Barrett粘膜・食道に対する狭帯域フィルター内視鏡システム併用拡大内視鏡観察の意義

Clinical Significance of Magnifying Endoscopy Combined with the Narrow Band Imaging System for Barrett's Esophagus

要旨　Barrett 粘膜・食道45例に対して狭帯域フィルター内視鏡（narrow band imaging；NBI）システム併用拡大内視鏡観察を行い，その有用性を明らかにすることを目的に拡大観察画像と病理組織像とを対比検討した．Barrett粘膜・食道において粘膜微細模様はround or oval，straight，villus，cerebriform，irregularの5つのpatternに，毛細血管像はType I～Vに分類された．“villus”または“cerebriform”を呈する粘膜微細模様の特殊腸上皮化生（specialized intestinal metaplasia；SIM）に対するsensitivityは81％であった．“Type IV”〔螺旋状に蛇行しつつ複雑に分岐し，絡み合う蔦（an ivy）あるいはDNA螺旋様構造を示す．しかも，隣接する毛細血管同士が鎖状またはネット状に連結している毛細血管像〕のSIMに対するspecificityは93％であった．表在型Barrett腺癌部では，“irregular”な粘膜微細模様とType V（不規則な走行と形状不均一を伴う異常毛細血管像）を認めた．粘膜微細模様と毛細血管像に基づいたNBI併用拡大内視鏡診断は，発癌母地として重要視されているSIMのより確実な拾い上げとともに，Barrett腺癌の早期発見とその範囲診断に有用である可能性が示唆された．

　We studied the possibility as a diagnostic tool of specialized intestinal metaplasia (SIM) and adenocarcinoma in Barrett's esophagus, using magnifying endoscopy combined with the narrow-band imaging (NBI) system. SIM has been detected by random or four-quadrant biopsy using conventional endoscopy. However, little is known about the fine mucosal structure of SIM. Magnifying endoscopy combined with the NBI system yields very clear images of not only the fine mucosal patterns but also the capillaries on the mucosal surface. Magnifying endoscopic findings for 124 regions in Barrett's esophagus were recorded and compared with histological findings. Fine mucosal structure was classified into 5 patterns ; round or oval, straight, villus, cerebriform and irregular. In addition to this capillary patterns were classified into five categories of Type I～V. Fine mucosal patterns showing “villus” or “cerebriform” indicated SIM with a sensitivity of 81％ as compared with histological findings by biopsy specimens. Type IV, intertwining capillary pattern showing an ivy or the spiral structure of DNA with a chain or a net-like connection, was peculiar to the histological region of SIM (specificity 93％). “Irregular” fine mucosal pattern and the abnormal capillary pattern (Type V) were characteristic features of the Barrett's adenocacinoma. Fine mucosal patterns and capillary patterns, which were identified by magnifying endoscopy combined with the NBI system, correlated well with histological diagnoses. We believe that magnifying endoscopy combined with the NBI system enables us to predict the histological diagnosis of SIM and adenocarcinoma in Barrett's esophagus.

　1) Department of Endoscopy, The Jikei University School of Medicine, Tokyo

　2) Department of Pathology, The Jikei University School of Medicine, Tokyo