膵癌の病理

Pathology of pancreatic cancer

膵癌の大部分は浸潤性膵管癌であり，膵上皮内腫瘍性病変（pancreatic intraepithelial neoplasia：PanIN），膵管内乳頭粘液性腫瘍（intraductal papillary mucinous neoplasm：IPMN），粘液性嚢胞腫瘍（mucinous cystic neoplasm：MCN）などの前駆病変を経て進展すると考えられている。その他，悪性またはmalignant potentialのある膵腫瘍として，神経内分泌腫瘍（neuroendocrine neoplasm：NEN），腺房細胞癌，充実性偽乳頭状腫瘍（solid pseudopapillary neoplasm：SPN）などがある。本稿では，膵癌ならびにmalignant potentialを有する膵腫瘍の肉眼像および組織像について概説する。

The predominant form of pancreatic cancer is invasive ductal adenocarcinoma, a highly aggressive malignancy that often develops from precursor lesions, including pancreatic intraepithelial neoplasia, intraductal papillary mucinous neoplasms, and mucinous cystic neoplasms. In addition to conventional ductal adenocarcinoma, histological variants including adenosquamous carcinoma, colloid carcinoma, and anaplastic carcinoma, have been recognized. Other pancreatic tumors, including neuroendocrine neoplasms, acinar cell carcinomas, and solid pseudopapillary neoplasms, require careful pathological evaluation. This article summarizes the gross and histological features of pancreatic cancer and related tumors, providing a practical overview to improve pathological understanding and diagnostic accuracy in daily clinical practice.