膵頭部膵管分枝囊胞状拡張を呈した4例

Cystic Dilatation of the Pancreatic Duct System, Report of Four Cases

要旨　膵頭部領域の膵囊胞性病変4例を経験した．いずれもERP上，主膵管との交通を有する類円形，ブドウの房状あるいは不整形の囊胞状拡張としてみられ，十二指腸乳頭部から粘液排泄はみられなかった．これら4例は，病理組織学的に粘液産生能のある高円柱上皮の乳頭状増殖が特徴的であった．このうち2例は，その細胞異型あるいは構造異型から腺腫と診断され，2例は癌と診断された．癌2例のうち1例は実質浸潤が軽度であったが，1例は浸潤が強く進行癌であった．これらの病変は画像診断上，あるいは組織学的にも同一の範疇と考えられ，一連の経過をみている可能性があり，その点からも興味ある症例であった．

　Cystic dilatation of the pancreatic duct in the uncinate process was found in four patients. Endoscopic retrograde pancreatography showed that these lesions were either round or irregular in shape and communicated with the main pancreatic duct (Figs. 2, 5, 8, 12). Mucin was not seen flowing out of the orifice of the major papilla. Pathological study of resected specimens from these four cases revealed that the dilated duct was composed of papillary projection of columnar epithelium with a potential of mucus production. Histologically, adenoma with moderate dysplasia was seen in two cases (Case 1 and 2) and carcinoma in part of the dilated ducts in the remaining two cases (Case 3 and 4). In the latter cases of pancreatic carcinoma, invasion of cancer to the parenchyma was mild in one and massive in the other. These different patterns of the lesion probably represent different stages of development of cystic lesion of the pancreas.