FDG PET/CT in a Case of α-Fetoprotein-Producing Urothelial Carcinoma With Hepatoid Differentiation of the Renal Pelvis.

An α-fetoprotein-producing tumor in the urinary tract is rare. We describe FDG PET/CT findings in a case of α-fetoprotein-producing urothelial carcinoma with hepatoid differentiation of the left renal pelvis with a significantly elevated serum α-fetoprotein level (1035 ng/mL). FDG PET/CT showed intense activity of the left renal pelvic tumor with invasion of the renal parenchyma. This case indicates that α-fetoprotein-producing urothelial carcinoma with hepatoid differentiation should be considered in the differential diagnosis of FDG-avid tumors of the urinary tract in patients with elevated serum α-fetoprotein levels.