A urinoma is the result of a breach of the integrity of the pelvis or calices of the kidney or of the ureter.[4] The urine collection in the perirenal fat causes an inflammatory response with lipolysis resulting in its fibrous encapsulation. Urinomas are usually caused by blunt trauma to the kidneys. While extravasation of urine is common as a result a severe blunt trauma (2-18%), spontaneous resolution is typical, and urinoma formation develops only in few instances.[5] Less common causes of urinoma development are ureteral obstructions due to cancer, calculus formation, pregnancy, or congenital causes.[3][4][5]