単房性囊胞様所見を呈した粘液産生膵癌の1例

Mucus-producing Pancreatic Cancer with a Unilocular Cystic Pattern, Report of a Case

要旨　患者は70歳の男性．尿濃染を主訴に来入院．US，CTで膵全体の著明な腫大と主膵管の単房性の囊胞状拡張像を認めた．PTCD造影では膵部総胆管の圧排しめつけ様狭窄像を呈し，内視鏡検査では主乳頭開口部の開大と副乳頭の腫大，主乳頭，副乳頭，胃体部後壁および前庭部小彎の瘻孔から粘液流出が観察された．ERCPでは著明に拡張した主膵管と副膵管が認められた．経口的膵管鏡検査では主膵管内に乳頭状腫瘤が観察され高度に進行した粘液産生膵癌と診断した．門脈合併膵全摘術を行った．拡張した主膵管内には粘液が充満し，肉眼的に5か所に乳頭状腫瘤を認めた．病理組織学的には乳頭状腺癌で主膵管から膵管分枝全体，副乳頭にも癌が浸潤していた．膵実質は著明な線維化に置き換わり，一部にmuconodularな浸潤とその部位から胃粘膜に浸潤していた．進行した粘液産生膵癌の浸潤様式を考えるうえで示唆に富む症例と考えられたので報告した．

　A 67-year-old man was admitted to our hospital because of jaundice. Ultransonogram showed dilatation of the main pancreatic duct and enlarged pancreatic head with an irregular internal echo pattern. Abdominal CT showed a unilocular cyst and cholangiogram revealed tubular stenosis of the intrapancreatic bile duct. ERCP showed a dilatation with a filling defect of the main pancreatic duct. Endoscopically mucus flowing out from the fistula to the body and antrum of the stomach was observed as well as enlarged papilla of Vater with a dilated orifice and a papillary lesion at the minor papilla. Peroral transpapillary pancreatoscopy demonstrated the presence of a papillary tumor with capillary vein in the dilated main pancreatic duct. We diagnosed the lesion as an advanced mucus-producing pancreatic cancer. Extended total pancreatectomy was performed. When resected specimen was cut and opened along the main pancreatic duct, papillary lesions emerged in the dilated main pancreatic duct which was plugged with mucinous substance. Histologically the lesion was composed of papillary adenocarcinoma, muconodular carcinoma and marked fibrosis. Cancer invasion was shown to involve the minor papilla and the branch of the pancreatic duct.