[Renal sinus disorders: imaging findings and pitfalls]

Renal sinus pathology can be classified into 3 groups: intrinsic lesions that arise from the anatomical components of the sinus (fatty tissue, collecting system, arteries and veins, lymphatic vessels, and nerves); extrinsic lesions that develop within the renal sinus from the renal parenchyma; secondary lesions including metastases and retroperitoneal tumors with renal sinus involvement. The diagnosis of renal sinus disorders often relies on a multimodality approach including IVU, doppler-ultrasonography, and CT. The wide variety of renal sinus diseases that may origin either from the renal parenchyma or the retroperitoneum, and the numerous pitfalls mostly due to anatomic variations, may prevent from making a right etiological diagnosis in numerous cases.