In the Western Hemisphere, Europe, and Japan the most common cause of chronic calcifying pancreatitis is alcoholism. Other etiologies include idiopathic (up to 40%), biliary tract disease (usually acute rather than chronic), hyperparathyroidism, hereditary pancreatitis, cystic fibrosis, trauma, tropical pancreatitis, and hyperlipidemia.

CLINICAL FINDINGS: Chronic pancreatitis can present with mild recurrent bouts of pain, constant abdominal or back pain, or in a small number of patients, painless exocrine and endocrine deficiency. Alcoholism is usually present for 5-10 years prior to the development of clinical pancreatitis. Initially, exocrine function is minimally impaired, but as insufficiency develops, fat and protein malabsorption occur with weight loss. Diabetes occurs in 10% of cases and impaired glucose tolerance in 14-90%. Duodenal obstruction and/or obstructive jaundice may occur in 45% of patients with moderate or advanced chronic pancreatitis.

PATHOLOGY: Chronic calcifying pancreatitis is characterized by a nodular, misshapen, hard gland that can be enlarged or shrunken. Calculi are present and are almost always within the ductal system. They vary in size from microscopic concretions to 1-2 cm stones.

RADIOLOGY: Demonstration of pancreatic lithiasis on plain films is a fast and inexpensive means of confirming a clinical diagnosis of chronic pancreatitis and effectively excluding carcinoma. In various series the frequency of plain film calcification has varied from 20 to 50% in alcoholic chronic pancreatitis. By contrast, only 2% or less of patients with chronic pancreatitis from biliary disease develop pancreatic calculi.

SONOGRAPHY: Due to the presence of fibrosis within the gland, there is sometimes sonographic evidence of an inhomogeneously abnormal echo texture often accompanied by calcifications. These calcifications are in the ductal system; their distribution may be focal or diffuse, and if large enough they are associated with acoustical shadowing. The gland is often irregular in outline and there may be enlargement (focal or diffuse) or parenchymal atrophy. Pancreatic ductal dilatation is often visible due to obstructing stones or stricture.

Chronic pancreatitis can be associated with thrombosis of the portal venous system. This usually involves the splenic vein; however, extension to involve the main portal vein can also occur. Echogenic thrombus may be identified within the involved portion of the vein accompanied by demonstration of collateral channels. In some instances, the obstructed vein itself cannot be sonographically identified.

CT: The gland in chronic pancreatitis can be normal in size or enlarged or it may be small, atrophic and replaced by fat. When the gland is enlarged, this enlargement may be focal or diffuse. Focal enlargement due to chronic pancreatitis (which is nearly always in the pancreatic head) is hard to distinguish on CT grounds alone from carcinoma unless punctate calcifications are present as these are almost never found in carcinoma (except sometimes following chemotherapy). The incidence of pancreatic carcinoma is low (except for familial pancreatitis) in patients with chronic pancreatitis. The calcifications that are often present in chronic pancreatitis are easily seen on CT (which is the most sensitive modality for their demonstration) and are usually multiple. They may occur in only one part of the gland or be present throughout.

Pancreatic ductal dilatation (greater than 3 mm) is often present, especially when a focal mass with calcification involves the head. The ductal dilatation may be irregular (73%), smooth (15%), or beaded (12%). Common bile duct dilatation may be associated. Occasionally in chronic pancreatitis, CT may show only a markedly dilated beaded pancreatic duct which can simulate a number of small intrapancreatic pseudocysts.

The presence of thrombosis in the portal system can be inferred when a vein fails to opacify normally following intravenous contrast injection and collateral channels are demonstrated.

Patients with chronic pancreatitis can have all the symptoms and signs of pancreatic carcinoma. If a noncalcified focal mass is found in the pancreas of such a patient, then pancreatic carcinoma has to be considered. The presence of the characteristic dense calcifications of chronic pancreatitis within a mass makes it unlikely that it represents a pancreatic cancer. If a diagnostic dilemma exists, then a percutaneous needle aspiration should be considered.