An unusual cause of lumbar pain after physical exercise: Caval vein duplicity and its detection by ultrasound.

This paper deals with two recent cases of Inferior Caval Vein (IVC) duplicity, congenital anomaly often but not always asymptomatic that should be considered in the differential diagnosis of flank pain when other more common disorders have been excluded. Here are described the clinical and surgical significance together with the typical sonographic findings useful for the diagnosis of IVC duplicity. Particular attention is given to a peculiar and easily repeatable sonographic aspect associated with IVC duplicity, not previously reported in Literature and that we called the "Neptune's sign".