**35. Tumor embolism**

Pulmonary tumor emboli are defined as clumps of malignant cells within the lumina of pulmonary arteries and arterioles (Kane et al., 1975). Microscopic pulmonary tumor emboli involve the small pulmonary arteries, arterioles and alveolar septal capillaries which are occluded by aggregates of tumor cells accompanied by platelet-fibrin thrombosis. Types:

