[A study on gastric and small intestinal aberrant pancreas by endoscopic ultrasonography--with special reference to comparison with histological appearance].

To obtain characteristic findings of gastrointestinal aberrant pancreas by endoscopic ultrasonography (EUS), we made comparison between endoscopic ultrasonograms and histological findings in 5 cases (6 lesions) of resected gastric aberrant pancreas and 1 case (1 lesion) of small intestinal one. By EUS, gastrointestinal aberrant pancreases were delineated as hypoechoic masses with blurred boundary containing fine scattered hyperechoic spots, and also there were thickening of the fourth layer below the mass. Occasionally, there were some duct-like structures within the mass or marginal lobular structures. Moreover, the ultrasonographic patterns of aberrant pancreases were classified into 2 types, that is, M and S types. On histological examination, M type cases, in which the mass attached to the thickened fourth layer by EUS, were corresponded to acinar type and the pancreatic acinar cells penetrated into the proper muscle layer of the gastrointestinal wall, whereas S type cases, in which the mass was separated from the fourth layer, to ductal or mixed type. We conclude, therefore, that not only making the accurate diagnosis of aberrant pancreas but also drawing an inference of its histological type might become possible by EUS.