Surgical management of complex renal cysts: a series of 32 cases

The differentiation between benign cysts of the kidney and those that require surgical exploration remains difficult. The accuracy of radiological techniques (ultrasound, computerized tomography [CT], angiography, magnetic resonance imaging, cyst puncture and intraoperative pathological examination) is analyzed.

Surgical exploration was performed in 30 patients with 32 asymptomatic renal cysts, and the pathological specimens were compared retrospectively to the radiological findings. The classification of Bosnaik was used to categorize the ultrasound and CT findings.

Of our complex renal cysts 41% proved to be malignant. Our results suggest that the radiological techniques are not well suited for characterization of these cysts. None of the Bosnaik types was sufficiently predictive of the lesion. Only a Bosnaik score of 4 (the sum of ultrasound and CT Bosnaik types) was not associated with renal cell carcinoma. According to the radiological findings, 1 patient was under treated (recurrent renal cell carcinoma) and 4 were over treated (radical nephrectomy for benign lesions).

A practical therapeutic strategy is described in which radical nephrectomy is performed when malignant lesions are detected either by preoperative or intraoperative techniques. Conservative surgery is indicated for benign cysts according to the clinical status and risks of nephron sparing surgery.