Renal hydatid cysts: communicating with collecting system.

The clinical and radiological features of five patients with renal hydatid disease communicating with the collecting system are described. Rupture into the renal pelvis of a hydatid cyst gives rise to acute flank pain followed by voiding of scolices or daughter cysts with or without hematuria and/or urinary obstruction. Intravenous urography demonstrates a renal mass frequently involving the collecting system; arteriography shows it to be avascular; sonography reveals a multicystic lesion of mixed echogenicity. When daughter cysts are present, computed tomography establishes the diagnosis.