Hydronephrosis:
This is accumulation of urine in the pelvis of the kidney due to an obstruction to the passage of urine from the pelvis to the bladder. The stretching and dilatation of the renal pelvis can form a palpable mass in the abdomen. This will be discussed separately later, but requires a proper investigation and then appropriate surgery to relieve the obstruction and allow urine to flow smoothly into the bladder.