A 22-year-old woman with Turner syndrome has a 2.5-centimeter mass in the right adnexa. An abdomi¬nal radiograph reveals focal areas of calcification in the mass. The patient has a?

The patient most likely has a gonadoblastoma, which is sometimes associated with certain types of Turner syndrome. Turner syndrome is characterized by an XO geno­type (~ 60%) without any Barr body. Approximately, 40% of patients are mosaics with an XX/XO, a 45 XO/46 XX, or an XO/46 XY karyotype. The presence of a Y chromosome poses an increased risk for germ cell tumors of the streak gonads (ovary without eggs). Dysgerminomas and gonadoblastomas (germ cell plus sex cord stromal tumor) are the two most common tumors associated with this abnormality. Both of these tumors are also seen in certain types of gonadal dysgen­esis where there is female pseudohermaphroditism, that is, genotypic females with male appearing external genitalia. Gonadoblastomas, unlike dysgerminomas, frequently contain foci of calcification that are visible on abdominal films, as in this patient. Other primary ovarian tumors that frequently produce visible calcifi­cations on abdominal films are cystic teratomas (bone and teeth) and fibromas. Dysgerminomas of the ovary are the female counter­part of seminomas of the testicle and pinealomas in the central nervous system. They are the most common malignant germ cell tumor of the ovary, whereas cystic teratomas are the most common benign germ cell tumor. Dysgerminomas are bilateral in 10% of cases. They are solid tumors that contain large, anaplastic cells with prominent nucleoli intermixed with a benign lymphoid infiltrate. Dysgerminomas, like seminomas, are extremely radiosensitive tumors and have an excel­lent 5 year survival rate. Cystic teratomas, fibromas, and Brenner tumors of the ovary are not associated with Turner syndrome.