A novel unbalanced whole-arm translocation der(3;10)(q10;q10) in acute monocytic leukemia

We describe here a novel unbalanced whole-arm translocation der(3;10)(q10;q10) in a 58-year-old man with acute monocytic leukemia. Bone marrow was massively infiltrated with 22.2% monoblasts, 55.4% promonocytes, and 5.6% monocytes. These monocytic cells were positive for myeloperoxidase and α-naphthyl butyrate esterase staining. Surface marker analysis revealed that they were positive for CD4, CD13, CD33, CD56, and HLA-DR but negative for CD14 and CD34. Chromosome analysis of the bone marrow cells showed 46,XY,+3,der(3;10)(q10;q10)[18]/46,XY[2]. Spectral karyotyping confirmed der(3;10)(q10;q10) as a sole structural abnormality. By acquisition of a normal chromosome 3 but not a chromosome 10, the der(3;10)(q10;q10) resulted in trisomy 3q and monosomy 10p. The +3,der(3;10)(q10;q10) is thought to play a crucial role in the pathogenesis of acute monocytic leukemia because of the gain of 3q or the loss of 10p.