The largest reported papillary thyroid carcinoma arising in struma ovarii and metastasis to opposite ovary: case report and review of literature

Background Malignant struma ovarii (MSO) is a very rare, germ cell tumor of the ovary, histologically identical to differentiated thyroid cancers. Struma ovarii (SO) is difficult to diagnose on clinical basis or imaging and is mostly discovered incidentally, with few published cases in the literature.