褪色像により診断可能であった純粋Ⅱb型早期胃癌の1例

Pure Type Ⅱb Early Gastric Cancer Detected by Its Discoloration on Endoscopy, Report of a Case

はじめに

　通常内視鏡検査にてⅡb型早期胃癌の診断指標が得られるとすれば，それはより浅いⅡcやより低いⅡaの診断指標の延長線上にのみ得られるものと考えられる．すなわち，内視鏡所見としては粘膜面の槌色，発赤といった色調異常や，わずかな凹凸異常の中にⅡbの診断指標を求めうると考えられるのである．今回われわれは褪色所見から術前Ⅱc型早期胃癌と診断したが，切除標本の病理組織学的検討から純粋Ⅱbとされた1例を経験したので，若干の知見を加え報告する．

　A 43-year-old woman visited our hospital because of an abnormality of the stomach found on mass screening.Endoscopic examinatlon revealed a small, round and minimally excavated lesion with discoloration on the posterior wall near the greater curvature. It led us to make an initial diagnosis of type Ⅱc early gastric cancer, Indigocarmine spray, however, did rather make the lesion obscured. On x-ray, a barium fleck with irregular margin was noted at the comparable site. Although this finding suggested typeⅡc it fell short of giving a definitive evidence. Gastrectomy was carried out.

　Gross appearance of the resected specimen, either fresh or fixed, dit not point to the presence of the lesion. Histologically, however, main lesion consisted of signet-ring cell carcinoma, measuring 6mm in diameter. Oral to it was found another signet-ring cell carcinoma of 2mm in diameter. Both lesions were limited in the mucosa. Thus in this case endoscopic diagnosis of Ⅱc was not supported by pathological study, which gave rise to the final diagnosis, type Ⅱb early gastric cancer, with the naked eye.

　The difference between these two findings, we assume, arose from the differing nature of the stomach in vivo and the one in vitro, This case illustrates the facts that the discoloration, the diagnostic clue of type Ⅱc early gastric cancer, can be the clue of the pure type Ⅱb early gastric cancer and that endoscopy cannot identify the discoloration until it exceeds certain level in size.