Perirenal cobwebs are the presence of prominent perinephric septa. It is best appreciated on CT images.
Pathology
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
- renal malignancies
- renal vein thrombosis
- other acute conditions