A 74-year-old man with multiple soft tissue lesions in the lung, which were suspected to be metastatic neoplasms, underwent F-FDG PET/CT scan to detect primary malignancy. The images demonstrated that the lung and 2 retroperitoneal lymph nodes were the only affected organ or tissues with suspected primary lung neoplasms. Multiple intestinal-type adenocarcinoma was eventually diagnosed by CT-guided transthoracic needle aspiration biopsy.