[Two cases of what was regarded as cerebral vasculitis]

Two cases of cerebral vasculitis of the central nervous system are reported. In our cases, systemic investigation found no underlying cause for vasculitis. Case 1: A 59-year-old female presented severe headache due to subarachnoid hemorrhage. CT scan obtained one month later demonstrated a low density area with ring-like enhancement in the right frontal lobe. A surgical specimen revealed inflammation of the leptomenigeal vessels with many lymphocytes. Case 2: A 64-year-old female came to us with dysarthria and slight left hemiparesis. CT scan and MRI obtained after admission demonstrated an abnormal mass lesion with enhancement in the right frontal lobe. The histological examination revealed vasculitis. After systemic disease and central nervous system infection were excluded, we diagnosed this case as cerebral vasculitis of unknown origin. In this paper, the clinical and pathological features of cerebral vasculitis and differential diagnosis were discussed.