Purpose: Toxoplasmosis gondii is a common worldwide parasite that presents in the eye with focal retinochoriditis and vitritis. Although it is rare, ocular toxoplasmosis has been linked to primary intraocular (retinal) lymphoma, which is mostly a diffuse large B-cell lymphoma.
Methods: An elderly female patient was treated for recurrent ocular toxoplasmosis, and because of progressive vitritis, a diagnostic vitrectomy was performed. Shortly afterward, she developed multiple brain lesions. Pathologic examinations of the vitreous specimen and cerebral tissues were conducted, including tests for T. gondii, Epstein-Barr virus, and cytomegalovirus DNA.
Results: The patient initially responded to antitoxoplasmosis treatment but continued to have persistent vitritis. She was diagnosed with primary intraocular lymphoma, and a repeated magnetic resonance imaging revealed cerebral lesions. Brain biopsy confirmed lymphoma. T. gondii DNA was found in malignant vitreous cells but was absent in the nonmalignant vitreous cells and brain lymphoma cells. The cytomegalovirus and Epstein-Barr virus genes were not found in any of the lymphoma cells.
Conclusion: T. gondii may have played a role in lymphoproliferation and primary intraocular lymphoma development.