Pyloric gland adenoma (PGA) is an uncommon variant of gastric adenoma exhibiting pyloric gland/mucous neck cell differentiation. We present a sporadic PGA associated with a large fundic gland polyp (FGP) in a woman in her 40 s without Helicobacter pylori infection. The polyp, measuring 25 mm in size, was located in the middle gastric body and was removed by endoscopic submucosal dissection. Histological examination revealed three morphologically distinct components: FGP, FGP with large cysts, and PGA. A genetic analysis identified a truncating APC mutation in all the three components, supporting their histogenetic relationship. Additionally, a GNAS mutation was detected in two components, FGP with large cysts and PGA, whereas a KRAS mutation was exclusively found in the PGA component. Thus, despite the unusual presentation, the PGA component harbored prototypical genetic alterations. The differential genetic alterations observed in the three components imply that they represent stepwise progression from FGP to PGA.

中文翻译：

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与大胃底腺息肉相关的散发性幽门腺腺瘤：逐步进展的遗传证据。

幽门腺腺瘤 (PGA) 是一种罕见的胃腺瘤变体，表现出幽门腺/粘液颈细胞分化。我们介绍了一名 40 多岁未感染幽门螺杆菌的女性的与大胃底腺息肉 (FGP) 相关的散发性 PGA。息肉大小为 25 毫米，位于胃中部，通过内窥镜黏膜下剥离术切除。组织学检查揭示了三种形态不同的成分：FGP、具有大囊肿的 FGP 和 PGA。遗传分析确定了所有三个成分中的截断 APC 突变，支持它们的组织遗传学关系。此外，在两个成分中检测到 GNAS 突变，即具有大囊肿的 FGP 和 PGA，而 KRAS 突变仅在 PGA 成分中发现。因此，尽管呈现方式不同寻常，PGA 组件包含原型遗传改变。在这三个成分中观察到的差异遗传改变意味着它们代表了从 FGP 到 PGA 的逐步进展。