Chronic myeloid leukemia. A possible new variant in a child.

A case of Philadelphia (Ph') chromosome negative chronic myeloid leukemia (CML) in a child is reported. The age of onset (7 years) and duration of survival (40 months) are not typical of juvenile CML and the relatively low leukocyte and hemoglobin F concentrations are more akin to the findings in Ph' negative CML in adults. There was refractoriness to chemotherapy with the exception of a dramatic response to a combination of prednisone and vincristine, despite the absence of terminal transferase activity in circulating blood cells. Splenic irradiation, splenectomy, and leukapheresis were ineffective. Transition to a terminal aggressive phase caused a marked change in the growth characteristics of peripheral blood cells in vitro. This patient may represent a new variant in the spectrum of childhood CML.