We report two cases of intravascular malignant lymphomatosis (IML) with a clinical expression limited to the central nervous system. The first patient presented with signs of cerebral, cerebellar and spinal cord involvement. The second had an isolated involvement of the spinal cord. In both cases the diagnosis was made at post-mortem examination; pre-mortem examination of biopsy tissue from peripheral nerve and muscle in the first case, spleen and liver in the second were unhelpful for the diagnosis of lymphoma. We review the published literature on IML, its ante-mortem diagnosis and treatment.