endodermal sinus tumor of ovary

例句：

1. 1. This raretumor has been found in only a fewpatients.
   这种罕见的肿瘤仅在少数患者中发现。
2. 2.The patient underwent surgery to remove the tumor.
   患者接受了手术以切除肿瘤。
3. 3. The treatment forthis type of tumor is still under investigation.
   治疗这种肿瘤的方法仍在研究中。