The pathogenesis, diagnosis, and management of metastatic tumors to the ovary: a comprehensive review

Secondary tumors of the ovary account for 10–25% of all ovarian malignancies. The most common tumors that give rise to ovarian metastases include breast, colorectal, endometrial, stomach, and appendix cancer. The correct diagnosis of secondary ovarian tumors may be challenging as they are not infrequently misdiagnosed as primary ovarian cancer, particularly in the case of mucinous adenocarcinomas. The distinction from the latter is essential, as it requires different treatment. Immunohistochemistry plays an important role in distinguishing primary ovarian tumors from extra-ovarian metastases and, furthermore, may suggest the primary tumor site. Despite extensive study, some cases remain equivocal even after assessing a broad spectrum of antigens. Therefore, gene expression profiling represents an approach able to further discriminate equivocal findings, and one that has been proven effective in determining the origin of cancer of unknown primary site. The available data concerning secondary ovarian tumors is rather limited owing to the relative heterogeneity of this group and the practical absence of any prospective trials. However, several intriguing questions are encountered in daily practice, including rational diagnostic workup, the role of cytoreductive surgery, and consequent adjuvant chemotherapy. This review seeks to address these issues comprehensively and summarize current knowledge on the epidemiology, pathogenesis, and management of secondary ovarian tumors, including further discussion on the different pathways of metastatisation, metastatic organotropism, and their possible molecular mechanisms.