We report herein computed tomography and F-fluoro-2-deoxyglucose positron emission tomography findings of primary pulmonary follicular dendritic cell sarcoma in a 51-year-old man, which is an extremely rare malignancy originating from follicular dendritic cells. Computed tomography scan revealed a 2.4-cm, well-defined solitary pulmonary nodule with delayed contrast enhancement but without regional lymphadenopathy, distant metastasis, or calcification within the nodule. On F-fluoro-2-deoxyglucose positron emission tomography scan, this nodule showed moderate hypermetabolic activity with a maximum standardized uptake value of 3.2.