Findings: A hypodense mass is seen in the head of the pancreas. The body and tail are atrophic, and the pancreatic duct is dilated proximally. The superior mesenteric vein (SMV) is not visualized. The hypodense mass has invaded the area where the SMV normally is located. The SMV is most likely obstructed by the mass. The superior mesenteric artery (SMA) is almost completely encased by the mass. On the CT angiogram, only a tiny remnant of the SMV can be seen, and the SMA appears indented. Several 1 - 1.5 cm lymph nodes are visualized in the portal caval space and in the porta hepatis.
Diagnosis: Pancreatic cancer.
Discussion: The findings of an invasive hypodense mass in the head of the pancreas which involves the SMV and SMA along with pathologically enlarged lymph nodes are most suggestive of pancreatic cancer.
Pancreatic cancer is the 5th most common cause of cancer deaths in the U.S. It is approximately twice as common in males compared to females and somewhat more common in blacks compared to whites. Patients with pancreatic cancer are usually greater than 50 years old.
Greater than 90% of pancreatic cancers are ductal adenocarcinoma and its variants. Most of the remaining 5 - 10% are islet cell tumors. Pancreatic cancer arises in the head of the pancreas 70% of the time, in the body 20%, and in the tail 10%. Abdominal pain and weight loss are present in greater than 75% of patients with pancreatic cancer, and jaundice is present in greater than 80% of patients with pancreatic head tumors secondary to biliary obstruction.
CT is the best modality for imaging the pancreas. A mass deforming the size and contour of the pancreas is the most common finding for duct cell carcinomas occurring in 96% of cases. A central zone of decreased attenuation is present in 83% of pancreatic head and 60% of pancreatic body carcinomas. CT can be used for staging purposes with the findings of retroperitoneal extension, major vascular involvement, invasion of contiguous organs, ascites, lymphadenopathy, and distant metastases suggesting unresectability.
The prognosis for pancreatic cancer is grim. Surgery represents the only method of a possible cure; however, 85-90% of patients present with surgically unresectable disease. Of those who undergo surgery, the five year survival rate is still only 10%, but survival is 3-4 times that of patients who do not undergo resection. Those with unresectable tumors have a median survival of five months. The utilization of 5-fluorouracil (f-FU) in combination with radiation therapy has increased the survival time of patients with unresectable tumors which have not spread beyond the pancreas although their prognosis is still poor.
References:
Gore, et al. Textbook of Gastrointestinal Radiology. 1994:2161-2183.
Isselbacher, et al. Harrison’s Principles of Internal Medicine. 1994:1532-1534.
Webb, et al. Fundamentals of Body CT. 1991:189-196.
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