Intraocular lymphoma

There are two distinct forms of intraocular lymphoma. One originates within the central nervous system (CNS) and is called primary CNS lymphoma. The second form arises outside the CNS and metastasizes to the eye. When primary CNS lymphoma initially involves the retina, it is named primary intraocular lymphoma (PIOL). Although PIOL is a rare malignancy, the incidence has dramatically increased in the past 15 years. Typical clinical manifestations include blurred vision and floaters. Ophthalmic examination reveals vitreitis and subretinal infiltrates. Diagnosis of PIOL can be difficult and requires neuroimaging, examination of the cerebrospinal fluid and/or vitreous. Molecular analysis detecting immunoglobulin gene rearrangements and ocular cytokine levels showing elevated interleukin (IL)-10 with an IL-10 to IL-6 greater than 1.0 are helpful adjuncts for the diagnosis. Treatment includes systemic chemotherapy and radiation with current regimens favoring the use of chemotherapy first. In contrast, metastatic systemic lymphoma, like other metastatic ocular tumors, is usually confined to the uvea, in particular the choroid. Compared with PIOL, metastatic systemic lymphomas have a much lower prevalence, better prognosis, and are less likely to create a diagnostic dilemma.