Abstract
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.