Lymphomatous meningitis in primary central nervous system lymphoma

Lymphomatous meningitis (LM) due to primary central nervous system (CNS) lymphoma is an uncommon problem in neurooncology and can occur at time of diagnosis or recurrence. Notwithstanding frequent focal signs and symptoms, LM is a disease affecting the entire neuraxis, and therefore staging and treatment need to encompass all cerebrospinal fluid (CSF) compartments. Central nervous system staging of LM includes contrast agent-enhanced cranial computed tomography (CT) or Gd-enhanced magnetic resonance (MR) imaging, Gd-enhanced spinal MR imaging, CT myelography, and radionuclide CSF flow study. Treatment of LM includes involved-field radiotherapy of bulky or symptomatic disease sites and intra-CSF drug therapy. The inclusion of concomitant systemic therapy can benefit patients with LM and can obviate the need for intra-CSF chemotherapy. At present, intra-CSF drug therapy is confined to three chemotherapeutic agents (methotrexate, cytosine arabinoside, and thiotepa) administered by a variety of schedules either by intralumbar or intraventricular drug delivery. Although treatment of LM is palliative and the expected median survival of patients is 4 to 6 months, it often provides stabilization and protection from further neurological deterioration. In patients with primary CNS lymphoma, CNS prophylaxis has been recommended (using a combination of high-dose systemic chemotherapy and intra-CSF chemotherapy), but the strategy remains controversial because high-dose systemic methotrexate is commonly used as an adjuvant therapy. Patients with primary CNS lymphoma at high risk as defined by positive CSF cytology or neuroradiography consistent with LM may benefit from the inclusion of intra-CSF chemotherapy.