深達度診断が困難であったⅡa型早期胃癌の1例

Early Gastric Cancer, Type Ⅱa, Which Was Clinically Diagnosed as Mucosal Involvement but Histopathologically Confirmed as Submucosal Involvement, Report of a Case

　Ⅱa型早期胃癌の深達度診断は比較的容易であるとされているが，われわれは術前，深達度が粘膜内癌mと診断したが，病理組織学的検索の結果，深達度smであった深達度診断困難症例を経験したので報告する．

　The patient was a 63-year-old man who underwent a medical examination at a certain institution in November 1978 although he had no subjective symptoms at that time. Stomach x-ray performed then demonstrated abnormalities with which he consulted us at our department.

　Gastric x-ray revealed a small elevated lesion on the anterior wall near the lesser curvature in the lower body. The lesion was approximately 15×10 mm in diameter. The elevated surface was slightly irregular, but there was no defect or ulceration. An x-ray diagnosis of Ⅱa type early cancer with a depth of invasion of m was thus made.

　Gastroscopy disclosed an elevated lesion with reddening on the anterior wall near the lesser curvature at lower body, thus confirming the x-ray finding. The elevated surface of the mucosa appeared slightly irregular. The endoscopic diagnosis was Ⅱa type early gastric cancer with a depth of invasion of m and operation was performed then.

　Histopathological examination revealed the lesion to be Ⅱa type early cancer involving submucosa. There was a minimal degree of infiltration of the submucosa by cancer cells; hence it would have been virtually impossible to detect involvement of sm without surgery. The essentials in the diagnosis as to the degree of involvement of elevated type early cancer are (1) shape and surface appearance and (2) size. However, it seems that, merely by these criteria alone, it is quite difficult, even virtually impossible, to differentiate between cancers involving only m and slightly infiltrating sm.