Metabolic Resolution of Lytic Lesions in Erdheim-Chester Disease on 18F-FDG PET/CT.

Erdheim-Chester disease (ECD) is a rare non-Langerhans cell histiocytic disorder with variable clinical presentation most commonly involving the skeletal system. The long bones are the most common site of involvement giving a characteristic bone scintigraphy pattern of increased bilateral symmetric uptake in metadiaphyseal regions. We describe the findings of serial F-FDG PET/CT in a 16-year-old adolescent girl with ECD, emphasizing the role of F-FDG PET/CT in response assessment of ECD.