[Cancer of a renal cyst wall]

It is reported on three cases of cyst wall carcinomata in altogether 202 patients (= 1.5%) in whom a resection of the cyst wall was clinically indicated. Only in one case there was preoperatively an angiographically proved suspicion of the presence of a cyst wall carcinoma. Since there do not exist any exact methods for proving cyst wall carcinomata and the slight size of the tumour does not evoke systemic, unspecific tumour signs, their evidence remains depending upon accidentally found, discrete changes in the picture-producing techniques.