Project Summary Primary central nervous system lymphoma (PCNSL) is an extranodal variant of non-Hodgkin lymphoma (NHL) that is confined to the brain, spinal cord, leptomeninges and eye. The diagnostic and therapeutic approaches to PCNSL are different from those that are applied to other forms of NHL. The International Primary Central Nervous System Lymphoma Collaborative Group (IPCG) consists of specialists from multiple disciplines dedicated to the study of PCNSL. The IPCG holds an annual scientific conference at the American Society of Hematology meeting in which various research topics related to PCNSL are discussed. Experts on the topic under discussion are selected each year by an executive committee to chair the scientific conference. These meetings have led to multiple collaborative projects that have positively impacted the field and that have been published in the peer reviewed literature. The annual IPCG meeting is a critical forum for generating new ideas and approaches to this unique and rare form of lymphoma. The 2021 conference topic is Primary Vitreoretinal Lymphoma (PVRL): Advances in Diagnostics and Management. PVRL is rare and there are no standard guidelines for management of this disease. The IPCG previously published results from a large series of patients with PVRL (Grimm et al, Ann Oncol 2007). Since then, there has been development in the diagnostics of PVRL and studies demonstrating efficacy of targeted agents. Accordingly, it is of great interest to IPCG members to have a symposium of diagnosis and treatment of PVRL.