Intraocular lymphoma: a clinical perspective.

Primary vitreoretinal lymphoma (PVRL) is a rare malignancy that is speculated to arise extraocularly, and preferentially invade and flourish in the ocular and CNS microenvironments. The eye is involved in about 20% of primary central nervous system lymphomas, but the brain is eventually involved in about 80% of PVRL. Most are B-cell lymphomas with small numbers of T-cell lymphomas metastatic to the vitreous and retina. Metastatic systemic B-cell lymphoma usually involves choroid. Primary choroidal lymphoma is rare. Intraocular lymphoma can usually be distinguished from uveitis clinically, although there are overlaps, which may be pronounced in eyes with a large component of reactive inflammation related to tumor surveillance and control. There are controversies in diagnosis and treatment. Diagnosis through examination of ocular fluid is technically difficult and can utilize cytology, immunohistochemistry, flow cytometry, molecular detection of gene rearrangements, and cytokine profiling. Treatment of intraocular lymphoma without detectable CNS disease could consist of a full course of systemic chemotherapy with ocular adjunctive treatment, or ocular treatment alone depending on the preference of the clinical center. In ocular only cases where the vitreous has been debulked to improve vision and there is no sight-threatening involvement of the RPE, orbital irradiation or intravitreal chemotherapy stabilizes the intraocular process but does not seem to modify the CNS component, which can present symptomatically in an advanced state. This is a highly malignant disease with a poor prognosis. Close collaboration with a pathologist and oncologist, and good communication with patients is essential.