Sagittal sinus thrombosis associated with transient free protein S deficiency after L-asparaginase treatment: case report and review of the literature.

Cerebral sinus thrombosis associated with acquired free protein S deficiency is very rare. We report the case of an adult patient with acute lymphoblastic leukemia who presented with repeated transient ischemic attacks followed by a seizure during consolidation treatment with L-asparaginase. Magnetic resonance of the brain showed a small cortical hemorrhagic infarct. Superior sagittal sinus thrombosis was demonstrated by cerebral angiogram. A marked decrease of the free form of protein S was documented. One month later, when the patient was free of symptoms, the follow-up free protein S antigen level was restored to the normal range. We suggest that the sagittal sinus thrombosis in this patient was caused by acquired, transient free protein S deficiency. This case also extends the clinical spectrum of cerebral sinus thrombosis to include recurrent transient ischemic attacks alternating with seizures.