PurposeTo describe the clinical features and histologic classification of orbital lymphoma secondary to systemic non-Hodgkin lymphoma, to evaluate the efficacy of various treatment modalities for controlling the orbital component of disease, and to analyze vision-related outcomes.MethodsIn this retrospective case series, the clinical records of patients diagnosed with orbital lymphoma who were treated between January 1999 and May 2001 at the University of Texas M.D. Anderson Cancer Center were reviewed. Demographic data, histologic classification of lymphoma, immunophenotype, stage of disease, treatment outcomes, vision-related outcomes, and duration of follow-up after the diagnosis of orbital lymphoma were recorded in each case.ResultsAt the time of diagnosis, all 15 patients identified either had a previous history of non-Hodgkin lymphoma or had simultaneous involvement of lymph node or other sites. Ten patients (67%) had intermediate-grade or high-grade lymphoma. All 15 patients had a B-cell phenotype. Systemic chemotherapy or immunotherapy was the initial treatment modality in 13 patients; the other 2 patients were treated with radiation as the initial mode of therapy. Eleven patients (73%) achieved complete regression of the orbital tumor; one patient had partial regression of the orbital lymphoma. Loss of vision secondary to compressive optic neuropathy was seen in 5 patients (33%); in 3 of these patients, the orbital lymphoma was diagnosed early and treatment was successful in reversing the loss of vision. One patient had irreversible vision loss secondary to compressive optic neuropathy; in this case, therapy had not been initiated until several months after onset of symptoms. Another patient died of lymphoma before the orbital disease could have responded to therapy.ConclusionsBecause of often widespread systemic involvement and a usually more aggressive histologic classification than primary orbital lymphomas, secondary orbital lymphomas warrant treatment with systemic chemotherapy or systemic immunotherapy. In some cases, combining such systemic therapy with local radiation treatment is beneficial. Loss of vision as the result of compressive optic neuropathy in this setting can be reversed if systemic therapy is initiated soon after the onset of progressive signs and symptoms of orbital disease.