Rosai-Dorfman Disease Presenting as a Pulmonary Artery Mass on FDG PET/CT

Rosai-Dorfman disease (RDD) is an uncommon histiocytic disorder typically involving the lymph nodes and occasionally manifests as extranodal disease. Extranodal RDD involving pulmonary artery without lymphadenopathy or other extranodal lesions is very rare. We present the case of a 48-year-old woman complaining of shortness of breath on exertion for 6 months. F-FDG PET/CT revealed a pulmonary artery mass with intense FDG avidity. No other abnormal FDG-avid lesion was observed. The pulmonary artery mass was then surgically removed, and the pathological and immunohistochemical results confirmed RDD.