Ultrastructural observation of the outer membrane of chronic subdural hematoma

Abstract

Objective To explore the pathophysiological mechanisim underlying the development and progression of chronic subdural hematoma (CSDH) through an ultrastructural observation of the outer membrane of CSDH. Methods A total of 8 samples of CSDH outer membrane were obtained from the 8 patients who had uncergone surgery of hematoma removal in our department from January 2008 to January 2009.CT scanning revealed 2 cases of low hematoma density,2 cases of hematoma isodensity, 2 cases of high hematoma density and 2 cases of mixed hematoma desity.Conventional light microscopy and electron microscopy were used to observe the ultrastructure of the outer membrane. Results Light microscopy showed numerous dilatated and congested macrocapillaries with a wide vascular lumen in the outer membrane of the hematoma capsule.Electron microscopy showed weak, discontinous or partially dissolved endothelial cells in the macrocapillaries.Scattered red blood cells in the extracellular space were found, indicating bleeding within the outer membrane.Eosinophils increased with enlarged granules within the cellular cytoplasm.Neutrophils and macrophages were also present in some specimens.Fibroblasts showed a state of significant proliferation and activation. Conclusions There are abundant newly formed vascular networks in the outer membrane of CSDH. Neomembrane formation, neovascularization and repeated micro-haemorrhages from these fragile new vessels may play a key role in the development and progression of CSDH. Key words: Chronic subdural hematoma; Electron microscopy; Pathology