A caliceal diverticulum is a cystic cavity of the kidney, which is lined with urothelium and has (or had) a connection to a renal calyx. If the diverticulum communicates with the renal pelvis, is is called pyelogenic cyst.
Epidemiology of caliceal diverticula:
4,5:1000 (from studies with intravenous urography)
Etiology of Caliceal Diverticula
Caliceal diverticula may result from rests of the ureteric bud of the 3rd or 4th Generation, which usually degenerate.
Resulting from a cortical kidney abscess, a cortical cyst or from caliceal obstruction, a caliceal diverticulum may form. Complications of urinary stasis are recurrent urinary tract infections, milk of calcium or nephrolithiasis.
Signs and Symptoms of Caliceal Diverticula
- Pain, hematuria or recurrent infections
- Cystic mass in imaging
Renal ultrasound reveals a cystic structure near a calyx, often filled with echogenic content (milk of calcium, often changing with the position of the examination).
Caliceal diverticula are often visible on the plain kub abdominal x-ray (milk of calcium). Otherwise, the caliceal diverticulum present as a mass, pooling of contrast media is not always visible within a few minutes and films after 1–3 hours after injection of contrast medium are needed.
Prefered alternative to intravenous urography [fig. caliceal diverticulum in CT].
The creatinine concentration of the aspirated fluid is significantly higher than the serum creatinine concentration. Cytological examination may be done to exclude a malignant cyst.
Caliceal diverticulum: CT shows the filling of the cystic mass with contrast media. With kind permission of Dr. G. Antes, Kempten.
Simple renal cyst
Treatment of Caliceal Diverticula
Percutaneous access into the caliceal diverticulum, removal of stones and ablation of the mucosa or dilatation of the connection between diverticulum and calyx to secure the urine drainage.
Open or Laparoscopic Surgery:
Partial nephrectomy: removal of the diverticulum with surrounding renal parenchyma.
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