There is an increasing incidence of primary central nervous system (CNS) non-Hodgkin's lymphoma (NHL) in immunocompromised and immunocompetent patients. The lymphoma commonly abuts a ventricular or meningeal surface and enhances homogeneously after injection of intravenous contrast medium. The radiological features of 39 patients with cerebral lymphoma were reviewed and five patients with less commonly observed manifestations of this disorder are presented. A differential diagnosis of lateral and third ventricular masses is given.