In a 52-year-old man with gastric signet-ring cell tumor FDG PET/CT was performed for initial staging purposes. PET/CT study showed slightly increased FDG uptake at the gastric wall as well as diffuse lytic lesions with slightly heterogeneous increased FDG uptake suggestive of metastases. Despite normal complete blood count indices bone marrow biopsy revealed signet-ring cell carcinoma infiltration.