[Disseminated intravascular coagulation syndrome: morphological criteria]

Occlusion of the microcirculatory bed vessels with various kinds of microthrombi: fibrin, erythrocytic, leukocytic, and thrombocytic is pathognomonic for the morphological picture of the disseminated intravascular blood coagulation syndrome. Fibrin is the mandatory component of all kinds of microthrombi. The term "fibrinembolism" does not reflect all the complexity of the morphological manifestations of the process. In the group of fibrin thrombi, true fibrin, hyalin, globular thrombi as well as separate strands and filaments of fibrin are distinguished. True fibrin thrombi occur in the venous part of the microcirculatory bed and represent rounded formations of tightly interwoven fibrin filaments. Hyalin thrombi are dense homogeneous formations ultrastructurally different from true fibrin ones by the degree of polymerization (they are particularly characteristic of renal glomerular capillaries). Globular thrombi consist of erythrocytes coated with fibrin and occur in shock. Individual strands and filaments of fibrin are not thrombi but possibly represent a certain stage in the formation of fibrin thrombi; they occur in sinusoids of the liver and spleen. It is for these formation that the term "fibrin-embolism" is most suitable.