Acute B-lymphocytic leukemia with L1 morphology: a report of two pediatric cases

Two pediatric cases of acute lymphoblastic leukemia with L1 morphology who also demonstrated immunoglobulin on the leukemic cell surface are presented. The first patient's disease progressed on standard induction therapy, despite the presence of good prognostic features at presentation. The second patient has achieved a sustained remission with an aggressive lymphoma regimen. These two cases represent the first report on the outcome of patients with this rare phenotype. They indicate the importance of assessing cell surface immunoglobulin in children with acute leukemia, even in the absence of the L3 phenotype, in addition to the currently utilized batteries of monoclonal antibodies. Failure to recognize this phenotype may have significant therapeutic implications.