MS4A1 and myelodysplastic syndrome: She achieved partial remission (PR) and the FL cells disappeared: FL cells – CD10 and CD19 double-positive cells and IgH-BCL2 positive in polymerase chain reaction (PCR); however, in her peripheral blood (IgH-BCL2 negative by PCR and CD20-positive cell was negative in peripheral blood), FL recurred and a therapy-related MDS simultaneously developed 16 months after the diagnosis.