[The value of sonography in the differential diagnosis of pseudotumours of the kidney (author's transl)].

Two hundred and three patients with urographic appearances suspicious of a space-occupying lesion were examined by sonography. Seventy-nine showed normal results; there were 65 cysts, 20 malignant lesions, 20 pseudo-tumours and 19 with other abnormalities such as hydronephrosis, urolithiasis and inflammatory lesions. Pseudotumours are due to varients of the structure of the kidney, which resemble space-occupying lesions in the excretory urogram. The sonogram shows them as low echo, centrally protruding structures arising from the edge of the parenchyma. Angiographically they are islands of parenchyma with normal vessels. Sonography has proved to be a necessary complement to excretion urography and provides a more certain indication for renal arteriography. Angiography can be limited to changes in the parenchyma, since sonography is able to define cystic processes.