肛門管扁平上皮内癌の1例

Squamous Cell Carcinoma in situ of the Anal Canal, Report of a Case

要旨　症例は54歳，男性．比較的多量の新鮮血下血を主訴に来院した．注腸造影，内視鏡で中央に陥凹を伴う扁平な隆起性病変がみられ生検で扁平上皮癌と診断された．経肛門的粘膜切除術が施行され組織学的には粘膜内扁平上皮癌（carcinoma in situ ; CIS）であった．本邦では肛門管の粘膜内癌の報告は極めてまれだが，米国では肛門性交を行うHIV感染者の同性愛，両性愛者においてヒト乳頭腫ウイルスに関連した肛門管扁平上皮癌（CISを含めて）が多く報告されており，今後本邦でも痔疾患との鑑別が必要な疾患として念頭に置く必要があると思われる．

　A 54-year-old Japanese male was introduced to our hospital because of fresh, mild, anal bleeding to the amount of 200～250 ml. He had had several episodes of anal bleeding before coming to us. Emergency colonoscopy revealed a flat-elevated lesion on the dental line of the anus, but the bleeding had already stopped. Biopsy specimens which were taken from the elevated lesion during this colonoscopy study were diagnosed as squamous cell carcinoma (SCC). After other examinations, no metastasis was suspected and transanal anorectal mucosectomy was performed. The lesion surface was villous and 20 mm in size at its maximum diameter, and a hemorrhagic area was observed in the center of the lesion. The resected specimen was diagnosed, histologically, as SCC in situ. Serum anti-human papilloma virus antibody was negative, and no anal bleeding has occurred since the mucosectomy.