A 21-year-old woman was admitted to the hospital because of indigestion and poor oral intake. Her most prominent clinical features were short stature, diarrhea and hematologic abnormality. She was pancytopenic (Hb 9.7 g/dL white cell count of 4,200/muL [neutrophils 800/muL] and platelets 220,000/muL). Marrow aspirate showed high cellularity with massive infiltration by blast cells which were positive for Sudan black and myeloperoxidase (Figure 1). She was diagnosed as AML, M2 according to the FAB classification. The blast population displayed the following immunophenotype: CD13 48%, CD33 59%, CD34 61%, HLA-DR 59% and CD20 negative. A bone marrow sample was processed for cytogenetic analysis. A complex karyotype was found in 20 out of 20 metaphases: 47XX, del (20)(q11.2), tas (21;22) (q22;q13), +22 (Figure 2). A skeletal survey showed an mild metaphyseal dystosis. The abdominal MRI showed an enlarged pancreas, a hyperintense signal on T1-and T2-weighted image and low signal on fat-suppressed image (Figure 3A, B). She was treated with conventional chemotherapy (idarubicin plus cytarabine). The period of aplasia was characterized by numerous complications, including persistent fever despite empiric antibacterial and antifungal therapy and hematemesis. Marrow recovery was slow. The patient achieved remission 41 days after the beginning of chemotherapy. Conventional cytogenetics at that time showed a normal karyotype. She received BMT from her sister who was HLA identical. Unmanipulated donor marrow was given following conditioning with cyclophosphamide (60 mg/kgx2) and total body irradiation (TBI) (1200 cGy in 6 fractions) using a combination of cyclosporin A and methotrexate as graft-versus-host disease (GVHD) prophylaxis. The post-transplant period was complicated by staphylococcal septicemia and acute GvHD in grade II. But she has been alive disease free and off any immunosuppressives, for a follow-up of 13 months after BMT.