Increased 68 Ga-FAPI Uptake of Ureteric Fibroepithelial Polyp and Costal Cyst Mimicking Malignancy With Bone Metastasis.

A 70-year-old man presented with progressive dysuria. 18 F-FDG PET/CT showed no abnormal metabolic activity. 68 Ga-FAPI PET/CT revealed intense 68 Ga-FAPI in the lower left ureter and the left rib, mimicking malignancy with bone metastasis. However, postoperative pathological biopsy demonstrated the diagnosis of ureteric fibroepithelial polyp. In addition, the prior CT scan confirmed a bone cyst. Our case highlights the necessity of reviewing the patient's skeletal history when encountering a primary tumor with FAPI uptake and a concurrent FAPI-avid bone lesion.