Analysis of bone marrow cell morphological abnormalities in patients treated with methotrexate

Abstract

Methotrexate (MTX) is a key drug in the treatment of rheumatoid arthritis, but it sometimes causes hematopoietic disorders with morphological abnormalities of bone marrow cells, which may be difficult to distinguish from myelodysplastic syndrome (MDS). Originally, bone marrow biopsy should not be carried out in the initial diagnosis, but in practice, samples are occasionally obtained and submitted for analysis. However, since there is little detailed information in the literature on how much morphological abnormalities appear in the initial diagnosis, we analyzed the morphology of bone marrow cells from 12 patients treated with MTX. As a result, seven patients were found to have more than one lineage of morphological abnormalities, and three of them had more than 10% of ring sideroblasts. If the history of MTX use is not known, there is a risk that such finding would lead to the diagnosis of MDS; therefore, a detailed check of drugs taken that may affect results is necessary at the time of diagnosis.