Imaging using diffusion-weighted whole-body imaging with background signal suppression for methotrexate-associated lymphoproliferative disorder: A case report.

Patients with rheumatoid arthritis (RA) receiving immunosuppressive therapy including methotrexate (MTX) are at risk of developing lymphoproliferative disorder (LPD). Herein, we report the case of a 61-year-old man who has been treated with MTX and sulfasalazine for seropositive RA since the age of 52 years. He underwent diffusion-weighted whole-body imaging with background signal suppression (DWIBS), which revealed high-intensity lesions in the affected lymph nodes of the cervical, clavicular, and axillary regions. Follow-up DWIBS after MTX withdrawal showed the suppression or disappearance of the high-intensity lesions. This case demonstrates the potential of DWIBS as a new standard imaging modality for MTX-LPD in patients with RA in clinical practice.