A 37 year-old man who developed a fatal middle cerebral territory infarct was found at autopsy, to have widespread granulomatous angiitis involving meningeal and intracranial--extracerebral vessels but not intracerebral vessels or other extra-cranial vessels. The findings are unique and overlap with those of granulomatous angiitis of the nervous system (GANS) and classic giant cell arteritis (GCA). A possible precipitant for this devastating illness was a recent Chlamydia infection. The salient clinical and pathologic differences between GANS and GCA of the nervous system are discussed.