胃肠间质瘤影像学特点PPT文档格式.ppt

1、3040%）,S100（5%）,DES（desmin;12%）,and keratin（1-2%）.KIT is the most specifi c and sensitive marker.。v另外，CD34（+），S-100（-），GFAP（-）有助于协助鉴别诊断，S-100（-）可除外神 经源性肿瘤，GFAP（-）可除外胶质瘤。临床特点v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。v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

2、在眼底及贲门，75在胃体，11的胃窦。v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指标是肿瘤的大小及细胞核分裂相数目（每50HPF 下的数目）vFletcher 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。v。Chiappa 等3报道胃肠间质瘤术后复发或转移的时间是436 个月。v个别报道时间长达十

3、几年。临床症状v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、腹痛及可触及包块等症状，偶尔症状由肿瘤内出血引起。v肿瘤出血是由于溃疡所致。v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。v十二指肠的间质瘤引起梗阻性黄疸时易与胰腺癌相混淆。肿瘤位于Vater壶腹部。钡餐检查v表现为粘膜下边缘清晰的充盈缺损。（Forty-two-year-old female with GIST at the gastroesophageal junction.）CT影像学征象v边界清晰不均质的肿块v边缘强化明显，厚度不均，中心密度减低。v原因是由于出血、坏死、囊变。

4、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.v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）。v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。v小肠的间质瘤发现时已经很大且倾向于恶性，绝大多数病灶发生于十二指肠。v有的较大的肿瘤平扫时可发现出血F

5、ig.2.48-year-old woman with small-bowel gastrointestinal stromal tumor.Axial contrast-enhanced CT scan of pelvis shows exophytic heterogeneously enhancing mass（arrow）.Fig.3.30-year-old man with gastric gastrointestinal stromal tumor.Axial contrast enhanced CT scan of upper abdomen shows intense homo

6、genous enhancement of tumor arising from gastric wall（arrow）.v偶尔也会在CT上发现腔内的肿瘤（Fig.4）.。v口服造影剂时可发现粘膜下溃疡（Fig.5）。v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，要认真辨认肿瘤的起源。v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）。Fig.4.69-year-old woman with gastric gastrointestinal stromal tumor.Axial contrast-enhance

7、d CT scan of upper abdomen shows large intraluminal component of tumor（arrow）.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.Fig.5.Gastric gastrointestinal stromal tumor（GIST）.A,A

8、xial contrast-enhanced CT scan of upper abdomen of 69-year-old woman shows large intraluminal component of tumor with pocket of gas（arrow）.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

9、 with oral contrast agent（arrow）.Fig.6.30-year-old man with gastric gastrointestinal stromal tumor.B）.This tumor was originally mistaken for infected pancreatic pseudocyst.fig.776-year-old man with small-bowel gastrointestinal stromal tumor.Axial contrast-enhanced CT scan of pelvis shows smooth mese

10、nteric metastasis （arrowheads）at presentation.v和小肠的淋巴结相同，胃肠间质瘤可以是小肠管腔瘤样扩张。（Fig.8）.v原因：肿瘤迅速生长。肿瘤破坏肌间神经丛。v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。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 smal

11、l bowel,causing aneurysmal dilatation of bowel.Proximal（arrowheads）and distal segments of small bowel were of normal caliber.肿瘤如果与管腔交通，使肿瘤空洞化及窦道形成。Seventy-seven-year-old male with GIST of the ileum.Postcontrast CTshows a large intra-abdominal mass with central cavitation.v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

12、。这一点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.直肠结肠的间质瘤表现为边界清晰的壁结节，向管腔内侵犯。Seventy-seven-year-old male with rectal GIST.Postcontrast CT shows the heterogeneously enhancing mass with intraluminal

13、 extension（arrow）.胃肠间质瘤的转移途径 淋巴道转移：v到目前为止还没有文献有报道。v腺癌和淋巴瘤主要为淋巴道转移。v如果发现有淋巴结转移就应该考虑其他诊断。肠系膜转移v肠系膜转移通常见于肿瘤的复发，与术后腹膜种植相关。v也可与较大的小肠的间质瘤同时发现，胃的间质瘤较少见。v绝大多数肠系膜的病灶为中心低密度。v因为病灶通常较小且远离原发病灶而漏诊。（Fig.10）.v较大的病灶围绕肠系膜血管生长，但不引起远端机静脉栓塞。（Fig.11）.Fig.10.76-year-old man with small-bowel gastrointestinal stromal tumor.

14、Axial contrast-enhanced CT scan of mid abdomen shows rounded nodule（arrowhead）in mesentery in keeping with metastases.Metastasis is far from site of resected tumor （arrow）.Fifty-six-year-old male with GIST of the ileum.（a）Postcontrast CTshows 12 cm,partially necrotic primary tumour arising from the small bowel.（b）Three years later postresection of