Individuals with 45,X/46,XY karyotype are at increased risk for germ cell tumor development. We report a case with a diagnosis of 45, X/46, XY gonadal dysgenesis who presented with short stature, physical stigmata of Turner syndrome. Her pubertal development was at Tanner stage 3. At follow-up, bilateral prophylactic gonadectomy was performed when considering the risk factors. Pathological assessment was consistent with gonadoblastoma in the left gonad, and dysgerminoma and gonadoblastoma in neighboring areas in the right gonad. The karyotype analysis of the right and left gonadal tissues reveled 45,X[97,3]/46,XY[2,7] and 45,X[92,7]/46,XY[4,5]/47,XYY [2,8] mosaic, respectively. The clinical management of such patient should be individualized according to the present risk factors. Additionally, signs of estrogenization like advanced breast development always suggest the possible presence of germ cell tumor.