Hyperestrogenism on 18F-FDG PET/CT in a Patient With Estrogen-Producing Ovarian Clear Cell Carcinoma

A 78-year-old woman was referred to the gynecologic outpatient department because she was suspected of having ovarian cancer based on an imaging study performed during a general medical examination. Further examination using F-FDG PET/CT revealed a bulky mass lesion with low FDG avidity, as well as surprisingly strong bilateral breast radiotracer uptake despite the patient's age. Thus, an estrogen-producing tumor was suspected. Bilateral salpingo-oophorectomy was performed, and surgical pathology diagnosed the tumor as clear cell carcinoma of the ovary.