Genitourinary Radiology > Kidneys > Masses > Solid > Renal Abscess

Renal Abscess


Renal abscesses are usually a complication of untreated pyelonephritis, caused by ascending infection from gram negatives organisms (especially E. Coli). Predisposing factors include stone disease, diabetes, or AIDS. Complications include retroperitoneal spread and renocolic fistula.

CT findings include a well-defined focal renal mass with central necrosis (central portions showing no IV contrast enhancement), a thickened, hyperemic (enhancing) abscess wall, and perinephritic inflammation with thickening of Gerota’s fascia and stranding of perirenal fat.

Contrast enhanced CT scan through the kidneys in a patient with pyelonephritis and persistent fevers despite antibiotics shows left intrarenal fluid collection with areas of poor or no enhancement consistent with intrarenal abscess (arrows) with perinephric extension (*).

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