Philadelphia chromosome--positive pre-B-lymphocytic leukemia in a child.

A boy with acute lymphocytic leukemia (ALL) associated with a pre-B-cell phenotype and the Ph' chromosome is described. The Ph'-positive blasts with L3 morphology contained intracytoplasmic IgM but lacked surface immunoglobulins. The child's response to intensive chemotherapy was unsatisfactory. The short survival of our patient suggests that childhood leukemias expressing the pre-B-cell phenotype and Ph' chromosome may carry a poor prognosis. For that reason, the usefulness of cytogenetic and immunologic characterization of leukemic blasts at diagnosis is emphasized.