Hydrocele is an inappropriate collection of fluid secreted by one or both kidneys in the renal sinusoids renal pelvis. The part of the kidney called the renal pelvis that collects urine in hydrocele accumulates too much urine. A common cause of hydronephrosis is an obstruction in the urinary tract that prevents the urine from draining out of the body; urinary tract obstruction can be caused by different reasons. The urethra is the tube through which urine passes out of the body. With prostate cancer or cancer of other organs in the lower abdomen, a cancerous mass can compress the urethra thus blocking the flow of urine. Urinary stones can block the urethra. The blockage can occur suddenly or slowly and can involve one or both kidneys. The causes of recurrent hydronephrosis are the three reasons mentioned above: 1. prostate enlargement. 2. prostate cancer or other cancers near the lower abdomen. 3. urethral stones. See if these factors are not removed or temporarily removed, not completely removed, after the above factors are completely removed hydrocele will not recur.