A large mediastinal benign myoepithelioma effacing the entire hemithorax: case report with literature review

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1 Hshmi et l. Dignostic Pthology (2015) 10:100 DOI /s y CASE REPORT A lrge medistinl enign myoepitheliom effcing the entire hemithorx: cse report with literture review Atif Ali Hshmi 1,2,3, Amn Khurshid 1,2,3, Nveen Fridi 1,2,3, Muhmmd Muzzmmil Edhi 1,2,3 nd Mehmood Khn 1,2,3* Open Access Astrct Bckground: Myoepithelil neoplsms, lthough sometimes encountered in soft tissues re descried very rrely in medistinum nd lung. We reported rre cse of such tumor which ws very lrge in size nd not connected to respirtory tree. Cse presenttion: A 24 yer old mle presented with lunt chest pin nd respirtory distress. A CT scn ws performed which showed lrge heterogeneously enhncing soft tissue mss occupying the left hemithorx. It mesures 18.5 X 15.8 X 7.6. Thorcotomy with excision of the tumor ws done. Opertive findings include multiloulted nd nodulr lrge glistening white tumor locted in nterior medistinum dherent to prietl pleur nd effcing the pulmonry prenchym. However tumor ws not connected or seems to originte from trche or lung. Microscopic sections show neoplstic lesion composed of nests, cords nd trecule of smll to medium sized cells with round nuclei nd cler cytoplsm. Bckground showed myxoid ppernce with res of crtilginous differentition. Immunohistochemicl expression of CKAE1/AE3, p63, ASMA, S100 nd GFAP fvored the dignosis of enign myoepitheliom. Conclusion: Myoepithelil tumors re rre soft tissue tumors thought to rise from stem cells cple of divergent differentition nd occur nywhere in the ody. Histopthologic recognition of these tumors is essentil s these tumors my ehve in enign fshion despite lrge sizes. Keywords: Myoepitheliom, Benign mixed tumor, Medistinum Bckground Myoepithelil neoplsms re commonly encountered lesions of slivry glnds nd re rrely seen in soft tissues [1]. On the other hnd myoepithelioms re extremely rre in medistinum [2]. A few cse reports of enign mixed tumors descried so fr in medistinum were thought to rise from ectopic slivry glnd tissue long trcheoronchil tree nd secondrily involved the medistinum [3]. The term egin mixed tumor is used when there is ductulr differentition. On the other hnd, myoeptheliom y definition don t show ovious ductl differentition. * Correspondence: mehmoodkhn955@yhoo.com 1 Deprtment of Histopthology, Liqut Ntionl Hospitl nd Medicl College, Krchi, Pkistn 2 Intern, Liqut Ntionl Hospitl nd Medicl College, Krchi, Pkistn Full list of uthor informtion is ville t the end of the rticle Soft tissue myoepithelioms re incresingly recognized tumors, formerly designted s prchordoms. They occur in ll ge groups nd pek in 2 nd to 4 th decde of life. There is no significnt gender predilection. They usully present with slowly growing pinless mss in deep soft tissues of the extremities with hed n neck nd trunk eing other sites involved in decresing order of frequency. 9 Grossly myoepithelioms form nodulr msses rnging in size from 1 to 12 cm. They re usully well circumscried nd glistening, myxoid to geltinous consistency. Histopthologiclly, wide spectrum of morphologic ppernces cn e seen with predominnt reticulr growth pttern of epitheloid to spindled cells. The ckground strom is collgenous to chondromyxoid. Most myoepithelioms show mild nucler typi with low mitotic ctivity (<1/10HFFs). Histologicl 2015 Hshmi et l. This is n Open Access rticle distriuted under the terms of the Cretive Commons Attriution License ( which permits unrestricted use, distriution, nd reproduction in ny medium, provided the originl work is properly credited. The Cretive Commons Pulic Domin Dediction wiver ( cretivecommons.org/pulicdomin/zero/1.0/) pplies to the dt mde ville in this rticle, unless otherwise stted.

2 Hshmi et l. Dignostic Pthology (2015) 10:100 Pge 2 of 5 fetures indicting dverse prognosis include ovious cytologic typi (lrge cells with corse chromtin/ prominent nucleoli), res of necrosis, significnt mitotic ctivity nd invsive orders. Tumors with these fetures re termed s mlignnt myoepitheliom or myoepithelil crcinom. 9 Myoepthelioms consistently co-express epithelil mrkers (cytokertin nd EMA) nd S100. Expression of other myoepithelil mrkers including GFAP, p63, ASMA, Clponin re seen in suset of tumors (15-50 %). 9 Cytogeneticlly myoepithelil tumors re chrcterized y EWSR1 gene rerrngements with vriety of different fusion prtners including EWSR1-PBX1 fusion [t(1;22)(q23;q12)] nd EWSR1-ZNF444 fusion [t(19;22)(q13;q12)]. Antonescu et l. in lrge series of 66 myoepithelioms found EWSR1 rerrngement y FISH in 30 (45 %) cses. RT-PCR studies performed on these 30 cses showed EWSR1-POU5F1 (5 cses), EWSR1-PBX1 (5 cses) nd EWSR1-ZNF444 (1 cse) fusion nd 19 cses lcking n identifile fusion prtner [4]. Ultrstructurlly cells of myoepitheliom show incomplete epithelil differentition with primitive cell junctions, frgmented sl lmin nd microvillous projections [5]. We descried cse of enign myoepitheliom which isuniqueinthespectthtitwsnotrisingfromrespirtory tree nd ws extremely huge in size(18.5 X 15.8 X 7.6 cm) lmost effcing the entire hemithorx. Cse presenttion A 24 yer old mle presented with lunt chest pin nd respirtory distress. A CT scn ws performed which showed huge heterogeneously enhncing soft tissue mss hving solid component, fluid loculi nd morphous clcifictions occupying the left hemithorx. It mesures 18.5 X 15.8 X 7.6. The min ulk of the tumor ws in the lower hlf nd it reched inferiorly upto the left costophrenic sulcus. It ws extending long the pleurl surfce reching upto the lung pex. The left lung ws lmost encsed y this mss. Similr huge soft tissue density msses were seen on the medistinl surfce of left sided pleur where it took the form of conglomerte mss in the superior medistinum nd on the lterl spect of pulmonry trunk nd hert. Medistinum ws pushed to right side. The min pulmonry trunk showed extrinsic compression nd left min pulmonry trunk ws severely compressed. Extrinsic compression of left trium ws lso noted. There ws no pleurl effusion or ony erosion y the mss. Right lung ws norml (Fig. 1). In two initil ultrsound guided preopertive needle iopsies, dignosis of chondroid hmrtom nd srcomtoid mesotheliom were fvored from outside institutions. Bronchoscopy didn t revel ny intrluminl growth. Metsttic workup including CT scn domen nd one scn were unremrkle. Serum tumor Fig. 1 CT scn &: showing lrge heterogeneously enhncing mss effcing the left hemithorx nd nterior medistinum

3 Hshmi et l. Dignostic Pthology (2015) 10:100 Pge 3 of 5 mrkers including lctte dehydrogense, lph fetoprotein, et humn chorionic gondotropin were within norml limits. Thorcotomy with excision of the tumor ws plnned nd intropertive consulttion ws requested in which n initil dignosis of chondroid neoplsm ws given with finl dignosis deferred till permnent sections. Opertive findings include multiloulted nd nodulr lrge glistening white tumor locted in nterior medistinum dherent to prietl pleur nd effcing the pulmonry prenchym. However, tumor didn t pper to invde the lung prenchym nd there ws no trcheronchil connection. Borders of the tumor were well defined. Tumor ws not firmly dherent to the medistinl structures, pericrdium nd pleur nd ws esily scooped out during surgery. There ws no pprent invsion into ny of the djcent structures. During surgery left thorcotomy incision ws given nd pleurl cvity is entered through 7th intercostl spce. Excision of the tumor ws done nd cvity ws repired. The specimen received in histopthology deprtment is composed of multiple white glistening nodules of tumor with myxoidy cut surfce mesuring 20 X 10 cm in ggregte. Twenty two sections from the tumor were sumitted. Microscopic exmintion show neoplstic lesion composed of nests, cords nd trecule of smll to medium sized cells with round nuclei nd cler cytoplsm. Bckground showed myxoid ppernce with res of crtilginous differentition. Foci of metplstic one formtion were lso noted. Borders of the tumor were well defined nd no invsive into djcent soft tissue noted. There ws not ductl differentition in tumor cells. No germ cell component (including tertomtous component) noted. No significnt typi, necrosis or mitotic ctivity ws seen in tumor cells (Fig. 2). Immunohistochemicl stins were lso performed. Tumors cells showed positive expression with CKAE1/AE3, CK7, Vimentin, MIC2, S100, ASMA, p63 nd GFAP immunostins while CK20, LCA, Chromogrnin A, clretinin, TTF1 nd CD5 were negtive (Fig. 3). Focl expression of CD117 nd WT1 (cytoplsmic) ws lso noted. On the sis of these morphologic fetures nd immunohistochemicl profile dignosis of enign myoepitheliom ws fvored. Cytogenetic studies were not performed. Postopertive course ws unremrkle. No recurrence or metstsis ws oserved t 6 months follow up. Discussion Myepithelioms nd enign mixed tumors re descried in thorcic loction including lung with confusing terminology [6, 7]. Some uthors illustrted cses of pleomorphic denom in lung nd medistinum with n c d Fig. 2 Microscopic sections of tumor. tumor in nests, cords nd trecule with myxoid ckground,. Crtilge formtion with clcifiction nd ossifiction, c nd d. higher power showing tumor cells showing no significnt typi or mitosis

4 Hshmi et l. Dignostic Pthology (2015) 10:100 Pge 4 of 5 c d Fig. 3 Positive expression with,. CKAE1/AE3 immunostin,. Vimentin, c. S100, d. p63 immunostins ssumption tht they rise from sumucosl glnds of respirtory tree or ectopic slivry glnd tissue [8, 9]. However occurrence of these tumors unrelted to trche nd ronchi speks ginst its origin from sumucosl glnds, s now it is well known tht tumors of this kind cn occur nywhere in the ody nd no site is exempted. Cses descried s unusul dnexl tumors in sucutneous tissue nd pleomorphic denom in lungs nd medistinum my ctully represent myoepithelioms. In our cse, no connection with respirtory mucos or sumucos ws seen nd therefore cn e ssumed tht these tumors like in other soft tissue loction rise from stem cells cple of divergent differentition. Histopthologiclly, these tumors show diverse growth ptterns in the form of cords, nests nd trecule with heterologous stroml components. Immunohistochemicl requirement for the dignosis of myoepithelil tumors is the expression of S100, GFAP or ASMA in ddition to cytokertin stins [10]. The criteri for mlignncy in myoepithelil tumors is invsion into djcent tissues, necrosis, mrked nucler typi nd mitotic ctivity [11]. None of these fetures ws seen in our cse. On the other hnd, our cse is unique in the spect tht it is quite lrge in size effcing the structures of thorcic cvity nd lungs. Histopthologic recognition of myoepithelil tumors is very essentil s incorrect dignosis my led to grve consequences. As in our cse, two previous iopsies reveled the dignosis of chondroid hmrtom nd srcomtoid mesotheliom respectively. The dignosis of chondroid hmrtom ws rendered due to presence of lrge mount of crtilge mixed with epithelil elements. On the other hnd, there ws focl expression of WT 1 which led to the misdignosis of mesotheliom. Conclusion Myoepithelil tumors re rre soft tissue tumors thought to rise from stem cells cple of divergent differentition. Histopthologic recognition of these tumors is essentil s these tumors my ehve in enign fshion despite lrge sizes. Consent Written informed consent ws otined from the ptient for puliction of this Cse Report nd ccompnying imges. A copy of the written consent is ville for review y the Editor-in-Chief of this journl. Approvl otined from Liqut ntionl hospitl nd medicl college ethicl committee. Competing interests The uthors declre tht they hve no competing interests. Authors contriutions AAA first identified this cse nd prticipted in providing the clinicl informtion, AK contriuted to the concept nd design of the mnuscript nd NF performed the literture review, MME nd MK contriuted to design

5 Hshmi et l. Dignostic Pthology (2015) 10:100 Pge 5 of 5 nd pproved the finl version. All uthors red nd pproved the finl mnuscript. Acknowledgement We cknowledge ll memers of histopthology deprtment, Liqut ntionl hospitl nd medicl college, Krchi, Pkistn for their coopertion. Author detils 1 Deprtment of Histopthology, Liqut Ntionl Hospitl nd Medicl College, Krchi, Pkistn. 2 Intern, Liqut Ntionl Hospitl nd Medicl College, Krchi, Pkistn. 3 Dhk Medicl College, Dhk, Bngldesh. Received: 7 My 2015 Accepted: 29 June 2015 References 1. Jo VY, Fletcher CD. Myoepithelil neoplsms of soft tissue: n updted review of the clinicopthologic, immunophenotypic, nd genetic fetures. Hed Neck Pthol. 2015;9(1): Gle JT, Mendelson DS, Cohen BA, Teirstein AS. Benign mixed tumor of slivry glnd origin presenting s medistinl mss. J Comput Tomogr. 1986;10(1): Feigin GA, Roinson B, Mrchevsky A. Mixed tumor of the medistinum. Arch Pthol L Med. 1986;110(1): Antonescu CR, Zhng L, Chng NE, Pwel BR, Trvis W, Kti N, et l. EWSR1- POU5F1 fusion in soft tissue myoepithelil tumors. A moleculr nlysis of sixty-six cses, including soft tissue, one, nd viscerl lesions, showing common involvement of the EWSR1 gene. Genes Chromosomes Cncer. 2010;49(12): Kuhnen C, Herter P, Ksprzynski A, Vogt M, Jworsk M, Johnen G. Myoepitheliom of soft tissue cse report with clinicopthologic, ultrstructurl, nd cytogenetic findings. Pthologe. 2005;26(5): Veermchneni R, Gulick J, Hlldorsson AO, Vn TT, Zhng PL, Herrer GA. Benign myoepitheliom of the lung: cse report nd review of the literture. Arch Pthol L Med. 2001;125(11): Kourd J, Ismil O, Smti BH, Aydi A, Kilni T, El Mezni F. Benign myoepitheliom of the lung cse report nd review of the literture. Cses J. 2010;3(1): Sim DW, Oh IJ, Kim KS, Choi YD, Kwon YS. Pleomorphic denom of the trche. J Bronchology Interv Pulmonol. 2014;21(3): Yn HC, Shen CY, Ching CH, Hsu K, Lee SC, Ln GY, Lee HS. Pleomorphic denom of the trche: report of two cses. J Formos Med Assoc. 1991;90(11): Rekhi B, Sle M, Jmhekr NA. Histopthologicl, immunohistochemicl nd moleculr spectrum of myoepithelil tumours of soft tissues. Virchows Arch. 2012;461(6): Hornick JL, Fletcher CD. Myoepithelil tumors of soft tissue: clinicopthologic nd immunohistochemicl study of 101 cses withevlution of prognostic prmeters. Am J Surg Pthol. 2003;27(9): Sumit your next mnuscript to BioMed Centrl nd tke full dvntge of: Convenient online sumission Thorough peer review No spce constrints or color figure chrges Immedite puliction on cceptnce Inclusion in PuMed, CAS, Scopus nd Google Scholr Reserch which is freely ville for redistriution Sumit your mnuscript t