As described in Chap.​ 1 “Basic Principles for the Interpretation of Magnified Endoscopic (ME) Findings: Vessels (V) plus Surface (S) Classification System,” we should interpret ME findings by first assessing the mucosal subepithelial microvascular pattern (V) and mucosal microsurface pattern (S) separately and then integrate both findings using a uniform set of diagnostic criteria to arrive at a diagnosis. The reason is that V and S are in concordance (capillaries are observed in the intervening part: VS concordance) in the normal mucosa, and V and S dissociation (divergence) occurs as the state becomes more pathological, or the degree of atypia increases, or the disease stage progresses [1] (VS discordance).

More macroscopic and histological heterogeneity is seen in gastric cancers than any other cancers of the gastrointestinal tract, so production of a pattern classification of VS combinations would run into many, possibly hundreds, of combinations and likely be of little practical use. In general, findings of the V component alone are sufficient for magnified examination with WLI, and with M-NBI we can visualize a variety of microanatomical findings of the mucosal surface layers. In addition to the V findings, we now have the S component as a diagnostic marker for interpretation.

In this chapter, I will set out the markers and definitive features, as well as findings requiring interpretation, and the diagnostic criteria used in the VS classification system I use to make the differential diagnosis between cancer and noncancer.

We analyze capillaries, collecting venules (CVs), and microvessel in terms of individual morphology, presence of heterogeneity, and overall distribution and arrangement. We classify the pattern as regular, irregular, or absent.

We can identify capillaries and venules, normal anatomical microvessels, in the normal gastric mucosa and in mucosa affected by chronic gastritis. New blood vessels, associated with pathology such as neoplasia or inflammation accompanying mucosal defects, cannot be definitely classified as capillaries or venules, however, so we use the overall term “microvessel,” encompassing capillaries, venules, and new blood vessels.

First we assess whether each of the above features is present. When each individual feature is visualized, we analyze its morphological characteristics, evaluating heterogeneity, distribution, and arrangement. We classify the pattern as regular, irregular, or absent. In this section, I will refer mainly to the MCE (for explanations of the other features, please refer to the other chapters and presentations of actual cases).

It is worth noting that when the MCE is visualized, irrespective of whether it is classified as regular or irregular, linear, curved, or polygonal, the MCE tends to be histologically of the tubular type. When the MCE shows a circular or oval morphology, and the structure shows IPs isolated by MCE closed curves, the tubular histological type is common with a broad IP stroma, and the papillary type is common with a narrow IP stroma.