Synchronous cancers of the stomach and esophagus in a patient with autoimmune gastritis and pernicious anemia: a case report and review of the literature.

Type-A gastritis/autoimmune gastritis (AIG) has gained renewed attention due to declining infection rates and increasing eradication. AIG is associated with pernicious anemia (PA) and is prone to complicate various tumors, such as gastric cancer and neuroendocrine tumors. This report describes a case of AIG with PA in which gastric and esophageal cancers arose simultaneously. An 86-year-old woman had been diagnosed with PA and AIG 9 years earlier. As routine blood tests revealed high levels of carcinoembryonic antigen, she underwent esophagogastroduodenoscopy, which revealed a type 0-IIa lesion in the middle part of the stomach and a type 0-IIa + IIb lesion in the lower esophagus. Endoscopic submucosal dissection was performed on both lesions, since neither distant nor lymph node metastases were identified. Histological examination showed gastric tubular adenocarcinoma and esophageal squamous cell carcinoma. Immunohistology revealed that cells from neither cancer expressed gastrin, gastrin receptor, or p53. Whole-exome sequencing showed 8 gene mutations in the esophageal cancer and 6 mutations in 5 genes in the gastric cancer. The reason for the lack of p53 immunostaining was that was mutated in these cancers, although mutations differed. Thus, mutations may not be detected by immunostaining alone. When treating patients with AIG/PA, clinicians must be aware of the possibility of esophageal cancer coexisting with gastric cancer.