You are here: Urology Textbook > Kidneys > Calyceal diverticulum

Calyceal Diverticulum

Definition

A calyceal diverticulum is a renal cystic cavity. It is lined with urothelium and has (or had) a connection to a pyelocalyceal system. Synonym: pyelogenic cyst.

Epidemiology of calyceal diverticula:

2–5:1000 (from studies with intravenous urography).

Etiology of Calyceal Diverticula

Congenital:

Result of failed degeneration of ureteric bud branches.

Acquired:

Calyceal diverticula may develop from a cortical kidney abscess, a cortical cyst, or from calyceal obstruction. Complications of urinary stasis are recurrent urinary tract infections, milk of calcium, or nephrolithiasis.

Signs and Symptoms of Calyceal Diverticula

Many calyceal diverticula remain asymptomatic and are discovered incidentally during imaging. Possible complications include nephrolithiasis, pain, infections, or hematuria.

Diagnostic Workup

Renal sonography:

Renal ultrasound reveals a cystic structure near a calyx, often filled with echogenic content (milk of calcium, changing with the position of the examination).

CT:

Best imaging procedure for the diagnosis of unclear renal cysts [fig. Calyceal diverticulum in CT]. The delayed contrast filling of the cavity via the cavity system, and, if necessary, the detection of stones or calcium deposits, are key indicators.

Intravenous Urography:

Caliceal diverticula are often visible on the plain KUB abdominal X-ray (milk of calcium). Otherwise, the calyceal diverticulum presents as a mass, pooling of contrast medium is only sometimes visible within a few minutes. Late films after 1–3 hours are helpful. Today, IVP has largely been replaced by CT urography for diagnostic evaluation.

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

MRI/MR urography:

MR urography can be helpful in cases of contrast allergy, to avoid radiation exposure, or for specific diagnostic questions.

Retrograde pyelography:

Perform retrograde pyelography before treatment of nephrolithiasis or during invasive diagnostic workup of hematuria [fig. Calyceal diverticulum in retrograde pyelography].

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 medium in the calyceal diverticulum. With kind permission, Dr. F. Schmidt, Augsburg.

Differential Diagnosis:

Simple or parapelvic renal cysts, hydrocalyx due to infundibular obstruction, renal abscess, papillary necrosis, tuberculous cavities, and, rarely, cystic renal tumors.

Treatment of Calyceal Diverticula

Asymptomatic calyceal diverticula without stone formation, infection, or symptoms generally do not require treatment. Intervention is indicated in cases of pain, recurrent infections, hematuria, significant stone burden, or an indeterminate renal mass.

Endoscopic Therapy:

First, obtain percutaneous access into the calyceal diverticulum and remove calyceal stones, if present. Consider fulguration of the diverticular mucosa to induce shrinkage. Dilate the connection between the diverticulum and calyx to secure urine drainage. Place a thick nephrostomy into the renal pelvis.

Flexible ureteroscopy is an option for anterior and medial calyceal diverticula that are difficult to access percutaneously.

Open or Laparoscopic Surgery:

Laparoscopic (robot-assisted) or open surgical diverticulectomy is rarely necessary, for example in cases of large anterior diverticula, failed endourologic treatment, or an indeterminate renal mass.

References

Waingankar, N., Hayek, S., Smith, A. D., and Okeke, Z. (2014). Calyceal Diverticula: A Comprehensive Review. Reviews in Urology, 16(1), 29-43. https://doi.org/https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4004282/

  Deutsche Version: Kelchdivertikel

Urology-Textbook.com – Choose the Ad-Free, Professional Resource

This website is designed for physicians and medical professionals. It presents diseases of the genital organs through detailed text and images. Some content may not be suitable for children or sensitive readers. Many illustrations are available exclusively to Steady members. Are you a physician and interested in supporting this project? Join Steady to unlock full access to all images and enjoy an ad-free experience. Try it free for 7 days—no obligation.

New release: The first edition of the Urology Textbook as an e-book—ideal for offline reading and quick reference. With over 1300 pages and hundreds of illustrations, it’s the perfect companion for residents and medical students. After your 7-day trial has ended, you will receive a download link for your exclusive e-book.