all anterior mediastinal tumors, 15–20% are GCTs of which about 50% are benign teratomas. Ovarian teratomas may be associated with anti-NMDA receptor encephalitis. Location Despite their name, GCTs occur both within and outside the ovary and testis. They are found in:} head inside the cranium — pineal and suprasellar locations are most commonly reported inside the mouth — a fairly common location for teratoma neck mediastinum — account for 1% to 5% of all germ cell neoplasms pelvis, particularly sacrococcygeal teratoma In females, GCTs account for 30% of ovarian tumors, but only 1 to 3% of ovarian cancers in North America. In younger women, they are more common, thus in patients under the age of 21, 60% of ovarian tumors are of the germ-cell type, and up to one-third are malignant. In males, GCTs of the testis occur typically after puberty and are malignant (testicular cancer). In neonates, infants, and children younger than 4 years, most are sacrococcygeal teratomas. Males with Klinefelter syndrome have a 50 times greater risk of GSTs. In these persons, GSTs usually contain nonseminomatous elements, present at an earlier age, and seldom are gonadal in location. Treatment Women with benign GCTs such as mature teratomas (dermoid cysts) are cured by ovarian cystectomy or oophorectomy. In general, all patients with malignant GCTs have the same staging surgery that is done for epithelial ovarian cancer. If the patient is in her reproductive years, an alternative is unilateral salpingoophorectomy, while the uterus, the ovary, and the fallopian tube on the opposite side can be left behind. This is not an option when the cancer is in both ovaries. If the patient has finished having children, the surgery involves complete staging, including salpingoophorectomy on both sides, as well as hysterectomy. Patients with germ-cell cancer often need to be treated with combination chemotherapy for at least three cycles, but female patients with early-stage disease may not require this treatment. The chemotherapy regimen most commonly used in GCTs is called PEB (or BEP), and consists of bleomycin, etoposide, and a platinum-based antineoplastic (cisplatin). Targeted treatments, such as immunotherapy, hormonal therapy and kinase inhibitors, are being evaluated for tumors that do not respond to chemotherapy. Prognosis The 1997 International Germ Cell Consensus Classification is a tool for estimating the risk of relapse after treatment of malignant germ-cell tumor. A small study of ovarian tumors in girls reports a correlation between cystic and benign