Patients receive fludeoxyglucose F 18 (FDG) IV followed 1 hour later by positron emission tomography (PET) imaging. Patients with metastatic disease identified by FDG PET imaging may receive adjuvant chemotherapy according to the standard clinical practice at each participating center. Patients with no metastatic disease identified by FDG PET imaging are considered for entry into the MRC-TE08 trial (randomized trial of 2 CT scan frequencies in the surveillance of stage I teratoma) or are followed according to the standard surveillance schedule.