[Normal renal variations as a cause of sonographically suspect tumors]

106 cases of 470 computed tomographic studies of suspected renal tumors were referred to us because a tumor was expected by ultrasound examination. 67 suspected renal tumors proved to be physiological variations, in 39 cases tumor suspicion was confirmed by computed tomography. Since ultrasound findings frequently seem to be false positive, criteria for the diagnosis of renal tumors were reviewed. Our experience is that the combination of inhomogeneity in echo pattern, irregularity of the outer contour and/or the inner parenchymal border seems to be relevant for ultrasound diagnosis of renal tumors whereas isolated widening of parenchyma does not seem to be suspicious by itself.