Minimal Thorotrast deposition in parapancreatic lymph nodes.

The characteristic roentgenologic features of Thorotrast deposition in the perihepatic and parapancreatic lymphatics are described. Minimal deposits of Thorotrast were seen in the liver and spleen on the abdominal radiograph in 6 patients who had no clinical symptoms. Inquiry into the patient's history invariably disclosed angiography for vascular surgery several years earlier. The typical configuration of the affected lymph node is an oval, heavy density with a long tail, resembling a tadpole or teardrop. Other irregular radiopacities in the same area, including linear ones, probably represent colloid deposition along the lymphatics. Roentgenologic differentiation of Thorotrast deposits from pancreas stones and calcified lymph nodes is discussed.