腹腔胃肠外间质瘤8例临床病理分析

Extragastrointestinal stromal tumors in soft tissues of abdominal cavity: a clinicopathologic analysis of 8 cases

目的 研究腹腔胃肠外间质瘤 (EGISTs)的临床病理特征。方法 对 8例腹腔EGISTs进行临床病理学观察 ;免疫组化EnVision法检测CD117、CD34等的表达 ;并进行随访。结果 8例腹腔EGISTs发病平均年龄 6 3 5岁 ;临床上以腹部肿块伴疼痛为主 ,胃肠道症状不明显。瘤块平均大小 17 4cm ,结构类型和免疫表型类似于GISTs,但多数细胞密度较高。以短梭形细胞型为主 ,类似于平滑肌肿瘤结构 ,呈短束状或束状排列趋势 ,很少见长束状或丝球状结构 ;CD117阳性表达率 10 0 % (8 8) ,CD34为 75 % (6 8)。随访 6例 ,有 5例预后差 ;预后差者瘤体直径 >5cm ,核分裂 >2个 5 0HPF ,细胞密度高 ,有坏死。结论 腹腔EGISTs好发于中老年 ,具有GISTs类似的病理特征与免疫表型 ;恶性潜能高 ,预后差 ;瘤体直径 >5cm、核分裂 >2个 5 0HPF。

Objective To analyze clinicopathologic features of extragastrointestinal stromal tumors (EGISTs) in the soft tissues of abdominal cavity. Methods Morphologic characteristics of 8 cases of EGISTs in abdominal cavity were studied under light microscope, and the expression of CD117 and CD34 was detected with immunohistochemical staining. The cases with follow up data were analyzed. Results The patients with abdominal EGISTs ranged in age from 45 to 80 years (mean, 63 5 years). 8 tumors occurred in 3 women and 5 men. 5 tumors arose from mesentery and three from omentum. Most of the patients presented with an enlarging abdominal mass often accompanied by variable abdominal pain, but no overt gastrointestinal symptoms. Their diameters ranged from 5 0 to 25 0?cm (mean 17 4?cm). The histopathologic features and immunophenotypes of the tumors was similar to GISTs, but microscopically high cellularity were relatively common. Most cases were consisted predominantly of short fusiform cells which closely resembled a conventional smooth muscle tumors, but long well oriented fascicles like a leiomyosarcoma or skeinoid fibers were less noted in the tumors; All were positive for CD117, 6 for CD34 (75 0%), 2 for S 100 (25 0%), 3 for α SMA (37 5%), 3 for MSA (37 5%) and 3 for NSE (37 5%). 5 out of 6 patients with follow up data presented with adverse outcome in which the tumor in displayed >5?cm tumor in diameter, >2/50HPF mitosis activity, high cellularity and necrosis. Conclusion Patients with EGISTs in abdominal cavity predominantly are the elderly. The tumors are similar histopathologically and immunophenotypically to their gastrointestinal counterpart, but display high potential malignancy and adverse outcome; The tumor diameter >5?cm, mitosis >2/50HPF, high cellularity and necrosis in the tumor tissue tend to be the diagnostic parameters of malignancy.