title: Megakaryocytic blast crisis as a presenting manifestation of chronic myeloid leukemia.
abstract: Acute megakaryocytic leukemia is a rare form of acute myelogenous leukemia and may occur either de novo or by transformation of a preexisting myelodysplastic or myeloproliferative process including blast crisis of chronic myeloid leukemia (CML). Megakaryocytic blast crisis as the presenting manifestation of CML is extremely rare. We describe such a patient with no prior hematologic disease who presented with acute megakaryoblastic leukemia and extramedullary involvement, in whom the leukemic cells carried the BCR-ABL1 translocation as part of a complex karyotype. Using targeted sequential fluorescence in situ hybridization (T-FISH) technique, we detected two copies of BCR-ABL1 fusion gene in the leukemic blasts while the neutrophils carried a single copy of BCR-ABL1 fusion gene, thereby proving the origin of the megakaryoblastic leukemia from a previously undiagnosed CML clone. Blast crisis as a presenting manifestation of CML is rare and detecting clonal evolution of acute leukemia by specialized cytogenetic techniques may have important diagnostic and therapeutic implications.
authors.affiliation: Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, United States. spullarkat@mednet.ucla.edu
authors.forename: Sheeja T
authors.initials: ST
authors.lastname: Pullarkat
authors.forename: James W
authors.initials: JW
authors.lastname: Vardiman
authors.forename: Marilyn L
authors.initials: ML
authors.lastname: Slovak
authors.forename: Dinesh S
authors.initials: DS
authors.lastname: Rao
authors.forename: Nagesh P
authors.initials: NP
authors.lastname: Rao
authors.forename: Victoria
authors.initials: V
authors.lastname: Bedell
authors.forename: Jonathan W
authors.initials: JW
authors.lastname: Said
mesh_terms: D001752:Blast Crisis / Q000175:diagnosis* / Q000235:genetics / Q000628:therapy; D016044:Fusion Proteins, bcr-abl / Q000235:genetics*; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007947:Leukemia, Megakaryoblastic, Acute / Q000473:pathology*; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000175:diagnosis* / Q000235:genetics / Q000628:therapy; D008297:Male; D008533:Megakaryocytes / Q000473:pathology*; D008875:Middle Aged; D014178:Translocation, Genetic
chemical_list: D016044:Fusion Proteins, bcr-abl