Ovarian Yolk Sac Tumor With High-Grade Serous Carcinoma in a 62-Year-Old Woman

Ovarian yolk sac tumors are germ cell tumors that usually present in children and young women. Rarely, these tumors can arise in older women, usually in conjunction with surface epithelial tumors, suggesting divergent differentiation from the latter. The combination of mixed ovarian yolk sac tumor and high-grade serous carcinoma is rare, with only one case documented in the literature. We present a case of mixed ovarian yolk sac tumor and high-grade serous carcinoma in a postmenopausal woman, including a brief discussion of the immunohistochemical findings and differential diagnosis. Despite the rarity of mixed ovarian yolk sac tumor and surface epithelial tumors, it is important to recognize the biphasic nature of the tumor, which should prompt a thorough immunohistochemical evaluation. The therapeutic and prognostic implications of proper diagnosis cannot be overemphasized.