*2.4. Malignant Ureteral Obstruction*

A malignant ureteral obstruction develops secondary to a malignant tumor. A primary tumor may infiltrate the ureteral wall and compress the ureter, swollen lymph nodes may wrap around the ureter, edema and retroperitoneal fibrosis that develop after radiotherapy may distort the ureter or cause luminal stenosis, or ureter elasticity may be weakened [8]. The condition may be unilateral or bilateral. Clinical removal of the obstruction and rapid improvement in renal function are the aims of treatment. Although ureteral stenting or nephrostomy is performed in severe cases, these procedures reduce the quality of life. Markers of severity are required.
