膵の囊胞性疾患の診断―ERCPを中心に

Diagnosis of Pancreatic Cystic Diseases by ERCP

要旨　膵囊胞は，その背景に慢性膵炎や膵癌などの重要な疾患を有することが多い．そこで膵囊胞の自験103例の膵管像を詳細に検討し，ERCPの膵囊胞に対する診断能につき検討した．炎症性膵囊胞の診断においてはERCPは背景病変の診断に優れていた．すなわち囊胞を合併した慢性膵炎においては，囊胞を直接証明しえた症例は約60％（貯溜囊胞100％，仮性囊胞37％）であったが，囊胞との交通のない症例の91％の症例で慢性膵炎の膵管像が得られ，背景に慢性膵炎のあることが診断しえた．腫瘍性囊胞の診断では，膵管像の特徴として，われわれの言う圧排型や拡張型のほかに膵管内透亮像や陰影欠損像がみられ，腫瘍性囊胞の診断においてERCPは従来考えられているより有用であることが判明した．二次性囊胞においてもERCPは背景病変の診断に有効であった．最近注目されている粘液産生膵癌（腫瘍）を膵管像や病理組織像より検討すると，腫瘍性囊胞と極めて類似し，これらは互いに関連性のある疾患であると推測された．

　Pancreatic cysts are caused by various kinds of pancreatic diseases, especially pancreatic cancer or chronic pancreatitis. One hundred and three cases of pancreatic cysts were analyzed with special reference to their pancreatograms. In cases of inflammatory cysts, ERCP is a useful method to diagnose their underlying causes, because ERCP was able to describe, as pooling of radiopaque, about sixty percent of pancreatic cysts with chronic pancreatitis. In addition to this, ninety one percent of cases without communication to pancreatic ducts showed abnormal pancreatograms indicating chronic pancreatitis. Even in cases of neoplastic cysts, most of them appeared as dislocation of pancreatic ducts or as massive dilatation of the main pancreatic duct or large branch ducts with filling defect. For this reason, when we get these typical pancreatograms without changes of chronic pancreatitis, we can easily make correct diagnosis of neoplastic cyst. Moreover, ERCP was useful to aid speculation about the origin of pancreatic neoplastic cysts. According to the analysis of pancreatograms and histology, mucinous cystic tumors such as mucinous cystadenoma and cystadenocarcinoma are thought to be very similar to mucinous adenocarcinoma.