Cystic renal cancers: CT characteristics.

Abstract
The preoperative distinction between renal cyst and tumor has long been a dilemma. A cystic renal adenocarcinoma may appear similar to a largely necrotic tumor or a cancer incorporated into a cyst or arising from a cyst wall. Overall, these cystic cancers present the same preoperative features. In our series of 15 cases, the characteristic pattern on computed tomography scans included size .gtoreq. 10 cm, localized thickening of cyst walls wtih contract enhancement, and irregularly and poorly defined implantation in the kidney.