5）表層拡大型

Superficial Spreading Type of Carcinoma of the Stomach

要旨　過去19年間に，当センターで経験した表層拡大型早期胃癌69例を対象として，臨床病理組織学的特徴について検討した．男性37例，女性32例，平均年齢64.2歳，平均腫瘍長径8.8cm，占居部位は，M領域44例，小彎41例に最も多かった．肉眼型は，陥凹型49例，隆起型20例で，0 IIb進展を31例（44.9％）に認め，境界診断が病変の口側小彎で困難な症例が多かった．組織型は，混在型40例，分化型17例，未分化型12例の順に多く，SM浸潤率は44.9％で，リンパ節転移を20.3％（14例）と高率に認めたが，そのうち混在型が13例を占めていた．混在型のSM癌についてみると，68.4％にリンパ節転移を認めていた．以上より，表層拡大型早期胃癌は，占居部位ではM領域，小彎を中心に発育するものが多く．小彎口側の境界診断が困難な特徴を有する．組織型では混在型が多く，そのうちのSM癌は，高率にリンパ節転移を来すため，治療法選択において十分に注意する必要がある．

　Sixty-nine cases of superficial spreading early gastric cancer encountered at our center over the past 18 years were examined with regard to clinicopathological and histopathological features. Of these 69 patients, 37 were male and 32 were female, with an average age of 64.2 and mean tumor diameter of 8.8cm. The tumors were most often seen in the M region（44 cases）and in the lesser curvature of the stomach（41 cases）. With regard to morphological classification, 49 cases were sinus cancer and 20 cases were elevated cancer. Phase 0 IIb expansion was observed in 31 cases（44.9%）, many of which had the boundaries on the oral side of the lesion, which made diagnosis difficult. With regard to tissue types, 40 cases were mixed form, 17 cases were differentiated, and 12 cases were undifferentiated. SM seroprevalence was seen in 31 cases（44.9%）, and lymph node metastases were observed in 14 cases（20.3%）; 13 of these cases were of the mixed type. Lymph node metastases were detected in 68.4% of cases of mixed type SM cancer. The above observations indicated that most cases of superficial spreading early gastric cancer are of the mixed tissue type. SM cancer had a significantly higher ratio of lymph node metastases compared to single tissue type cancers. Borderline diagnosis was also difficult, and thus treatment options must be considered very carefully.