Validation of the definition of gastro-oesophageal junctional zone: an immunohistochemical study using resected mucosal specimens

Abstract

In 2022, the gastro-oesophageal junctional zone (GOJZ) was proposed at the International Consensus Conference in Kyoto as the area extending 1 cm proximally and 1 cm distally from the gastro-oesophageal junction (GOJ), defined by the distal end of the palisade vessels (DEPV).1 2 The definition of GOJ remains a matter of debate. In the globally recognised GOJ cancer classification, a Siewert type II tumour is an adenocarcinoma located 1 cm above to 2 cm below the GOJ, representing a ‘true carcinoma of the cardia’.3 Although the distribution of cardiac glands should determine GOJZ, distinction between native cardiac glands and metaplastic changes at the GOJZ remains a histological challenge due to conventional H&E staining limitations. The previous studies failed to differentiate between pyloric/pseudopyloric metaplasia and cardiac or oxyntocardiac glands, as they did not use immunohistochemical stainings of pepsinogen I (PPGI). This was a single-centre retrospective study that analysed GOJ mucosal specimens that had been resected via endoscopic submucosal dissection for treating refractory gastro-oesophageal reflux disease (GORD) (online supplemental material 1).4 Only those cases where the palisade vessel was identifiable in more than half of the specimens were included, resulting in an analysis of 11 cases comprising 120 slices from 51 patients who underwent endoscopic mucosal resection. Mucosal specimens containing the GOJZ were analysed to identify cardiac glands, parietal cells, and chief cells or pyloric/pseudopyloric metaplastic glands, using immunohistochemical staining for MUC6, H+/K+-ATPase and PPGI (online supplemental material 2). The distances from the DEPV to the proximal and distal edges of the cardiac glands, …