Ovarian endometrioid adenocarcinoma a with yolk sac tumor in a 41-year-old woman: a case report.

Background: Yolk sac tumors (YSTs) are the second most common germ cell malignancy of the ovaries generally present in children and young women. YSTs arising in combination with epithelial ovarian carcinoma (EOC) in older women are rarely reported. The YST components in such cases often show a marked morphological and immunophenotypic overlap with epithelial neoplasms, making diagnosis difficult.

Case Report: A 41-year-old woman presented with irregular vaginal bleeding and a bilateral adnexal mass. The postoperative pathology confirmed a poorly differentiated adenocarcinoma and YST of the left ovary. The short tandem repeat (STR) analysis further indicated that the YST component was probably derived from an epithelial precursor neoplasm.

Conclusion: This case improves our ability to detect and diagnose YST coexisting with epithelial tumors in older patients by summarizing its histopathologic characteristics and immunohistochemical stains. Molecular analysis should be used to further identify such mixed neoplasms.