胃底腺領域の分化型癌の特徴―病理学的特徴と組織発生

Differentiated Adenocarcinoma in Fundic Glandular RegionIts Characteristics and Histogenesis

要旨　胃底腺領域に囲まれた分化型癌の病理学的特徴を検討するために，2cm以下の胃癌手術症例375病巣を検討した．胃底腺内に限局した病巣は17病巣（4.5％）で，そのうち分化型の成分を持つものは5病巣（1.3％）であり，うち4病巣は未分化型との混合型で，純粋の分化型は1病巣（0.3％）のみであった．混合型の分化型の成分および分化型癌は，組織学的には，構造異型が強く核異型の少ない腺管形成性の癌であり，粘液組織学的には，表層部ではGOS陽性で，深部ではCon A Ⅲ陽性の胃型の形質を示す胃型の腺管形成性の癌（腺窩上皮型癌）であった．胃底腺内にみられた腺窩上皮型癌の背景粘膜は，腸上皮化生はなく，軽度な幽門腺化生を認める粘膜で，粘液所見も含めて，未分化型癌と同様であり，腺窩上皮型癌は胃固有粘膜を基盤として発生するものと思われた．混合型の未分化型癌の成分は，純粋の未分化型癌と同様の組織学的，粘液組織学的所見を示し，腺窩上皮型癌から未分化型癌への組織型の転化の可能性が示唆された．

　To investigate the pathological characteristics of differentiated adenocarcinoma in the fundic glandular region, we reviewed 375 cases of gastric carcinoma less than 20 mm in diameter.

　Cancer foci surrounded continuously by normal fundic glands were found in 17 cases (4.5%). Among these 17 cases, 12 were undifferentiated type, 4 were mixed differentiated and undifferentiated type, and only one was differentiated type.

　Histologically, differentiated parts of the mixed type carcinomas and the differentiated type carcinomas were gastric type adenocarcinoma (foveolar type adenocarcinoma) containig GOS and Con A Ⅲ positive cancer cells. The undifferentiated parts of the mixed type carcinomas showed similar histological appearances as pure undifferentiated carcinomas.

　On the other hand, the noncancerous epithelium surrounding the cancer foci of all 17 cases showed mild pyloric glandular metaplasia. Intesinal metaplasia was never obseved.

　Other clinico-pathological appearances were also similar in all 17 cases.

　As a result, we concluded that differentiated carcinoma in the fundic glandular region is gastric type adenocarcinoma (foveolar type adenocarcinoma) originating from the gastric proper mucosa. There was a possibility of its changing into undifferentiated carcinoma.