Favorable 99m Tc-FAPI-46 Uptake in Primary Mucinous Adenocarcinoma of the Bladder.

We present a 34-year-old woman diagnosed with primary mucinous adenocarcinoma of the bladder, confirmed after transurethral resection. Two years postinitial diagnosis, despite chemotherapy, she developed pulmonary and skeletal metastases, leading to progressive symptoms including cough, hemoptysis and refractory bone pain. She was evaluated via 99m Tc-FAPI-46 scintigraphy, which showed significant uptake in metastatic lesions, suggesting suitability for radio-ligand therapy. However, the patient's condition deteriorated rapidly, and she passed away before treatment could be initiated. This case underscores the sensitivity of FAPI-targeted imaging in mucinous adenocarcinoma of the bladder and highlights the need for further investigation into its therapeutic applications.