[Erroneous diagnoses of space-occupying processes of the kidney]

Renal masses are occasionally misdiagnosed because: (1) there are two lesions present; the important lesion (the mass) is small and hidden by the second, less important lesion, which is more prominent on the film; (2) there is misleading or insufficient clinical information: (3) previous results and films are disregarded and/or unavailable. In individual cases, differentiation between malignant and benign masses may be impossible, despite the application of all of the imaging modalities available.