[Ultrastructural aspects of intra- and extravascular coagulopathy in lung cancer]

Four cases of lung cancer were analysed for aspects relating to optical light microscopy and ultrastructure of coagulation disorders. Criteria of intravasal coagulopathy were positively verified from all four cases and were found to have grown manifest in the form of prethrombi in veins, arterioles, and venules, masses of fibrin monomer in capillaries, and the sludge phenomenon. Extravasation of fibrin was also observed around highly differentiated cancer cells as well as in tumour stroma and in necrotic foci. Most of the fibrin was identified in the forms of monomers and their ultrastructural variants. Morphological criteria of locally delimited coagulation disorders in the microcirculation of tumours are discussed together with the role played by fibrin in growth and dissemination of neoplasms.