Fig. 21

Metastasis. Abdominal and pelvic CT (a, b) of a patient with sigmoid colon cancer, performed to stage the disease, clearly demonstrated the sigmoid tumor (arrowheads) but failed to show distant metastases. However, MPR and retrospective analysis revealed a discrete circumferential thickening on D3 and D4 (arrows) which was not recognized initially. This duodenal lesion progressed to become an “apple core” lesion (arrows) causing obstructive symptoms, as evaluated by a barium study performed 2 months later (c)