[Erdheim-Chester disease : a case report].

We report the case of a 47-year-old woman with unexplained inflammatory syndrome and asthenia. Imaging findings show bilateral abnormalities of femurs and tibias, suggesting an Erdheim-Chester disease, which is confirmed by a bone marrow biopsy of the left femur. The BRAF V600E mutation is detected, allowing the administration of targeted therapies such as BRAF and MEK inhibitors that lead to the improvement of symptoms.