Predicting Malignancy in Adnexal Tumors With FAPI PET/CT and FDG PET/CT

Abstract

A 54-year-old woman presented with a 55 × 64-mm tumor in the ovary with high [¹⁸F]FDG uptake on [¹⁸F]FDG PET/CT highly suggestive of ovarian cancer. Prior to surgery, the patient underwent [⁶⁸Ga]-Ga- fibroblast activation protein inhibitor (FAPI)-46 PET/CT, which revealed low [⁶⁸Ga]-Ga-FAPI-46 tumor uptake. Histopathology revealed a borderline ovarian tumor, which has low malignant potential and a 10-year survival rate greater than 93%. High [¹⁸F]FDG uptake is considered a fair predictor of malignancy in adnexal tumors. The present case demonstrates the potential superiority of [⁶⁸Ga]-Ga-FAPI-46 PET/CT over [¹⁸F]-FDG PET/CT in differentiating malignant adnexal tumors from borderline ovarian tumors.