Ovarian Malignant Mixed Germ Cell Tumor Composed Mainly of a Polyembryoma Pattern With Vasculogenic Mesenchymal Tumor Components.

Ovarian germ cell tumors composed of numerous well-formed embryonal bodies have been described as exhibiting a "polyembryoma pattern." In addition, some germ cell tumors are occasionally concomitant with neoplastic vascular proliferation. These include angiosarcomas and the recently reported mediastinal vasculogenic mesenchymal tumors. A 9-yr-old Japanese girl underwent surgery for a right ovarian tumor. Histologically, the polyembryoma pattern, nongestational choriocarcinoma, and vasculogenic lesions characterized by a neoplastic repetition of embryonic vasculogenesis have been intermingled. The polyembryoma pattern consisted of numerous complete and incomplete embryonal bodies and glandular structures resembling adult-type and fetal-type intestines. Vasculogenic lesions were composed of variously developed neoplastic vessels within the myxomatous stroma, which extended well beyond one low-power (40×) microscopic field. We concluded that the vasculogenic lesion in our case was the ovarian counterpart of the mediastinal vasculogenic mesenchymal tumor. After the surgery, the patient was administered adjuvant chemotherapy and was alive with no evidence of recurrence or other malignancy at 28 mo postsurgery.