RESUMO
Pediatric ALK-positive anaplastic large cell lymphoma (ALK+ ALCL) is usually associated with a favorable prognosis. ALK+ ALCL associated with a leukemic phase is uncommon, but has been associated with an aggressive clinical course and unfavorable prognosis. Overexpression of c-myc has been shown to be a consistent finding in ALK+, but not ALK-negative ALCL (ALK- ALCL), and the c-myc gene is considered a downstream target of deregulated ALK signaling. We describe a pediatric ALK+ ALCL with a leukemic phase at relapse. Similar to other rare cases described in the literature, it followed an aggressive clinical course despite multiple regimens of chemotherapy and bone marrow transplantation. Lymphoma cells showed aberrant ALK expression and c-myc overexpression. In addition to the characteristic t(2;5)(p23;q35) translocation, a t(3;8)(q26.2;q24) translocation was also present, and c-myc gene rearrangement was confirmed by FISH analysis. The findings in this case demonstrate the association of peripheral blood leukemic involvement and aggressive clinical course, and suggest that other factors, such as c-myc rearrangement, may be responsible for the aggressive clinical behavior in ALK+ ALCL.
Assuntos
Cromossomos Humanos Par 3/genética , Cromossomos Humanos Par 8/genética , Rearranjo Gênico , Leucemia/genética , Linfoma Difuso de Grandes Células B/genética , Proteínas Tirosina Quinases/genética , Proteínas Proto-Oncogênicas c-myc/genética , Translocação Genética , Quinase do Linfoma Anaplásico , Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Evolução Fatal , Humanos , Hibridização in Situ Fluorescente , Leucemia/tratamento farmacológico , Leucemia/patologia , Leucemia/fisiopatologia , Linfoma Difuso de Grandes Células B/tratamento farmacológico , Linfoma Difuso de Grandes Células B/patologia , Linfoma Difuso de Grandes Células B/fisiopatologia , Masculino , Receptores Proteína Tirosina QuinasesAssuntos
Antineoplásicos/uso terapêutico , Deleção de Genes , Leucemia Promielocítica Aguda/tratamento farmacológico , Proteínas de Fusão Oncogênica/genética , Tretinoína/uso terapêutico , Adolescente , Resistencia a Medicamentos Antineoplásicos , Feminino , Humanos , Leucemia Promielocítica Aguda/genética , Masculino , Pessoa de Meia-IdadeRESUMO
Patients presenting with thrombocytosis require thorough clinical and laboratory evaluation to determine whether they suffer from essential thrombocythemia or another myeloproliferative disorder. This distinction becomes increasingly relevant as targeted agents become available to treat specific myeloproliferative diseases. Cytogenetic testing plays a major role in this analysis. This study presents a patient with Philadelphia chromosome positive (Ph + ) thrombocytosis and a cryptic der(9q)t(5;9)t(9;22) not found by conventional cytogenetics, whose disease progressed within 2 years to typical myeloblastic crisis of CML. It discusses the entity of Ph + ET, the utility of molecular cytogenetic testing in the diagnosis of this unusual disease entity and the importance of cytogenetic testing in the prognosis of ET.
