Primary yolk sac tumor of endometrium: report of two cases and review of literature.

Primary YST of the endometrium is very rare, therefore there is no guideline for treatment. We report two cases of endometrial YSTs presenting different symptoms and showing different prognoses and discuss the clinical management of these tumors. The present report shows first time that bone and lung metastasis in primary YSTs of endometrium. As the number of reported cases with endometrial YSTs, more information about the prognosis of the disease may be obtained.