Approximately 10% of patients with malignant lymphoma will show neurological symptoms at some time during the course of their illness. In non-Hodgkin lymphoma, CNS involvement is more frequent than in Hodgkin's disease. Diffuse histiocytic and poorly differentiated lymphomas, bone marrow involvement, advanced tumor stage and hematogenous spread are particular risk factors. Invasion of the spinal canal is the most common type of CNS involvement. Intracranial lesions, which are comparatively rare, may present as intracerebral metastases, epi- or subdural masses or focal or diffuse leptomeningeal disease. Lymphomatous leptomeningitis usually cannot be demonstrated by CT. On the other hand, dural and cerebral parenchymal lesions are sometimes highly characteristic of lymphoma as a result of their features and location.