2) 胃 (1)pit pattern 分類

Pit Pattern Classification of Gastric Mucosa

要旨　胃粘膜表面を拡大観察すると胃腺口（胃小窩）と被蓋上皮で形成されたpit patternが観察される．拡大内視鏡観察された胃粘膜のpit patternは点と線で構成され，萎縮性胃炎の影響や粘膜の破壊と再生によって様々な形態を示す．1970年代に拡大ファイバースコープを用いてpit patternを観察した筆者らは，胃小窩の形状からA（点状陥凹），B（短線状），C（縞状），D（顆粒状）に複合型AB，BC，CDを加えた胃粘膜微細模様の拡大内視鏡分類を作った．一方，CとDに不整模様（i）の亜分類を加えて癌病変を表現した．2000年代の電子内視鏡の時代になって，胃粘膜のpit patternを分類する多くの試みが始まっているが，筆者らのABCD分類はその基本となると考える．

　Under magnified observation of the gastric mucosal surface, gastric pit patterns which are composed of openings of gastric glands (gastric pit) and surrounding covering epithelium are observed. Gastric pit patterns observed by magnifying endoscopes are fundamentally characterized by dots and lines and from a complex pattern under the influence of atrophic gastritis and as the result of destruction and reproduction of mucosa. We observed gastric pit patterns by using a magnifying fiberscope in the1970s and classified them into4basic patterns and3mixed patterns ; such as A (dotted pattern), B (short-linear), C (striped) and (granular) and mixed patterns AB, BC and CD, from the shape formed by gastric pits. On the other hand, subgroups with irregularity (i) are used to express cancer lesions. Intestinal type gastric cancers with structural atypia are easily diagnosed by a characteristic irregular C pattern with a well-demarcated margin. Diffuse-type cancers are characterized by an amorphous depression surrounded with irregular D pattern.

　During the era of the magnifying videoscope in the2000s, many attempts to characterize gastric pit patterns have been undertaken and our ABCD classification may be regarded as a good model for new trials.