膵・胆管の形成異常と病理

Pathological Study on the Duct Anomalies of the Pancreas and Biliary Tract

要旨　膵・胆管の形成異常のうち，膵癒合不全と膵胆管合流異常は画像診断により見出され臨床的に多くの関心を呼んでいる．膵癒合不全は，2つの膵原基が癒合せず分離したままの状態あるいは癒合しても主膵管系と副膵管系に結合のないものを言い，副乳頭よりの膵液排出不全による背側膵障害が惹起される．膵胆管合流異常は膵管と胆管が十二指腸の壁外で合流するものを言い，圧勾配により一般に膵液が胆道系に逆流し種々の病変を引き起こす．例えば総胆管拡張症では，その病因として定説化し，胆道癌でも前癌状態ではないかと注目されている．

　Pancreas divisum and an abnormal pancreatico-choledocho-ductal junction are duct anomalies of the pancreas and biliary tract which should attract attention.

　Pancreas divisum when occurs either the embryological ventral and dorsal parts of the pancreas fail to fuse, or when the main and accessory pancreatic duct systems fail to connect after the fusion of the pancreas.

　The result of these defects is that pancreatic drainage takes place mainly through the accessory papilla, which is really too small to cope with the drainage requirements properly. This results in pancreatitis.

　In cases of abnormal pancreatico-choledocho-ductal junction, the junction is situated outside the propria muscularis of the duodenum. In this case, the pancreatic juice may flow back into the bile duct and produce repeated inflammation of the biliary tract. For this reason, abnormal pancreatico-choledocho-ductal junction is widely recognized as the etiology of congenital biliary tract dilatation, and is also suspected to be onc of the pathological factors which cause biliary tract carcinoma.