Fewer than 5% of all ovarian tumors are germ cell in origin. They include teratoma, dysgerminoma, endodermal sinus tumor, and embryonal carcinoma. Germ cell tumors of the ovary generally occur in younger women (75% of ovarian malignancies in women <30), display an unusually aggressive natural history, and are commonly cured with less extensive nonsterilizing surgery and chemotherapy. Women cured of these malignancies are able to conceive and have normal children.

These neoplasms can be divided into three major groups: (1) benign tumors (usually dermoid cysts); (2) malignant tumors that arise from dermoid cysts; and (3) primitive malignant germ cell tumors including dysgerminoma, yolk sac tumors, immature teratomas, embryonal carcinomas, and choriocarcinoma.

Dermoid cysts are teratomatous cysts usually lined by epidermis and skin appendages. They often contain hair, and calcified bone or teeth can sometimes be seen on conventional pelvic x-ray. They are almost always curable by surgical resection. Approximately 1% of these tumors have malignant elements, usually squamous cell carcinoma.

Malignant germ cell tumors are usually large (median -  16 cm). Bilateral disease is rare except in dysgerminoma (10 to 15% bilaterality). Abdominal or pelvic pain in young women is the usual presenting symptom. Serum human chorionic gonadotropin (β-hCG) and α fetoprotein levels are useful in the diagnosis and management of these patients. Before the advent of chemotherapy, extensive surgery was routine, but it has now been replaced by careful evaluation of extent of spread followed by resection of bulky disease and preservation of one ovary, uterus, and cervix, if feasible. This allows many affected women to preserve fertility. After surgical staging, 60 to 75% of women have stage I disease and 25 to 30% have stage III disease. Stages II and IV are infrequent.

Most of the malignant germ cell tumors are managed with chemotherapy after surgery. Regimens used in testicular cancer such as PVB (cisplatin, vinblastine, bleomycin) and BEP (bleomycin, 30 units IV weekly; etoposide, 100 mg/m² days 1 to 5; and cisplatin, 20 mg/m² days 1 to 5), with three or four courses given at 21-day intervals, have produced 95% long-term survival in patients with stages I to III disease. This regimen is the treatment of choice for all malignant germ cell tumors except grade I, stage I immature teratoma, where surgery alone is adequate, and perhaps early-stage dysgerminoma, where surgery and radiation therapy are used.

Dysgerminoma is the ovarian counterpart of testicular seminoma. The tumor is very sensitive to radiation therapy. The 5-year disease-free survival is 100% in early-stage patients and 61% in stage III disease. Unfortunately, the use of radiation therapy makes many patients infertile. BEP chemotherapy is equally or more effective and does not cause infertility. In incompletely resected patients with dysgerminoma, the 2-year disease-free survival is 95% and infertility is not observed. Combination chemotherapy (BEP) has replaced postoperative radiation therapy as the treatment of choice in women with ovarian dysgerminoma.

Ovarian Stromal Tumors

Stromal tumors make up <10% of ovarian tumors. They are named for the stromal tissue involved: granulosa, theca, Sertoli, Leydig, and collagen-producing stromal cells. The granulosa and theca cell stromal cell tumors occur most frequently in the first three decades of life. Granulosa cell tumors frequently produce estrogen and cause menstrual abnormalities, bleeding, and precocious puberty. Endometrial carcinoma can be seen in 5% of these women, perhaps related to the persistent hyperestrogenism. Sertoli and Leydig cell tumors, when functional, produce androgens with resultant virilization or hirsutism. Some 75% of these stromal cell tumors present in stage I and can be cured with total abdominal hysterectomy and bilateral salpingo-oophorectomy. Stromal tumors generally grow slowly, and recurrences can occur 5 to 10 years after initial surgery. Neither radiation therapy nor chemotherapy have been documented to be consistently effective, and surgical management remains the primary treatment.