Thrombosis in the pleural and subpleural regions.
Thrombosis was observed in the pulmonary veins of the thickened pleura and small vessels in the subpleural area (Figure 4ab, 5d). In the right middle lobe, old thrombus was organized and recanalized (Figure 4b, read arrow). However, most thrombi were fresh without organization (Figure 4ab, 5d). Hemorrhagic area included necrotic alveoli and blood vessels, as well as fragmented alveolar septum, where the presence or absence of thrombi was hardly evaluated. The cause of pulmonary hemorrhage was not be concluded. Although hemorrhagic infarct was one of the possibilities, it usually occurs in the subpleural area, which is distinct from this case.