Lineage switch from acute myeloid leukemia to acute lymphoblastic leukemia: Report of an adult case and review of the literature

Lineage switch from AML to ALL is an extremely rare phenomenon, and we repo rt the case of an adult diagnosed with AML at 46 years of age who relapsed with ALL. At initial diagnosis, blast cell morphology and immunophenotyping were consistent with the diagnosis of M4-AML. Complete remission was achie ved, and the patient underwent autologous BMT, At relapse, six months after ABMT, blast cells were different from those seen at initial diagnosis, for morphology (LP-ALL), cytochemistry, and immunophenotyping, The karyotype w as normal at both diagnosis and relapse. No evidence of bcr-abl fusion gene s was found by RT-PCR, Monoclonal IgH and TCR gamma gene rearrangement were evidenced by PCR analysis at relapse but not on blast cells at AML diagnos is. (C) 2000 Wiley-Liss, Inc.