Pure nongestational ovarian choriocarcinoma: A scoping review

Choriocarcinoma of the ovary is a rare and highly malignant germ cell tumor. There are three ways in which an ovarian choriocarcinoma can arise: as a primary gestational choriocarcinoma that results from an ectopic ovarian pregnancy, as a metastatic choriocarcinoma that arises from a gestational choriocarcinoma, and as a germ cell tumor with differentiation into trophoblastic structures. Ovarian choriocarcinomas are therefore classified as gestational or nongestational. Recently, DNA polymorphism analysis has allowed investigators to determine the etiology of choriocarcinoma (gestational versus nongestational). Herein, in this scoping review, we detail the classification of, and clinical aspects of, pure ovarian choriocarcinoma. Introduction Choriocarcinoma is a very rare and highly malignant germ cell tumor that accounts for <1% of all malignant germ cell tumors [1]. There are three ways in which an ovarian choriocarcinoma can arise: as a primary gestational choriocarcinoma that results from an ectopic ovarian pregnancy, as a metastatic choriocarcinoma that arises from a gestational choriocarcinoma from another primary site in the female genital tract, and as a germ cell tumor with differentiation into trophoblastic structures [2]. Choriocarcinoma is classified as gestational or nongestational. Gestational choriocarcinoma is a form of gestational trophoblastic disease, which arises from a partial mole, a complete mole, or a normal pregnancy. Gestational choriocarcinoma is estimated to occur in about 2 to 7 pregnancies per 100,000 in the United States [3]. Nongestational choriocarcinoma does not arise from a pregnancy event and is an extremely rare occurrence. The incidence of primary ovarian nongestational choriocarcinoma is estimated to be 1 in 369,000,000 [4]. Differentiating gestational and nongestational choriocarcinoma can be difficult, as their clinical presentation and pathology can be identical. Traditionally, a definitive diagnosis of nongestational choriocarcinoma has been restricted to prepubescent females in whom the possibility of a pregnancy event can be eliminated with certainty. Choriocarcinoma of the ovary can be pure choriocarcinoma or, more commonly, mixed with other germ cell components [1]. When examined histologically, if other germ cell components are present mixed with choriocarcinoma, a diagnosis of a nongestational origin can be made. However, if no other germ cell component is present, differentiating a nongestational from gestational origin is impossible using histologic means alone. Recently, however, DNA polymorphism analysis has allowed investigators to determine the etiology of choriocarcinoma via analysis of the patient’s DNA, her partner’s DNA, and the DNA of the choriocarcinoma. By examining the DNA composition of the tumor and comparing it to the maternal and paternal DNA, the etiology of the Correspondence to: Joshua P. Kesterson, Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, Penn State Hershey Medical Center, 500 University Drive, Hershey, PA 17036, USA, Tel: (717) 531-8144, Fax: (717) 531-0007, E-mail: [email protected] Received: February 03, 2017; Accepted: February 26, 2017; Published: February 28, 2017 Garrett A (2017) Pure nongestational ovarian choriocarcinoma: A scoping review Integr Cancer Sci Therap, 2017 doi: 10.15761/ICST.1000229 Volume 4(1): 2-8 search string: ((("choriocarcinoma"[MeSH Major Topic] OR choriocarcinoma [Title/Abstract]) AND (nongestational[Title/ Abstract] OR non-gestational[Title/Abstract])) AND ((ovary[Title/ Abstract] OR ovarian[Title/Abstract]) OR gonad[Title/Abstract])) AND english[Language] which resulted in 66 titles. Additionally, we searched Web of Science using All Databases with the following search string: (ts=(choriocarcinoma AND (nongestational OR nongestational)) OR ti=(choriocarcinoma AND (nongestational OR nongestational))) AND LANGUAGE: (English), which yielded 57 titles for a sum total of 123 titles. The final search in PubMed and Web of Science was performed on January 6, 2016. Duplicates (n=43) were excluded. We included case reports and retrospective chart reviews. Review articles and book chapters were excluded (n=7). Review articles and those articles included in the analysis were cross-referenced to identify additional studies missed in initial database search (n=6). Included articles were limited to those dealing with pure non-gestational choriocarcinoma of the ovary. Criteria used to define a non-gestational origin of the tumor were cases occurring in prepubertal girls or a cases establishing a diagnosis of non-gestational origin via DNA analysis. All other cases were excluded from the results and discussion. Some literature described young G0 females without mention of their history of sexual activity. In these cases, if the patient was <20 years of age, these cases were included (unless nongestational origin was confirmed upon DNA analysis). Because Jacobs et al published an exhaustive literature review on pure choriocarcinoma of the ovary of cases occurring prior to 1981; we included only studies published after 1980. Those articles not meeting this criteria (n=49) were excluded, see Table 4. Additionally, nine articles were inaccessible to us despite multiple requests for full-text articles, and so these were excluded [6-14]. The total number of articles included in this review is 21 (Figure 1). Results Classification Since 1980, a total of 22 possible cases of pure nongestational ovarian choriocarcinoma have been published in the English language. Of these, nine occurred in premenarchal females [12-18], 11 occurred in postmenarchal females but were confirmed by DNA analysis [18,1925], and eight were considered possible cases of pure NGOC according to the strict criteria described above in the methods section [18,26-32] (Tables 1-3).