Biphenotypic hematological malignancy with T-lymphoid and myeloid differentiation: association with t(3;12)(p25;q24.3). Case report and review of the literature

Mixed-phenotype acute leukemia: clinical and laboratory features and outcome in 100 patients defined according to the WHO 2008 classification

The features of 100 mixed-phenotype acute leukemias (MPALs), fulfilling WHO 2008 criteria, are documented. Myeloid and T-lineage features were demonstrated by cytoplasmic myeloperoxidase and CD3; B-lineage features were demonstrated by at least 2 B-lymphoid markers. There were 62 men and 38 women; 68% were adults. Morphology was consistent with acute lymphoblastic leukemia (ALL; 43%), acute myeloid leukemia (AML; 42%), or inconclusive (15%). Immunophenotyping disclosed B + myeloid (59%), T + myeloid (35%), B + T (4%), or trilineage (2%) combinations. Cytogenetics evidenced t(9;22)/(Ph(+)) (20%), 11q23/MLL rearrangements (8%), complex (32%), aberrant (27%), or normal (13%) karyotypes. There was no correlation between age, morphology, immunophenotype, or cytogenetics. Response to treatment and outcome were available for 67 and 70 patients, respectively; 27 received ALL, 34 AML, 5 a combination of ALL + AML therapy, and 1 imatinib. ALL treatment induced a response in 85%, AML therapy in 41%; 3 of 5 patients responded to the combination therapy. Forty (58%) patients died, 33 of resistant disease. Overall median survival was 18 months and 37% of patients are alive at 5 years. Age, Ph(+), and AML therapy were predictors for poor outcome (P < .001; P = .002; P = .003). MPAL is confirmed to be a poor-risk disease. Adults and Ph(+) patients should be considered for transplantation in first remission.

Coexistence of neocentromeric marker 3q and trisomy 3 in two different tissues in a 3-year-old boy with peripheral T-cell lymphoma: support for a gene dosage effect hypothesis

A very small supernumerary de novo marker chromosome was ascertained during cytogenetic diagnosis of a 3 1/2-year-old boy with peripheral T-cell lymphoma, unspecified. The marker, which was C-band and alpha-satellite DNA negative, was identified in the pleural effusion and involved cervical lymph node whereas the involved bone marrow cells had trisomy 3 as a clone. The neocentromere marker was characterized by multiple probes demonstrating an inversion duplication of the distal portion of chromosome 3q involving the BCL6 gene. Whole or partial trisomy 3q represents one of the most recurrent chromosomal abnormalities occurring in T-cell lymphomas, suggesting that the 3q contains a critical region for the pathogenesis of T-cell lymphoma. Our present case showed that the critical region may reside within the neocentromere marker 3q27~q29 in this case in particular and revealed a different mechanism in increasing gene dosage rather than gene disruption. In addition, this type of neocentromere is one most often reported in constitutional cases. Here, we report its presence in cancer for the first time.

Acute leukemia with B-lymphoid and myeloid differentiation associated with an inv(5)(q13q33) in an adult patient

A paracentric inversion in the long arm of chromosome 5, inv(5)(q13q33), was found as a clonal abnormality in a patient with a treatment-resistant biphenotypic acute leukemia with B-lymphoid and myeloid differentiation. This cytogenetic aberration has not been reported previously in biphenotypic acute leukemia, although rearrangements of chromosome bands q13 and q33 have been implicated in the development of several hematologic malignancies. The presence of this aberration as the sole chromosomal abnormality suggests an important role in the pathogenesis of biphenotypic acute leukemia.