[Imaging of Erdheim-Chester disease].

Erdheim-Chester disease is a form of Histiocytosis which involves the adults and is distinct from Histiocytosis X. It is characterized by a constant diaphyseal and metaphyseal bone involvement predominating in the lower links. The diagnosis can readily be envisaged when the typical radiological findings are present. Bone involvement may be isolated and well tolerated, or can be associated with systemic involvement and a severe prognosis. We describe three cases of women aged 46, 50 and 73 years. One patient presented with isolated bone lesions, while the two others had a multiorgan localization. From the three cases and from an extensive review of the literature, we describe the spectrum of bone and visceral lesions that can be seen by imaging. The emphasis is put on lesions of the skeletal system, the retroperitoneum, the nervous system, and the pericardium. Furthermore, the relationships between Erdheim-Chester disease and Histiocytosis X are discussed.