Primary CNS lymphoma in Immunocompetent patients: Appearances on Conventional and Advanced Imaging with Review of literature.

Primary central nervous system lymphoma (PCNSL) constitutes about 3% of all primary brain tumors and nearly 1 to 3% of all Non Hodgkin Lymphomas. In the recent years the incidence of primary CNS lymphoma is increasing in immunocompetent patients. As PCNSL are chemosensitive as well as radiosensitive, its early and accurate diagnosis is imperative for optimal management. Contrast enhanced Magnetic Resonance Imaging (MRI) is the recommended imaging modality for PCNSL; however, contrast enhanced Computed Tomography (CE-CT) is done in cases where MRI is contraindicated. Advanced imaging techniques like DWI (diffusion weighted imaging), MRS (MR Spectroscopy), MR perfusion, DTI (Diffusion tensor imaging) are important in diagnosis and help in its differentiation from other tumors.