46 XY pure gonadal dysgenesis with gonadoblastoma and dysgerminoma

Swyer syndrome is a distinct type of pure gonadal dysgenesis characterized by a 46 XY karyotype in female phenotypic patients. It shows an abnormality in testicular differentiation. It is usually revealed by primary amenorrhea. The tumor that usually develops in Swyer syndrome is gonadoblastoma. Although gonadoblastoma is considered benign, the risk of malignant germ cell tumor development is high.The aim of this report is to stress on the risk of occurrence of malignant germ cell tumors on these dysgenesic gonads.We present the clinical, sonographic and endocrine findings in the case of a 13 year-old phenotypic young girl with a 46 XY karyotype and gonadal dysgenesis. The patient underwent surgery for adnexal torsion. An examination of the gonads revealed gonadoblastoma associated to dysgerminoma. The treatment and the follow up are detailed.The presence of Y chromosome in the karyotype of a patient presenting a gonadal dysgenesis must lead to prophylactic bilateral gonadectomy in order to avoid a malignant transformation. Gonadectomy must be followed by a hormone replacement therapy.