Benign multilocal cystic nephroma.

Three cases of multilocular cystic nephroma are described. This entity differs from congenital multicystic kidney and adult polycystic disease in that it involves only a segment of one kidney. While the excretory urogram, nephrotomogram, and arteriogram show the lesion to be primarily avascular, the two cases studied by ultrasound were predominantly solid. This finding is felt to relate to the small size of the cysts as well as the presence of some solid primitive components. Because it is difficult to differentiate this lesion from an avascular renal carcinoma, surgical biopsy should be considered to help avoid a needless nephrectomy.