A 57-year-old woman had recalcitrant uveitis with anterior chamber and vitreous cells. Three years later she was found to have reticulum cell sarcoma (RCS) of the left frontoparietal area; it responded well to radiotherapy. Two years later a cataract extraction was performed. Two years later a cataract extraction was performed, and one year afterward the uveitis worsened. Ocular RCS was suspected but was not confirmed by examination of smears of aqueous aspirates on two occasions. When nodular thickening of the iris developed the patient was treated with azathioprine for 14 days. During this time the lesion in the iris enlarged, and a large extrabulbar and disclosed RCS of the uveal tract, vitreous, and external limbal area. This case is exceptional in that it shows the association of uveal tract and CNS RCS. This case also supports the observation that the use of low-dosage immunosuppressive agents is potentially harmful in RCS.