title: Lineage ambiguity in acute leukemia.
abstract: Two cases of acute nonlymphocytic leukemia that showed surface phenotypes characteristic of lymphoid cells are reported. The cases, both involving female patients were studied by a variety of methods including flow cytometry and karyotyping. In Case 1, the patient, a 10-year-old girl, had poorly differentiated myeloblasts (FAB M1), which were weakly positive for Sudan black B (SBB), but negative for alpha naphthyl acetate esterase (NAE) and naphthol ASD chloroacetate esterase (CAE). Myeloperoxidase was demonstrated ultrastructurally in some of the blasts. In Case 2, the 30-year-old patient had typical myelomonocytic leukemia (FAB M4), with SBB-, NAE-, and CAE-positive blasts. Both cases were negative for terminal deoxynucleotidyl transferase. Case 1 was negative for myeloid membrane markers, whereas Case 2 was strongly positive for My7 and My9. Surprisingly, both cases showed significant positivity for B-cell restricted antigens B1, B2, and B4. These findings suggest ambiguous or dual lineage, supporting the concepts that some leukemias could arise from a pluripotent hematopoietic progenitor cell (Case 1) or from cells that though differentiated in some respects, could still preserve some early antigens (Case 2).
mesh_terms: D000208:Acute Disease; D000328:Adult; D000911:Antibodies, Monoclonal; D001853:Bone Marrow / Q000473:pathology / Q000648:ultrastructure; D002454:Cell Differentiation; D002648:Child; D005260:Female; D006801:Humans; D007938:Leukemia / Q000145:classification / Q000473:pathology*; D008854:Microscopy, Electron
chemical_list: D000911:Antibodies, Monoclonal