title: Mixed Phenotype Acute Leukemia with Two Immunophenotypically Distinct B and T Blasts Populations, Double Ph (+) Chromosome and Complex Karyotype: Report of an Unusual Case.
abstract: Mixed phenotype acute leukemia (MPAL) is considered as a rare type of leukemia with an incidence of less than 4% of all acute leukemia based on the most recent 2008 WHO classification. Common subtypes are the B/myeloid and T/myeloid; B/T and trilineage MPAL being extremely rare. We present a case of a male in his 20s, whose peripheral blood smears showed 34% blast cells and bone marrow with 70% blasts. Immunophenotyping by multiparametric flow cytometry showed two populations of blasts, the major one with B-lineage and the minor one with T-lineage. Conventional karyotyping revealed complex karyotype with the presence of double Philadelphia chromosome (Ph (+)). BCR/ABL1 rearrangement was confirmed by fluorescent in situ hybridization (FISH) analysis. The BCR/ABL1 ES probe on interphase cells indicated p190 minor m-BCR/ABL fusion in 46% and a second abnormal clone with double Ph (+) in 16% of the cells analyzed confirmed by reverse transcription-PCR (RT-PCR). The case was diagnosed as MPAL with double Philadelphia chromosome Ph (+). The patient was treated with dasatinib, four cycle hyper CVAD/methotrexate cytarabin protocol, and allogeneic transplant. He is still alive in complete hematological, cytogenetic, and molecular remission. Mixed phenotype B/T acute leukemia is an extremely rare disease, particularly those with double Philadelphia chromosomes and clinically presents challenges in diagnosis and treatment.
authors.affiliation: Department of Laboratory Medicine and Pathology, Hematopathology Section, Hamad Medical Corporation, Doha, Qatar.
authors.forename: Samah A
authors.initials: SA
authors.lastname: Kohla
authors.affiliation: Department of Laboratory Medicine and Pathology, Hematopathology Section, Hamad Medical Corporation, Doha, Qatar.
authors.forename: Ahmad Al
authors.initials: AA
authors.lastname: Sabbagh
authors.affiliation: Department of Haematology and Medical Oncology, Hamad Medical Corporation, Doha, Qatar.
authors.forename: Halima El
authors.initials: HE
authors.lastname: Omri
authors.affiliation: Department of Laboratory Medicine and Pathology, Hematopathology Section, Hamad Medical Corporation, Doha, Qatar.
authors.forename: Firyal A
authors.initials: FA
authors.lastname: Ibrahim
authors.affiliation: Department of Laboratory Medicine and Pathology, Cytogenetics and Molecular Cytogenetics Section, Hamad Medical Corporation, Doha, Qatar.
authors.forename: Ivone B
authors.initials: IB
authors.lastname: Otazu
authors.affiliation: Department of Laboratory Medicine and Pathology, Cytogenetics and Molecular Cytogenetics Section, Hamad Medical Corporation, Doha, Qatar.
authors.forename: Hessa
authors.initials: H
authors.lastname: Alhajri
authors.affiliation: Department of Haematology and Medical Oncology, Hamad Medical Corporation, Doha, Qatar.
authors.forename: Mohamed A
authors.initials: MA
authors.lastname: Yassin
keywords: double Philadelphia; mixed phenotype acute leukemia B/T