Carcinoma in a renal cyst: computed tomography diagnosis.

We report a case of carcinoma in a renal cyst diagnosed by computed tomography. Ultrasound was unavailable because of scheduling difficulties and computed tomography provided a useful alternative in identifying the cystic and solid features of the mass. There was a good correlation of the computed tomography scan with pathology except for a small tumor nodule at the base of the cyst, which was not seen on the scan.