Erdheim-Chester disease: A rare diagnosis with evocative imaging

Observation A 60-year-old male patient was examined for the exploration of bilateral retro-orbital tumours. These tumours were discovered two years earlier in a brain scan for the exploration of an exophthalmous. Two biopsies of these lesions were taken. The first one revealed a polymorphous inflammatory tissue. The second one revealed a strong granulomatous reaction, rich in non-specific foamy histiocytes. During his hospitalisation, the patient described a weight loss of 12 kg over the last year as well as diffuse periodic inflammatory bone pain. The thoracic-abdominal-pelvic CT scan detected peri-aortic infiltration with the typical appearance of an aortic sleeve (Fig. 1) associated with ‘‘hairy’’ kidneys (Fig. 2). The association of these signs pointed to a diagnosis of Erdheim-Chester disease, confirmed by a bone scan (Fig. 3) and the re-examination of the histological samples.