title: A case of biphenotypic blast crisis of unclassified myeloproliferative disorder.
abstract: We report a first case of biphenotypic blast crisis of unclassified myeloproliferative disorder (MPD). A 20-year-old patient presented with fever, splenomegaly, marked leukocytosis (603 x 10(3)/ micro l), and blasts in the peripheral blood. Since Ph chromosome and bcr-abl gene rearrangement were absent, the diagnosis of an unclassified MPD in the blast crisis phase was established. Immunophenotyping confirmed a biphenotypic crisis of myeloid and T-lymphoid antigens. The patient went into a complete remission after chemotherapy, but marked granulocytic hyperplasia (M:E ratio of 5.7) and 90% cellularity remained. Blast crisis recurred during subsequent intensification chemotherapy and the patient did not go into a complete remission regardless of the intense chemotherapy. The blast crisis transformed from unclassified MPD had a grave prognosis as it responded poorly to chemotherapy. This unique blast crisis is distinguishable from the blast crisis of chronic myelogenous leukemia.
authors.affiliation: Department of Clinical Pathology, University of Ulsan College of Medicine and Asan Medical Center, Seoul, Korea.
authors.forename: J
authors.initials: J
authors.lastname: Kim
authors.forename: C J
authors.initials: CJ
authors.lastname: Park
authors.forename: E J
authors.initials: EJ
authors.lastname: Seo
authors.forename: J H
authors.initials: JH
authors.lastname: Lee
authors.forename: S J
authors.initials: SJ
authors.lastname: Yoo
authors.forename: S J
authors.initials: SJ
authors.lastname: Choi
authors.forename: H S
authors.initials: HS
authors.lastname: Chi
mesh_terms: D000328:Adult; D001752:Blast Crisis / Q000175:diagnosis* / Q000473:pathology; D020732:Cytogenetic Analysis; D006801:Humans; D008297:Male; D022423:Myeloid Cells / Q000473:pathology; D009196:Myeloproliferative Disorders / Q000145:classification / Q000473:pathology*; D010641:Phenotype; D013601:T-Lymphocytes / Q000473:pathology