Summary Background: The pediatric hematology-oncology service of

began its activities in 1988. We report on unusual high inci-dence of acute promyelocytic leukemia (APL) observed in Nicaragua in the last three years. Patients and methods: From 1990 to 1992,17 of 110 chil-dren with acute leukemia were diagnosed as having acute non-lymphoblastic leukemia (AnLL). The diagnosis was per-formed according to the FAB criteria. In two cases DNA was recovered for molecular analysis of the t(15; 17). Results: Ten of 17 cases of AnLL were classified as APL. PML and RARa gene rearrangements were observed in the two cases where molecular analysis was performed. Nine children received chemotherapy; one was treated with all-trans-retinoic acid (ATRA), achieving complete remission. Eight children who received chemotherapy died early of hemorrhage and/or sepsis. Discussion: In Nicaragua, APL may be much more com-mon than is generally observed elsewhere. In recent years initial treatment of APL with ATRA has proved to reduce the incidence of early hemorrhagic deaths, and complete remis-sions can be achieved without marrow aplasia and thus pre-vent infectious complications. From that perspective APL might become a curable disease, also in developing countries where the treatment of AnLL is not usually affordable. Key words: acute promyelocytic leukemia, all-trans-retinoic acid, children, developing countrie