title: Mechanisms producing color change in flat early gastric cancers.
abstract: OBJECTIVE
  Although highly refined endoscopes have made it possible to detect not only early gastric cancers with morphological changes, but also flat-type tumors (type IIb) on the basis of the color changes observed in them, the factors responsible for color changes in type IIb carcinomas have not been fully elucidated. The aim of this study was to analyze the potential mechanisms underlying these color changes.
  
  
  METHODS
  Thirteen type IIb cancers were selected from a total of 589 resected gastric cancers detected preoperatively using endoscopic examination. All of the tumors showed color changes alone, without surface changes, and the color changes included redness, discoloration, and spotty bleeding. Detailed histological examination of the resected stomachs revealed twelve more II b lesions that had not been identified at endoscopy. The endoscopic appearance of the IIb cancers were correlated with the degree of tumor differentiation, the extent of wall infiltration, and the number of capillaries.
  
  
  RESULTS
  In cases that were detectable by endoscopy, the endoscopic color appearance correlated significantly with both tumor size (P < 0.02) and with the extent of mucosal cancer infiltration (P < 0.02). Histological examination of the IIb lesions revealed that redness and discoloration were significantly more frequent in the differentiated and undifferentiated cancer types, respectively (P < 0.01). There was a significant difference in the number of capillaries between type IIb carcinoma and the adjacent normal mucosa, but not between cancers. The numbers for differences in redness and discoloration were 7.0 +/- 5.6 and -14.0 +/- 8.8, respectively.
  
  
  CONCLUSIONS
  These results suggest that the main factor underlying color change in type IIb early gastric cancers may be the number of capillaries in the lesions, in comparison with the adjacent mucosa. Whether the lesion is visible on endoscopy, however, depends more on its size than on the number of capillaries.
authors.affiliation: Dept. of Surgery II, Kumamoto University Medical School, Japan.
authors.forename: U
authors.initials: U
authors.lastname: Honmyo
authors.forename: A
authors.initials: A
authors.lastname: Misumi
authors.forename: A
authors.initials: A
authors.lastname: Murakami
authors.forename: S
authors.initials: S
authors.lastname: Mizumoto
authors.forename: I
authors.initials: I
authors.lastname: Yoshinaka
authors.forename: M
authors.initials: M
authors.lastname: Maeda
authors.forename: S
authors.initials: S
authors.lastname: Yamamoto
authors.forename: S
authors.initials: S
authors.lastname: Shimada
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002196:Capillaries / Q000473:pathology; D003116:Color; D005260:Female; D005773:Gastroscopy; D006801:Humans; D008297:Male; D008875:Middle Aged; D013270:Stomach / Q000098:blood supply / Q000473:pathology*; D013274:Stomach Neoplasms / Q000098:blood supply / Q000473:pathology*