膵臓―膵嚢胞性病変

Pancreas：cystic lesions of the pancreas

近年の画像診断の進歩，CTやMRIの普及により，偶発的に診断される膵嚢胞性病変は増加の一途をたどっている^1-3）。膵嚢胞性病変には非腫瘍性嚢胞と腫瘍性嚢胞があり，腫瘍性嚢胞には良性から境界悪性，悪性まで様々な種類が含まれ，早急に手術が必要となるものから経過観察が選択されるものまで治療方針も大きく異なる。したがって，不必要な治療介入や適切な治療の遅れを防ぐためにも正確な画像診断を行うことは重要である。

Various cystic lesions can occur in the pancreas. Broadly, pancreatic cystic lesions can be classified into non-neoplastic and neoplastic lesions. Pancreatic non-neoplastic cysts consist of pseudocyst, retention cyst, lymphoepithelial cyst, etc. On the other hand, neoplastic cysts consist of intraductal papillary mucinous neoplasm, mucinous cystic neoplasm, serous cystic adenoma and cystic degeneration of solid neoplasms（namely, neuroendocrine neoplasm, solid pseudopapillary neoplasm, etc.）. These lesions include benign, premalignant, and malignant lesions. The diagnosis and discrimination of these lesions are very important because of the risk for concurrent or later development of malignancy. In this paper, I will review the characteristic clinical and imaging features of pancreatic cystic lesions.