RESUMO
BACKGROUND: Turner syndrome is a genetic disorder resulting from the absence of or structural abnormality of one X chromosome. The presence of Y chromosome material in girls with Turner syndrome confers an increased risk of benign and malignant germ cell tumor and prophylactic bilateral gonadectomy is recommended. CASE: A 10-year-old Turner mosaic syndrome (45X/46XY) patient underwent prophylactic gonadectomy after unremarkable preoperative pelvic imaging. Histopathology showed a streak right gonad, and left gonad with gonadoblastoma with limited degree of infiltrating germinoma. SUMMARYAND CONCLUSION: Gonadoblastoma and dysgerminoma have been reported in girls with Turner mosaic who carry Y chromosome material. Prophylactic gonadectomy should be considered in these girls without delay.