Globular hyaline microthrombi--their nature and morphogenesis

The ultrastructure of globular hyaline microthrombi (GHM) is characterized by a spherical space lattice of frequently interconnected bundles of fibres of different width, with a periodic transverse striation and the fibrin-characteristic axial periodicity of 23 nm. These are surrounded by plump or slender bundles of fibres spreading radially over the surface which are only ocassionally interlinked. These filamentary formations of the so-called corona are also characterized by the fibrin-characteristic periodicity. Part of the GHM, however, lacks this axial periodicity, and periodic striation is then only visible in the radially extending fibrils of the corona. The spherical sace lattices with their plump or slender fibrillary fibrin bundles are also replaced by mosaic-like or nearly amorphous fine-grained precipitates. All intermediate stages between these main types of GHM can be found. The disappearance of the axial periodicity and of the fibrillary structure of the spherical space lattices is considered to be the morphological equivalent of seocndary fibrinolysis, here called endolysis, in the centre of the GHM. The morphogenesis of the GHM in states of shock of different aetiologies is discussed.