Diffusion-weighted MR imaging improves diagnosis of CNS lymphomas. A report of four cases with common and uncommon imaging features.

The frequency of CNS lymphomas is increasing in immunocompetent as well as in immunocompromised patients and its incidence accounts for approximately 1-2% of all primary cerebral neoplasms. It is a challenge to recognize CNS lymphomas by MR imaging as early as possible in order to dispose an optimal therapy. The aim of this report is to demonstrate, how diffusion-weighted MR imaging improves the accuracy of the differential diagnosis of CNS lymphomas.