Renal Cyst Sclerotherapy

Background and indications

Percutaneous renal cyst sclerotherapy is a minimally invasive treatment for symptomatic simple renal cysts (Bosniak I-II). Simple renal cysts are very common (increasing with age, > 50% after age 50) but rarely symptomatic. Sclerotherapy is indicated for large cysts (> 5 cm) causing lumbar pain, collecting system compression (hydronephrosis), hypertension, or functional impairment.

Sclerotherapy is an alternative to surgical (laparoscopic) marsupialization, with lower morbidity.

Pre-procedure assessment

Assessment includes renal CT or MRI (confirming simple character — Bosniak I or II, excluding complex Bosniak III-IV cyst requiring surgical exploration), and renal function panel.

Procedure

Under local anesthesia and ultrasound (or CT) guidance, a drainage catheter (8-10F) is inserted into the cyst. Cyst contents are aspirated (cytological and biochemical analysis). A sclerosing agent (95% ethanol, 10-50% of aspirated volume, maximum 100 mL) is injected, left in contact 20-30 minutes with patient rotation, then reaspirated. The procedure may be performed in a single session or with prolonged drainage for 24-48h for large cysts. The procedure takes 30-45 minutes.

Results and scientific evidence

Success rate (volume reduction > 50% and symptom resolution) is 75-95% after 1-2 sessions. Retreatment recurrence rate is 10-20%. Ethanol sclerotherapy is superior to simple aspiration (80-100% recurrence for aspiration alone). A meta-analysis confirmed sclerotherapy efficacy with significant long-term regression rate (Zerem et al., European Urology, 2008; DOI: 10.1016/j.eururo.2007.10.049).

Risks and complications

Lumbar pain (20-40%, transient), hematuria (5-10%), fever (5-10%), cyst infection (< 2%). Systemic ethanol absorption is minimal at used volumes. Major complications are rare (< 2%).

Recovery

Same-day discharge or 1 night hospitalization. Control ultrasound at 3 and 6 months.

Practical information

The procedure is performed as an outpatient or short inpatient stay depending on the case. It is performed by an interventional radiologist, in coordination with the urologist or nephrologist.