Rosai-Dorfman Disease Involving Thymus and Aorta Revealed by 18F-FDG PET/CT

Rosai-Dorfman disease (RDD) is a rare non-Langerhans cell histiocytosis primarily involving lymph nodes, with occasional extranodal manifestations. Thymic and aortic involvement is exceptionally uncommon. We reported a case of a 33-year-old woman presenting with a mediastinal mass on 18 F-FDG PET/CT, revealing intense metabolic activity in the thymic region and thoracic aorta. Histopathology confirmed the diagnosis of RDD.