Acute lymphoblastic leukemia with the 4;11 translocation exhibiting early T cell features

We describe a case of ALL with the t(4;11) (q21;q23) translocation in which both surface markers and molecular analyses suggest an unusual early T cell involvement. While the morphologic and cytochemical studies showed an undifferentiated pattern, immunophenotypic data were suggestive of a very immature cell population which stained only for TdT and CD7. Moreover, in contrast to previous reports but in agreement with the immunologic findings, the IgH gene region retained a germ-line configuration. T cell receptor β and γ chain gene loci also showed a germline pattern, in accordance with the expansion of immature CD7+, TdT+ T cells.