title: [Atypical myeloproliferative neoplasm with a small population of Philadelphia chromosome-positive clones in the bone marrow].
abstract: A 52-year-old woman presented with isolated thrombocytosis in 2003. After 5 years of observation under a tentative diagnosis of essential thrombocythemia (ET), she was referred to our hospital because of anemia and leukopenia. Bone marrow biopsy demonstrated increases of megakaryocytes and myelofibrosis, but splenomegaly was absent. A karyotype study of bone marrow detected t(9;22) (q34;q11.2) in 6 of the 20 metaphases studied. Peripheral blood neutrophil BCA-ABL fusion signals (FISH) were not detected. Because RT-PCR assay of bone marrow detected major-BCR-ABL mRNA (b3a2), treatment with imatinib (400 mg/day) was started. After transient thrombocytopenia, normalization of blood cell counts and improvement of myelofibrosis were achieved. JAK2 V617F mutation and M-BCR-ABL mRNA was negative in peripheral blood. Clinical and laboratory data suggest that this case represents a rare and atypical myeloproliferative neoplasm with BCR-ABL translocation restricted mainly to the megakaryocyte lineage.
authors.affiliation: Division of Hematology, Niigata City General Hospital.
authors.forename: Kazue
authors.initials: K
authors.lastname: Takai
authors.forename: Takashi
authors.initials: T
authors.lastname: Ushiki
authors.forename: Koji
authors.initials: K
authors.lastname: Nikkuni
authors.forename: Hideki
authors.initials: H
authors.lastname: Hashidate
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Shibuya
mesh_terms: D001549:Benzamides; D001853:Bone Marrow / Q000473:pathology; D005260:Female; D016044:Fusion Proteins, bcr-abl / Q000235:genetics; D006801:Humans; D000068877:Imatinib Mesylate; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000188:drug therapy / Q000235:genetics* / Q000473:pathology; D008533:Megakaryocytes; D009196:Myeloproliferative Disorders; D010677:Philadelphia Chromosome; D010879:Piperazines / Q000627:therapeutic use; D011743:Pyrimidines / Q000627:therapeutic use; D013922:Thrombocytosis; D014178:Translocation, Genetic
chemical_list: D001549:Benzamides; D010879:Piperazines; D011743:Pyrimidines; D000068877:Imatinib Mesylate; D016044:Fusion Proteins, bcr-abl