5mm以下のヨード不染帯の検討―微小不染帯の臨床的意味は何か

Histopatholoical Study on Tiny Iodine Unstained Lesions Smaller Than 5mm in Length

要旨　14例の食道癌の術前内視鏡検査で発見された5mm以下の微小ヨード不染帯81病巣を切除標本上で確認し病理組織学的に検討すると，扁平上皮癌が6病巣（7.4％），異形成が10病巣（12.3％）で，その他は1例を除き良性の病変であった．上部消化管スクリーニング検査での89例から，5mm以下のヨード不染帯230病巣と5mmより大きく10mm以下の75病巣，計305病巣を発見し生検したが，癌は5mm以下で2病巣（0.9％），5＜ ≦10mmで9病巣（12.0％）と，5＜ ≦10mmでは頻度が約13倍高くなった．異形成はそれぞれ65病巣（28.3％），21病巣（28.0％）と頻度の差はなかった．内視鏡検査で小さいヨード不染帯を発見したとき，①10mm前後であれば中央から1個生検を採る，②5＜≦8mmでは生検により病変が不明となったり，基底層型上皮内癌では，病理診断が難しく，癌を疑う場合にはEMRを行う，③5mm以下では経過を観察すること，がよいと考えている．

Eighty one of tiny iodine unstained lesions smaller than 5 mm in length from 14 patients with esophageal carcinoma were examined. These lesions were endoscopically observed and histopathologically evaluated on surgical specimens. Six lesions (7.4%) of squamous cell carcinoma. 10 lesions (12.3%) of dysplasia and the others were benign lesions. On the other hand, total of 305 lesions of esophageal biopsy specimens were taken from both 230 iodine unstained lesions smaller than 5 mm and 75 lesions up to 10 mm in length from 89 patients had no known esophageal cancer. Two lesions (0.9%) of carcinoma less than 5 mm, nine lesions (12.0%) of carcinoma up to 10 mm were discovered and found that the latter was apporoximatery 13 times higher of frequency. Dysplasia was respectively present in 65 lesions (28.3%) and in 21 lesions (28.0%) . There were no differences in frequency of size as for dysplasia. We thought that tiny iodine unstained lesions should be treated as follows. 1) If the unstained lesions were nearly 10 mm in length, only one biopsy should be taken from the center of these lesions. 2) If the unstained lesions were 5～8mm in length and strongly suspected carcinoma, we would like to propose endoscopic mucosal resection (EMR) rather than biopsy because biopsy not only make them unclear but also can not offer us a correct diagnosis on intraepitherial esophageal carcinoma of the basal layer type. 3) Observation of course is eligible for the lesions smaller than 5 mm in length.