Unusual presentation of chronic ureteral obstruction

A case is reported of chronic unilateral ureteral obstruction presenting as lower back pain 1 year after radiotherapy and surgical treatment of an endometrial malignancy. The computerized axial tomogram was interpreted as showing a large retrohepatic mass. Urological evaluation with excretory urography, retrograde pyelography and sonography revealed the mass to be a large right subcapsular renal urinoma with spontaneous subcapsular renal parenchymal rupture. The differential diagnosis, pathophysiology and management of unilateral ureteral obstruction, as well as the pathogenesis of subcapsular renal urinoma, are discussed.