OBJECTIVES: To improve the level of 'definitive' diagnosis of Langerhans cell histiocytosis by immunohistochemical investigation of the CD1a surface antigen and to compare outcomes in respect to age, gender, stage of the disease, treatment response and level of diagnostic accuracy. METHODS: A retrospective study was carried out of 37 children and adolescents with possible Langerhans cell histiocytosis between 1988 and 2008. The diagnoses were revisited using immunohistochemical investigations for CD1a, S-100 and CD68 in an attempt to reach definitive diagnoses for all cases. RESULTS: Before the study, only 13 of 37 patients (35.1%) had a 'definitive' diagnosis; by the end of the study, this number rose to 25 patients (67.6%). All reviewed cases were positive for the CD1a antigen. Overall survival was 88.5%. Multisystem disease (Stage 2; n=19) and absence of response at the 6th week of therapy (n=5) were associated to significantly lower overall survival (p-value = 0.04 and 0.0001, respectively). All deaths occurred in patients with multisystem disease and organ dysfunction at diagnosis. Other potential prognostic factors were not significant. Reactivation episodes occurred in 75% of the patients with multisystem disease. Diabetes insipidus was the most common sequel (21.6%). CONCLUSION: The level of diagnostic accuracy was increased through immunohistochemistry. The overall survival rate was similar to international multicentric studies. Multisystem disease and absence of response at six weeks of treatment were the most important unfavorable prognostic factors. The frequency of reactivation for patients with multisystem disease was higher than described in the literature, probably because maintenance chemotherapy was used only in two cases.

OBJETIVOS: Descrever a apresentação clínica da histiocitose das células de Langerhans e comparar sua evolução de acordo com a idade, estadiamento e resposta ao tratamento. MÉTODOS: Análise retrospectiva dos dados referentes a 33 crianças com histiocitose das células de Langerhans acompanhadas no Hospital das Clínicas da Universidade Federal de Minas Gerais no período de 1988 a 2004. RESULTADOS: A idade ao diagnóstico variou de 2 meses a 16 anos (mediana: 2,5 anos). Dezessete crianças eram do sexo masculino. O tempo de seguimento variou de 21 dias a 16,2 anos (mediana: 3,4 anos). As manifestações clínicas mais comuns ao diagnóstico foram lesões osteolíticas, linfadenomegalia e lesões cutâneas. A sobrevida global para todo o grupo foi de 86,1% aos 16 anos (IC95% 66,6-94,6). Os óbitos ocorreram em pacientes com doença multissistêmica e disfunção orgânica ao diagnóstico. Os pacientes que apresentaram resposta "melhor" à sexta semana de tratamento apresentaram uma probabilidade estimada de sobrevida global significativamente maior em relação aos que apresentaram progressão da doença. A sobrevida global foi significativamente maior para os pacientes com doença em um único sistema. A probabilidade de sobrevida livre de eventos para todo o grupo foi de 30,9% aos 16 anos (IC95% 15,6-47,5), sendo significativamente maior para os portadores de doença em um único sistema. A idade não se associou com a sobrevida livre de eventos. A seqüela mais comum foi o diabetes insipidus. Não foram observados casos de neoplasias secundárias. CONCLUSÃO: A histiocitose das células de Langerhans apresenta uma grande variedade de manifestações clínicas, com alta taxa de recidivas e baixa taxa de mortalidade.

OBJECTIVES: To describe the clinical course of Langerhans cell histiocytosis and to compare its outcome according to age, staging of the disease and treatment response. METHODS: Retrospective analysis of data on 33 children with Langerhans cell histiocytosis followed at Hospital das Clínicas, Universidade Federal de Minas Gerais, Brazil, between 1988 and 2004. RESULTS: Age at diagnosis ranged from 2 months to 16 years (median: 2.5 years). Seventeen children were male. The follow-up period varied from 21 days to 16.2 years (median: 3.4 years). The most common clinical manifestations at diagnosis were osteolytic lesions, enlarged lymph nodes and skin lesions. The overall survival rate for the whole group was 86.1% at 16 years (95%CI 66.6-94.6%). Deaths occurred in patients with multisystem disease and organ dysfunction at diagnosis. Those patients who had a "better" response to treatment in the sixth week were likely to have a significantly higher overall survival rate than those who showed disease progression. Overall survival rate was significantly higher for patients with single-system disease. The disease-free survival rate for the whole group was 30.9% at 16 years (95%CI 15.6-47.5%), and was significantly higher for those with single-system disease. Age groups were not associated with different disease-free survival rates. Diabetes insipidus was the most common sequela. No cases of secondary neoplasms were observed. CONCLUSION: The clinical manifestations of Langerhans cell histiocytosis vary widely, with a high relapse rate and low mortality rate.