Philadelphia-chromosome positive thrombocythemia in a child.

Philadelphia-chromosome positive thrombocythemia without features of chronic myeloid leukemia in peripheral blood has been described in adults. It is rare in children. We present a case of Philadelphia positive thrombocythemia in a child who was managed with a combination of imatinib and hydroxyurea. Although a reduction in the BCR-ABL transcript was documented, the thrombocytosis was refractory to imatinib alone and required the addition of hydroxyurea.