Mixed gonadal dysgenesis: case reports and a review of 65 Japanese cases.

Four cases of mixed gonadal dysgenesis encountered in our institute are described here, and 65 cases of mixed gonadal dysgenesis in the Japanese literature, including our cases, are reviewed. Of the four cases reported here, three had a chromosomal structure of 46,XY and one of 45,XO/46,XYq-. A chromosomal structure of 45,XO/46,XY accounts for 35% of all cases of mixed gonadal dysgenesis reported in the Japanese literature, 46,XY for 31%, and other types for 24%. Two of our cases (50%) also had a gonadal tumor. The overall incidence of gonadal tumor occurring after onset of puberty and reported in the Japanese literature is 17%.