Unmasking the high-risk phenotype in autoimmune gastritis: A pathologist's roadmap for the clinician.

Li et al's recent work on the risk factors for autoimmune gastritis provides clinical context for the vast majority of gastric neuroendocrine tumors (G-NETs). However, a deeper understanding of the underlying pathology is needed for precise clinical management. Our letter details the predictable stepwise progression of type 1 G-NETs from autoimmune-driven corporal atrophy and hypergastrinemia to a clear microscopic sequence of enterochromaffin-like cell precursor lesions, including linear hyperplasia, micronodular hyperplasia, and dysplasia. We highlight the definitive diagnostic thresholds that separate these precursors from overt neoplasia: The 0.5 mm size rule and the presence of submucosal invasion. We advocate for a "prognostic biopsy protocol" in which pathologists actively report these precursor lesions and use Ki-67 to grade G-NETs, providing a quantitative risk assessment. This pathology-centric approach transforms surveillance, allowing clinicians to act on objective microscopic milestones rather than waiting for macroscopically visible tumors.