Adult Embryonal Rhabdomyosarcoma of the Prostate Presented on 18 F-FDG and Al 18 F-FAPI-74 PET/CT.

A 21-year-old man with a 2-week history of abdominal pain and urinary hesitancy was admitted to our hospital. Sarcoma was suspected based on his PSA level, age, and MRI findings. He underwent 18 F-FDG and Al 18 F-FAPI-74 PET/CT scans. The scans revealed an irregularly dense prostate mass with indistinct borders to the rectum. The mass exhibited increased and heterogeneous FDG uptake and FAPI activity, with different distribution patterns between the 2 tracers. Histopathological analysis confirmed the diagnosis of embryonal rhabdomyosarcoma.