Endoscopic ultrasonographic diagnosis of pancreatic cancer complicating chronic pancreatitis.

BACKGROUND AND STUDY AIMS

Pancreatic cancer is a rare complication of chronic pancreatitis (CP), and its diagnosis remains difficult. The present study attempted to evaluate the ability of endoscopic ultrasonography (EUS) to diagnose pancreatic masses associated with CP and provide evidence of malignancy in patients with a pancreatic mass on EUS.

PATIENTS AND METHODS

Between 1991 and 1994, EUS examinations yielded a diagnosis of CP in 85 patients at our institution. Forty patients had early CP, 18 had pancreatic pseudocysts complicating CP, and 27 had advanced chronic pancreatitis - five of whom were considered as presenting pancreatic cancer associated with CP.

RESULTS

The five patients studied had jaundice, weight loss, and calcifications visible on plain abdominal films. Three of them had histological confirmation of pancreatic carcinoma. The pancreatic carcinomas were hypoechoic masses of 20-35 mm, with an irregular, rounded shape. Calcifications were limited to the periphery of the hypoechoic masses. Two patients had negative EUS-guided cytological punctures, and are still alive two years later. They were considered as false-positive cases. EUS showed a hypoechoic mass with peripheral calcifications in one of these false-positive patients, with a large central calcification in the other case. The overall sensitivity of EUS for the diagnosis of pancreatic carcinoma was 100%, but the positive predictive value was 60%.

CONCLUSION

EUS is highly sensitive in detecting abnormal masses in cases of CP, but the positive predictive value of the diagnosis of pancreatic cancer seems to be weak.