Significance of eosinophilic granulocytes in chronic subdural hematomas.

Despite a number of studies on infiltration of eosinophilic granulocytes into the outer membrane of chronic subdural hematomas, the significance of this phenomenon is not clear. We investigated histologically the membranes of 40 patients with chronic subdural encapsulated hematoma. Infiltrations with eosinophilic leucocytes were found in the granulation tissue of the inner layer of the outer membrane, either diffuse and sporadic (12 cases) or as massive agglomerations (28 cases). Fifty percent of the patients with marked infiltrations were between 61 and 80 years old. In 5 cases Charcot-Leyden crystals were identified. The numerous functions of the eosinophils play a more important role in repair than in maintenance of fluidity of hematomas.