Lymphomatous Meningitis in Primary Central Nervous System Lymphoma

Marc C. Chamberlain, M.D.


Neurosurg Focus. 2006;21(5) 

In This Article

Incidence of LM

Because the definition of LM and the methods of assessment differ from study to study, defining its incidence in newly diagnosed patients with primary CNS lymphoma is problematic. The authors of the majority of studies have defined LM by a positive CSF cytopathology, which is the traditional method of assessment. The authors of other studies, however, have reported incidences based on CSF flow cytometry, polymerase chain reaction, neuroimaging, or autopsy results as alternative methods of assessment. Another issue that likely affects the variability in incidence encountered between studies is the timing of surgery, volume of the lesion, site of sampling (ventricular or lumbar region), and frequency of CSF assessment. Cerebrospinal fluid sampling and yield of CSF cytology may, in addition, be affected by treatment, and the authors of most studies have not elaborated on how or when CSF sampling is performed.

In studies in which investigators define LM as a positive CSF cytopathological finding, the results are similar.[3,29] Balmaceda and colleagues[3] each reported a prevalence of 27%, whereas other investigators, including Ferreri and colleagues[29] who reported on a larger series of patients, noted a prevalence of LM of 12 to 16%. When other methods of assessment, such as biopsy sampling and MR imaging, are integrated with CSF cytopathological examination, the reported prevalence increases, and in one study of patients with newly diagnosed primary CNS lymphomas it was 42%. The authors of other studies using different modalities, including polymerase chain reaction for a component of immunoglobulin G heavy chain or contrast agent-enhanced brain and spinal imaging alone, have reported lower prevalence values for LM: 13 and 12.5%, respectively.[41,47] Thus, on the basis of published reports the frequency of LM ranges from 12.5 to 42% in patients with newly diagnosed primary CNS lymphomas.

Isolated leptomeningeal relapse is uncommon in patients with primary CNS lymphomas; however, simultaneous disease in the brain and leptomeninges has been reported in up to 40% of patients with primary CNS lymphoma at the time of relapse.[3,5,53]

In summary, LM is sufficiently common that leptomeningeal-directed therapy is indicated as part of the treatment regimen in patients with newly diagnosed primary CNS lymphomas. Leptomeningeal-directed therapy takes several forms: intra-CSF chemotherapy, radiotherapy, or high-dose systemic chemotherapy that in addition treats the leptomeningeal compartment (for example, high-dose intravenous methotrexate).[36]


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