Mixed lineage leukemia with cytogenetically unrelated abnormal clones.

We present a case of acute leukemia with morphologic, cytochemical, and immunophenotypic markers indicating that the population of blasts have characteristics of lymphoid and myelomonocytic origin. The cytogenetic study revealed the following mosaic abnormal karyotype: 46XX,dup(1)(q21----32)/46,XX,dup(11)(q13----25)/47,XX,trip(11) (q13----25),+der(17)t(17;?) (q24;?). The two clones involving #11 are obviously related. It is reasonable to assume that the third clone is an evolutionary result of the second one. Because no cytogenetic similarities were found among the first clone and the other two, we suggest that this mixed leukemia was of biclonal origin. To our knowledge, acute leukemia with mixed lineage characteristics and with the simultaneous presence of cytogenetically unrelated clones has not previously been reported.