Obliteration of the fat surrounding the celiac axis and superior mesenteric artery is not a specific CT finding of carcinoma of the pancreas

Partial or complete obliteration of the fat surrounding the celiac axis and superior mesenteric artery on CT is considered so characteristic of pancreatic carcinoma that many consider it diagnostic. However, this finding may be present on CT scans of some treatable tumors. During a 2-year period, we retrospectively collected 10 cases of nonpancreatic tumors that obliterated the fat surrounding the celiac axis and/or superior mesenteric artery. Four patients had metastatic disease, three had lymphoma, two had primary small-bowel adenocarcinoma, and one had a diffuse retroperitoneal endocrine tumor. The scans were analyzed for presence, location, and morphology of the mass and biliary and/or pancreatic ductal dilatation. Of the patients with metastatic disease, three had focal, retropancreatic, periceliac masses without ductal dilatation. One had an infiltrative retroperitoneal process enveloping the pancreas and causing biliary dilatation. Of the patients with lymphoma, two had focal masses in the mesenteric root without ductal dilatation, and one had an infiltrative retroperitoneal process. Of the two patients with primary carcinoma of the small bowel, one had a mesenteric mass without ductal dilatation and the other had an infiltrative retroperitoneal process enveloping the pancreatic head and obstructing the ducts. The patient with the neuroendocrine tumor had an infiltrative retroperitoneal process enveloping the pancreas without ductal dilatation. Obliteration of the fat surrounding the celiac axis and superior mesenteric artery is not a specific CT finding of carcinoma of the pancreas. One cannot rely solely on its presence for the diagnosis of pancreatic carcinoma but should use other important findings such as a focal pancreatic mass and ductal dilatation.