A 76-year-old man complaining of exertional dyspnea was admitted to our hospital. Chest computed tomography revealed bilateral diffuse ground-glass opacities and small nodules. A transbronchial lung biopsy revealed tumor cell emboli in the pulmonary arteries. The patient was diagnosed with gastric adenocarcinoma using an endoscopic stomach biopsy; however, the interstitial opacities progressively worsened and he died of acute respiratory failure. An autopsy revealed extensive pulmonary tumor embolisms (PTE) with associated ischemic damages, e.g., infarctions, alveolar wall thickening with cuboidal metaplasia, hemorrhage, and diffuse alveolar damage. The ground-glass opacities in the chest computed tomography findings appear to correlate with the pathological ischemic changes associated with PTE.