Bone marrow cell populations mimicking common acute lymphoblastic leukemia in infants with stage IV-S neuroblastoma

Immunophenotyping of bone marrow mononuclear cells of 2 infants with stage IV-S neuroblastoma revealed the presence of many lymphoblasts and immature lymphocytes. Immunophenotyping showed that a high percentage of bone marrow cells were positive for the HLA-DR, CD19, CD20 and CD10 phenotype, similar to common acute lymphoblastic leukemia cells. Within 6 months of follow-up, without any treatment, complete regression of the tumors was observed. The coexistence of these two unusual populations will be discussed.