[LANGERHANS CELL HISTIOCYTOSIS: A SINGLE CENTER EXPERIENCE IN THE PEDIATRIC HEMATO-ONCOLOGY DIVISION OF THE TEL-AVIV SOURASKY MEDICAL CENTER].

Langerhans cell histiocytosis (LCH) is a histiocytic disorder which is characterized by a wide variety of clinical presentations and is prevalent mostly in children .This is a single center study reviewing experience in the treatment of LCH in a pediatric hemato-oncology ward over 25 years. We summarized the demographics, the locations of the disease, the treatments administered, the reactivations and the survival of the patients. A retrospective analysis of files was performed from patients who were referred and treated at the Dana-Dwek Children's hospital in the Tel-Aviv Sourasky Medical Center between the years 1996-2020. One hundred and six patients with LCH were treated during the period 1996-2020 in the Pediatric Hemato-Oncology division. The diagnosis was confirmed by a biopsy from a lesion. The primary location of the disease was single system in 91% of patients (mostly bone lesions) and 9% multisystem disease. Forty-five patients (42.4%) were treated by upfront chemotherapy according to the Histiocyte Society guidelines. Twenty patients (19%) had reactivation of their disease. Ninety percent of the reactivations occurred in the first four years after diagnosis. There was no mortality in this cohort. This is a single center study summarizing the experience of a Pediatric Hemato-Oncology division in the Tel-Aviv Medical Center in the treatment of 106 patients with LCH over 25 years and is the first review of a large cohort of patients in Israel. The cohort was characterized by abundance of patients with bone disease and paucity of patients with multisystem disease with risk organ involvement. There was overall good response to treatment and all patients survived.