Iron deficiency anemia with marked thrombocytosis complicated by central retinal vein occlusion.

We report a case of severe iron deficiency anemia with marked thrombocytosis that was complicated by central retinal vein occlusion. Platelet count was over one million per microliter and an increased number of megakaryocytes was observed in the bone marrow at the time of diagnosis of iron deficiency anemia, features that resemble those of essential thrombocythemia. However, the platelet count rapidly declined with the administration of ferrous fumarate. Accordingly, central retinal vein occlusion was improved and has not recurred. In this case, significant thrombocytosis caused by iron deficiency anemia may have been involved in the development of central retinal vein occlusion.