The Onset of Sarcoidosis After COVID-19 Vaccination Revealed by the 18 F-FDG PET.

Sarcoidosis is a heterogeneous multisystem disease characterized by noncaseating granulomas. We presented 18 F-FDG PET/CT findings of sarcoidosis in a previously healthy 43-year-old man who presented intermittent cough after the third dose of COVID-19 vaccination. 18 F-FDG PET/CT showed high uptake of one solitary nodule in the right middle lobe, mediastinal lymph nodes, bilateral hila, and multiple nodules under the right pleura, mimicking the malignancy. Nevertheless, the biopsy confirmed distinct noncaseating granulomas. This case emphasizes the onset of sarcoidosis revealed by 18 F-FDG PET/CT after COVID-19 vaccination.