摘要目的：探讨发生在直肠的胃肠道间质瘤（ GIST）的临床病理及治疗特点。方法收集北京协和医院2001年3月至2015年3月收治的53例患者58份直肠GIST标本，总结、分析其临床资料、病理学表现。结果53例直肠GIST 患者，男性33例、女性20例，发病年龄19～81岁，平均49.7岁。直肠GIST的首发症状有29例是肠道症状，22例患者是体检发现或自行发现直肠内结节而就诊；2例是因阴道肿物就诊。原发直肠、手术前没有用药治疗并完整切除者35例，13例穿刺明确诊断后经甲磺酸伊马替尼（格列卫）治疗后手术，另5例患者有一次甚至多次复发。35例原发完整切除直肠GIST，肿瘤最大径0.4～13 cm，中位最大径2.5 cm。危险度分级：极低危险度17例（48.6％），低度危险度6例（17.1％），高度危险度12例（34.3％），没有中度危险度病例。其中8例为最大径不超过1 cm的小GIST。13例治疗后病例，靶向药物治疗可减小肿瘤体积，软化肿瘤质地；显微镜下显示细胞密度降低，有明显的玻璃样变，但少见坏死。5例患者复发，随着复发次数增多，肿瘤细胞密度逐步增加，核分裂象数增多，Ki-67阳性指数也逐渐增高。免疫组织化学显示CD117、CD34和DOG1阳性，S-100蛋白阴性，有些病例SMA局灶阳性。结论直肠GIST相对少见，男性患者居多；自行发现或体检发现的比例高；肿瘤最大径≤2 cm的比例较高，＞5 cm比例较低；位置表浅易于活检，常行手术前治疗。

abstractsObjective To investigate the clinicopathologic characteristics and therapy of rectal gastrointestinal stromal tumors ( GISTs ) . Methods Clinical findings , morphologic features , immunophenotype and prognosis of 53 cases ( 58 samples ) of rectal GISTs were investigated.Results Thirty-three patients were male and 20 were female.The age of patients ranged from 19 to 81 years, with an average of 49.7 years.The main symptoms included rectal disorders in 29 patients and vaginal mass in 2 patients, while the tumors in 22 patients were found by routine physical examination.Thirty-five primary GISTs were resected completely without preoperative therapy , and thirteen tumors were resected after therapy of imatinib.Five tumors were recurrent.Imatinib therapy in 13 patients led to smaller and softer tumor mass grossly and decreased cellularity and marked degeneration histologically .Of the 35 primary rectal GISTs , there were 17 (48.6%), 6 (17.1%), 0(0), and 12 (34.3%) cases diagnosed as very low risk, low risk, medium risk, and high risk respectively.Eight cases had tumor of 1 cm or less in diameter.In the five recurrent cases, the tumors showed increased cellularity , mitotic figures, and Ki-67 index.Imatinib therapy led to smaller and softer tumor mass grossly and decreased cellularity and marked degeneration histologically .Immunohistochemical stains showed CD117, DOG1, and CD34 positivity, S-100 protein negativity and indefinite SMA stain.Conclusions Rectal GISTs are rare tumors with a male predominance.Patients without obvious sypmtoms are found by themselves and by routine physical examination .The tumor diameter less than 2 cm is common while larger than 5 cm is few.Diagnosis of rectal GISTs is easily made by biopsy and patients often acquire preoperative therapy for preserving anal sphincter function .