Epidemiology Although 20% to 25% of all benign and malignant ovarian neoplasms are of germ cell origin, only about 3% of these tumors are malignant (2,3). Germ cell malignancies account for fewer than 5% of all ovarian cancers in Western countries. Germ cell malignancies represent up to 15% of ovarian cancers in Asian and African American societies, where epithelial ovarian cancers are much less common.
In the first two decades of life, almost 70% of ovarian tumors are of germ cell origin, and one-third of these are malignant (2,3,342). Germ cell cancers are seen in the third decade, but thereafter they become quite rare.
In contrast to the slower-growing epithelial ovarian tumors, germ cell malignancies grow rapidly and are characterized by subacute pelvic pain related to capsular distention, hemorrhage, or necrosis. The rapidly enlarging pelvic mass may produce pressure symptoms on the bladder or rectum, and menstrual irregularities may occur in menarcheal patients. Some young patients misinterpret the early symptoms of a neoplasm as those of pregnancy, which can lead to a delay in the diagnosis. Acute symptoms associated with torsion or rupture of the adnexa can develop. These symptoms may be confused with acute appendicitis. In more advanced cases, ascites may develop, and the patient can have abdominal distention (336).
Primordial germ cell Germinoma: dysgeminomaAFP (−)hCG (−) Embryonalcarcinoma AFP (+)hCG (+) Trophoblast Yolk sac Extraembryonicdifferentation Immature teratoma AFP (−)hCG (−) Embryonicdifferentation Choriocarcinoma AFP (−)hCG (+) Endodermal sinus tumor AFP (+)hCG (−) Mature teratoma AFP (−)hCG (−)
Figure 37.17 Relationship between types of pure malignant tumors. Germ cell tumors and their secreted marker substances. (From Berek JS, Hacker NF. Berek & Hacker’s Gynecologic Oncology. 5th ed. Philadelphia: Lippincott Williams & Wilkins, 2010:511, with permission.
For a patient with a palpable adnexal mass, the evaluation can proceed as outlined. Some patients with germ cell tumors will be premenarcheal and may require examination under anesthesia. If the lesions are principally solid or a combination of solid and cystic, as might be noted on an ultrasonographic evaluation, a neoplasm is probable and a malignancy is possible (see Fig. 14.8 and Chapter 14). During the remainder of the physical examination, effort should be directed to searching for signs of ascites, pleural effusion, and organomegaly.
Adnexal masses measuring 2 cm or larger in premenarcheal girls or 8 cm or larger in other premenopausal patients will usually require surgical exploration. For young patients, blood tests should include serum hCG and AFP and LDH. A CT scan of the chest is important because germ cell tumors can metastasize to the lungs or mediastinum. A karyotype should be obtained preoperatively for all premenarcheal girls, particularly those with dysgerminomas, because of the propensity of these tumors to arise in dysgenetic gonads (343,349). A preoperative CT scan or MRI may document the presence and extent of retroperitoneal lymphadenopathy or liver metastases; however, because these patients require surgical exploration, preoperative imaging is not usually required. If postmenarcheal patients have predominantly cystic lesions up to 8 cm in diameter, they may be observed or given oral contraceptives for two menstrual cycles (350).
CHAPTER 37 Ovarian, Fallopian Tube, and Peritoneal Cancer