25.肛門疾患痔核，癌，その他

Anorectal Diseases Causing Hemorrhage

要旨　肛門部の主な出血性疾患である，内痔核，裂肛，扁平上皮癌，悪性黒色腫，類基底細胞癌について述べた．内痔核の出血は鮮紅色で，多くの場合排便時のみ出血する．鑑別疾患としては，直腸脱，直腸粘膜脱症候群，直腸腫瘍などがある．裂肛は疼痛が主で，出血は拭紙につく程度の少量の鮮血である．扁平上皮癌は，放射線感受性が高いため放射線治療が第一選択である．悪性黒色腫は血行性遠隔転移が多いことから予後は悪い．類基底細胞癌は放射線化学療法が有効である．肛門腫瘍を正確に診断するためには，臨床の現場で頻回に肛門鏡検査を行い，普段から多くの痔核病変や正常肛門を観察しておくことが肝要である．

　Internal hemorrhoids, anal fissure, squamous cell carcinoma, malignant melanoma and basaloid cell carcinoma are recognized as the chief bleeding diseases of the anorectal region. Patients with internal hemorrhoids have scarlet colored hemorrhage which occurs mostly when they evacuate. Differential diagnosis of hemorrhoids includes rectal prolapse, mucosal prolapse syndrome and rectal tumor. Anal fissure is mainly accompanied by pain, and its bleeding is small in quantity. Because squamous cell carcinoma has high radio-sensitivity, radiotherapy is the first choice of treatment. Malignant melanoma has a very poor prognosis because of the high frequency of distant metastasis through blood vessels. Chemoradiation is very effective for treatment of basaloid cell carcinoma. It is important to examine many cases of hemorrhoids or normal anus using an anoscope in clinical work. Experiential knowledge gained by this procedure should lead to precise diagnosis of anorectal tumors.