Carcinoma of the pancreas with widening of the duodenal sweep:

Generally, widening of the duodenal sweep is usually associated with advanced disease, and therefore it is imperitive to detect subtle changes on UGI early. Mass impressions on the inner aspect of the duodenum may create a double-contour effect, in which there is differential filling. The outer edge of the duodenum in this circumstance tends to opacify to a greater degree than the inner edge. Frostberg's sign, or an 'inverted-3' sign, is indicative of wall infiltration, but can also be mimicked (and is more commonly seen) by acute pancreatitis or pancreaticoduodenal lymph node enlargement. If duodenal diverticula are present, distortion is highly predictive of an enlarging pancreatic mass. Specifically, contour distortion, such as flattening or indentation, of a diverticulum (as opposed to merely displacement), is much more predictive of malignancy. Spiculation, especially when splaying or displacement of the spikes is present, may be seen with tumor infiltration and subsequent fixation of the duodenal folds. Nodularity, especially distal to the papilla, is suggestive of malignancy as well. Proximal nodularity of duodenal folds may be seen with postbulbar peptic disease.

Other entities which may cause widening of the duodenal sweep include acute and chronic pancreatitis, pancreatic pseudocysts, lymph node enlargement, retroperitoneal tumors, cystic lymphangiomas, aortic aneurysms, and choledochal cysts. The constellation of clinical and radiographic data should make differentiation of these entities simple.