title: Hybrid leukaemia of T cell and myeloid lineages: cytogenetic distinction from second (induced) malignancy.
abstract: The therapeutic and prognostic implications of relapse and clonal evolution of leukaemia are substantially different from those of secondary (induced) malignancy. This report documents the case of a patient who presented with apparent acute non-lymphocytic leukaemia (ANLL) following therapy for acute (T-cell) lymphoblastic leukaemia (ALL) 4 years previously. Morphologically and cytochemically the cells were of myeloid type, but the cell markers showed a T cell lineage. Cytogenetic studies confirmed that this was a relapse of T cell ALL with a phenotypic change, rather than a second malignancy induced by chemotherapy. A 14q deletion present at initial diagnosis recurred at relapse, with the addition of cells with complete deletion of chromosome 14, indicating clonal evolution.
authors.forename: E M
authors.initials: EM
authors.lastname: Simpson
authors.forename: M G
authors.initials: MG
authors.lastname: Mott
mesh_terms: D002648:Child; D003937:Diagnosis, Differential; D006801:Humans; D007945:Leukemia, Lymphoid / Q000175:diagnosis / Q000188:drug therapy / Q000235:genetics*; D015470:Leukemia, Myeloid, Acute / Q000139:chemically induced / Q000175:diagnosis / Q000235:genetics*; D008297:Male; D009378:Neoplasms, Multiple Primary / Q000175:diagnosis / Q000235:genetics*