We report on a patient with Philadelphia chromosome-positive acute lymphoblastic leukemia, who acquired a novel chromosomal abnormality, a dic(19;21)(p13;p13), during relapse of the disease. The cytogenetic result was confirmed by fluorescence in situ hybridization using alpha-satellite and library probes specific for chromosomes 19 and 21, respectively, as well as a chromosome 19q13.1-specific DNA probe. In our case, the dic(19;21) represents a secondary genetic change and was associated with disease progression and poor prognosis.
