Isolated angiitis of the central nervous system (IACNS) is a rare form of angiitis limited to the central nervous system. The clinical finding of the combined series revealed that headache was the most common symptom within a combination of focal and diffuse neurological deficits. The case, a 28-year-old man, is presented; the clinical presentation and diagnostic difficulties are discussed. The patient's symptoms began with an obvious atypical depression. In spite of an antidepressive treatment, his symptoms continued to worsen with personality, mood changes and euphoria added to the clinical picture. Meanwhile after several transient ischemic attacks, 6 months later, he was admitted with neurological symptoms including headache, diplopia, and cerebellar ataxia. The radiological investigation was mimicked by primary brain lymphoma. The brain biopsy excluding of lymphoma revealed parenchymal hemorrhage with nonspecific degenerative changes. In systemic investigation, no underlying cause for vasculitis could be found. Neurological but not psychological deficits and radiological lesions of the patient improved with steroid therapy. Since we could not find features of systemic vasculitis, the patient's lesions responded to corticosteroid treatment and neuropathological investigation revealed no lymphoma, We concluded that the most probable diagnosis would be IACNS. (c) 2005 Elsevier Inc. All rights reserved.