直腸肛門部の巨大basaloid carcinomaの1例

An Anorectal Giant Basaloid Cell Carcinoma, Report of a Case

要旨　症例は70歳，男性．肛門痛を主訴に，緊急入院した．入院時，肛門部に15×7cm大の巨大な潰瘍性病変がみられた．潰瘍部からの生検で，basaloid carcinomaの診断であった．S状結腸瘻造設後に，放射線照射(60Gy)および化学療法(MMC 15mg，5FU 1,500mg×4日)を行った．放射線化学療法終了後，肛門部の潰瘍性病変は，15×7cm→14×4cmと縮小した(縮小率47％)．その後，腹会陰式直腸切断術が施行された．標本上，組織学的に大部分の腫瘍細胞が消失していた．類基底細胞癌に対する治療法として，放射線化学療法が非常に有効であることが示唆された．

　We describe here a rare case of an anorectal giant basaloid carcinoma treated by chemoradiation and surgical therapy. A 70-year-old man was admitted to our hospital with anal pain as his chief complaint. He was found to have a 15×7cm sized giant ulcerated lesion at his anus. A biopsy of the ulceration showed basaloid carcinoma. After the operation of sigmoidostomy, the patient was treated with chemoradiation therapy. The tumor bulk received a total dose of 60 Gy in 30 fractions. The patient was also given 15mg of mitomycin-C as a single bolus injection and 1,500mg of 5-fluorouracil in 5％ glucose in the form of a continuous 24-hour infusion for 4days. After chemoradiation, the lesion shrank in size to 14×4cm. Abdominoperineal resection of the rectum was performed. A histological study of the surgical specimen showed most of the carcinoma cells had disappeared. It is suggested that chemoradiation would be a very effective therapy for a basaloid carcinoma.