Abstract: An extranodal lymphoma, primary central nervous system lymphoma(PCNSL) has rarely been reported. PCNSL is commonly classified as a primary diffuse large B-cell lymphoma with pathology. The WHO classification of haematopoitic and lymphoid tissues(4th Edition, 2008) has listed primary diffuse large B-cell lymphoma as a independent disease entity. Current clinical diagnosis of PCNSL is this article in reviewed.