A 73-year-old Japanese male visited our hospital following an abnormal non-contrast computed tomography (CT) scan. He was diagnosed with rheumatoid arthritis 18 years ago, and 10 years ago began treatment with methotrexate (MTX). His chest contrast-enhanced CT scan revealed multiple pulmonary shadows. Pathological examination of the transbronchial lung biopsy showed massive necrosis, with immunohistology revealing numerous CD20-positive lymphocytes. We diagnosed MTX-associated lymphoproliferative disorders (MTX-LPD) based on clinical history and pathological findings. The multiple pulmonary shadows reduced only on withdrawal of MTX. Blood examination showed Epstein-Barr virus (EBV) reactivation, and EBV-encoded small RNA in situ hybridization (EBER-ISH) staining of lung tissue showed numerous EBV-RNA positive lymphocytes. We speculated that the case might have been caused by EBV infection.