A 74-year-old man was diagnosed with small cell lung carcinoma in the left upper lobe. (18)F-FDG PET/CT showed multifocal strong abnormal uptakes in the axial skeleton and those of the primary lung tumor. CT failed to demonstrate the bony abnormalities. A subsequent (99m)Tc-MDP bone scintigraphy was also almost negative. It is important to note that bone metastasis may be undetectable by both CT and bone scintigraphy even if it is massive.