Most primary central nervous system lymphomas (PCNSL) are highly malignant B-cell non-Hodgkin lymphomas. First-line therapy consists of high-dose methotrexate-based chemotherapy with or without whole brain radiotherapy. However, no standard of care is defined for refractory or recurrent PCNSL. We report a patient with lymphomatous meningitis, which was refractory to standard treatment but was successfully controlled for more than 6 years with intraventricular rituximab. Apart from two infections of the Ommaya reservoir, no severe side effects of intraventricular long-term treatment could be detected. This report indicates that intraventricular administration of rituximab might be beneficial in select patients with refractory or recurrent lymphomatous meningitis.