RESUMO
INTRODUCTION: Erdheim-Chester disease is a rare non-Langerhans form of histiocytosis. We report the use of combined fluorodeoxyglucose positron emission tomography and computed tomography (18F-FDG PET-CT) in this disease. EXEGESIS: Three men, aged from 55 to 74 years with confirmed Erdheim-Chester disease were included. 18F-FDG PET-CT allowed to detect visceral and vascular involvement of the disease which were overlooked with CT-scan or magnetic resonance imaging: left common carotid and ilio-femoral artery in one patient, coronary, femoral and tibia in the second, aortic, common carotid, femoral and mandibula in the remaining patient. Also, sequential 18F-FDG PET-CT was useful to appreciate treatment efficiency (decrease hyperfixation) and decide treatment modification (interferon alpha). CONCLUSION: 18F-FDG PET-CT combined imaging allows to assess the extent of involvement in Erdheim-Chester disease. 18F-FDG PET-CT may be also a useful tool in the management of Erdheim-Chester disease.