Plexiform fibromyxoma (PF) of the stomach is a very rare mesenchymal tumor of the gastrointestinal tract. We report the first case of PF with 2 different growth patterns pathologically confirmed after surgical resection. The tumor was characterized microscopically as infiltrative; it demonstrated diffuse growth into the smooth muscle bundles of the muscularis propria and was also multinodular and plexiform within the myxoid stroma. Immunohistochemical analysis revealed that the tumor cells were positive or weakly positive for smooth muscle actin, vimentin, and H-caldesmon and negative for desmin, CD117, CD34, CK-20, Pan-CK, Dog1, S100, ER, PR, and CD10. No mutations of C-kit and platelet-derived growth factor receptor alpha were detected. No genetic disruption of glioma-associated oncogene homolog 1 was detected by fluorescence in situ hybridization. The final diagnosis of PF was mainly based on the morphological and immunohistochemical findings.

中文翻译：

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组织学图像上具有两种不同生长模式的胃丛状纤维粘液瘤：病例报告。

胃丛状纤维粘液瘤 (PF) 是一种非常罕见的胃肠道间充质肿瘤。我们报告了第一例手术切除后病理证实具有 2 种不同生长模式的 PF。肿瘤在显微镜下表现为浸润性；它表现出弥漫性生长到固有肌层的平滑肌束中，并且在粘液样基质内也呈多结节状和丛状。免疫组化分析显示肿瘤细胞平滑肌肌动蛋白、波形蛋白和H-caldesmon阳性或弱阳性，desmin、CD117、CD34、CK-20、Pan-CK、Dog1、S100、ER、PR和CD10阴性. 未检测到 C-kit 和血小板衍生生长因子受体 α 的突变。荧光原位杂交未检测到神经胶质瘤相关癌基因同源物 1 的遗传破坏。PF的最终诊断主要基于形态学和免疫组化结果。