At present, the available clinical practice guidelines for the management of patients with germ cell tumor (GCT) assign to Positron Emission Tomography (PET) scan a role in the evaluation of the residual mass at the end of the treatment of advanced seminoma, while a possible role of this tool in the strategy of follow-up has not been defined yet. We are presenting a case of a patient treated for a GCT with an increase of the marker levels during the follow-up where a PET/CT with 18F-FDG was the only noninvasive examination able to correctly identify the site of disease recurrence. This case shows how this tool could have a role, in addition to morphological examinations, in the management of patients with GCT during the follow-up.