ULTRASOUND APPEARANCE AND EARLY DETECTION OF Vx2 CARCINOMA IN THE RABBIT KIDNEY

Vx2 carcinoma was induced in the rabbit kidney by percutaneous injection of a tumor-cell suspension. A focal renal mass similar in appearance to spontaneous renal carcinoma was produced. The mass could be detected with ultrasound as early as one week post injection, however it could not be identified until two weeks post injection using renal angiography and excretory urography. The renal tumor was recognized with ultrasound as an alteration in the cortical outline and obliteration of the renal medulla. A small amount of perirenal fluid was identified at two weeks. Intra-and extrarenal tumors were evident at three weeks with hypoechoic and anechoic areas evident within the large extrarenal mass observed four weeks post injection. Hypoechoic areas observed with ultrasound corresponded to areas of necrosis and hemorrhage while anechoic areas represented fluid accumulation within and around the tumor. Transplanted tumors were detected by ultrasound before they were evident on either the renal angiogram or excretory urogram. Ultrasound is useful as a screening procedure when renal tumor is suspected.