Immunohistochemical staining with neuroendocrine markers is essential in the diagnosis of neuroendocrine neoplasms of the esophagogastric junction

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Introduction: Neuroendocrine neoplasms (NENs) of the esophagogastric junction (EGJ) are uncommon and the classification of these tumors has been revised several times. Since 2016, at the Department of Pathology, Rigshospitalet, Denmark, all adenocarcinomas (ACs) and poorly differentiated carcinomas of the EGJ have been stained routinely with the neuroendocrine markers, Synaptophysin and Chromogranin A, in order to detect a possible neuroendocrine component.

Aim(s): This study aimed to determine if routine immunohistochemical (IHC) staining is necessary in order to detect neuroendocrine differentiation of the EGJ tumors by evaluating how often a neuroendocrine component of the tumors was correctly identified or missed on routine hematoxylin and eosin (HE) stained slides, and by evaluating the interobserver agreement among several pathologists.

Materials and methods: We included patients who received surgical resection of a tumor localized in the EGJ over a four-year period. Representative HE stained slides from 22 NEN cases and 66 cases with AC with no NEN component were blinded and mixed. Three pathologists reviewed the blinded HE stained tumor slides in order to identify possible neuroendocrine components, and the interobserver agreement was assed.

Conference: 18th Annual ENETS Concerence (2021)

Presenting Author: Jepsen D

Authors: Jepsen D, Fiehn A, Garbyal R, Engel U, Holm J,

Keywords: neuroendocrine neoplasm, neuroendocrine carcinoma, mixed neuroendocrine non-neuroendocrine neoplasm, esophagogastric junction, Synaptophysin, Chromogranin A,