多発早期胃癌の見逃し病巣の検討

Pre-operatively Missed Lesions of Multi-focal Early Gastric Cancer

要旨　十分な検索ができた84例(196個)の多発早期胃癌中45例(54％)に見逃し癌巣(58個)を認め，これらの特徴を発見癌(138個)と比較検討した．①見逃し癌(平均長径12mm)は発見癌(28mm)より有意に小さかったが，20mm以上の癌巣も10個(17％)認めた．②肉眼形態はⅡc(67％)とⅡb(16％)で80％以上を占めていた．③占居部位はCMA分類では下部(23％)が上部(30％)，中部(34％)より，また大彎(11％)，小彎(25％)が，前壁(40％)，後壁(33％)より見逃し率が低い傾向にあった．④上部の前壁と小彎，中部大彎，下部後壁では見逃し癌と発見癌の長径に有意差がなく，これらの部位は大きさに関係なく見逃しやすいことが示唆された．⑤見逃しⅡcでは，発見Ⅱcよりsmの線維化(潰瘍瘢痕)の出現率が低く，低分化腺癌の割合が多い傾向にあった．

　We analyzed pathologically evaluated 84 cases of multi-focal early gastric cancer (196 lesions) including 45 cases (58 lesions) of pre-operatively missed lesions. The pathological characteristics of pre-operatively missed and detected lesions were as follows: 1) The missed lesions (12 mm, the average in size) were significantly smaller than the detected ones (28 mm), but there were 10 lesions (17%) which were larger than 20 mm in size, 2) The macroscopic shapes of missed lesions were mainly type Ⅱc (67%) and type Ⅱb (16%) which occupied over 80% of the missed lesions. 3) Based on the CMA classification, the lesions in the lower part (23%) were less likely to be missed than those in the upper (30%) and the middle (34%) parts. The lesions on the greater (11%) and the lesser (25%) curvatures were less likely to be missed than those on the anterior (40%) and the posterior (33%) walls. 4) There was no significant difference in size between the missed and the detected lesions on the following areas: the anterior wall and the lesser curvature in the upper part, on the greater curvature in the middle part, and the posterior wall in the lower part. These results suggest that the lesions in these areas are easy to miss regardless of size. 5) The missed type Ⅱc cancers had less fibrosis (ulcer scaring), and were greater possibility of undifferentiated adenocarcinoma than the detected ones.