Immuno- and cytochemical characterization of congenital leukemia: a case report

Congenital leukemia (CL) is a rare disorder, which usually presents as a myelocytic leukemia based on morphological features. Very few reports include data on cyto- or immunochemical parameters. A case of CL with detailed description of immunochemical, cytochemical features, and colony formation properties of the progenitor cells is reported. This leukemia was classified as an M4 in FAB classification based on the morphological features and special stains. Two different cell populations were identified by flow cytometry. One consisted of small cells expressing early T- and early B-cell associating antigens as well as early myeloid-associated antigens, but not CD10 (CALLA antigen), which is normally present in cord blood lymphocytes. The other was a population of large cells expressing myeloid-associated antigens and a pan-T-antigen. The growth pattern of hematopoietic progenitors in the patient was compatible with both acute myeloid and acute lymphatic leukemia as well as erythroleukemia.