Methotrexate-associated lymphoproliferative disorder with an osteolytic vertebral lesion in an elderly patient with rheumatoid arthritis: A case report.

What is known and objective Methotrexate-associated lymphoproliferative disorder (MTX-LPD) is a rare complication that develops in patients treated with methotrexate (MTX). Case summary A 76-year-old male patient had been taking MTX for his rheumatoid arthritis. Computed tomography (CT) revealed masses in the liver, right adrenal gland and T6-T7 vertebra, including an osteolytic lesion. FDG-PET scan showed increased uptake in each lesion. MTX was discontinued, and CT showed complete remission of the tumours after three months. The disease course confirmed MTX-LPD diagnosis. What is new and conclusion Bone lesions in LPDs mimic those of metastatic cancer. MTX-LPD should be considered in patients on MTX presenting with mass lesions.