―最近注目されている膵の囊胞性腫瘍―粘液産生膵癌―予後の良い膵癌

Mucin-Producing Pancreatic Cancer

要旨　粘液産生膵癌とは“癌の産生する粘液が膵管内に充満して主膵管が拡張し，乳頭の腫大，開口部の開大を起こし，粘液の排泄が観察されるもの”である．その組織型は様々であるが，自験例7例と症例報告15例，合計22例を集計してみると，その特徴が明らかになった．特異な乳頭所見，ERP像のほかには，①60，70歳台の男性に多いこと，②膵炎の既往がある例が4例あった，③アミラーゼ値上昇，耐糖検査異常，胃X線検査での圧排像が約半数にみられた，④US，CTでは膵管拡張，囊胞と診断され，血管造影では膵周囲の血管の圧排所見のみられた例が多かった，⑤病変部は膵頭部が76.2％を占めて，膵頭十二指腸切除されたものが多く，予後は5年生存例3例を含めて良好であった．以上が粘液産生膵癌の特徴である．

　Mucin-producing pancreatic cancer is defined as follows: main pancreatic duct dilates diffusely because of viscous pancreatic juice secreted by cancer cells and the orifice of the pancreatic duct opens widely. Mucin can be observed draining out through the orifice. This type of cancer includes several different histological patterns. Since our first report in 1980, 22 cases of mucin-producing pancreatic cancer (including 7 of our own cases) have been analyzed with a view to discovering their clinico-pathological characteristics In addition to specific findings concerning the major papilla and the pancreatogram mentioned above, 5 other characteristics were revealed. Firstly, the disease is more prevalent in males than female. It is most prevalent in the 60 and 70 age group. Secondly, 4 patients had previous history of acute pancreatitis caused by impaction of viscous pancreatic juice at the papilla. Thirdly, there was elevation of serum and/or urinary amylase level, abnormality revealed in the glucose tolerance test and extra-gastric compression on barium meal study in nearly half of the cases. Fourthly, dilatation of the pancreatic duct or cystic mass was often observed on US and CT. Angiography showed displacement of peri-pancreatic artery at the main abnormality different from encasement. Fifthly, the tumor was located in the head of the pancreas in 76.2% of the patients. Pancreatoduodenectomy was the commonest method of operation. Prognosis of this cancer was favorable, e.g. 3 patients have survived more than 5 years after resection. Analysis of more cases will lead to a better knowledge of the development pattern of this tumor, and will enable the recongnition of the initial signs of this cancer on the pancreatogram.