Donor cell leukemia with bone marrow necrosis

A 60-year-old man with myelodysplastic syndrome underwent allogeneic transplantation of female umbilical cord blood in 2010 and sustained a complete remission. He experienced severe pain in his left hip joint and was admitted to the orthopedic surgery division of our institution in February 2015. After admission, he was suspected to have hemophagocytic syndrome (HPS) and was thus transferred to the hematology division. Bone marrow aspiration revealed hyper-cellular marrow filled with abnormal collapsed cells, consistent with bone marrow necrosis (BMN). As there was no evidence of infection, collagen disease, or occult cancer, he was diagnosed with HPS of unknown origin and treated with dexamethasone, cyclosporine A, and etoposide according to the HLH-2004 protocol. Although his general condition and laboratory findings showed amelioration, morphologically abnormal cells appeared in peripheral blood two weeks after treatment. Bone marrow aspiration showed BMN with increased abnormal cells, positive for CD117 and MPO. Sex chromosome FISH analysis revealed donor chimerism and cytogenetic analysis showed 46XX, +1, der (1;7) (q10;q10). He was diagnosed with donor cell leukemia (DCL) and received salvage chemotherapy. However, he died because of severe pneumonia and sepsis without neutrophil recovery at day 68. We herein report this rare case of DCL with BMN.