Abstract: 　Objective　To explore clinical characteristics of Erdheim-Chester disease (ECD) in children. Method The clinical manifestations, imaging findings and pathological finding of two childhood ECD patients in our hospital were retrospectively summarized. Results　The most common manifestations of ECD in children included polydipsia, polyuria, lower limb pain, and hepatomegaly, etc., which were similar to Langerhans cell histiocytosis in manifestations, but the pathological features were similar to yellow lipid granuloma, immunohistochemical features are CD68 (+), CD1a (?), and S-100 (?). Compared with that in adults, skeletal systems were also most likely to be involved in children, and nervous system seemed to be more likely to be involved in children, while heart and skin were rarely involved. Two children were treated with interferon with improved clinical situations. Conclusions　ECD is a rare non-Langerhans cell histiocytosis. Early identification and diagnosis can improve the prognosis of the disease.

Key words: Erdheim-Chester disease;　diabetes insipidus;　bone destruction;　Langerhans cell histiocytosis;　interferon