Two cases of childhood Ki-1 lymphoma occurred with the expression of Ki-1+/HLA-DR+/IL-2R+/EMA+/Leu-M1-/pan-T antigens-/pan-B antigens- in neoplastic cells. Patient 1 with nodular skin lesions expressed Leu-2a+ in the neoplastic cells and died 14 months later. Patient 2 with lymph node swelling and hepatosplenomegaly exhibited Leu-3a+ in the neoplastic cells and remains free of disease. The Leu-2a+ (case 1) or Leu-3a+ (case 2) findings suggest that the neoplastic cells in both cases were derived from T-lymphocyte lineage. However, Southern's blot analysis did not reveal any clonal rearrangements of T-cell receptor genes in the autopsy material from case 1. The Leu-3a+/Mcs-2+ finding in case 2 may indicate that the neoplastic cells were derived from monocyte/macrophage lineage.
Child, Preschool Diagnosis, Differential