胃肠道淋巴瘤课件.pptVIP

胃肠道淋巴瘤直肠淋巴瘤罕见，MR表现无特异性T1WI均匀中等信号，T2WI混杂高信号轻-中度强化胃肠道淋巴瘤食道继发多见，原发少见，占胃肠道原发淋巴瘤的1%，大部分Bcell来源。表现：粘膜下浸润、肿块、溃疡、结节穿孔、窦道胃肠道淋巴瘤*胃肠道淋巴组织位于上皮细胞层、粘膜固有层、粘膜下层及肠系膜淋巴结。上皮层内大多数为T淋巴细胞，粘膜固有层内有T细胞及B细胞，及产生体内免疫球蛋白的浆细胞，有的排列成滤泡状。在小肠内多个滤泡集结称Peyer滤泡集结（Peyers‘spatches），主要位于小肠（回肠末端为主）的肠系膜侧粘膜下层。上述这些淋巴组织是宿主免疫防御系统的主要组成部分，近来认为其为粘膜相关淋巴组织的一部分。发病部位和地域相关：上述西方国家的结果；中东、非洲和南亚以小肠最多见。**Figure2.DiffuselargeB-celllymphomaofthestomachinan81-year-oldmanwhopresentedwithepigastricpain.(a)Spotradiographfromanuppergastrointestinalstudyshowsamasswithluminalnarrowinginthegastricantrumanddeepulcerationintheinferiorwall(arrow).Othernodulesofvarioussizes(arrowhead)areseenadjacenttothemass.(b)Contrast-enhancedCTscanshowsdiffuse,homogeneousgastricantralwallthickeningwithalobulatedinnersurfaceandasmoothwell-definedouterwall(arrowheads).(c)High-powerphotomicrograph(originalmagnification,600;hematoxylin-eosin[H-E]stain)showsalargeblastcellinfiltrate(shortarrow)extendingaroundepithelialglands(arrowhead).Mitoses,animportantfeatureofhigh-gradetumors,areclearlyseen(longarrow).(d)High-powerphotomicrograph(originalmagnification,600;immunohistochemicalstainCAM5.2)showsthedestructionofepithelialglandsbyinfiltratingblastcells(arrow).Brownareasrepresentcytokeratin.*Primarygastriclymphomaoftenoriginatesasalow-gradeMALTlymphoma,which,ithasbeensuggested,transformsintointermediateorhigh-gradelargecelllymphomaifnotdiagnosedortreatedintime。However,non-Hodgkingastriclymphomashouldberecognizedasanothercauseoflinitisplastica,anappearancethatresultsfromdenseinfiltratesoflymphomatoustissueinthegastricwallwithoutassociatedfibrosis**Figure4.Low-gradeMALTlymphomaofthestomachina56-year-oldwomanwhopresentedwithdyspepsia.(a,b)Axialcontrast-enhancedCTscan(a)andsagittalmulti