Superior sagittal sinus thrombosis in a patient with protein S deficiency.

A 30-year-old man presented with sagittal sinus thrombosis. He had a history of multiple thrombotic events since adolescence, and his father had had a similar history. Laboratory studies revealed the complete absence of free protein S in his plasma. Protein S deficiency, an autosomal dominant disorder, is an identifiable cause of cerebral thrombosis. The literature and our experience with this case suggest that long-term anticoagulant therapy may prevent thrombotic episodes in patients with this disorder.