Primary intracranial lymphoma. An important differential diagnosis in magnetic resonance imaging of the brain.

The magnetic resonance (MR) appearances are described in 6 pathologically verified cases of primary intracranial lymphoma, and comparison is made with the appearances on computed tomography (CT). In 5 cases, atypical CT appearances were seen and in these cases more extensive and multiple abnormalities were demonstrated by MRI. The importance of differentiating this condition from other pathologies affecting the white matter is discussed.