我们提出了一个罕见的病例，展示了在幽门螺杆菌阴性的胃中同时出现胃癌和粘膜相关淋巴组织（MALT）淋巴瘤的情况。一名72岁男性在耳鼻喉科手术后接受随访。他因PET-CT异常积聚而接受上消化道内窥镜检查，结果显示胃底部分泌腺腺癌和上部胃体的MALT淋巴瘤。因此，我们对胃癌进行了内镜下黏膜切除术，并诊断其为一种来源于错构性翻转息肉的分泌腺腺癌。随后，由于呈现API2-MALT1基因阳性且幽门螺杆菌感染呈阴性，胃MALT淋巴瘤被放射治疗。完全缓解。即使在幽门螺杆菌阴性的胃中，类似于本病例的情况也会出现特殊类型的胃癌和MALT淋巴瘤，因此内镜检查应考虑这些疾病。©2023年。日本消化内科学会。

We present a rare case that showed the coexistence of gastric cancer and mucosa-associated lymphoid tissue (MALT) lymphoma in Helicobacter pylori-naive stomach. A 72-year-old man was followed up after surgery for epithelial carcinoma of the glottis at the Department of Otolaryngology. He underwent an upper gastrointestinal endoscopy for an abnormal PET-CT accumulation, which revealed gastric adenocarcinoma of fundic gland type in the gastric fundus and MALT lymphoma in the upper gastric body. Hence, we performed an endoscopic submucosal dissection for gastric cancer and diagnosed gastric adenocarcinoma of fundic gland type derived from a hamartomatous-inverted polyp. Subsequently, Gastric MALT lymphoma was treated with radiation therapy because the API2-MALT1 gene was positive and the Helicobacter pylori infection was negative. A complete response was observed. Even in Hp-naive stomachs, cases such as the present case are complicated by special types of gastric cancer and MALT lymphoma, and endoscopic examination should be performed with these diseases in mind.© 2023. Japanese Society of Gastroenterology.