Background. The aim of study was to evaluate outcome of international treatment protocol LCH II for children with Langerhans cell histiocytosis treated in FN Motol. Methods and Results. Between November 1995 and December 2003, 46 children were treated, sex ratio M:F 29:17 and median age at diagnosis 6 years 8 months. 28 children (60.9%) suffered from monosystem disease with majority of bone lesions (23 times) with skull predominance (16 times). Surgery was primary treatment modality for monosystem disease. Five children with recurrence were successfully treated by protocol LCH II – LR (3x) and LCH III – LR /G2/, respectively. Eighteen children (39.1%) suffered from multisystem disease. 6 out of 18 patients were treated according to low-risk protocol LCH II – LR and 12 children by high-risk scheme LCH II – HR at the nonrandomized branch included etoposide. Recurrence was revealed in 11 patients and 10 of them reached 2nd or 3rd complete remission (CR) by 2 – chlorodeoxyadenosine (CDA) monotherapy, and 1 child reached 2nd CR by LCH II – HR scheme. Two children underwent irradiation after bone lesion excision as well as 1 child as supplemental treatment. Totally, 29 children (63.0 %) achieved 1st CR, 14 (30.4 %) 2nd CR, 2 (4.4 %) 3rd CR, and 1 child died because of LCH progression. There were no severe side effects of chemotherapy. Follow-up median time was 5 years 8 months (range 9 months – 9 years 6 months). Conclusions. LCH II protocol is safe and effective. Results revealed that treatment of patients with multisystem disease might demand some treatment modification.

        Key words: Langerhans cell histiocytosis, children, LCH II protocol, outcome.