Swyer syndrome is characterized by a higher risk of developing genital malignancies. In this disorder, the most common is gonadoblastoma and dysgerminoma but also, in rare cases, choriocarcinoma. The prognosis in choriocarcinoma is poor. The early diagnosis of dysgenetic gonads is necessary in view of the risk of malignancies. It can be difficult due to its different clinical masks. When the neoplasm precedes the diagnosis of gonadal dysgenesis, adequate oncological treatment should be introduced with parallel gonadectomy. We present a case of 14-year-old female with 46, XY karyotype with choriocarcinoma in one gonad and dysgerminoma in the second one. Pediatr Blood Cancer 2011;56:482–483. © 2010 Wiley-Liss, Inc.