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Caliceal Diverticulum

Definition

A calyceal 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 calyceal diverticula:

4,5:1000 (from studies with intravenous urography)

Etiology of Caliceal Diverticula

Congenital:

Caliceal diverticula may result from rests of the ureteric bud of the 3rd or 4th Generation, which usually degenerate.

Acquired:

Resulting from a cortical kidney abscess, a cortical cyst or from calyceal obstruction, a calyceal 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
• Nephrolithiasis
• Cystic mass in imaging

Diagnostic Work-Up

Renal sonography:

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).

Intravenous Urography:

Caliceal diverticula are often visible on the plain kub abdominal x-ray (milk of calcium). Otherwise, the calyceal 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.

CT:

Prefered alternative to intravenous urography [fig. calyceal diverticulum in CT].

Caliceal diverticulum: CT shows the filling of the cystic mass with contrast media. With kind permission of Dr. G. Antes, Kempten.

Retrograde pyelography:

Often performed before treatment of nephrolithiasis or invasive diagnostic work-up.

Retrograde pyelography of a calyceal diverticulum on the right side. Invasive imaging was indicated for single-sided hematuria. Some clots lead to filling defects of the contrast media in the calyceal diverticulum. With kind permission, Dr. F. Schmidt, Augsburg.

Diagnostic Puncture:

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.

Differential Diagnosis:

Treatment of Caliceal Diverticula

Endoscopic Therapy:

Percutaneous access into the calyceal 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 corresponding renal parenchyma.

References

  Deutsche Version: Kelchdivertikel