MIXED GONADAL-DYSGENESIS - HISTOLOGICAL AND ULTRASTRUCTURAL FINDINGS IN 2 CASES

Mixed gonadal dysgenesis (MGD) is an intersex genetic abnormality char acterized by a streak gonad and a contralateral testis (that is typica lly cryptorchid) or bilateral streak testes. A uterus and one or both fallopian tubes also may be present. The external genitalia are freque ntly ambiguous, We studied two phenotypic ''females'' with MGD. One ha d a mosaic 45X (40%) and 46XYq (60%) karyotype, a left streak gonad, a nd a small testis in a right inguinal hernia, whereas the other had a 46XY karyotype, a left streak gonad, and, on the right, a testis with gonadoblastoma. On histological and ultrastructural examination the te stis in the first case showed prepubertal tubules lined by a few sperm atogonia and immature Sertoli cells with asynchronism in nuclear-cytop lasmic maturation. Ultrastructural examination of the gonadoblastoma i n the second case showed neoplastic Sertoli cells. Irregular maturatio n of Sertoli cells appears to be a feature of MGD. Gonadal extirpation and pathological examination in these cases are important in order to make the correct diagnosis and prevent neoplastic changes.