Langerhans cell histiocytosis: retrospective analysis of 217 cases in a single center.

Langerhans cell histiocytosis (LCH) is a disorder with unclear etiology and pathogenesis, which is characterized by abnormal clonal proliferation and accumulation of langerhans cells at various tissue and organs. A total of 217 patients with LCH were evaluated retrospectively for clinicopathological features, laboratory findings, treatment modalities, long-term outcome, and factors affecting the outcome. Median age at the time of diagnosis was 3.5 years and male/female ratio was 1.8. The most common complaint at presentation was a bone lesion-related symptom. Fifty percent of the patients younger than 2 years had organ dysfunction (OD). Treatment consisted of surgery, chemotherapy, and radiotherapy alone or in combination. Vinblastine with or without prednisolone was the most common used chemotherapy regimen. Overall (OS) and event-free survival (EFS) rates were 84% and 51.5%, respectively, at an 8-year median follow-up time. Overall survival was significantly lower in patients younger than 2 years of age and patients with OD. The age at diagnosis, pulmonary, liver, or hematological involvement, and elevated acute-phase reactants were found to have a statistically significant effect on the OS or EFS rates.