S状結腸憩室症に合併した粘膜脱と考えられる多発性隆起性病変の1症例

Polyp-simulating Mucosal Prolapse in the Sigmoid Colon with Diverticulosis, Report of a Case

要旨　患者は51歳，男性で，憩室症を伴うS状結腸に5個のポリープ様病変が認められた．手術標本では，発赤し周囲粘膜との境界が不明瞭な径17×9mm，20×15mmの2個の大きなポリープ様病変のほかに，3個の小隆起の存在が確認された．大きなポリープ様病変は組織学的には表層のびらん，腺管の増生・分岐・拡張，粘膜固有層における毛細血管の増生・拡張と共に線維筋症がみられ，粘膜下層には血管の壁肥厚・内腔狭小化が認められた．他の3個の小病変のうち1個では軽度の線維筋症が観察されたが，残りの病変では腺管の軽度の過形成が認められたのみであった．これらの組織学的所見は直腸粘膜脱症候群にみられる所見に類似しており，憩室症腸管において粘膜脱症候群と同様の機序により発生したポリープ様病変である可能性が示唆された．

　A case of a 51-year-old man with polypoid lesions complicating sigmoid colon diverticulosis was reported. Sigmoidectomy was performed, and five polypoid lelions were observed on the resected specimen; two of them were injected, pedunculated polypoid lesions sized 17×9 mm and 20×15 mm, and the others were small. The histological findings of the large lesions included surface erosion, proliferation of glands in irregular arrangement, proliferation and dilatation of capillaries and the presence of fibromusculosis in the lamina propria, and wall thickening and luminal narrowing of the vessels in the submucosa. In one of the small polypoid lesions, mild fibromusculosis was observed. These findings are in accordance with those of mucosal prolapse syndrome of the rectum. Therefore, similar mechanism was considered to have participated in the evolution of the polypoid lesions in this case.