[Mixed retinal thrombosis in a patient carrying prothrombin gene mutation in a homozygote state].

We reported a case of a thrombosis of the retinal and central artery and vein in a 44-year-old patient, with high-grade T-cell lymphoma. Cardiovascular family history and a medical history of cerebral ischemia caused by in situ fibrinolysis, led to perform thorough hematologic and genetic examinations. These disclosed a prothrombin gene G 20210 a variant in a homozygous state. In a heterozygous state, this mutation leads to an increase in plasma prothrombin rate of the order of 30%. Therefore, it is considered to be a major risk factor for venous thrombotic disease. Otherwise, acute leukemia or non-Hodgkin's lymphoma may induce thrombosis of retinal artery and vein by means of an optic nerve infiltration, as well as beta-thalassemia, ocular trauma and retrobulbar anesthesia. Retinal central artery and vein are seldom both involved; whereas occlusions of their branches are more frequent.