Multiple, primary spinal-paraspinal hydatid cysts.

A patient is presented with widespread primary hydatid cysts in spinal-paraspinal locations, secondary to Echinococcus granulosus. An alternative mechanism to explain how the embryos gained access to the body is proposed: The embryos penetrated the intestinal muscle and may have directly entered into the inferior vena cava system through small venous connections between this system and portal circulation. Various conditions in daily life associated with Valsalva maneuver might have caused such an atypical passage of the embryos to the inferior caval system toward the retroperitoneum and spinal-paraspinal structures via lumber epidural venous plexuses.