A case of Löfgren's syndrome evaluated by imaging modalities: musculoskeletal ultrasound, MRI and PET-CT.

Löfgren's syndrome is an acute form of sarcoidosis that is characterised by articular symptoms, erythema nodosum and bilateral hilar lymphadenopathy. This syndrome is rare in Japan. We report a 62-year-old Japanese woman with Löfgren's syndrome and describe the articular manifestations as evaluated by multiple imaging modalities. Musculoskeletal ultrasound, magnetic resonance imaging and positron emission tomography-computed tomography findings indicated periarticular and subcutaneous inflammation. These imaging modalities facilitated the diagnosis of Löfgren's syndrome and helped differentiate from other rheumatic diseases.