Primary phlebitis of central nervous system revealed by black-blood magnetic resonance imaging.

Primary phlebitis of the central nervous system (PPCNS) is a rare condition that might be a subset of primary angiitis of the CNS. In this case report, the patient was a 39-year-old man with a 2-week history of anterograde amnesia and abnormal behaviours. Black-blood MRI (BB-MRI) showed contrast enhancement of the left basilar vein and cerebral superficial veins. Angiography showed unremarkable change in arteries. After a thorough differential diagnosis, we diagnosed PPCNS and then administered methylprednisolone pulse and cyclophosphamide pulse. The neuropsychological symptoms and MRI findings gradually improved, and after 2 months, the dose of prednisolone was gradually reduced to 20 mg. No recurrence was observed. This case shows that BB-MRI may be useful for diagnosing PPCNS.