組織学的に粘膜脱症候群に類似する大腸ポリープの臨床病理学的検討―inflammatory myoglandular polypの提唱

A Clinicopathological Study of Colorectal Polyps Histologically Resembling Mucosal Prolapse Syndrome: Proposal of the Term ‘Inflammatory Myoglandular Polyp'

要旨　既存の分類には当てはまらない大腸の孤立性，有茎性ポリープ28例の臨床病理学的検索を行った．患者は15歳から78歳で平均年齢は53歳であった．男性に多く，左半結腸，特にS状結腸に発生する．症状は出血または潜血だが半数以ヒの患者では特別の症状はなかった．内視鏡では平滑で発赤のある孤立有茎性ポリープであった．組織学的には直腸下部・肛門部に発生する粘膜脱症候群（mucosal prolapse syndrome；MPS）に類似していた，このポリープの臨床病理学的特徴を明らかにすると共に，MPSや他の既存の大腸ポリープとの鑑別を行った．原因は不明であるが，慢性の刺激がこのポリープの成因に関与していることが推測された．粘膜固有層の肉芽性炎症，線維筋症および過形成性腺管が組織学的特徴で，したがってこのポリープの名称をinflammatory myoglandular polypとすることを提唱した．

　Twenty-eight patients with unclassified colorectal polyps were reported. Twenty-one of the patients were men and 7 were women with the total mean age of 53 years. Symptoms were passage of blood or occult blood, but more than half of the patients had no specific complaints. Endoscopic examination showed each patient had a solitary pedunculated reddened polyp with a smooth surface. These polyps were found in the left-side colon, especially in the sigmoid colon. Histologically, they were similar to mucosal prolapse syndrome found in the anorectal region. Etiology was obscure, however, chronic stimulation might play a part in their pathogenesis. We discussed the differential diagnosis of these polyps from other types of colorectal polyps. Inflammatory granulation in the lamina propria, fibromusculosis and hyperplastic glands with occasional cystic dilatation were characteristic features of these polyps and we propose that the term ‘inflammatory myoglandular polyp' be used for these unclassified colorectal polyps.