[Philadelphia-positive acute mixed leukemia with monosomy 7]

A 26-year-old male was admitted to our hospital because of fever and leukocytosis. On admission, a white blood cell count was 28,300/microliters with 46.5% blast cells and 16.0% atypical monocytoid cells, a hemoglobin level 13.7 g/dl, and a platelet count 15.0 X 10(4)/microliters. Bone marrow contained 58.8% of peroxidase-negative blast cells. He was diagnosed as acute lymphoblastic leukemia (ALL L2) according to the FAB classification. Chromosome analysis revealed the marrow cells to contain 45, XY, -7, t(9; 22) (q34; q11). On surface marker analysis, the leukemic cells were positive for both lymphoid (CD10) and myeloid markers (CD13). Two color flow-cytometric analysis showed two distinct populations with CD10 and CD1 3, respectively. Rearrangements of both immunoglobulin heavy chain and T cell receptor beta-chain were observed. The "breakpoint cluster region" on chromosome 22 was not rearranged. On the basis of these findings, we thought this case being acute mixed leukemia. He was refractory to AdVP therapy and BHAC-DMP therapy. He is now under treatment with A-Triple-V therapy.