Development of acute promyelocytic leukemia with isochromosome 17q after BCR/ABL positive chronic myeloid leukemia.

We describe a pediatric case of acute promyelocytic leukemia with an i(17q) after treatment of BCR/ABL positive chronic myeloid leukemia (CML) for 3.5 years. The patient was treated with Busulphan, alpha-2a interferon, hydroxyurea, and cytosine arabinoside at various times in the course of the chronic phase of CML, because he had no HLA-identical donor for bone marrow transplantation. Hematologic remission was achieved for a short time, but cytogenetic remission was never possible. When promyelocytic blast crisis was diagnosed according to the French-American-British classification, cytogenetic studies revealed an i(17q) as a new feature in our patient. The promyelocytic transformation was associated with the appearance of an i(17q) preceding CML are discussed in the light of recent literature.