Comprehensive clinicopathologic features in autoimmune atrophic gastritis: Insights from a European cohort of 57 patients.

Autoimmune atrophic gastritis (AAG) is a frequently underdiagnosed disease due to its broad-spectrum clinical presentation. The diagnosis is based on histological confirmation of corpus-restricted metaplastic chronic atrophic gastritis. To thoroughly describe the histological features of a European cohort of AAG patients. Clinical and pathological data of 57 out of 676 patients diagnosed with AAG were reviewed. Thirty-nine patients were female and eighteen were male. The mean age was 62 years. Antibodies were identified in 32/42 patients (76 %). Vitamin B12 levels were low (< 200 pg/mL) in 37/54 patients (69 %). Serum gastrin levels was elevated (> 115 pg/mL) in all cases tested. Associated autoimmune/inflammatory conditions were identified in 20/57 patients (35 %). Histologically, deep chronic inflammation was present in 46/57 (81 %) patients. Complete destruction of oxyntic glands was observed in 45/57 (79 %) patients. Pyloric metaplasia was present in 54/57 (95 %) patients, intestinal metaplasia in 51/57 (89 %) patients, and pancreatic metaplasia in 20/57 (35 %) patients. Among ECL cell proliferation, linear hyperplasia was present in all 57/57 patients, micronodular hyperplasia in 55/57 patients, and adenomatoid hyperplasia in 10/57 patients. ECL cell dysplasia was identified in 5/57 patients, and neuroendocrine microtumor in 4/57 patients. The diagnosing of AAG remains challenging due to the greater variability in symptoms than previously recognized. It is important to consider chronic AAG, especially with other concurrent autoimmune conditions. The importance of accurate diagnosis and surveillance is based on the potential development of type 1 gastric neuroendocrine tumor and increased risk of gastric adenocarcinoma. [ABSTRACT FROM AUTHOR]