Diagnosis of systemic metastatic retinal lymphoma

Systemic metastatic retinal lymphoma (SMRL) is exceptionally rare, as systemic lymphomas most often metastasize to the uvea. We have evaluated a series of SMRL cases to elucidate the clinical and pathological features of SMRL.

The pathological specimens of intraocular lymphomas (IOLs) at the National Eye Institute from 1991 to 2009 were retrospectively reviewed. These cases were diagnosed by cytology, cytokine measurement (ELISA for interleukin (IL)-10 and IL-6 levels) and Immunoglobulin-Heavy (IgH) and T-cell-receptor (TCR) gene analyses.

There were nine B-cell SMRLs (B-SMRL) among 96 B-cell retinal lymphomas (9.4%) and three T-cell SMRLs (T-SMRL) among five T-cell retinal lymphomas (60%) from a total of 116 IOLs, in which 101 were retinal lymphoma. The original sites were nasopharynx (3), testis (2), skin (2), breast (1), blood (1), retroperitoneum (1), ileo-caecum (1) and stomach (1). Cytology of vitreous samples illustrated atypical lymphoma cells with either B- or T-monoclonality. More B-SMRLs had a high ratio of vitreal IL-10 to IL-6 than T-SMRLs. Molecular pathology demonstrated lymphoma cells with gene rearrangements of IgH in all B-SMRLs and TCR in all T-SMRLs.

SMRL and primary retinal lymphoma present with similar clinical manifestations. Systemic T-cell lymphoma invades the retina and vitreous more aggressively than systemic B-cell lymphoma. A diagnosis of SMRL is made when there is a clinical history of systemic lymphoma (particularly from nasopharynx, testis and skin), and lymphoma cells are identified in the vitreous or retina. Molecular analysis is more useful than vitreal cytokine measurement for SMRL diagnosis.