胃神经鞘瘤的临床及病理学特点

Clinical and pathologic features of gastric schwannoma

目的 探讨胃神经鞘瘤的临床病理学特点.方法 分析9例胃神经鞘瘤患者的临床表现、肿瘤病理形态特征及免疫表型特点等并复习相关文献.免疫组织化学采用SP法,检测用抗体包括：S-100蛋白,CD117,CD34,神经丝蛋白（NF）,结蛋白,巢蛋白,胶质纤维酸性蛋白（GFAP）,血小板源性生长因子受体α（PDGFR-α）,波形蛋白等；并对1例进行了c-kit和PDGFR-α基因突变检测.结果 9例患者中,男性5例,女性4例,平均年龄56.5岁（42 ～81岁）.肿瘤最大径为2～9 cm（平均4.5 cm）.术后随访未见肿瘤复发、转移.大体观察：肿瘤未见明确包膜,切面呈灰黄色或灰白色,质地实,出血坏死不明显,有一定的光泽.镜下观察：肿瘤细胞呈长梭形,局部排列呈栅栏状,可见antoni A区及antoni B区,verocay小体少见.肿瘤边缘均见淋巴组织增生.有些病例局部见钙化、囊性变及出血坏死等.免疫组织化学染色显示：S-100蛋白表达均为弥漫阳性（9/9）,CD117、CD34、NF和结蛋白均为阴性（0/9）,巢蛋白8例阳性表达（8/9）,胶质纤维酸性蛋白6例阳性表达（6/9）,1例出现PDGFR-α灶状阳性.对PDGFR-α阳性病例进行c-kit和PDGFR-α基因突变检测,未检测出c-kit外显子9、11、13、17及PDGFR-α基因外显子12、18的突变.结论 胃神经鞘瘤是一种良性的间叶来源肿瘤,其病理特点和软组织神经鞘瘤相比具有自身特点.

Objective To study the clinical and pathologic features of gastric schwannomas.Methods The macroscopic and microscopic features of 9 cases of gastric schwannoma were analyzed.Immunohistochemical study for S-100 protein,CD117,CD34,neurofilament,desmin,nestin,glial fibrillary acidic protein,platelet derived growth factor-alpha （PDGFR-α） and vimentin was carried out. Mutation analysis of c-kit gene （exon 9,11,13 and 17） and PDGFR-α gene （exon 12 and 18） in 1 case was examined by PCR amplification and direct sequencing. Results The patients included 5 males and 4 females.The age of patients ranged from 42 to 81 years （median =56.5 years）.The size of the tumors ranged from 2 to 9 cm in greatest diameter.Follow-up data in 8 cases （from 1 month to 65 months） showed no evidence of recurrence or metastasis. Gross examination showed that gastric schwannomas were homogeneous,firm,yellow-white and bore no true fibrous capsule.Histologically,all cases were composed of fascicles of spindle cells associated with nuclear palisading,Verocay body formation and peripheral cuff of reactive lymphoid aggregates. Some of them showed degenerative changes including cyst formation,calcification,hemorrhage,necrosis and hyalinization. Immunohistochemical study showed that the tumor cells were strongly positive for S-100 protein and vimentin.There was various degree of staining for nestin （8/9） and glial fibrillary acidic protein （6/9）.They were negative for CD117,CD34,neurofilament,desmin and smooth muscle actin.One case showed focal positivity for PDGFR-α （1/9）,with no mutations found.Conclusions Gastric schwannomas share similar histologic features with conventional sofi tissue schwannomas,in addition to the presence a reactive lymphoid cuff.The clinical,macroscopic,histologic and immunohistochemical features of gastric schwannomas were different from those of gastrointestinal stromal tumors and leiomyomas.