Perirenal cobwebs is the presence of prominent perinephric septae. It is best appreciated on CT images.
The cobweb is considered to be due to engorged venous collaterals or due to edema and fluid extravasation into the perirenal space 1.
Perirenal cobwebs may be seen in many benign and malignant conditions of the kidney. The commonest cause is acute uretral obstruction due to stone. It may also be seen in other situations such as
- 1. Dyer RB, Chen MY, Zagoria RJ. Classic signs in uroradiology. Radiographics. 2004;24 Suppl 1 (suppl 1): S247-80. Radiographics (full text) - doi:10.1148/rg.24si045509 - Pubmed citation
- 2. Lien HH, Lund G, Talle K. Collateral veins in left renal vein stenosis demonstrated via CT. Eur J Radiol. 1983;3 (1): 29-32. Pubmed citation