生検による経過観察からみた食道の早期癌と“dysplasia”―癌組織発生と生検組織診断基準について

Early Carcinoma and Dysplasia of the Esophagus Histogenesis and Histological Diagnostic Criteria Based on Follow-up Biopsy Specimens

要旨　全割のなされた早期食道癌切除症例40例（ep癌10例，mm癌14例，sm癌16例）と，それらから採取された生検標本205例とを対象として，癌といわゆるdysplasiaとの関係を検討し，更に切除標本と生検標本との組織学的1対1対応を行うことによって，生検組織診断基準について検討した．その結果，①早期食道癌の異型組織所見はモザイク様であることが多く，それらの間には境界は認められず連続的であり，癌に随伴する異型上皮は認められなかった．②切除標本と生検標本との組織学的検討からは，異型上皮巣と診断された生検組織のほとんどは癌と診断すべきものであり，異型上皮巣の癌化を裏付ける所見は認められなかった．③したがって，食道癌は直接扁平上皮から発生すると推測された．④生検標本の癌組織診断には，核の大小不同，N/C比の増加，配列の乱れ，肥厚した上皮の乳頭状下方進展の所見が認められれば容易である．更に，水滴様下方進展が認められれば，浸潤癌を疑うべきである．また，紡錘状細胞集団の所見に注意すべきである．

　Forty superficial carcinomas of the esophagus (10intraepithelial and 14 intramucosal carcinoma, and 16 carcinomas infiltrating in the submucosa) and 205 biopsy specimens taken from these cases were histologically studied on the relationship between carcinoma and dysplasia.

　Conclusions obtained are as follows:

　1) Most of superficial carcinomas of the esophagus exhibited mosaic pattern of carcinomatous epithelium, the border of which was not distinct. Dysplastic lesions were infrequently seen in these mosaic areas.

　2) When checked with surgical specimens, many biopsy specimens originally diagnosed as dysplasia turned out to be carcinoma.

　3) Thus, the majority of squamous carcinoma of the esophagus were considered to arise directly from the squamous epithelium.

　4) The following histological findings were important in diagnosing carcinoma based on biopsy specimen: Enlargement of nucleus, irregular shape and size of the nucleus, increase in nucleocytoplasmic ratio, irregular arrangement of the basal cell layer, and downward papillary growth of the atypical squamous epithelium. Tear drop-like downward growth was suggestive of carcinoma infiltrating in the mucosa. Atypical squamous epithelium showing fusocellular pattern was also highly suggestive of malignancy.