Echinococcus of the urinary tract: radiologic findings

Echinococcal involvement of the urinary tract is extremely rare. We present 11 such cases, 10 with renal and 1 with bladder involvement. Clinical and laboratory findings were nonspecific. Calcification was present in all but 1 case. The excretory urogram and retrograde pyelogram demonstrated parenchymal soft-tissue masses causing pressure on and dilatation of the collecting system. Angiography in 3 cases showed the masses to be avascular. The ultrasound findings of a multicystic lesion with mixed echogenicity were typical of echinococcal cysts, while a CT scan in 1 patient showed a cyst with densely calcified border. The combined findings of these different modalities aid greatly in establishing the correct diagnosis.