Occlusion of a branch of the central retinal vein as a manifestation of hypercoagulability in a patient with lung cancer. A possible paraneoplastic event.

The author describes the case of a patient with occlusion of a branch of the retinal central vein associated with lung carcinoma. He attributes the occlusive event, at the level of the retinal venous microcirculation, to a condition of hypercoagulability induced by cancer in coexistence with a slowing down of the blood flow as a result of a slight increase of serum viscosity. In the clinical discussion the author first considers the pathogenesis of the clinical and laboratory alterations concerning the coagulation observed in patients with cancer, and then hypothesises that the retinal vein thrombosis in the patient under question might be produced by way of a mechanism of interaction between tumor cells, plasmatic systems of the coagulation, leucocytes, platelets and endothelial cells.