Epidemiological evaluation and survival of children with acute myeloid leukemia

Abstract Objective: This study aims to describe the epidemiological characteristics and survival rates of children with acute myeloid leukemia treated in hospitals in southern Brazil and compare them with international data. Methods: A multicenter cohort study was conducted with retrospective data collection of all new patients with acute myeloid leukemia under 18 treated at five referral centers in pediatric hematology-oncology in southern Brazil between January 2005 and December 2015. Results: Of the 149 patients with acute myeloid leukemia, 63.0% (n = 94) were male. The median age at diagnosis was 10.5 years (range 0-18 years) and 40.3% (n = 60) had a white blood cell count below 50,000/mm2. The most common Franco-American-British (FAB) subtype was M3 (n = 43, 28.9%). Nine (6.0%) patients had central nervous system disease. In M3 patients, overall survival (OS) was 69.2% and 3-year event-free survival was 67.7%; in non-M3 patients, these rates were 45.3% and 36.7%, respectively. In non-M3 patients, OS was significantly different between transplanted (61.8%) and non-transplanted (38.2%) patients (p = 0.031). Conclusions: These results show a higher prevalence of the Franco-American-British M3 subtype than that reported in the international literature, as well as a decreased OS compared with that of developed countries. Further multicenter Brazilian studies with a larger sample size are encouraged to better understand the characteristics of acute myeloid leukemia, and to improve the treatment and prognosis in this population.

Hemophagocytosis by blasts in a child with acute monocytic leukemia after chemotherapy / Hemofagocitose por células blásticas em paciente pediátrico com leucemia monocítica aguda após quimioterapia

ABSTRACT Objective: To describe the case of a child who presented hemophagocytic lymphohistiocytosis (HLH) associated with acute monocytic leukemia after chemotherapy, with hemophagocytosis caused by leukemic cells. Case description: In a university hospital in Southern Brazil, a 3-year-old female was diagnosed with acute monocytic leukemia with normal karyotype. The chemotherapy regimen was initiated, and she achieved complete remission six months later, relapsing after four months with a complex karyotype involving chromosomes 8p and 16q. The bone marrow showed vacuolated blasts with a monocytic aspect and evidence of hemophagocytosis. The child presented progressive clinical deterioration and died two months after the relapse. Comments: HLH is a rare and aggressive inflammatory condition characterized by cytopenias, hepatosplenomegaly, fever, and hemophagocytosis in the bone marrow, lymph nodes, spleen, and liver. Although rare, malignancy-associated HLH (M-HLH) is fatal. The patient in this case report met five out of the eight established criteria for HLH. The evolution of the patient's karyotype, regardless of the diagnostic profile, seemed secondary to the treatment for acute monocytic leukemia. In this case, the cytogenetic instability might have influenced the abnormal behavior of leukemic cells. This is a rare case of HLH in a child with acute monocytic leukemia.

RESUMO Objetivo: Descrever um caso de um paciente pediátrico que apresentou linfo-histiocitose hemofagocítica (LHH) associada à leucemia monocítica aguda pós-quimioterapia, com hemofagocitose causada pelas próprias células leucêmicas. Descrição do caso: Em um hospital universitário do Sul do Brasil, uma menina de três anos foi diagnosticada com leucemia monocítica aguda com cariótipo normal. Após receber protocolo quimioterápico, atingiu remissão seis meses depois do início do tratamento, recaíndo quatro meses após com um cariótipo complexo envolvendo ambos os cromossomos, 8p e 16q. A medula óssea mostrava-se infiltrada por células blásticas vacuolizadas com aspecto monocítico, com evidências de hemofagocitose. A criança apresentou um declínio clínico progressivo e dois meses após a recaída foi a óbito. Comentários: A LHH é uma condição inflamatória rara e agressiva caracterizada por citopenias, hepatoesplenomegalia, febre e hemofagocitose na medula óssea, linfonodos, baço e fígado. A LHH associada a doenças malignas, embora seja uma condição rara, é potencialmente fatal. A paciente deste caso apresentou cinco dos oito critérios estabelecidos para o diagnóstico de LHH. A evolução do cariótipo do paciente, independentemente do perfil do diagnóstico, pareceu ser secundária ao tratamento da leucemia monocítica aguda, sendo que a instabilidade citogenética pode ter influenciado o comportamento atípico observado nas células leucêmicas. Este é um dos raros casos de LHH em uma criança com leucemia monocítica aguda.