Therapy-related myelodysplastic syndrome following cyclophosphamide pulse and/or methotrexate therapy in a patient with systemic lupus erythematosus.

A 27-year-old woman exhibited progressive pancytopenia during cyclophosphamide pulse therapy for lupus nephritis and low-dose methotrexate therapy for severe arthralgia. Bone marrow aspiration revealed highly abnormal cell morphology, indicating therapy-related myelodysplastic syndrome. Pancytopenia and bone marrow cell morphology improved 3 months after discontinuation of cyclophosphamide. It is necessary to promptly examine bone marrow cell morphology and chromosomal aberration in cases with connective tissue diseases complicated by sudden cytopenia during immunosuppressive therapy with chemotherapeutic agents.