Primary central nervous system lymphoma presenting as diffuse cerebral infiltration.

We report a case of primary central nervous system lymphoma presenting as diffuse cerebral infiltration. On T2-weighted spin echo MR imaging using a 1.0 Tesla unit, high signal intensity lesions were presented mainly in the bilateral pyramidal tracts and also diffusely extended to white matter with brain swelling. No enhancing lesion was demonstrated after the intravenous injection of Gadolinium-DTPA, during the course of her disease. Radiological diagnosis of gliomatosis cerebri was made because of the characteristic MR appearance. Stereotactic biopsy was performed, and diffusely scattered lymphocytes, probably neoplastic, in the cerebral white matter were demonstrated histopathologically. Oral corticosteroids, radiation therapy, and chemotherapy were applied soon after her admission. The patient's condition improved dramatically. MR imaging using a 1.5 Tesla unit after the treatments showed marked regression and reduction of high intensity lesions on T2-weighted images and improvement of brain swelling. It should be emphasized that brain biopsy is important method for correct diagnosis in case of diffuse non-enhancing brain lesions like our case.