Atypical presentations of primary lymphoproliferative processes in the central nervous system.

Central nervous system (CNS) involvement by lymphoproliferative disorders is rare and associated with a poor prognosis. CNS involvement can be exclusive, primary or appear in a secondary manner as part of a systemic process. The spectrum of involvement that we encounter is varied and neuroimaging plays a key role in diagnosis. This article reviews less commonly presented patterns of primary involvement of CNS lymphoproliferative processes such as lymphomatosis cerebri, intravascular lymphoma or dural lymphoma. We will also review other atypical lymphoproliferative processes associated with Epstein-Barr virus (EBV) infection, such as lymphomatoid granulomatosis (LG) or post-transplant lymphoproliferative disorders (PTLD). An awareness of these patterns of presentation and less frequent entities will allow us to make earlier diagnoses and establish treatments that will lead to better prognoses for patients.