Association between Wilms tumor and gonadal dysgenesis.

The classification of intersexuality was determined in 10 patients with an intersex disorder who subsequently suffered a Wilms tumor. Of these 10 patients 7 (70 per cent) had a disorder of gonadal dysgenesis: 5 had mixed gonadal dysgenesis, 1 had dysgenetic male pseudohermaphroditism and 1 had 46XY pure gonadal dysgenesis. Because the gonads of patients with either of these 3 disorders have a high predilection for the development of testicular neoplasia, the concomitant occurrence of renal tumors in such a patient population suggests that a common defect in the urogenital ridge, the embryonic precursor of the kidneys and gonads, may be the cause of this association.