The evaluation and treatment of primary intraocular lymphoma

Abstract

Primary intraocular lymphoma (PIOL) is a relatively rare form of Non-Hodgkin's Lymphoma arising in the lymphoid tissues of the eye. It is highly correlated with primary CNS lymphoma (PCNSL) and it is estimated that up to 80% of patients presenting with PIOL will eventually manifest intracranial malignancy, which is the largest contributor to mortality. Most patients present with nonspecific visual symptoms, including floaters and blurry vision, and are often initially diagnosed with uveitis or retinitis. Definitive diagnosis requires biopsy of malignant tissues with demonstration of malignant lymphoid cells. Optimal therapy is to this point undefined, and the available literature is limited to case reports and retrospective series. Currently employed therapies include the use of localized external beam radiation therapy (EBRT), whole brain radiation therapy (WBRT), systemic chemotherapy, intrathecal chemotherapy, and, most recently, direct intravitreal (IVT) chemotherapy. While radiation therapy and chemotherapy can produce a high response rate, they have not been shown to effectively prevent relapse or the incidence of CNS spread. Methotrexate has been the most popular therapy used for the treatment of intraocular lymphoma. It has been administered systemically, intrathecally or intravitreally. However due to multiple mechanisms of resistance developed by lymphoma cells against methotrexate, this drug has been unable to prevent disease recurrence. The newest, and perhaps most promising, reported therapy includes the use of rituximab anti-CD20 monoclonal antibody either alone or in combination chemotherapy via intrathecal or IVT administration. Most cases in the literature employ combinations of available therapies, and there are no comparative studies of significant power to date. Multicenter collaboration will be required to determine the true relative efficacy and adversity of the therapeutic options available.