胃丛状血管黏液样肌纤维母细胞性肿瘤临床病理学观察

Plexiform angiomyxoid myofibroblastic tumor of stomach

目的探讨胃丛状血管黏液样肌纤维母细胞性肿瘤（PAMT）的临床病理学特征、免疫学表型及其鉴别诊断。方法收集3例PAMT患者的临床和病理资料，进行胃镜、肉眼及光镜观察并行免疫组织化学（EnVision法和sP法）染色，复习文献和总结。结果例1为31岁男性，例2和例3分别为47岁和42岁女性，例1、2因上腹部疼痛就诊，例3为持续性上腹胀2个月就诊。胃镜检查显示3例肿瘤均主要位于胃窦部，呈团块状突向腔内，最大径分别为8．0、4．5和4．6cm，其中例2伴有溃疡。3例肿瘤均位于胃壁内，低倍镜下显示特征性的丛状或多结节状生长方式，由梭形细胞、纤细的小血管和黏液样的基质所组成。免疫组织化学标记显示，梭形瘤细胞主要表达平滑肌肌动蛋白和肌特异性肌动蛋白（MSA），例3灶性表达结蛋白和h-caldesmon。例1中的部分瘤细胞尚表达上皮细胞膜抗原和CAM5．2，例3灶性表达CDl0、孕激素受体。结论胃PAMT是一种非胃肠道间质瘤性间叶性肿瘤，好发于胃窦部，熟悉其病理学特点有助于与其他良恶性肿瘤的鉴别诊断。

Objective To study the clinieopathologic features, immunophenotype and differential diagnosis of plexiform angiomyxoid myofibroblastie tumor （PAMT） of the stomach. Methods The clinical and pathologic findings of 3 cases of PAMT in the gastric antrum were retrospectively analyzed. Immunohistochemieal study was carried out and the literature was reviewed. Results The age of patients ranged from 31 to 47 years. The male-to-female ratio was 1： 2. The clinical presentation included epigastric pain and distension. Endoscopically, the tumor mass protruded into the gastric cavity at the antrum and ranged from 4. 5 em to 8.0 cm in greatest dimension. One of the tumors studied was associated with surface ulceration. Histologically, the tumors were located in the gastric wall. They were composed of bland spindle cells and small vessels arranged in a plexiform or nodular pattern within a myxoid stroma. Immunohistochemical study showed that the spindle cells were consistently positive for smooth muscle actin and muscle-specific actin. There was focal staining for h-caldesmon, desmin in case 3 and focal positive for epithelial membrane antigen, CAMS. 2 in case 1. Further, CD10 and progesterone receptor were positive in ease 3. Conclusions PAMT represents a rare novel mesenchymal tumor of the stomach, with a propensity of gastric antral involvement. The distinctive pathologic features help to differentiate this entity from other benign and malignant tumors.