Cases of extramedullary relapse after alloBMT in AML1/ETO positive AML

The occurrence of granulocytic sarcoma as a pattern of relapse after allogenic bone marrow transplantation (allo-BMT) is rare. We report two AML1/ETO positive patients with granulocytic sarcoma as a pattern of relapse after allo-BMT. The first case is 39-year-old woman who had lower back pain without any abnormal peripheral blood exam. MRI showed a paraspinal mass, and the pathologic report was granulocytic sarcoma. The second case is 34-year-old woman who had breast humps without any abnormal peripheral blood exam. CT showed multiple breast masses, and the pathologic report was granulocytic sarcoma. We believe that this is the first cases report of extramedullary relapse after allo-BMT in AML1/ETO positive AML in Korea. These cases suggest that we should be aware of the possibility of an extramedullary relapse in bone marrow transplant recipients with AML1/ETO positive AML.