Background and methods: B-cell acute lymphoblastic leukemia (B-ALL) presents FAB L3 morphology and surface Ig, CD19, CD20, CD24. This pattern may show some morphological and immunological heterogeneity. Seventeen pediatric cases of B-ALL at onset, treated in twelve AIEOP Centers (Italian Association for Pediatric Hematology and Oncology), are presented.
Results and conclusions: Clinical and hematological features were characterized by low WBC counts at presentation, high M/F ratio, older age and association with extramedullary involvement. The overall survival curve at 78 months is 40%. All patients showed blasts positive for surface Ig (sIg), DR, CD19, and CD24. Ten/17 cases presented the classical features of B-ALL: FAB L3 morphology, sIg+ restricted to light chains, CD20+, cytoplasm mu (c mu)-, CD10-, TdT-. The remainder showed some differences in this pattern, such as non-L3 morphology (3 cases), absence of CD20 (3 cases), CD10+ (4 cases), TdT+ (3 cases), c mu+ (1 case), lack of surface light chains (1 case). This rare ALL subset seems to be characterized by a high phenotype heterogeneity, indicating various degrees of differentiation.