The large spontaneous aorta inferior vena caval fistula.

The subject of spontaneous aortocaval fistula due to a ruptured abdominal aortic aneurysm into the inferior vena cava is reviewed and discussed. An interesting case is presented with particular emphasis on the pre-operative findings which include lower body cyanosis; pain, numbness, and paralysis of the lower extremities; a cyanotic partial penile erection; and moderate shock. The cause of this syndrome is postulated.