Histological Classifications of Gastric Tumors: Toward a Global Harmonization

From the pathological point of view, there are two main differences between the East and the West: the first is the diagnostic criteria used to discriminate between high-grade intra-epithelial neoplasia/dysplasia and invasive carcinoma; the second is the classifications used to identify morphologically different subtypes of gastric carcinoma. Harmonization of these two issues is desirable in order to provide strong evidence that would be applicable worldwide. In order to uniform the diagnosis, the Vienna and Padova classifications could be used. However, also the underlying difference, which is the adoption of cyto-architectural criteria by the Japanese and the anatomic criteria of invasion by the Western pathologists should be made explicit and harmonized. This would homogenize the diagnosis on gastric biopsies in those cases in which invasion of the lamina propria is strongly suspected but not directly seen. With regards to the pathological classification, the more recent WHO classification should be used worldwide, as this would also better define the histological subgroup of poorly cohesive carcinoma, which has been subdivided into three categories according to the amount of tumor cells displaying the features of signet ring cells.