RESUMEN
This paper describes the treatment of promyelocytic blast crisis of chronic myelogenous leukemia with all-trans-retinoic acid (ATRA). The patient, a 22-year-old male, was diagnosed to have APL and had been treated with busulfan and then with three and half years interferon (IFN) alpha in the chronic phase. A cytogenetic study of blast cells showed the t(1;17) (p11;q11) translocation as the second chromosomal abnormality without morphological abnormality of chromosome 15. Molecular analysis showed cells to have a chimera gene consisted of PML and retinoic acid receptor alpha genes. Though maturation and differentiation of leukemic cells were seen after ATRA therapy, hematological complete remission did not occur. The ineffectiveness of ATRA may be dut to different pathological conditions from de novo APL, or progressive reduction in plasma ATRA concentration as reported by Muindi et al. When our case was compared with a similar case reported by Wiernick et al., both cases were treated with IFN alpha in the chronic phases, had no t(15;17) translocation involving No.1 chromosome abnormality and did not develop complete remission after ATRA therapy.