The association of mucinous tumors of ovary with other ovarian neoplasma, such as dermoid cyst and Brenner tumor, is well recognized. Bettinger described a pseudomucinous cystadenoma of the ovary that showed a large focus of giant cell tumor of bone. We reported a case of ovarian borderline mucinous cystadenoma associated with areas of benign cystic teratoma and carcinosarcomatous and giant cell tumor-like lesions in nulliparous 22 year-old woman and reviewed the literatures about its pathogenesis and prognostic significance.