手つなぎ・横這い型癌の新展開—手つなぎ・横這い型癌の病理学

Pathology of “Hand-shaking/Crawling-type” Adenocarcinoma of the Stomach

要旨●手つなぎ・横這い型癌はしばしば完全型腸上皮化生腺管に類似し，特徴的な腺管の分岐・吻合を示す腺癌である．内視鏡的に領域性が不明瞭であるばかりでなく，病理診断においては細胞異型度の低さから生検診断が難しいため，その臨床的・病理組織学的特徴を理解することが正確な診断に必要である．近年，筆者らは手つなぎ・横這い型癌における遺伝子変異の解析を行い，これまで未分化型腺癌に特異的と考えられてきたRHOA変異を半数の症例で同定した．本稿では手つなぎ・横這い型癌の病理組織像を概説するとともに，近年得られた分子生物学的な知見についても紹介したい．

　“Hand-shaking/Crawling-type” adenocarcinoma often resembles complete-type intestinal metaplasia and exhibits characteristic branching and anastomosing glands. These lesions endoscopically show an indistinct border, and their biopsy diagnosis is often difficult due to their low-grade histology. Thus, understanding the clinicopathological features of this adenocarcinoma is essential for making an accurate diagnosis. Recently, we conducted a mutation analysis of “hand-shaking/crawling-type” adenocarcinomas and identified RHOA mutations in half of the cases. In this article, we review the histological and molecular features of “hand-shaking/crawling-type” adenocarcinoma, including recent study results.