Incidental Detection of Second Primary in Bladder on PET scan of a Patient with Colon Adenocarcinoma.

18F-FGD PET-CT scan has a well-established role in staging and restaging gastrointestinal tract carcinomas and less commonly for bladder malignancies. FDG detects tumours by the presence of increased metabolic activity in tumour cells showing as foci of increased uptake on the scan. Bladder malignancy is often masked by physiological excretion of radiotracer into the urinary bladder. Fortunately, fused CT images help in lesion detection. We present the case of a 45-year-old male with adenocarcinoma of the colon, referred for staging PET-CT. The scan showed a hypermetabolic lesion in the bladder which was later diagnosed as urothelial carcinoma.