Gastric metastasis of choriocarcinoma is rarely reported in the literature. This case report presents the case of multiple metastatic testicular choriocarcinoma mimicking gastric cancer, with melena as the initial symptom. In this case, (18)fluorine-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) showed that the testis was the primary focus. The contribution of PET/CT is significant to primary focus detection in metastatic diseases of unknown primary origin that presented gastrointestinal bleeding. In addition to its use in staging of testicular carcinoma, PET/CT provides significant benefit in evaluating patients with increased levels of tumor markers and in detecting recurrence.