[Endosonography in tumors of the pancreas and bile ducts].

The sensitivity of EUS in demonstrating pancreatic tumors lies above 90% and tumors smaller than 2 cm in diameter can be visualized. Therefore EUS can be applied e.g. in the early diagnosis of symptomatic endocrine tumors. However, it is not suited as a screening method for pancreatic carcinoma in asymptomatic patients. The EUS findings do not permit a clear differentiation between malignant and inflammatory (pseudo) tumors. The specificity for the demonstration of malignant tumors is 74%. Its main importance is in the locoregional staging of tumors. EUS is superior to all other imaging tools in determining tumor extension and infiltration into the portal or splenic vein. The pT-stage is determined correctly preoperatively in 90% and lymph node metastases (N1) in about 73% (sensitivity 80-90%/specificity 50%) of the cases. Malignant tumors of Vater's papilla (ampullary tumors) and of extrahepatic bile ducts can be demonstrated endosonographically in nearly all cases. However, tumors of the proximal bile ducts, especially of the right hepatic duct are difficult and sometimes impossible to visualize. The value of EUS in bile duct cancer is in local tumor staging. The pT-stage is determined correctly in 80-90%, the sensitivity and specificity for N1-stage is 80-90% and 30% respectively. Comparative studies with other methods are lacking at the present time. The value of EUS in gall bladder tumors is not yet determined. Stones in the gall bladder may hinder the visualization of the gall bladder wall. In one study the pT-stage for gall bladder carcinoma was determined correctly preoperatively in 76.9% and the N1-stage in 80.7% of cases.(ABSTRACT TRUNCATED AT 250 WORDS)