A 57-year-old man visited our hospital due to abnormal chest X-ray findings. Chest computed tomography(CT)showed amalgamated beaded solid nodules in the right upper lobe of the lung. Lobectomy of the right upper lobe was performed and the nodule was histologically determined to be seminoma. Positron emission tomography(PET)-CT showed high 18F-fluorodeoxyglucose(FDG)uptake in the lung nodules and faint uptake in the left testicle. As ultrasound and palpation detected no tumor in the testes, consent to perform orchiectomy was not obtained. Considering the PET-CT findings, we diagnosed testicular seminoma with solitary pulmonary metastasis, which is extremely rare.