The authors report on a 46 year-old patient who presented with a chronic unilateral vitritis. A diagnosis of cerebral lymphoma was made 4 years earlier and a maxillary sinus recurrence was treated with chemotherapy and radiotherapy. A vitrectomy was performed and the level of Interleukin-10, a lymphoma cells growth factor, was found very high, giving a clue for the lymphomatous cause of the vitritis.