食道乳頭腫の2切除例

Esophageal Squamous Papilloma, Report of Two Resected Cases

要旨　過去には珍しいとされた食道乳頭腫は，内視鏡機器の発展により遭遇する機会が増えている．中部や上部食道にも発生するが下部食道に多く，病因は食道裂孔ヘルニアに伴う逆流性食道炎による慢性刺激と考えられている．また，古くからhuman papilloma virus（HPV）感染との関係が議論されているが，その頻度は低いものと考えられている．組織学的には，血管を中心とした細い間質と過形成性の重層扁平上皮の乳頭状の増殖から成り，異型を伴うことはまれである．その診断は，拡大内視鏡を用いるようになったことで，血管構造を含めて詳細な形態観察が可能になり，より小さな乳頭腫を発見できるようになった．透明感がある白色で表面が細かく分葉したイソギンチャクのような形状や，半球状・桑実状の形態を呈する．拡大観察では分葉した1つ1つの突起の中央に細い血管が観察され，下部食道では発赤調のものもあり，1つ1つの顆粒の中に拡張・蛇行した微細血管が観察された．乳頭腫と食道表在癌の合併例は極めて珍しく，これまで3例の報告が認められた．

　Progress in endoscopic devices has facilitated the detection of esophageal squamous papilloma, previously considered rare. Esophageal squamous papilloma most frequently arises in the lower esophagus, but can also occur in the middle or upper esophagus. Esophageal squamous papilloma is thought to be caused by chronic stimulation due to reflux esophagitis in association with esophageal hiatal hernia. The causal relation between esophageal squamous papilloma and human papilloma virus (HPV) remains controversial; however, the incidence of esophageal squamous papilloma caused by HPV is considered low. Histopathologically, esophageal squamous papilloma consists of a thin interstitium surrounding blood vessels and hyperplastic papillary proliferation of stratified squamous epithelium, rarely associated with atypia. The use of magnifying endoscopy permits detailed observation of vascular structures, allowing smaller papillomas to be detected. Esophageal squamous papilloma has a sea anemone-like appearance with a finely lobulated, translucent, white surface or a hemispheric mulberry-like appearance. Magnifying endoscopy revealed micro vessels in the middle of each lobulated process. In the lower esophagus, some lesions were red;dilated, tortuous micro vessels were observed in each granule. Esophageal squamous papilloma associated with superficial esophageal cancer is extremely rare. To our knowledge, only 3 cases have been reported.