Axial slice of an abdominal CT in a scan during portal venous phase in a patient with metastatic malignant melanoma. The image shows enterocolic intussusception (arrowhead) with mesenteric fat (small arrow) and mesenteric vessels (thick arrow) being drawn into the intussusception. Surgical treatment revealed intraluminal metastasis of malignant melanoma which was not seen on the CT scan.