AN ABNORMAL CLONE WITH MONOSOMY-7 AND TRISOMY-21 IN THE BONE-MARROW OF A CHILD WITH CONGENITAL AGRANULOCYTOSIS (KOSTMANN-DISEASE) TREATED WITH GRANULOCYTE-COLONY-STIMULATING FACTOR - EVOLUTION TOWARDS MYELODYSPLASTIC SYNDROME AND ACUTE BASOPHILIC LEUKEMIA

Cytogenetic analysis of bone marrow cells revealed on abnormal clone w ith monosomy 7 and trisomy 21 in a 12-year-old child with Kostmann dis ease (KD). The patient presented with anemia, thrombocytopenia, and sp lenomegaly after 5 years of treatment with granulocyte colony-stimulat ing factor (G-CSF). The bone marrow morphology was consistent with the diagnosis of myelodysplastic syndrome (MDS). Administration of G-CSF was discontinued at this point. Bone marrow studies 2 and 5 months lat er showed persistence of both myelodysplasia and the abnormal clone wi th monosomy 7 and trisomy 21. Monosomy 7 was also confirmed by fluores cence in situ hybridization (FISH). After 2 months of follow-up, the p atient presented with acute basophilic leukemia, a very rare variant o f acute myeloid leukemia (AML), expressing the same bone marrow chromo some abnormalities as observed earlier. This is a rare case of KD with prolonged survival and a cytogenetically abnormal clone evolving to M DS and acute basophilic leukemia. The significance of monosomy 7 and t risomy 21 in KD treated with G-CSF is discussed.