A micrometric classification of intramucosal carcinomas of the stomach

BACKGROUND: The aim of this study was to assess whether the results of micrometric measurements could be correlated with the macroscopic-endoscopic classification of intramucosal carcinomas of the stomach.METHODS: The thickness of 86 consecutive intramucosal gastric carcinomas (IMGCs) was micrometrically assessed. IMGCs having more than twice the thickness of the non-involved gastric mucosa (NIGM) were regarded as protruding (type I) and those having twice or less of the thickness of the NNGM, as non-protruding (type II). Non-protruding IMGCs were subclassified as elevated (thicker than NNGM, or type IIa), flat (the same thickness as NNGM, or type IIb), and depressed (thinner than NNGM, or type IIc).RESULTS: Only 9.3% ( n = 8) of the 86 IMGCs were protruding and 90.7% ( n = 78) were non-protruding. Of the 78 non-protruding IMGCs, 46.2% ( n = 36) were elevated (type IIa), 38.5% ( n = 30) were flat (type IIb), and the remaining 15.4% ( n = 12) were depressed (type IIc). A low correlation was found when the micrometric and a similar gross classification were compared. Protruding and elevated IMGCs were often histologically of intestinal type (60.3%), whereas flat and depressed IMGCs were often of diffuse type (73.9%).CONCLUSION: Tumor differentiation may be related to the micrometric profile of the tumor. Non-protruding IMGCs (type II) may expand laterally, without "becoming" protruding and without invading the submucosal layer.