[A case of orbital hematic cyst]

A case of orbital hematic cyst is reported. The patient was a 3-year-old boy in whom swelling of the left upper lid and left exophthalmos appeared after blunt trauma in the region of the left eye. A hematoma was thought to be present from upper lid to the orbit. The hematoma was absorbed but the swelling of the eyelid and exophthalmos increased though more than seven days elapsed after the trauma. The existence of the cyst located from the upper lid to the orbital deep portion and collection of blood were confirmed during operation. Histopathologically the cyst consisted of thickened fibrogranulomatous tissue and the inner wall lacked endothelial or epithelial lining. The blood collected in the cyst hardly coagulated and was examined hematologically. Extreme delay of activated partial thromboplastin-time and prothrombin time, extreme decrease of fibrinogen and abnormal increase of fibrin degradation products were recognized. This indicated that the blood in the cyst had been in a localized accelerated fibrinolytic state. The results support the hypothesis of the mechanism leading to the enlargement of hematic cyst proposed by Pearson et al.