—大腸上皮性ポリープの鑑別診断—非腫瘍性ポリープ—内視鏡診断の立場から

Endoscopic Findings of Colorectal Epithelial Non-neoplastic Polyps

要旨●過去23年間に当科および関連施設にて診断された大腸の孤立性若年性ポリープ（JP）101例，孤立性PJP（Peutz-Jeghers type polyp）29例，IMGP（inflammatory myoglandular polyp）18例を対象とし，その臨床像，内視鏡像，病理組織像を遡及的に検討した．その結果，JPは平均年齢が低かった．内視鏡所見では，JPはびらん，白苔，白斑，NBI拡大観察下の開大した腺管開口部や疎に分布した腺窩辺縁上皮，細かい血管の増生，色素拡大観察下の星芒状，疎に分布したpitの，PJPは分葉状，NBIや色素拡大観察下の樹枝状構造の，IMGPは白斑，NBI拡大観察下の開大した腺管開口部，細かい血管の増生，色素拡大観察下の星芒状pitの頻度がそれぞれ高かった．以上よりJP，IMGPとPJPは異なる内視鏡像を呈していたが，JPとIMGPの内視鏡像は比較的類似していた．しかしながら，JPはIMGPに比べ，白苔，NBIや色素拡大観察下の疎に分布する腺窩辺縁上皮やpitの頻度が高いことを加味すると鑑別できる可能性があるものと推察する．

　In this retrospective study, we reviewed reports of colonoscopies performed between 2000 and 2023 in our institutions and identified patients who underwent endoscopic or surgical resection for colorectal solitary JPs（juvenile polyps）, colorectal solitary PJPs（Peutz−Jeghers polyps）, and IMGPs（inflammatory myoglandular polyps）. The clinicopathologic findings of 101, 29, and 18 patients with JPs, PJPs, and IMGPs, respectively, were compared. The patients with JPs were younger than those with PJPs. JPs frequently exhibited erosions, whitish exudates, chicken skin mucosa, expanded crypt openings, decreased marginal crypt epithelial density, and increase of thin vessels by magnifying M-NBI（narrow-band imaging endoscopy）and a star-like pit pattern and decreased pit density by MCE（magnifying chromoendoscopy）. PJPs frequently exhibited a lobular surface and branching surface pattern by M-NBI or MCE. IMGPs frequently exhibited chicken skin mucosa, expanded crypt openings, and increase of thin vessels by M-NBI and a star-like pit pattern by MCE. In conclusions, PJPs had endoscopic features distinct from JPs and IMGPs. Also, endoscopic findings of JPs were similar to those of IMGPs. However, the higher rates of polyps with whitish exudates, decreased marginal crypt epithelial density by M-NBI, and the higher rate of pit density by MCE observed in patients with JPs might help differentiate JPs from IMGPs.