Rare “Burned-Out” Testicular Mixed Germ Cell Tumor on 18F-FDG PET/CT

Spontaneous regression of testicular mixed germ cell tumor is rare and is also called burned-out testicular tumor. We herein present the case of a 20-year-old man who was initially diagnosed with metastatic embryonal carcinoma. 18 F-FDG PET/CT demonstrated apparent metastases in the lymph node regions and both lungs. A covert right testicular lesion was noted according to the features on the CT component of PET/CT, which was subsequently confirmed as burned-out testicular mixed germ cell tumor.