Intracranial Methotrexate-Associated Lymphoproliferative Disorder in Rheumatoid Arthritis

BACKGROUND: Methotrexate (MTX) is widely used as an anchor drug for the treatment of rheumatoid arthritis (RA) because of its ability to control pain and inflammation. However, few studies have shown that long-term MTX use can lead to lymphoproliferative disorders (LPDs) in these patients. Here we describe a rare case of intracranial MTX-associated LPD in a patient with RA. CASE DESCRIPTION: A 68-year-old woman was admitted to our hospital because of progressive right limb palsy. She was diagnosed with RA 15 years ago and has been receiving MTX therapy for the past 5 years. Magnetic resonance imaging of the head revealed a ring-enhancing lesion in the left parietal lobe. Open biopsy was performed for making a definite diagnosis and planning treatment. Hematoxylin-eosin stain revealed dense proliferation of atypical lymphocytes in the perivascular lesion. Immunohistochemistry results were positive for CD20; this lesion was observed as a strong nuclear signal on in-situ hybridization for the Epstein-Barr virus-encoded RNA. Finally, the patient was diagnosed with MTX-associated LPD. We discontinued MTX administration and initiated steroid therapy for RA. The intracranial lesion reduced in size, and her symptoms resolved after MTX discontinuation; no recurrence has been observed at 3 years after MTX discontinuation. CONCLUSIONS: Intracranial MTX-associated LPD is extremely rare. Here we describe a particular case and review the literature pertaining to intracranial MTX-associated LPD. More attention should be paid to LPD in a patient receiving immunosuppressive treatment for RA.