Supplementary Material for: A case of autoimmune gastritis and hepatitis with enlarging gastric polyps after reducing the dose of prednisolone

Autoimmune gastritis is immune-mediated gastritis that destroys the oxyntic mucosa. Autoimmune hepatitis is an inflammatory liver disease caused by an autoimmune reaction. These diseases share the same pathogenesis as organ-specific autoimmune disorders; however, cases with both diseases are quite rare and scarcely reported. Here, we report a patient with concurrent autoimmune gastritis and hepatitis who developed enlargement of hyperplastic polyps and progression of gastric atrophy. A 79-year-old woman was referred to our hospital for the treatment of hyperplastic polyps detected on a follow-up upper gastrointestinal endoscopy. Her previous upper gastrointestinal endoscopy from 3 years before referral revealed small hyperplastic polyps and no mucosal atrophy. The current upper gastrointestinal endoscopy revealed three 10-mm red polyps, severe mucosal atrophy in the corpus, and mild atrophy in the antral area. Biopsy samples from the gastric body revealed decreased parietal cells and diffuse lymphocytic infiltration of the deep mucosa. Further, chromogranin A-positive endocrine cell micronests and enterochromaffin-like cell hyperplasia were detected. After confirming the diagnosis of autoimmune gastritis, endoscopic mucosal resection was performed for all polyps histopathologically diagnosed as hyperplastic polyps without malignancy. Clinicians should consider autoimmune gastritis for enlarged hyperplastic polyps and gastric atrophy progresses.

自身免疫性胃炎（Autoimmune gastritis）是一类由免疫介导的、会破坏泌酸黏膜（oxyntic mucosa）的胃炎。自身免疫性肝炎（Autoimmune hepatitis）是由自身免疫反应引发的炎症性肝脏疾病。这两种疾病的发病机制与器官特异性自身免疫性疾病一致，但同时罹患这两种疾病的病例极为罕见，相关报道寥寥。本文报告1例同时并发自身免疫性胃炎与肝炎的患者，该患者出现增生性息肉增大及胃萎缩进展。1名79岁女性因随访上消化道内镜检查发现的增生性息肉前往我院就诊。就诊前3年的上消化道内镜检查结果显示，其当时仅存在小型增生性息肉，未见黏膜萎缩。本次上消化道内镜检查可见3枚直径10mm的红色息肉，胃体部存在重度黏膜萎缩，胃窦部可见轻度萎缩。胃体活检标本显示壁细胞（parietal cells）数量减少，黏膜深层可见弥漫性淋巴细胞浸润。此外，还检测到嗜铬粒蛋白A（chromogranin A）阳性的内分泌细胞微灶及肠嗜铬样细胞（enterochromaffin-like cell）增生。明确自身免疫性胃炎的诊断后，对所有经组织病理学确诊为无恶性病变的增生性息肉病灶均实施了内镜黏膜切除术（endoscopic mucosal resection）。临床医师对于出现增生性息肉增大及胃萎缩进展的患者，应考虑自身免疫性胃炎的可能。