Last revised by Ashesh Ishwarlal Ranchod on 27 Sep 2023

Urinomas, or uriniferous fluid collections, are urine collections usually found in the retroperitoneum, most commonly in the perirenal space, as a consequence of renal tract leakage caused by urinary obstruction, trauma, or post-instrumentation. 

As there is no definitive distinction between the terms urinoma and urine leak in the literature, the terms are often used interchangeably. This article will treat them differently with the former as a consequence of the latter, i.e. urinomas are encapsulated urine collections due to urine leakage. 

As urine extravasates into the retroperitoneum, it can cause lipolysis of the surrounding fat with resultant encapsulation of urine, forming a urinoma.

Urinomas are most often due to urinary obstruction secondary to 2,3:

Urinomas also may be due to:

  • cystic mass in perirenal space: localized perirenal urinoma (most common)
  • cystic mass filling entire perirenal space: diffuse perirenal urinoma
  • sickle-shaped collection: subcapsular urinoma
  • encapsulated expanding intrarenal cystic mass separating renal tissue fragments: intrarenal urinoma 3

Contrast extravasates outside of the collecting system, into the surrounding retroperitoneal tissues.

Presents as a thinned-walled anechoic collection usually found partially contouring any portion of the renal tracts. 

On CT and MRI, a urinoma shows water attenuation, low signal intensity on T1-weighted imaging, and very high signal intensity on T2-weighted imaging, similar to simple fluid elsewhere in the body.

Urine leakage is usually directly demonstrated on contrast-enhanced studies on the excretory phase due to direct contrast extravasation from the urinary tract 2.

  • small urinomas are usually treated conservatively
  • larger, persistent or symptomatic urinomas: percutaneous drainage is often used with the treatment of the underlying cause of urine leakage

ADVERTISEMENT: Supporters see fewer/no ads

Cases and figures

  • Case 1: post op
    Drag here to reorder.
  • Case 2: calculus
    Drag here to reorder.
  • Case 3: ultrasound
    Drag here to reorder.
  • Case 4: post traumatic urinoma
    Drag here to reorder.
  • Case 5: after extracorporeal shock wave lithotripsy
    Drag here to reorder.
  • Case 6: post gun shot injury
    Drag here to reorder.
  • Case 7: penetrating trauma
    Drag here to reorder.
  • Case 8
    Drag here to reorder.
  • Case 9: calculus
    Drag here to reorder.
  • Case 10: trauma in pregnancy
    Drag here to reorder.
  • Case 11: after surgery
    Drag here to reorder.
  • Case 12: uriniferous collection
    Drag here to reorder.
  • Case 13
    Drag here to reorder.
  • Case 14: Post iatrogenic ureteric injury
    Drag here to reorder.
  • Case 15: after stone passage
    Drag here to reorder.
  • Case 16: post Cesarean section
    Drag here to reorder.
  • Updating… Please wait.

     Unable to process the form. Check for errors and try again.

     Thank you for updating your details.