linitis plastica型胃癌，特にその初期病変の診断―X線診断を中心に

Early-stage Linitis Plastica Type Gastric Cancer for the Purpose of Radiological Detection

要旨　linitis plastica型胃癌の初期病変は，胃底腺粘膜領域内に存在する未分化型の早期胃癌である．臨床的には，潰瘍瘢痕合併の有無にかかわらず，少なくとも粘膜下層までの浸潤にとどまる1cm前後の未分化型胃癌を標的病変とする．X線診断では，明瞭な陥凹境界と大小不同の顆粒状陰影を示す典型的な未分化型癌のⅡc像だけでなく，透視下にも容易に観察できる小ニッシェ像と粘膜ひだの異常像を見逃さないように注意すべきである．特に，小ニッシェ像として現れる病変（微小Ⅲ型）は，小さくても粘膜下層に浸潤している特徴があり，中村の定義する前linitis plastica型癌¹⁾の形態的特徴を備えている．

　Early-stage linitis plastica type gastric cancer is manifested as undifferentiated early cancer present in the fundic gland mucosa. Clinically, irrespective of the presence or absence of ulcer scars, it implies undifferentiated gastric cancer about 1 cm in size with maximum infiltration into the submucosal layer. In X-ray based diagnosis, case should be taken not to overlook a small niche with irregular mucosal folds easily identifiable under fluoroscopy, as well as typical images of undifferentiated 0 Ⅱc cancer exhibiting clear demarcation of a depressed lesion and granular shadows in different sizes. In particular, a lesion identified as a small niche (minute 0 Ⅲ) is characterized by infiltration into the submucosal layer despite its small size, exhibiting the morphological features of pre-linitis plastica cancer defined by Nakamura.