_:vb50954813 "url:http://www.pathologyoutlines.com/topic/ovarytumoryolksac.html"^^ . _:vb50954813 . _:vb50954813 . _:vb50954813 "An ovarian endodermal sinus tumor that is characterized by a polyvesicular vitelline pattern, which involves vesicular structures with eccentric constrictions surrounded by a dense spindle cell stroma."^^ . _:vb50954813 . _:vb50954813 . _:vb50954813 .