Metastatic CNS lymphoma usually manifests as pachymeningeal or leptomeningeal infiltrates, and periventricular dissemination is rare. A 70-year old man first noticed a mass in the left supraclavicular fossa, and then presented with bilateral parkinsonism, followed by consciousness disturbance. Fluid attenuated inversion recovery (FLAIR) image of brain MRI demonstrated hyperintensities at the parenchyma around the lateral ventricle, third ventricle, and fourth ventricle. Gadolinium-enhanced T1-weighted image demonstrated enhancement along the whole wall of the ventricle. Biopsy of the left supraclavicular lymph nodes established a diagnosis of diffuse large B-cell lymphoma. The patient died of multiple organ failure about 5 months after the onset. Autopsy disclosed periventricular dissemination of lymphoma cells that was most severe around the lateral ventricle. We considered that the lymphoma cells entered the ventricular system through the choroid plexus of the lateral ventricle, followed by dissemination of the periventricular parenchyma.