胃癌診断体系以外の有用な所見—demarcation line：形状に着目した小陥凹型胃病変の鑑別診断

Differential Diagnosis of Small Depressed Gastric Lesions According to the Shape of Demarcation Line in Magnifying Narrow-band Imaging

要旨●胃のNBI併用拡大観察では，非腫瘍性の陥凹型病変に“背景粘膜の腺窩辺縁上皮によって縁取られた内側に凸の明瞭な境界線（MCDL）”が観察されることがある．DLは陥凹型病変の73%（252/347）にみられ，MCDLはDL陽性陥凹型病変の34%（86/252）にみられた．MCDL陽性病変の97%（83/86）は非癌病変であった．MCDLの非癌病変に対する感度，特異度，陽性的中率はそれぞれ38%，91%，97%であった．MCDL陽性病変の97%に腸上皮化生を認め，その程度はMCDL陰性病変と比較して有意に高かった．

　In magnifying narrow-band imaging of the gastric mucosa, a characteristic DL（demarcation line）has been occasionally found in non-cancerous depressed lesions. This DL forms multiple convex shapes along the edge of surrounding epithelial mucosa. We refer to this novel finding as MCDL（multiple convex DL）. DL was present in 252 out of 347 lesions（73%）, whereas MCDL was observed in 86 out of 252 lesions（34%）. Out of 86 lesions with MCDL, 83（97%）were non-cancerous. The sensitivity, specificity, and positive predictive values of MCDL for non-cancerous lesions were 38%, 91%, and 97%, respectively. Intestinal metaplasia was seen in 97% of the lesions that were positive for MCDL. The grade of intestinal metaplasia was significantly higher in the lesions with MCDL, compared with those without MCDL.