Peritoneal mesothelioma in a male pseudohermaphrodite with asymmetrical gonadal differentiation.

A diffuse peritoneal mesothelioma occurring in a patient with male pseudohermaphroditism and asymmetrical gonadal differentiation (mixed gonadal dysgenesis) is described. Malignancies of mesodermal origin, usually derivatives of the urogenital ridge, appear to occur with increased frequency in male pseudohermaphrodites. This appears to be the first reported instance of a mesothelioma in a male pseudohermaphrodite with mixed gonadal dysgenesis. The clinical and pathologic features of this tumor, including the electron microscopic findings, are presented.