This chapter aims to provide a complete knowledge over the primary intraocular lymphoma (PIOL) and a correct clinical approach towards this rare condition, to avoid delays in diagnosis, which is considered the most important prognostic factor. A PIOL arises with no specific symptoms and could mimic both inflammatory and non-inflammatory ocular conditions. Also known as reticulum cell sarcoma in the past, PIOL is an ocular malignant condition, with a strong bond with primary central system lymphoma (PCNSL). This linkage is underlined by the fact that approximately 30% of the patients with PIOL have also PCNSL at presentation, while 45–90% will develop PCSNL in the following months. A correct diagnosis is currently achieved by the means of many different techniques: cytology, flow cytometry, immunohistochemistry, molecular analysis, and cytokines assay. Treatment of this condition has been completely revolutionized with the introduction of monoclonal antibodies directed against specific proteins present on the surface of lymphomatous cells.
Primary Intraocular Lymphoma: The Masquerade Syndrome