2022年医学专题—胃肠间质瘤影像学特点(1).ppt

胃肠间质瘤(GIST),2009-01-01杨梅(yngmi),第一页，共四十六页。,流行病学(li xn bn xu)特点,胃肠道间质瘤（gastrointestinal stromal tumor，GIST）是一 种少见的源于胃肠道间质细胞的肿瘤，发病率约2/10 万，主 要发病人群在4070 岁，中位年龄58 岁，男性稍多于女性。本病临床表现及影像(yn xin)学所见缺乏特异性，确诊需要靠病理组织学及免疫组化检测。,第二页，共四十六页。,组织学特点(tdin),the GIST cells are closely related to the interstitial cells of Cajal(ICC)组织学上可表现为梭形细胞型、上皮细胞型，或两者的混 合型。分子(fnz)学上绝大多数该肿瘤表现为c-kit基因的变异及少部分（约5%）患者PDGFRA基因的变异 免疫组化绝大多数可检测到CD117 抗体阳性，表明组织 或细胞表达c-kit 原癌基因蛋白，即属赖氨酸激酶家族的 c-kit 原癌基因发生功能获得性突变导致。有,第三页，共四十六页。,50-year-old woman with small-bowel gastrointestinal stromal tumor(GIST).Photomicrograph of histopathologic slide shows typical GIST composed of fascicles of nondescript spindle cells.Appearance on H and E stain is similar to that of smoothmuscle tumor.,第四页，共四十六页。,免疫组化检查(jinch),The tumours can be positive for KIT(95%),CD34(6070%),ACAT2(smooth muscle actin;3040%),S100(5%),DES(desmin;12%),and keratin(1-2%).KIT is the most specifi c and sensitive marker.。另外，CD34（+），S-100（-），GFAP（-）有助于协助鉴别(jinbi)诊断，S-100（-）可除外神 经源性肿瘤，GFAP（-）可除外胶质瘤。,第五页，共四十六页。,第六页，共四十六页。,临床(ln chun)特点,最常见的间质性肿瘤，仅占胃肠道肿瘤的1-3%。好发于胃（60-70%）、小肠（1/3）、结肠/直肠（5%）、食管（2%）。还有发生于网膜、肠系膜及后腹膜。大多数间质瘤（约60-70%）为良性，且多发生于胃部。这些病灶多偶然发现，均可以手术切除。14的在眼底及贲门，75在胃体，11的胃窦。目前趋向认为小肠间质瘤有潜在恶性倾向，推测其恶性程度的主要(zhyo)指标是肿瘤的大小及细胞核分裂相数目（每50HPF 下的数目）,第七页，共四十六页。,Fletcher 等2认为：肿瘤直径2 cm 和细胞核分裂相数目5/50HPF 为极低度恶性；直径25 cm 和5/50HPF 为低度恶性；直径510 cm 和5/50HPF 或直径5 cm 和610/50HPF 为中度(zhn d)恶性；直径5 cm 和5/50HPF 或直径 10 cm 和10/50HPF 为高度恶性，但也有直径小的肿瘤发生 转移的报道。,第八页，共四十六页。,。Chiappa 等3报道胃肠间质瘤术后复发(f f)或转移的时间是436 个月。个别报道时间长达十几年。,第九页，共四十六页。,临床(ln chun)症状,临床症状主要取决于肿瘤的位置及大小，且无特异性的表现，仅表现为饱胀感、消化不良、腹痛及可触及(ch j)包块等症状，偶尔症状由肿瘤内出血引起。肿瘤出血是由于溃疡所致。,第十页，共四十六页。,肿瘤常表现为起源于粘膜下向腔外生长的特性，很少引起肠梗阻。十二指肠的间质瘤引起梗阻性黄疸(hungdn)时易与胰腺癌相混淆。肿瘤位于Vater壶腹部。,第十一页，共四十六页。,钡餐(bicn)检查,表现(bioxin)为粘膜下边缘清晰的充盈缺损。（Forty-two-year-old female with GIST at the gastroesophageal junction.）,第十二页，共四十六页。,CT影像学征象(zhngxing),边界清晰不均质的肿块(zhn kui)边缘强化明显，厚度不均，中心密度减低。原因是由于出血、坏死、囊变。,第十三页，共四十六页。,Seventy-year-old male with GIST of the stomach with liver metastases.A large intraluminal mass is seen in the stomach,with heterogenous liver metastases.,第十四页，共四十六页。,很多肿瘤发现时已经体积很大，约5-30cm，增强CT表现为不均质强化、腔外生长的肿块(Fig.2)。较小的原发于胃的间质瘤表现为明显的强化(Fig.3)，在小肠的原发间质瘤很少有此征象。小肠的间质瘤发现时已经很大且倾向于恶性，绝大多数病灶(bngzo)发生于十二指肠。有的较大的肿瘤平扫时可发现出血,第十五页，共四十六页。,Fig.2.48-year-old woman with small-bowel gastrointestinal stromal tumor.Axial contrast-enhanced CT scan of pelvis shows exophytic heterogeneously enhancing mass(arrow).,第十六页，共四十六页。,Fig.3.30-year-old man with gastric gastrointestinal stromal tumor.Axial contrast enhanced CT scan of upper abdomen shows intense homogenous enhancement of tumor arising from gastric wall(arrow).,第十七页，共四十六页。,偶尔也会在CT上发现腔内的肿瘤(Fig.4).。口服造影剂时可发现粘膜下溃疡(Fig.5)。还有部分腔外的间质瘤被误诊为胰腺的肿瘤或假性囊肿(Fig.6)。肿瘤与肠管壁常仅通过一个很薄的蒂相连，要认真(rn zhn)辨认肿瘤的起源。如果存在肠系膜转移，转移灶为边界清晰、边缘光滑，无牵拉改变(Fig.7)。,第十八页，共四十六页。,Fig.4.69-year-old woman with gastric gastrointestinal stromal tumor.Axial contrast-enhanced CT scan of upper abdomen shows large intraluminal component of tumor(arrow).,第十九页，共四十六页。,Fifty-six-year-old male with GIST of gastric fundus.Postcontrast CT shows homogenous intraluminal GIST along the lesser curve,extending into the gastrohepatic ligament.,第二十页，共四十六页。,Fig.5.Gastric gastrointestinal stromal tumor(GIST).A,Axial contrast-enhanced CT scan of upper abdomen of 69-year-old woman shows large intraluminal component of tumor with pocket of gas(arrow).,第二十一页，共四十六页。,B,In 63-year-old woman with gastric GIST,axial contrast-enhanced CT scan of upper abdomen shows large heterogeneously enhancing tumor in stomach and ulcer filled with oral contrast agent(arrow).,第二十二页，共四十六页。,Fig.6.30-year-old man with gastric gastrointestinal stromal tumor.,第二十三页，共四十六页。,B).This tumor was originally mistaken for infected pancreatic pseudocyst.,第二十四页，共四十六页。,fig.776-year-old man with small-bowel gastrointestinal stromal tumor.Axial contrast-enhanced CT scan of pelvis shows smooth mesenteric metastasis(arrowheads)at presentation.,第二十五页，共四十六页。,和小肠的淋巴结相同，胃肠间质瘤可以(ky)是小肠管腔瘤样扩张。(Fig.8).原因：肿瘤迅速生长。肿瘤破坏肌间神经丛。原发肿瘤没有钙化，但是，在特殊化疗后的转移灶内偶尔会出现钙化。,第二十六页，共四十六页。,Fig.8.45-year-old man with small-bowel gastrointestinal stromal tumor.A and B,Axial contrast-enhanced CT scans of mid abdomen show large mass(arrow)arising from small bowel,causing aneurysmal dilatation of bowel.Proximal(arrowheads)and distal segments of small bowel were of normal caliber.,第二十七页，共四十六页。,第二十八页，共四十六页。,肿瘤如果与管腔交通，使肿瘤空洞化及窦道(du do)形成。,Seventy-seven-year-old male with GIST of the ileum.Postcontrast CTshows a large intra-abdominal mass with central cavitation.,第二十九页，共四十六页。,肿瘤长大过程中，边缘光滑，仅推挤并不侵犯周围组织及血管。这一点(y din)可以与类癌及腺癌鉴别,Fifty-six-year-old male with GIST of the ileum.(a)Postcontrast CTshows 12 cm,partially necrotic primary tumour arising from the small bowel.,第三十页，共四十六页。,直肠结肠的间质瘤表现为边界(binji)清晰的壁结节，向管腔内侵犯。,Seventy-seven-year-old male with rectal GIST.Postcontrast CT shows the heterogeneously enhancing mass with intraluminal extension(arrow).,第三十一页，共四十六页。,胃肠间质瘤的转移(zhuny)途径,淋巴道转移：到目前为止还没有文献有报道。腺癌和淋巴瘤主要为淋巴道转移。如果发现(fxin)有淋巴结转移就应该考虑其他诊断。