Abstract
Methotrexate-related lymphoproliferative disorder is a rare but serious complication of methotrexate treatment. Recurrent methotrexate-related lymphoproliferative disorder in the central nervous system is uncommon. An 86-year-old woman, who had been on methotrexate for 3 years to treat rheumatoid arthritis, was admitted with left hemiplegia and sensory disturbance. Brain magnetic resonance imaging revealed a right basal ganglia lesion that was hyperintense on diffusion-weighted imaging and showed patchy enhancement. Methotrexate-related lymphoproliferative disorder was suspected, and methotrexate was discontinued, which led to improvement in her symptoms and partial remission. Twenty-eight months after methotrexate cessation, the patient presented with reduced activity and left hemiparesis. Brain magnetic resonance imaging showed homogeneously enhancing lesions in the right frontal lobe, basal ganglia, and brainstem. A craniotomy for biopsy of the right frontal lobe lesion confirmed the diagnosis of methotrexate-related lymphoproliferative disorder. Whole-brain radiation (40 Gy in 20 fractions) was administered without chemotherapy due to her advanced age and poor performance status. Her symptoms improved, and she was transferred to a rehabilitation hospital. Methotrexate-related lymphoproliferative disorder of the central nervous system can recur spontaneously, even without resumption of methotrexate, making long-term follow-up necessary after methotrexate cessation.