A 1010/12 years old virilized girl with the syndrome of asymmetrical gonadal differentiation is reported. The patient had a negative sex chromatin and positive Y chromatin (bright fluorescent body of Y chromosome) in the buccal smear and 45,X/46,XY karyotype in the peripheral blood lymphocytes. An exploratory laparotomy showed a small uterus, two Fallopian tubes, a tumoural testis on the right side and a streak on the left side. Pathological examination revealed the presence of gonadoblastoma in both gonads. The Y chromatin was identified on histological sections only on the side of the testis, and was absent on the streak and its gonadoblastoma's nests.
The distribution of the different cell lines and the fluorescence of the Y chromosome is discussed in relation to gonadal differentiation and the occurrence of gonadoblastoma.