Sousa- Rodrigues, C. F.; Alcântara, F. S.; Rocha, A. C.; Gusmão, L. C.; Monte-Bispo, R. F.; Ferreira, A. K. & Olave, E.

The development of the cava venous system is very complex, taking place to the raising of innumerous variations of the anatomical patterns already known, which could be more or less common and others, still, of rare incidence. One of these anomalies may occur in a low frequency on the left side, forming a vascular ring around the aorta constituted by a preaortic renal vein and other retro-aortic renal vein, entering in a lower level of the VCI, in a condition called as “ Renal Collar” consisted of persistence of the Intersupracardial embrionary anastomoses. In this case report, the vascular disposition corresponds to a type of the classification as related in literature, with exception of the independent emergency of the preaortic and retro-aortic components of the circum-aortic collar from the renal hilum and the distal diameter of the retroaortic renal vein. The preaortic vein had 90 mm of length, diameter of 20 mm in its end and led into the VCI on the lower level of L1. The retroaortic vein measured 125 mm of length, crossing L1 and L2 to discharge in the VCI, to the upper level of L3, where it had diameter of 14 mm. The importance of the study and description of the circumaortic renal collar is due to it representing a potentially hazardous anomaly of the left renal vein, occurring case reports where failure to recognize the dorsal component during retroperitoneal surgery may lead to abundant hemorrhage after inadvertent injury, unnecessary nephrectomy or, even death.

KEY WORDS: Kidney; Renal Veins; Anatomical variations

SOUSA- RODRIGUES, C. F.; ALCÂNTARA, F. S.; ROCHA, A. C.; GUSMÃO, L. C.; MONTE-BISPO, R. F.; FERREIRA, A. K. & OLAVE, E. Persistence of renal venous collar. Int. J. Morphol., 31(2):500-504, 2013.