PubMed1983
In 22 198 sonographic examinations of the epigastric region, the authors identified 759 renal cysts (3.4%) and 165 renal tumours (0.74%). The percentage of incidence of the renal cysts is identical with that found in post-mortem examinations, whereas tumours were distinctly more frequent. Tumours of the cystic wall had been found in 0.5% of all sonographically diagnosed cysts and in 4% of renal cysts examined via fine-needle biopsy. Of the latter cysts (i.e. out of the 4% of cysts diagnosed by fine-needle biopsy), which were associated with tumours, two had been diagnosed as tumour suspects via sonography. Hence, the sonographic absence of abnormal findings in carcinoma of the renal cyst wall is rare. However, cysts diagnosed via sonography which cannot be subjected to fine-needle biopsy, should be rechecked and followed up at regular intervals. If all possible methods of diagnosis are utilised (I.V. urography, sonography, fine-needle biopsy guided by sonography, computed tomography, angiography), successful differential diagnosis of localised pathological conditions of the kidneys can be achieved in 97% of all cases. Patient risk and cost of diagnosis can be kept at a minimum by proceeding in steps as described in the article. Primary surgical exposure of the kidneys in case of a cystic renal process would now appear justified for therapeutic reasons only, not for the purpose of arriving at a diagnosis.