Cerebral infarction associated with protein C deficiency.

BACKGROUND AND PURPOSE: A deficiency of plasma protein C, both the hereditary and acquired types, is one cause of thromboembolic disease. Several antineoplastic agents have been reported to decrease the production of protein C in the liver by impairing either the absorption or metabolism of vitamin K, leading to acquired protein C deficiency. CASE DESCRIPTION: We treated a young woman with protein C deficiency, who had developed a cerebral infarction of the right parietal cortex of sudden onset. On admission, the antigenic level of plasma protein C was 38%. Serial cerebral angiography revealed occlusion of the right middle cerebral artery, which subsequently recanalized completely. This patient had taken fluorouracil derivatives orally for as long as 3 years following a left mastectomy for stage II breast cancer. Tests revealed that the patient's mother had only one-half the normal activity of plasma protein C despite a normal antigenic level. CONCLUSIONS: We speculate that the etiology of the cerebral infarction in this patient might involve an embolic mechanism associated with protein C deficiency induced by an interaction between inherited and acquired factors.