Giant hydronephrosis: report of 4 cases with review of the literature.

Giant hydronephrosis is uncommon. In 1939, Stirling defined it as the presence of more than 1,000 ml of fluid in the collecting system [1]. We herein report 4 cases of giant hydronephrosis containing 1,900 ml, 3,400 ml, 2,100 ml and 3,200 ml, respectively. Only 6 cases with a malignant tumor have been reported in the literature. Our second case with multiple foci of transitional cell carcinoma with squamous metaplasia is presented. This is the first report of this kind of pathological morphology with giant hydronephrosis. An erroneous diagnosis is often made in cases of giant hydronephrosis. For example, 3 of our 4 patients were first diagnosed as ovarian cyst, retroperitoneal hamartoma and hepatic cyst, respectively. We have found 523 cases reported in the literature. It is seen more often in males than in females (2.4:1) and more often on the left side than on the right side (1.8:1). The amount of fluid in the hydronephrotic sac is often between 1 and 2 liters. It is usually secondary to ureteropelvic junction obstruction, stones or congenital abnormality. Nephrectomy is often performed due to severe impairment of renal function. Acute renal failure and cardiopulmonary distress developed in our second case after the operation. The reason may be the sudden decompression of the huge hydronephrotic sac, which resulted in a change in the hemodynamic balance. Therefore, a two-stage procedure with slow decompression by percutaneous nephrostomy before the nephrectomy is preferred in the compromised patient.