Skull Base Metastasis of Uterine Carcinosarcoma Mimicking Primary Carcinoma of the Middle Ear

Uterine carcinosarcoma is a rare type of endometrial carcinoma with poor prognosis. A bone metastasis to the skull base is extremely scarce in uterine carcinosarcoma. A 54-year-old woman with uterine carcinosarcoma complained of right ear otorrhea and otalgia. 18 F-FDG PET/CT presented an increased FDG uptake at the right middle ear involving the mastoid process and external acoustic meatus. Primary carcinoma of the middle ear was considered according to clinical symptoms and PET manifestation. However, the skull base metastasis from uterine carcinosarcoma was pathologically confirmed. The rare metastasis from uterine carcinosarcoma should be differentiated from primary carcinoma of the middle ear.