[T-lineage acute lymphoblastic leukemia. Report of 23 cases]

23 cases of T-lineage acute lymphoblastic leukemia (TALL) were identified by multiple monoclonal antibodies. TALL was characterized by a younger age of the patients (average age 28 years), strong male preponderance (M:F, 4.8: 1), mediastinal mass (19%), higher leucocyte count (71.4%), hepatomegaly (76.2%) and splenomegaly (90.5%). Of 19 cases of TALL who were subclassified according to the criteria for subclassification of TALL proposed by Reinherz, 10 cases expressed a surface antigen pattern consistent with the early thymocyte stage of TALL development, 8 cases were of common thymocyte stage and 1 case was of mature thymocyte stage. The phenotypes of TALL cells appear to be considerably heterogeneous. 12 of 18 patients who received chemotherapy had achieved complete remission (67%).