[Cystic renal cancers. 14 case reports].

The authors present 14 cases of renal cancers with a cystic appearance raising pre and intraoperative diagnostic difficulties. Although ultrasonography has become the first-line investigation, computed tomography is now the most accurate diagnostic examination. The diagnosis of complicated benign cyst must be proposed very cautiously and the persistence of doubtful images justifies surgical exploration. In order to be reliable, frozen section histological examination must include all of the cystic tumour. Polar nephrectomy with frozen section examination is therefore the recommended intraoperative diagnostic procedure in a case of suspicious cyst. The curative treatment of these cancers is classical radical nephrectomy.