双语病例丨原发性骨平滑肌肉瘤（XMRPET）

双语病例丨原发性骨平滑肌肉瘤（XMRPET）History:

A43-year-oldwoman

presentswithkneepainafterfeelingapoppingsensationwhileplayingtennis.病史：43岁女性，打网球时感觉到砰的感觉，膝部疼痛。Radiographswereobtained.平片如下所示。问答：Thereisalesionintheproximaltibiawithabenignappearance.TrueFalse

(correct!)胫骨近端病灶呈良性表现。答：错误。Thelesionintheproximaltibiahasaggressivefeatures,includinganinfiltrativeappearanceandill-definedmargins.胫骨近端病灶有侵袭性，呈浸润性表现，边界模糊。MRimagesAnMRIscanofthekneewasperformed.Intravenouscontrastwasnotadministeredduetoacutekidneyinjury.CoronalT1-weightednonfat-saturatedand

T2-weightedfat-saturatedimagesareshownbelow.行膝关节MR扫描。由于急性肾损伤未行增强扫描。冠状T1WI非压脂及T2WI压脂图像如下所示。问答Whatisthenextstep?

下一步该做什么？Short-termimagingfollow-up短期随访Noadditionalfollow-uprequired无需随访Biopsy

(correct!)

活检（正确答案）AdditionalquestionsBiopsyofthetibiallesionrevealedapathologicdiagnosisofleiomyosarcoma.胫骨病变活检，病理诊断为：平滑肌肉瘤。Primaryboneleiomyosarcomasarecommonprimarybonemalignancies.TrueFalse

(correct!)原发性骨平滑肌肉瘤是常见的原发性骨恶性肿瘤。（说法错误）Whichofthefollowingismorelikely?下列那种情况最可能？Primaryboneleiomyosarcoma原发性骨平滑肌肉瘤Leiomyosarcomametastasistobone

(correct!)平滑肌肉瘤转移至骨骼（正确）PelvicMRimagesAnMRIscanofthepelviswasperformed.SagittalandaxialT2-weightedimagesareshown.盆腔MR图像：行盆腔MR扫描，矢状及轴位T2WI图像如下所示。Theuterinefindingsarehighlysuspiciousforuterineleiomyosarcoma.TrueFalse

(correct!)子宫的表现应高度怀疑为子宫平滑肌肉瘤（说法错误）。Therearetypicalfindingsofsmallbenignleiomyomas.However,smallleiomyosarcomascanhavethesameappearanceasbenignleiomyomas.为小良性平滑肌瘤的典型表现，然而，小的平滑肌肉瘤可能与良性平滑肌瘤有着同样的表现。PET/CTimagesAwhole-bodyFDG-PET/CTscanwasperformed.FusedCT/PETimagesareshown(axialpelvisandcoronalknees).

行全身PET/CT，CT/PET融合图像如下所示（盆腔轴位、膝部冠状）TherightproximaltibiallesionshowsavidFDGuptake.True

(correct!)False右胫骨近端病灶可见明显FDG摄取（说法正确）。TheuterusshowsalesionwithavidFDGuptake.TrueFalse

(correct!)子宫病灶可见明显FDG摄取（说法错误）。AdditionalquestionsBecauseuterineleiomyosarcomasaremuchmorecommonthanprimaryboneleiomyosarcomas,thepatientunderwentahysterectomytoevaluateforaprimaryuterineleiomyosarcoma.Onpathologicevaluation,theuterushadonlybenignfindings.其他问题由于子宫平滑肌肉瘤比原发性骨平滑肌肉瘤更常见，患者接受了子宫切除术以评估是否为原发性子宫平滑肌肉瘤。最后病理诊断只有良性发现，为子宫平滑肌瘤。Primaryboneleiomyosarcomashaveadistincthistologicappearancetoleiomyosarcomasarisingfromothersites.TrueFalse

(correct!)原发性骨平滑肌肉瘤与其他部位的平滑肌肉瘤有不同的组织学表现（说法错误）。Primaryboneleiomyosarcomasmostcommonlyoccurinthespine.TrueFalse

(correct!)Theymostcommonlyoccurintheappendicularskeleton.原发性骨平滑肌肉瘤最常见于脊柱（说法错误），最常见于四肢骨。Primaryboneleiomyosarcomashaveadistinctradiologicappearancewhencomparedwithotherprimarybonesarcomas.TrueFalse

(correct!)与其他原发骨肉瘤相比，原发性骨平滑肌肉瘤有着不同的影像学表现（说法错误）。FindingsRadiographs:

Locatedcentrallywithintheproximaltibiaisaninfiltrative

mixedscleroticandlyticlesion,whichappearstohavecorticalbreakthroughalongthetibialplateau.KneeMRI:

AlargeinfiltrativelesionispresentwithintheproximaltibiathathasreplacedthenormalfattymarrowandhasintrinsicT1signalisointensetomuscle.OntheT2-weightedimage,thelesionhasheterogeneouslyhighintrinsicT2signal.PelvicMRI:

T2

hypointenselesionsarepresentarisingfromtheuterinemyometrium,mostconsistentwithbenignleiomyomas.FDG-PET/CT:

AvidFDGuptakeisseenwithintheproximalrighttibiallesion.Noabnormaluptakeisseenwithinthepelvis.Althoughimagesarenotshown,nootherabnormalFDGuptakeisseenintheremainderofthebody.影像表现：平片：胫骨近端中心性的浸润性的硬化和溶解混合性病变，病变突破了胫骨平台骨皮质。膝关节MRI：近端胫骨内较大的浸润性病变，已经取代了正常的脂肪骨髓，T1WI上与肌肉等信号，T2WI上呈不均匀高信号。盆腔MRI：子宫肌层内T2低信号灶，与良性平滑肌瘤的表现最为一致。FDG-PET/CT：在右侧胫骨损伤部位可见FDG摄取。骨盆内未见异常摄取。尽管没有显示图像，但在身体的其余部分没有看到异常的FDG摄取。DifferentialdiagnosisPrimaryboneleiomyosarcomaMetastasisMultiplemyelomaPrimarybonesarcomaLymphoma鉴别诊断：原发性骨平滑肌肉瘤转移瘤多发性骨髓瘤原发性骨肉瘤淋巴瘤Diagnosis:

Primaryboneleiomyosarcoma(pathology-confirmed)最后诊断：原发性骨平滑肌肉瘤（病理证实）Discussion

讨论Primaryboneleiomyosarcoma

(PBL)原发性骨平滑肌肉瘤（PBL）PathophysiologyandepidemiologyPrimaryboneleiomyosarcomas

areextremely

rareprimaryosseousmalignancies,withfewerthan200casesreportedintheliterature.Onlycasereportsandsmallcaseserieshavebeenreported,makingcommentsonepidemiologysomewhatdifficult.Thesetumorsoccurinadults,withconflictingreportsonanagepredilection.Thereappearstobeanequaldistributionbetweensexes.Theymostcommonlyoccurintheappendicularskeleton.Pathologically,primaryboneleiomyosarcomasarethoughttoarisefromintraosseousbloodvesselsorpossiblyintraosseouspluripotentmesenchymalstemcells.Theyareatypeofspindlecellbonesarcoma.Interestingly,theyarehistologicallyidenticaltoprimaryleiomyosarcomasarisinginothersitesinthebody(uterus,retroperitoneum,etc.).

Thesetumorsaresorarethatwhenencounteredtheyarelikelyclassifiedasothertypesofprimarybonesarcomas(i.e.,undifferentiatedpleomorphicsarcoma,fibrosarcoma,etc).Also,giventheirrarity,othermorecommonsitesofleiomyosarcoma(gynecologic,retroperitoneum,softtissues)mustfirstbeexcluded.病理生理学和流行病学原发性骨平滑肌肉瘤是非常罕见的原发性骨恶性肿瘤，文献报道少于200例，只有病例报告和小病例系列报道，使流行病学评论有些困难。这些肿瘤发生在成年人身上，有关年龄偏好的报道相互矛盾。男女发病率基本持平。肿瘤最常见于附肢骨骼中。↓病理上，原发骨平滑肌肉瘤被认为是由骨内血管或骨内多能间充质干细胞产生的。是一种梭形细胞骨肉瘤。有趣的是，它们在组织学上与体内其他部位（子宫，腹膜后等）中产生的原发性平滑肌肉瘤相同。这些肿瘤非常罕见，常可能被归类为其他类型的原发性骨的肉瘤（即未分化的多形性肉瘤，纤维肉瘤等）。此外，鉴于其稀有性，首先必须排除其他更常见的平滑肌肉瘤（妇科、腹膜后、软组织）。ClinicalpresentationClinically,mostpatientspresentwithpain.Asignificantproportionofpatientsalsopresentwithpathologicfracture.

临床表现临床上大多数患者表现出疼痛。相当一部分患者也存在病理性骨折。ImagingfeaturesRadiographs：Onradiographs,primaryboneleiomyosarcomasaregenerallyosteolyticlesionswithaggressivefeatures,includingirregularandinfiltrativemarginsandapermeativeappearance.Corticalerosionsandbreakthroughcanoccur.Theygenerallyarisefromthemetaphysisbutcanextendintoboththeepiphysisanddiaphysis.CT：CTfindingsaresimilartoradiographicfindings,withtheexceptionthatcorticalinvolvementisbetterevaluated.MRI：MRfindingsaregenerallynonspecific,withintrinsicT1signaloftensimilartomuscleandintrinsicT2signalthatisoftenheterogeneouslyhigh.影像表现：X线片：原发骨平滑肌肉瘤一般表现为具有侵蚀性特征的溶骨性病变，包括不规则的形态、浸润性的边缘，以及渗透性的表现，可出现皮质侵蚀和突破。它们通常起源于干骺端，但可以延伸到骨骺和骨干。CT：CT表现与X线相似，不同之处在于能更好地评估骨皮质受累的情况。MRI：MR表现一般无特异性，其内T1信号通常与肌