Perirenal cobweb

Last revised by Dr Daniel J Bell on 27 Jan 2018

Perirenal cobwebs are the presence of prominent perinephric septa. 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 ureteral obstruction due to a stone. It may also be seen in other situations such as 

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Cases and figures

  • Case 2 - transitional cell carcinoma of the renal pelvis
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