clinical signs for leptomeningeal disease. The authors report on the combination of morphology and flow cytometry in the diagnosis of leptomeningeal disease in patients with radiological, clinical, or cytological findings suspicious for leukemia or lymphoma with spread into the cerebrospinal fluid.

METHODS

The authors defined a set of antibodies for flow cytometric analysis, which is capable of distinguishing between malignant and nonmalignant hematopoietic cells. One hundred twenty-seven cases were analyzed with both methods.

RESULTS

The additional application of flow cytometry resulted in an improvement of diagnostic reliability in 29 of 127 cases. Diagnostic sensitivity was raised from 73% (cytology) to 96% (flow cytometry), specificity from 94% to 97%, the positive predictive value from 88% to 96%, and the negative predictive value from 76% to 97%.

CONCLUSIONS

Because the appropriate selection of markers is crucial to successful analysis, the authors suggested a highly selected panel of antibodies for flow cytometry analysis of cerebrospinal fluid samples. The authors were able to demonstrate that leptomeningeal disease caused by leukemia or lymphoma can be diagnosed by flow cytometry and discriminated from reactive pleocytosis in most cases of doubtful morphology.

Neurologic complications of intrathecal liposomal cytarabine administered prophylactically to patients with non-Hodgkin lymphoma

Central nervous system (CNS) prophylaxis is required during initial treatment of non-Hodgkin lymphoma (NHL) subtypes that carry a high risk of CNS involvement. Intrathecal (IT) liposomal cytarabine, a formulation with prolonged half-life, has been shown to be safe and effective in the treatment of meningeal disease in patients with high-grade lymphoma. We retrospectively reviewed all adult patients with high-grade NHL that received prophylactic therapy with IT liposomal cytarabine and developed neurologic complications in our institution between April 2007 and May 2009. We recorded information on hospital admission, chemotherapy regimens, clinical features, neuroimaging, cerebrospinal fluid, neurophysiology data, and outcome. Neurotoxicity was graded according to the National Cancer Institute Common Toxicity Criteria (NCI-CTC). Four of fourteen patients (28%) developed moderate or severe neurotoxicity (grades 2 and 3 of the NCI-CTC), manifested as conus medullaris/cauda equine syndrome or pseudotumour cerebri-like syndrome, after a median of 3.5 IT courses of liposomal cytarabine. All patients had received corticosteroids to prevent arachnoiditis. Liposomal cytarabine given via the IT route, even with concomitant corticosteroid administration, can result in significant neurotoxicity in some patients. We discuss the potential pathogenesis of these effects and suggest hypothetical therapeutic measures to prevent these complications. Specialists should be aware of these possible complications when administering prophylactic IT liposomal cytarabine in high-grade NHL patients, and additional prospective studies should be conducted to more clearly delineate the frequency and characteristics of these complications.

Central nervous system prophylaxis in adults with acute lymphoblastic leukemia: current and emerging therapies

Central nervous system (CNS) recurrence continues to be a significant complication in the treatment of adult patients with acute lymphoblastic leukemia (ALL). Preventing CNS recurrence has been a therapeutic challenge and has not been addressed critically in many clinical trials. Adult studies modeled on childhood ALL studies have used multiple treatment modalities, including radiation therapy, systemic therapy, intrathecal therapy, and combinations thereof. Cranial irradiation is effective but is offset by substantial toxicity, including neurologic sequelae. Systemic chemotherapy, especially with cytarabine (AraC) and methotrexate, has demonstrated promise in decreasing CNS recurrence, but therapeutic levels of drugs in the cerebrospinal fluid (CSF) are not maintained. Intrathecal chemotherapy with or without high-dose systemic therapy is the most common approach to CNS prophylaxis. Liposomal AraC recently has become available and confers prolonged levels of free AraC in the CSF, a critical requirement for CNS prophylactic therapy. This review discusses the various modalities used for CNS prophylaxis in patients with ALL and the emerging trends, with specific emphasis on the outcome in terms of event-free survival and toxicity.

Primary central nervous system Burkitt lymphoma as concomitant lesions in the third and the left ventricles: a case study and literature review

This study reports the case of a 75-year-old woman with intermittent speech disturbance, headache, and general malaise. Brain magnetic resonance imaging showed a double lesion located in the third ventricle and temporal horn of the lateral ventricle. We completely removed the lesion in the third ventricle, adhering to the septum pellucidum. The histopathological diagnosis was Burkitt lymphoma, which was confirmed to be primary in postoperative investigation. To our knowledge, this is the first case of primary Burkitt lymphoma involving cerebral ventricles. Finally, we reviewed the characteristics of primary central nervous system Burkitt lymphoma.

Treatment modalities for leptomeningeal metastases

Secondary involvement of the leptomeninges represents an infrequent but devastating (and nearly always fatal) complication of solid tumors, hematologic malignancies (both leukemia and lymphoma), and primary brain tumors. Clinical suspicion of neoplastic meningitis (NM) may be raised by the appearance of multivariate neurological symptoms; however, a definitive diagnosis is often difficult to obtain. Improved treatments for primary malignancies and advances in diagnostic imaging technology have led to an apparent increase in the number of patients diagnosed with NM. Unfortunately, therapeutic options remain limited, particularly for patients with chemoresistant tumors. Optimized treatment remains controversial and may rely upon a combination of chemotherapy (intrathecal and/or intravenous) and concurrent focal radiotherapy. This review discusses the advantages and disadvantages of intra-cerebrospinal fluid (CSF) versus systemic strategies for treating NM. Clinical trial evidence is presented for the different treatment modalities. In addition, the therapeutic potential of intra-CSF therapy for cancer prophylaxis is discussed. Earlier diagnosis and more aggressive preventive treatment regimens may provide substantial increases in survival and favorably affect quality of life. Additional data from large-scale, well-controlled trials are required to more accurately assess the efficacy of intra-CSF versus systemic treatment in NM. Future treatment options using novel targets for intra-CSF therapy will be addressed as well.

Aseptic meningitis and viral myelitis

Meningitis and myelitis represent common and very infrequent viral infections of the central nervous system, respectively. The number of cases of viral meningitis that occurs annually exceeds the total number of meningitis cases caused by all other etiologies combined. Focal central nervous system infections, such as occur in the spinal cord with viral myelitis, are much less common and may be confused with noninfectious disorders that cause acute flaccid paralysis. This article reviews some of the important clinical features, epidemiology, diagnostic approaches, and management strategies for patients with aseptic meningitis and viral myelitis. Particular focus is placed on the diseases caused by enteroviruses, which as a group account for most aseptic meningitis cases and many focal infections of the spinal cord.

High interleukin-15 expression characterizes childhood acute lymphoblastic leukemia with involvement of the CNS

PURPOSE

Applying current diagnostic methods, overt CNS involvement is a rare event in childhood acute lymphoblastic leukemia (ALL). In contrast, CNS-directed therapy is essential for all patients with ALL because without it, the majority of patients eventually will experience relapse. To approach this discrepancy and to explore potential distinct biologic properties of leukemic cells that migrate into the CNS, we compared gene expression profiles of childhood ALL patients with initial CNS involvement with the profiles of CNS-negative patients.

PATIENTS AND METHODS

We evaluated leukemic gene expression profiles from the bone marrow of 17 CNS-positive patients and 26 CNS-negative patients who were frequency matched for risk factors associated with CNS involvement. Results were confirmed by real-time quantitative polymerase chain reaction analysis and validated using independent patient samples.

RESULTS

Interleukin-15 (IL-15) expression was consistently upregulated in leukemic cells of CNS-positive patients compared with CNS-negative patients. In multivariate analysis, IL-15 expression levels greater than the median were associated with CNS involvement compared with expression equal to or less than the median (odds ratio [OR] = 10.70; 95% CI, 2.95 to 38.81). Diagnostic likelihood ratios for CNS positivity were 0.09 (95% CI, 0.01 to 0.65) for the first and 6.93 (95% CI, 2.55 to 18.83) for the fourth IL-15 expression quartiles. In patients who were CNS negative at diagnosis, IL-15 levels greater than the median were associated with subsequent CNS relapse compared with expression equal to or less than the median (OR = 13.80; 95% CI, 3.38 to 56.31).

CONCLUSION

Quantification of leukemic IL-15 expression at diagnosis predicts CNS status and could be a new tool to further tailor CNS-directed therapy in childhood ALL.

Assessment of free light chains in the cerebrospinal fluid of patients with lymphomatous meningitis - a pilot study

BACKGROUND

Lymphomatous meningitis (LM) represents a severe complication of malignant lymphomas. While clinical suspicion is raised by symptoms ranging from mild disturbances of sensation to severe pain or impaired consciousness, the definite diagnosis of LM is often difficult to obtain. Since B-cell lymphomas are clonally restricted to express either kappa or lambda immunoglobulin light chain, we hypothesised that analysis of free light chain (FLC) ratios might facilitate the diagnosis of LM.

METHODS

Kappa and lambda FLC were measured using a novel nephelometric assay in cerebrospinal fluid (CSF) and serum from 17 patients. 5/17 suffered from LM as demonstrated by cytology, immunocytology, and/or imaging procedures.

RESULTS

Measurement of FLC concentrations in CSF was achieved for all 17 patients. FLC levels in CSF were lower than serum FLC levels in samples for the same patient obtained at the same time (p < 0.01). CSF and serum FLC concentrations correlated weakly in all patients irrespective of LM status. Significantly more patients with cytopathologically and immunohistochemically proven LM displayed abnormal kappa/lambda FLC ratios in CSF compared to individuals with no LM (p < 0.01).

CONCLUSION

This is the first report demonstrating that a significant proportion of LM patients display an abnormal kappa/lambda FLC ratio in the CSF.

Chemotherapy and cerebral metastases: misperception or reality?

Cerebral metastases remain a common complication among patients with cancer. Surgery and radiotherapy remain the principal therapeutic interventions. In contrast, the benefit of chemotherapy has long been viewed with skepticism. Nonetheless, as survival in cancer patients improves and the incidence of cerebral metastases increases, so does the demand for effective therapies. It is now recognized that the blood-brain barrier within metastases is permeable and thus allows entry of otherwise excluded drugs. Limited data have suggested that cerebral metastases have modest sensitivity to chemotherapy. Furthermore, novel agents and delivery strategies have been developed to facilitate central nervous system penetration. Nonetheless, data are limited by methodological flaws, including heterogeneous inclusion criteria, small sample sizes, lack of randomization, and inconsistencies in defined end points and response assessment criteria. Well-designed clinical trials are needed to address the effect of chemotherapy. Acceptable control arms must be established to measure the effect of chemotherapies. Standardized response criteria and disease-specific studies are essential.

Peripheral nervous system involvement in patients with cancer

Involvement of the peripheral nervous system (PNS) is common in patients with cancer and any part, including motor neurons, sensory ganglia, nerve roots, plexuses, cranial and peripheral nerves, and neuromuscular junctions, can be affected. Different mechanisms can initiate damage associated with cancer-related PNS disorders. These include tumour infiltration, toxicity of treatments, metabolic and nutritional perturbations, cachexia, virus infections, and paraneoplastic neurological syndromes. The type of cancer, lymphoma, or solid tumour is a further determinant of a PNS disorder. In this Review we discuss the different causes and mechanisms of disorders of the PNS in patients with cancer and we will focus on their assessment and diagnosis.

Neurologic Complications of Lymphoma and Leukemia

Lymphoma and leukemia are systemic diseases that affect many end-organs, including the central nervous system. These cancers may directly affect the central or peripheral nervous systems by the production of intraparenchymal or extra-axial mass lesions or by meningeal infiltration. Vascular occlusion may occur as a result of blockage of blood vessels by tumor cells. A variety of paraneoplastic syndromes occur and are most commonly associated with plasma cell tumors. Coagulopathy and metabolic disturbances are direct and indirect effects of these cancers and also are associated with their treatment, resulting in disturbances of consciousness, intracranial hemorrhage, or ischemic stroke. The agents used in the treatment of lymphoma and leukemia are also associated with neurological toxicity. This chapter reviews these neurological manifestations of lymphoma and leukemia and their therapies.