A 53-year-old man was admitted to our hospital because of lumbago. Gastrointestinal endoscopic examination performed on admission did not reveal any gross gastric abnormalities. Lumbar radiogra- phy and bone scintigraphy revealed multiple bone osteoblastic changes. Chest radiography showed right pleural effusion. The findings ofthe chest computed tomography and cytological examination of the pleur al effusion were strongly suggestive of lung cancer. The patient was refr actory to chemotherapy, and he died of cancer and disseminated intravascular coagulation. The autopsy revealed absence of primary lung cancer and the presence of tumor emboli in the right lung fi eld. Swollen perigastric lymph nodes, tiny signet-ring cell carcinoma at the posterior wal1 of the stomach corpus, and severe vascular invasion were also observed at autopsy. Therefore, signet ring cell carcinoma ofthe stomach should be considered as a possible diagnosis in early-stage gastric cancer patients who develop osteoblastic metastasis and pleural effusion.