Ki-67染色態度からみたserrated adenomaの組織診断

Characteristic Feature of Serrated Adenoma on the Evidence of Ki-67 Positive Cell Pattern

要旨　serrated adenomaの性格を明らかにするために，61病巣のhyperplastic polypとserrated adenomaを組織学的に再検討し，Ki-67免疫染色で増殖能の検討を行った．serrated adenomaを組織学的に腺管内腔がserratedな様相を示し，種々の程度の細胞異型・核異型を伴い，表層へ向かっての分化傾向が少なく，腺管が分岐する傾向が強く，基底膜が凹凸不整を示すものと定義した．serrated adenomaの基本的なKi-67染色態度は，serratedな上皮の陥凹部に陽性細胞が認められ，陽性部は不連続であった．一方，hyperplastic polypは17例全例で腺管の腺底部から中層部まで連続性に陽性細胞がみられ，common type adenomaは腫瘍部全体にびまん性に認められた．以上の結果からserrated adenomaの診断は，上記のごとくの定義に基づいて診断するのが適当と思われた．

　Histological feature and Ki-67 index of 61 cases of hyperplastic polyps and serrated adenomas were examined.

　We divided Ki-67 positive cell pattern into three types (regenerative type, serrated type and common adenomatous type). The regenerative type is that Ki-67 positive cells were continuously seen from the base of glands to middle part of glands like the non-tumorous regenerative glands, but positive cells were numerous compared with regenerative glands. The serrated type is that Ki-67 positive cells were located in depressive part of serrated epithelium and the positive areas were discontinuous in a tumor gland. The common adenomatous type is that Ki-67 positive cells were continuously seen at almost all cells in the tumor glands.

　All 17 cases of hitologically hyperplastic polyps showed the regenerative type of Ki-67 positive cell pattern.

　Nine cases out of all 22 cases of histologically serrated adenomas showed the serrated type of Ki-67 positive cell pattern, others showed the mixed type.

　All 13 cases of histologically mixed types showed the mixed type of Ki-67 positive cell pattern.

　One histologically tubular adenoma showed adenomatous type of Ki-67 positive cell pattern.

　We concluded the serrated adenoma is a distinct form of neoplasm on the evidence of Ki-67 positive cell pattern.