Incidental, Early Diagnosis Of Urinoma By F-18 FDG PET/CT

An F-18 FDG positron emission tomography/computed tomography (PET/CT) scan was performed for staging purposes in a 51-year-old asymptomatic man 3 weeks after hand-assisted laparoscopic surgery (HALS) for colorectal cancer. The whole-body F-18 FDG PET/CT demonstrated a left retroperitoneal hyperintense focus of F-18 FDG. The degree of radioactivity was comparable with the bladder, suggesting a urine collection. A CT/IVP obtained after the PET/CT study found a left hydronephrosis and a dilated ureter to the visible level of the bilobed fluid mass. The urinoma was subsequently drained percutaneously. Follow up with CT scan of the abdomen and pelvis showed no reaccumulation of urine. A PET/CT performed 5 months later was negative for retroperitoneal reaccumulation of urine. With PET alone, a hypermetabolic retroperitoneal focus of FDG may have been interpreted as lymphadenopathy if a contemporaneous CT was not available. The integrated PET and CT displayed the structural and functional aspects of the fluid collection, correctly indicating a urine collection.