Abstract
Remarkable eosinophilic infiltration of the hematoma membrane, observed not infrequently around sinusoidal vessels, has not been well documented.
Histological analysis of the membrane obtained from 57 patients was performed and the findings were classified into 5 groups according to histological maturity and clinical stage. Eosinophils were most conspicuous in membrane which had attained a certain thickness and had completed the sinusoidal pattern of the vessels. It was considered that eosinophils were closely related to the membrane's histological maturity, indicating healing. Eosinophilic infiltration was found in 30% of male patients, whereas all of the female patients showed marked eosinophilic infiltration of the membrane. Significantly, the number of female patients was much smaller. In male patients, the degree of eosinophilic infiltration was related to the estrogen level.
An experimental work was undertaken to produce hematoma membrane in the subcutaneous tissue of the guinea pig, and eosinophilic infiltration of the membrane was examined in relation to estrogen administration and the animal's sex. The results suggested a significant relationship between the membrane eosinophilia and estrogen level, as well as to the sex. It was postulated that eosinophilic infiltration of the chronic subdural hematoma membrane was a manifestation of healing, as in chronic inflammatory granulation, and that it was closely related to the estrogen level as evidenced by the predominate occurence of chronic subdural hematoma in males.
