Renal cyst sclerotherapy

Last revised by Yahya Baba on 5 Jul 2023

Renal cyst sclerotherapy is a minimally invasive procedure performed to treat symptomatic simple renal cysts (i.e. Bosniak I) and is one of the primary methods to treat renal cysts along with surgical cyst de-roofing 1.

Note: This article is intended to outline some general principles of the procedure. The specifics will vary depending on the radiologist's and referrer's preference, institutional protocols, patient factors (e.g. allergy), and time constraints. 


It is indicated in all symptomatic simple (Bosniak 1) renal cysts with:

Pre-procedure assessment
  • exclude and correct coagulopathy

  • inquire for allergies

Patient preparation
  • monitoring of pulse and blood pressure

  • anxiolytics and analgesics

  • prone position in general

  • area sterilization

Material preparation

Generally, the material prepared consists of:

  • 5F centesis catheter

  • 0.035 glidewire

  • 8.5F drainage catheter and 8F dilator (optional)

  • various sclerosing agents are described including

    • absolute ethanol (99.5%) 1

    • n-butyl cyanoacrylate 2

    • 20% hypertonic saline 3

    • acetic acid4

    • ethanolamine oleate5


Local anesthesia

  • e.g. lidocaine 2%

Ultrasound-guided or CT-guided puncture of the renal cyst

  • puncture of the cyst using the 5F centesis catheter

  • secure the position with the glidewire

  • exchange the 5F sheath catheter with an 8.5F drainage catheter; tract dilation with an 8F dilator is optional

  • aspiration of the cyst content

Cyst opacification

This step is primordial to verify the absence of communication between the cyst, pelvicalyceal system and/or vessels

  • under fluoroscopy/CT, fill the residual cystic cavity with a mixture of saline and contrast medium (same volume of aspirated cystic fluid)

  • remove the injected mixture of saline and contrast


The sclerosing agent, volume and retention duration are highly variable, depending on institutions and operators.

  • inject through the drainage catheter, 25-50%1,6,7 of the aspirated volume with 99.5% ethanol (maximum of 100 mL 1)

  • to expose all of the cyst surfaces to the sclerosing agent, the patient should be placed in supine, lateral decubitus, prone positions at 10-15 minutes intervals for a total of 40-120 min of retention 1

  • aspirate the ethanol and remove the drainage catheter


  • sclerosis of the pelvicaleceal sytem if there is communication with the renal cyst

  • brain or visceral injury if there is vessel-cyst communication

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