We present coronal views of serial whole-body F-18 FDG PET scans obtained from a 71-year-old man with recently diagnosed oat cell carcinoma (OCC) of the bladder as well as pathology slides from bladder biopsy. Transmission images were first acquired and were followed by emission images at 1 hour after intravenous administration of 14.9 mCi of the radiopharmaceutical. F-18 FDG PET revealed widespread osseous metastatic disease, upstaging the patient and changing the management of disease. Repeat F-18 FDG PET after 2 and 6 cycles of cisplatin and etoposide chemotherapy showed reduction and resolution of osseous metastases. The tumor had a Ki-67 proliferation fraction of 90%, TTF1 was focally positive; chromogranin, PSA, and PAP were negative. Immunohistochemical stains for keratin and synaptophysin were positive. These findings are typical for OCC.