Ovarian Endometrioid Adenocarcinoma with a Yolk Sac Tumor Component

ABSTRACT

Ovarian endometrioid adenocarcinoma (EAC) with a yolk sac tumor (YST) component is extremely rare. Only twelve cases have been reported in the English literature. We report here two additional cases of this rare tumor. The YST component showed classic microscopic features, and immunohistochemically stained positive for alpha-fetoprotein (AFP), but negative for cytokeratin 7 (CK7), epithelial membrane antigen (EMA), estrogen receptor (ER) and progesterone receptor (PR). The EAC appeared to blend into the YST in several areas and immunohistochemically stained positive for CK7, EMA, ER, and PR, but negative for AFP.