RENAL VEIN THROMBOSIS DUE TO POSTERIOR NUTCRACKER SYNDROME.

Thrombosis of the left renal vein (LRV) is a rare occurrence usually associated with hypercoagulable disorders. It may also be caused by extrinsic compression due to anatomical variations. Such variations, known as nutcracker phenomenon (NP), are usually completely asymptomatic, and they have been described in three variants: a narrowed aortomesenteric angle (AMA) with entrapment of the LRV; a second, rarer variant with an anomalous retro aortic LRV compressed between the abdominal aorta (AA) and the spine (posterior nutcracker syndrome, PNCS); and a third variant with a duplicated LRV with a pre- and retroaortic course, compressed both anteriorly and posteriorly.