Pure nongestational choriocarcinoma of the ovary is an extremely rare tumor. Histologically, it has the same appearance as gestational choriocarcinoma metastatic to the ovaries (413). Most patients with this cancer are younger than 20 years. The presence of hCG can be useful in monitoring the patient’s response to treatment. In the presence of high hCG levels, isosexual precocity occurs in about 50% of patients whose lesions appear before menarche (413,414).
There are only a few limited reports on the use of chemotherapy for nongestational choriocarcinomas, but complete responses were reported with the MAC (methotrexate, actinomycin D, and cyclophosphamide) regimen used in a manner described for gestational trophoblastic disease (379) (see Chapter 39). Alternatively, the BEP regimen can be used. The prognosis of ovarian choriocarcinomas is poor, with most patients having metastases to organ parenchyma at the time of diagnosis.
Polyembryoma of the ovary is another extremely rare tumor, which is composed of embryoid bodies. This tumor replicates the structures of early embryonic differentiation (i.e., the three somatic layers: endoderm, mesoderm, and ectoderm) (2,346). The lesion tends to occur in very young, premenarcheal girls with signs of pseudopuberty and elevated AFP and hCG levels. Anecdotally, the VAC chemotherapeutic regimen is reported to be effective (346,415).
Mixed Germ Cell Tumors Mixed germ cell malignancies of the ovary contain two or more elements of the lesions described above. In one series, the most common component of a mixed malignancy was dysgerminoma, which occurred in 80%, followed by EST in 70%, immature teratoma in 53%, choriocarcinoma in 20%, and embryonal carcinoma in 16% (415). The most frequent combination was a dysgerminoma and an EST. The mixed lesions may secrete either AFP, hCG, or both or neither of these markers, depending on the components.
These lesions should be managed with combination chemotherapy, preferably BEP. The serum marker, if positive initially, may become negative during chemotherapy, but this finding may reﬂect regression of only a particular component of the mixed lesion. Therefore, for these patients, a second-look laparotomy may be indicated to determine the precise response to therapy if macroscopic disease was present at initiation of chemotherapy.
The most important prognostic features are the size of the primary tumor and the relative size of its most malignant component (416). For stage IA lesions smaller than 10 cm, survival is 100%. Tumors composed of less than one-third EST, choriocarcinoma, or grade 3, immature teratoma have an excellent prognosis, but it is less favorable when these components constitute most of the mixed lesions.
Late Effects of Treatment of Malignant Germ Cell Tumors of the Ovary
Although there are substantial data regarding late effects of cisplatin-based therapy in men with testicular cancer, sparse information is available for women with ovarian germ cell tumors. Among the adverse events from chemotherapy reported in men are renal and gonadal dysfunction, neurotoxicity, cardiovascular toxicity, and secondary malignancies.