Primary cauda equina lymphoma treated with high-dose methotrexate.

A 69-year-old man presented with a very rare case of primary central nervous system lymphoma originating in the cauda equina manifesting as progressive paraparesis. The patient underwent a biopsy, and was treated with intravenous high-dose (3.5 g/m(2)) methotrexate chemotherapy and local irradiation. Histological study revealed large B cell type lymphoma. Follow-up magnetic resonance imaging showed complete remission of the lesion, but the patient died of pneumonia at 18 months after the initial onset without tumor recurrence, so the efficacy of this strategy remains unknown.