小肠的恶性胃肠道间质瘤伴淋巴结转移病理分析

目的 探讨伴淋巴结转移的小肠恶性胃肠道间质瘤的临床病理特征、c-kit基因突变情况,以及对甲磺酸伊马替尼(imatinib mesylate,Glivec)的治疗反应.方法 对2例发生在小肠伴发淋巴结转移的胃肠道间质瘤进行光镜观察、免疫组织化学标志及基因突变分析并随访甲磺酸伊马替尼的治疗效果.结果 2例均为小肠浆膜面肿块,镜下观察肿瘤均以梭形细胞为主,伴有少量上皮样细胞,呈多结节状,并出现大片凝固性坏死;免疫组织化学标志肿瘤细胞CD117阳性,基因突变检测发现均存在c-kit基因第11号外显子的突变.例1显示第11号外显子559～569位点杂合性缺失,伴570、571位点TACATA杂合性突变为GACAGA;例2显示第11号外显子559～565杂合性缺失.结论 小肠胃肠道间质瘤伴淋巴结转移是一种少见病变,需要同发生在此处的其他恶性软组织肿瘤鉴别;该肿瘤对甲磺酸伊马替尼的治疗效果取决于c-kit基因的具体突变类型.

Gastrointestinal stromal tumor of small intestine associated with lymph node metastasis: a report of 2 cases with review of literatures

Objective To study the clinicopathologic features of gastrointestinal stromal tumor (GIST)of small intestine with lymph node metastasis and evaluate the respond to imatinib mesylate (Glivec)therapy.Methods Two cases of GIST of small intestine associated with lymph node metastasis were collected and investigated by light microscopy and immunohistochemistry.Mutation in exon 9,11 and of c-kit gene were analyzed by polymerase chain reaction and DNA sequencing.Results The cases presented as small intestinal mass of irregular shape.Histologically,the tumors consisted of epithelioid and spindled cells,with areas of coagulative necrosis and hemorrhage.The mitotic count measured about 2 per 50 highpower fields.Immunohistochemical study showed that the tumor cells were diffusely distributed and strongly positive for CD117.Mutation analysis revealed that case 1 had an in-frame deletion of 11 amino-acid residues corresponding to 559-569 and carried two missense mutions involving codons 570,571 in exon 11 of c-kit gene.Case 2 revealed an in-frame deletion involved condons 559-565 in exon 11 of c-kit gene.These two cases were all underwent primary chemotherapy with imatinib mesylate and without new tumor was found during follow-up periods(18,26 monthes)after operation.Conclusions GIST with nodal metastasis is very rare and needs to be distinguished from other soft tissue sarcomas occurring in this site.The responsiveness to imatinib mesylate therapy correlates with the mutation status of c-kit gene.