CT and MRI appearances of cystic lesions in the suprahyoid neck: a pictorial review

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1 Dentomxillofcil Rdiology (2007) 36, 1 9 q 2007 The British Institute of Rdiology REVIEW CT nd MRI ppernces of cystic lesions in the suprhyoid neck: pictoril review EK Woo*,1 nd SEJ Connor 2 1 Deprtment of Rdiology, Guy s Hospitl, London, UK; 2 Deprtment of Neurordiology, King s College Hospitl, London, UK Cystic lesions in the hed nd neck re importnt entities tht re incresingly investigted y crosssectionl imging. The ptient usully presents with neck swelling nd, fter initil clinicl exmintion, n ultrsound scn my demonstrte the cystic nture of the lesion. Further imging with CT nd MRI re often necessry to elucidte the etiology nd deep extent of the lesion. This pictoril review descries nd illustrtes the typicl ppernces nd loctions of rnge of cystic lesions in the suprhyoid neck on CT nd MRI. Dentomxillofcil Rdiology (2007) 36, 1 9. doi: /dmfr/ Keywords: tomogrphy, X-ry computed; mgnetic resonnce imging; cysts; neck Introduction There re mny types of cystic lesions within the soft tissues of the hed nd neck, which often cnnot e differentited y clinicl exmintion. The dignostic procedure cn usully e initited y performing n ultrsound exmintion. This my demonstrte the cystic nture of the lesion. However, with lrge lesions, complete visuliztion my not e possile nd the identifiction of the origin of the lesion cn e difficult. This occurs prticulrly with lesions in the suprhyoid neck. Those lesions tht involve the prphryngel, deep protid, mstictor nd other deep fscil spces re prticulrly prolemtic. Further imging with CT nd MRI is therefore often necessry to rrive t dignosis nd elucidte the extent of the lesion. A cyst is defined s closed cvity or sc lined y epithelium. It is typiclly filled with fluid, ut ir, lood products, pus nd other proteinceous mteril cn e seen. The different ttenution on CT nd the different signl intensities on MRI re determined y the content within the cystic lesion. A simple fluid-filled cyst is chrcteristiclly low density with thin wll on CT, homogeneous low signl on T 1 nd high signl on T 2 weighted MR imges. However, if complicted y proteinceous fluid or hemorrhge, it my pper s soft tissue density on CT nd high signl on T 1 weighted MR imges. MRI fetures which would confirm cystic origin re fluid fluid levels *Correspondence to: Dr EK Woo, Deprtment of Rdiology, Guy s Hospitl, St. Thoms Street, London SE1 9RT, UK; E-mil: e.woo@doctors.org.uk Received 20 My 2006; revised 14 Novemer 2006; ccepted 12 Decemer 2006 nd propgtion of rtefct in the phse encoding direction. A numer of cysts hve typicl loctions, which re helpful in determining the dignosis. Thyroglossl duct cyst The most common congenitl neck mss is thyroglossl duct cyst. 1 It is the remnnt of the thyroglossl duct which origintes etween the formen cecum of the tongue se nd the thyroid ed. Its loction is in the midline or prmedin nd is closely relted to the hyoid one. It my e suprhyoid, infrhyoid or t the level of the hyoid one. A low-density cystic midline mss emedded within the strp muscles with smooth, thin, well-defined wll is chrcteristic (Figure 1). Occsionlly it cn e septted nd peripherl rim enhncement my e seen. 3 Incresed ttenution nd wll enhncement is seen if complicted y infection. 4 The presence of murl nodules or foci of clcifiction within the cyst would suggest thyroglossl duct crcinom. 5 Lryngocoele A lryngocoele is dilted lryngel sccule nd ppers s cystic dilttion rising from the lryngel ventricle. The sccule cn e filled with ir or fluid. The size cn vry nd is ccentuted with rised intrglottic pressure. The lesion cn e shown to chnge size with the Vlslv mnoeuvre. It consists of three types internl, externl

2 2 Cystic lesions in the suprhyoid neck EK Woo nd SEJ Connor Q2 nd mixed. Internl lryngocoeles re locted in the prglottic spce lterl to the flse cord in the suprglottis (Figure 2). Externl lryngocoele occurs when the lesion hernites through the thyrohyoid memrne. Mixed lesions contin internl nd externl components. Lryngocoeles cn e primry (e.g. in glss lowers nd wind instrument plyers), or secondry due to n ostructing lesion. An occult squmous cell crcinom should e ctively excluded (Figure 2). MRI with its superior contrst Figure 1 Axil contrst-enhnced CT scn (soft tissue lgorithm) showing thyroglossl duct cyst (rrow) in typicl loction emedded in the strp muscles extending into the pre-epiglottic ft Figure 3 Axil short tu inversion recovery (STIR) MRI shows typicl loction of second rnchil cleft cyst (rrow). The cystic lesion t the ngle of the mndile displcing the sternocleidomstoid muscle posteriorly, crotid rtery nd jugulr vein medilly nd the sumndiulr glnd nteriorly is chrcteristic. The differentil dignosis will lso include cystic lymphdenopthy Figure 4 T 2 weighted xil MRI scn shows well-defined lesion in the right posterior cervicl spce which is of very high signl on T 2 consistent with cyst. This is typicl loction of third rnchil cleft cyst (rrow). However, the differentil dignosis includes n epidermoid, lymphngiom nd cystic lymphdenopthy resolution is more sensitive in identifying n underlying mlignncy in the presence of deris nd fluid. On T 2 weighted imges, the tumour would e of reltively low signl intensity to the cystic fluid within the lryngocoele. 6 Figure 2 () Axil contrst-enhnced CT scn (soft tissue lgorithm) showing left internl lryngocoele (rrow) with extension from the lryngel ventricle. () Coronl CT reformt (soft tissue lgorithm) showing secondry left internl fluid filled lryngocoele (rrow) from lryngel crcinom (rrowhed) Figure 5 CT scn (soft tissue lgorithm) of 3-month-old infnt with lrge trnsptil (protid, crotid nd retrophryngel spce) low ttenution cystic lesion which crosses the midline nd is ssocited with irwy ostruction (endotrchel tue in situ) in keeping with cystic hygrom (rrow) Dentomxillofcil Rdiology

3 Cystic lesions in the suprhyoid neck EK Woo nd SEJ Connor 3 Figure 6 T 1 weighted xil MRI scn of lymphngiom which shows lrge high signl lesion involving the protid spce nd prphryngel spce (rrow). The differentil would include other protid spce lesions Brnchil cleft cysts Brnchil cleft nomlies re thought to rise ecuse of incomplete olitertion of portion of the rnchil pprtus. A first rnchil cleft cyst rises from the residul emryonic trct, which extends from the externl uditory cnl (EAC) through the protid glnd to the sumndiulr region. There re two types chrcterized y its loction. Type 1 is periuriculr nd the most common loction is preuriculr. Type 2 is periprotid extending from the EAC to the ngle of the mndile. CT nd MRI show cystic lesion in the typicl loction. However, in most cses, it is difficult to differentite etween ny other cystic lesions in the protid glnd. 7 The second rnchil nomly my cuse fistuls, sinuses or cysts. Cystic nomly is the most common nd ccounts for 95% of ll rnchil cleft nomlies. 8 It cn occur nywhere from the tonsillr foss to the suprclviculr region. Biley clssified second rnchil cleft cysts into four types. Type I cyst is the most superficil nd lies long the nterior surfce of the sternocleidomstoid muscle, just deep to the pltysm muscle. The type II cyst is found long the nterior surfce of the sternocleidomstoid muscle, lterl to the crotid spce nd posterior to the sumndiulr glnd. A type III cyst extends medilly etween the ifurction of the internl nd externl Figure 7 Sgittl T 1 weighted MRI scn shows high signl lesion within the nsophrynx in n infnt in keeping with nsophryngel dermoid or hiry polyp (rrow) Figure 8 () Axil CT scn (soft tissue lgorithm) shows low ttenution lesion seen in the right sumndiulr spce consistent with n epidermoid cyst (rrow). The differentil dignosis would include cystic lymphdenopthy. () Axil T 2 weighted MRI scn shows high signl lesion in the left sulingul nd sumndiulr spces (rrow). Surgicl correltion showed n epidermoid cyst. The differentil would include diving rnul crotid rteries to the lterl phryngel wll nd the type IV cyst lies in the phryngel mucosl spce. 9 Its most common nd typicl loction is t or immeditely inferior to the ngle of the mndile (type II). On CT nd MRI, cystic lesion t the ngle of the mndile displcing the sternocleidomstoid muscle posteriorly, crotid rtery nd jugulr vein medilly nd the sumndiulr glnd nteriorly is chrcteristic (Figure 3). 10 Third nd fourth rnchil cleft cysts re quite rre. Cysts my occur nywhere long the course of the third rnchil cleft or pouch. However, most third rnchil cleft cysts lie in the posterior cervicl spce posterior to the sternocleidomstoid muscle (Figure 4). 11 Fourth rnchil cleft nomlies re usully sinus trcts which rise from the pyriform sinus, through the thyrohyoid memrne nd descend into the medistinum following the trcheoesophgel groove. 7 A cyst my clssiclly develop in the superior lterl spect of the left thyroid glnd with ssocited thyroiditis. Dentomxillofcil Rdiology

4 4 Cystic lesions in the suprhyoid neck EK Woo nd SEJ Connor Figure 9 () Axil T 2 weighted MRI shows high signl lesion in the left sulingul spce extending to the sumndiulr spce consistent with plunging rnul (rrow). () Axil T 1 weighted MRI with gdolinium enhncement of the sme rnul showing minor rim enhncement of the cystic lesion (rrow) Figure 10 () An xil CT scn (soft tissue lgorithm) shows smll cystic lesion with typicl clcifiction locted in the midline of the nsophrynx consistent with Tornwldt s cyst (rrow). () T 2 weighted Axil MRI scn showing smll high signl well-defined lesion in the midline of the nsophrynx. This is gin Tornwldt s cyst (rrow) Lymphngiom/cystic hygrom Lymphngiom is developmentl nomly of vsculolymphtic origin of which cystic hygrom is the most common. 12 There re four histologicl types of lymphngiom: cystic, cvernous, cpillry nd vsculolymphtic. Grding is mde from the microscopic ppernce of the size of the dilted lymphtic chnnels. The hed nd neck is the most common loction (80 90%) nd it ppers y the ge of 2 yers. 13 The mjority of cystic hygroms re symptomtic nd present with soft, pinless msses in the neck. 7 The size is vrile nd cn e huge, which my cuse irwy compression (Figure 5). The imging findings of uniloculted or multiloculted cystic neck or fcil mss with imperceptile wll tht insinutes Figure 11 T 1 weighted coronl scn shows slight hyperintensity indicting proteinceous fluid or hemorrhge within lesion which is off midline consistent with mucosl retention cyst (rrow) Dentomxillofcil Rdiology

5 Cystic lesions in the suprhyoid neck EK Woo nd SEJ Connor 5 Figure 14 Axil CT scn (soft tissue lgorithm) shows lrge cystic lesion with enhncing wll consistent with pthologicl level 1 lymph node (rrow). The enhncing mss on the left is lrge crcinom of the tongue extending to the floor of the mouth etween vessels nd other norml structures re chrcteristic (Figure 6). It is often trnsptil. In the suprhyoid neck, the mstictor nd sumndiulr spces re most commonly involved, wheres in the infrhyoid neck, it is the posterior cervicl spce which is the most common. 14 Dermoid nd epidermoid cysts Figure 12 () Axil CT scn (soft tissue lgorithm) shows low density lesion in the left vllecul. This is in keeping with vlleculr cyst (rrow). However, the differentil dignosis lso includes thyroglossl duct cyst. () Sgittl reconstructions in the sme ptient demonstrting the reltions of the cyst within the vllecul (rrow). Surgery confirmed vllecul cyst These re cystic lesions tht re differentited only y the presence of skin ppendges within the wll of dermoid cyst. Both dermoid nd epidermoid cysts re composed of Figure 15 Axil CT scn (soft tissue lgorithm) with intrvenous contrst shows lrge cystic lesion in the posterior cervicl spce in the infrhyoid neck. There is n re of nodulr enhncement (rrow). This ws confirmed to e cystic lymphdenopthy from ppillry thyroid crcinom epithelil elements. 7 On CT imging, ftty internl elements, mixed density fluid nd clcifiction cn e found in dermoid cysts wheres epidermoid cyst re fluid density with no or little complex fetures. The most common loction of dermoid cysts is in the lterl eyerow followed y the floor of mouth, which is typiclly in the midline. Other loctions hve een descried (Figure 7). 15 Epidermoid cysts re rre nd typiclly lso involve the floor of mouth incorporting the sulingul, sumndiulr spces nd the root of the tongue (Figure 8). Figure 13 Axil CT scn (soft tissue lgorithm) shows multiloculr cystic lesion with enhncing wlls t level 3 (rrow). The iopsy performed demonstrted this to e tuerculous lymphdenopthy. However, necrotic lymph nodes from metsttic squmous cell crcinom cn pper similr Figure 16 Axil CT scn (soft tissue lgorithm) with intrvenous contrst shows n irregulr low density lesion in the left medil pterygoid muscle consistent with n scess (rrow) Dentomxillofcil Rdiology

6 6 Cystic lesions in the suprhyoid neck EK Woo nd SEJ Connor Q2 Figure 17 () Axil CT scn (soft tissue lgorithm) shows ilterl multiple cystic lesions in oth the deep nd superficil loes of the protid glnds (rrow). The differentil dignosis includes Sjogren s syndrome nd enign lymphoepithelil lesions of HIV. In this cse, the dignosis is Sjogren s syndrome. () Coronl short tu inversion recovery (STIR) MRI shows multiple high signl lesions in oth protid glnds (rrow). This ws HIV relted lymphoepithelil cysts Rnul A rnul is retention cyst originting from ostruction of the sulingul or minor slivry glnds usully due to inflmmtion or trum. A simple rnul is confined to the sulingul spce. If it enlrges, the cyst extends into the sumndiulr nd inferior prphryngel spce nd it is clled diving or plunging rnul (Figure 9). 16 Tornwldt s cyst The Tornwldt s cyst is enign developmentl midline lesion on the posterior wll of the nsophrynx etween the preverterl muscles. 17 It is relted to the emryogenesis of the notochord. The contents of the cyst re generlly high in protein nd neroic cteri mking it high signl on T 1 nd T 2 weighted imges (Figure 10). Phryngel mucosl spce retention cyst A enign epithelil lined mucosl cyst cn occur within the phryngel mucosl spce of the nsophrynx (Figure 11), orophrynx nd vllecul (Figure 12). A well-defined cyst in this loction is chrcteristic. Cystic lymphdenopthy Infectious diseses (e.g. tuerculosis; Figure 13), metsttic lymph nodes from lymphom, squmous cell crcinom (typiclly tonsillr SCC; Figure 14) nd ppillry crcinom (Figure 15) re the most common cuses of cystic lymphdenopthy. Ascess Infection or scesses commonly occur in the sumndiulr, sulingul nd mstictor spces (Figure 16). These often pper cystic with vrile degree of rim enhncement oth on CT nd MRI. CT is often helpful in identifying dentl or mndiulr cuse. Mstoid disese, prnsl sinus disese, suppurtive lymph nodes nd congenitl cysts re other potentil soft tissue inflmmtory lesions presenting s cystic msses. Cystic lesions in the slivry glnds Figure 18 () Axil ft sturted T 1 weighted post gdolinium imge shows res of low signl within the left sumndiulr spce with no contrst enhncement (rrow). The ppernce is consistent with silocoele. () Coronl short tu inversion recovery (STIR) shows incresed high signl within the left sumndiulr glnd with septtions (rrow). This ws confirmed t surgery to e silocoele A rnge of conditions cn cuse cystic lesions within the slivry glnds. Infection, grnulomtous (e.g. srcoid), Dentomxillofcil Rdiology

7 Cystic lesions in the suprhyoid neck EK Woo nd SEJ Connor 7 utoimmune disese (e.g. Sjogren s syndrome) (Figure 17) nd enign lymphoepithelil lesions of HIV (Figure 17) re cuses of multiple cystic lesions within the protidglnds. The protid glnds re often enlrged in these conditions. There my e vrying degree of ssocited cervicl denopthy. Cystic chnge cn lso occur in other enign (e.g. Wrthin s tumour), mlignnt (e.g. cystic intrprotid lymphdenopthy) nd ostructive disorders (e.g. silocoeles) (Figure 18). Cystic schwnnom Cystic schwnnoms re uncommon tumours which rise from the crnil, peripherl, or utonomic nerves % occur in the hed nd neck, nd the most common site is the prphryngel spce. 19 The other typicl loction is in the posterior cervicl spce of the neck. The Schwnn cell neoplsm typiclly rises from crnil nerve XI, the distl rchil plexus or the cervicl sensory nerve. 14 Assocition with neurofiromtosis is sometimes seen. Our exmple of cystic schwnnom demonstrtes fluid fluid level which hs previously een descried (Figure 19). 20 Figure 19 () Coronl T 1 imge shows lrge cystic schwnnom in the right periverterl spce (rrow). () Axil short tu inversion recovery (STIR) imge from the sme ptient shows lrge high signl lesion in the right periverterl spce which demonstrtes fluid fluid level (rrow). Excisionl iopsy confirmed cystic schwnnom Conclusions CT nd MRI re useful in the investigtion of cystic lesions, prticulrly in the suprhyoid neck. Mny of the lesions hve chrcteristic ppernce nd typicl loctions which re helpful in estlishing their etiology. Q1 References 1. Allrd R. The thyroglossl cyst. Hed Neck Surg 1982; 5: Hrnserger RH. Hndook of hed nd neck imging (2nd edn). St Louis, MO: Mosy-Yerook, Reede D, Bergeron R, Som P. CT of thyroglossl duct cysts. Rdiology 1985; 157: Ahuj AT, Wong KT, King AD, Yuen EH. Imging for thyroglossl duct cyst: the re essentils. Clin Rdiol 2005; 60: Brnstetter BF, Weissmn JL, Kennedy TL, Whitker M. The CT ppernce of thyroglossl duct crcinom. Am J Neurordiol 2000; 21: Hrvey R, Irhim H, Yousem D, Weinstein G. Rdiologic findings in crcinom-ssocited lryngocele. Ann Otol Rhinol Lryngol 1996; 105: Koeller Kk, Almo L, Adir CF, Smirniotopoulos JG. Congenitl cystic msses of the neck: rdiologic pthologic correltion. Rdiogrphics 1999; 19: Vogl T. Hypophrynx, lrynx, thyroid, nd prthyroid. In: Strk D, Brdley W (eds). Mgnetic resonnce imging (2nd edn). St Louis, MO: Mosy-Yerook, 1992, pp Biley H. Brnchil cysts nd other essys on surgicl sujects in the fcio-cervicl region London: H.K. Lewis & Compny, Hrnserger HR, Mncuso AA, Murki AS, Byrd SE, Dillon WP, Johnson LP, et l. Brnchil cleft nomlies nd their mimics: computed tomogrphic evlution. Rdiology 1984; 152: Benson MT, Dlen K, Mncuso AA, Kerr HH, Cccirelli AA, Mfee MF. Congenitl nomlies of the rnchil pprtus: emryology nd pthologic ntomy. Rdiogrphics 1992; 12: Mkrious E, Pikis A, Hrley EH. Cystic hygrom of the neck: ssocition with growing venous neurysm. Am J Neurordiol 2003; 24: Zdvinskis DP, Benson MT, Kerr HH, et l. Congenitl mlformtions of the cervicothorcic lymphtic system: emryology nd pthogenesis. Rdiogrphics 1992; 12: Hrnserger HR, Hudgins PA, Wiggins RH III, Dvidson HC. Dignostic imging: hed nd neck Slt Lke City, UT: Amirsys, New G, Erich J. Dermoid cysts of the hed nd neck. Surg Gynecol Ostet 1937; 65: Coit WE, Hrnserger HR, Osorn AG, Smoker WR, Stevens MH, Lufkin RB. Rnuls nd their mimics: CT evlution. Rdiology 1987; 163: Miyhr H, Htsung T. Tornwldt s disese. Act Otolryngol suppl. 1994; 517: Leu YS, Chng KC. Extrcrnil hed nd neck schwnnoms: review of 8 yers experience. Act Otolryngol 2002; 122: Thurnher D, Quint C, Pmmer J, Schim W, Knerer B, Denk D. Dysphgi due to lrge schwnnom of the orophrynx. Arch Otolryngol Hed Neck Surg 2002; 128: Ctlno P, Fng-Hui E, Som P. Fluid fluid levels in enign neurogenic tumors. Am J Neurordiol 1997; 18: Dentomxillofcil Rdiology

8 8 Cystic lesions in the suprhyoid neck EK Woo nd SEJ Connor DENTOMAXILLOFACIAL RADIOLOGY PROOFS (pulished y the British Institute of Rdiology on ehlf of the Interntionl Assocition of Dentomxillofcil Rdiology) Der Author, Plese find enclosed proof of your rticle reference No for checking. When reding through your proof, plese check crefully uthors nmes, scientific dt, dt in tles, ny mthemtics nd the ccurcy of references. Plese void mking ny unnecessry chnges t this stge. Any necessry corrections should e mrked on the proof in red/lue ink (not lck). Mrk the plce in the text where the correction is to e mde nd write the correction clerly in the mrgin next to it; if corrections re written in the text, they my e ccidentlly overlooked. Any queries tht hve risen during preprtion of your pper for puliction re listed elow nd indicted on the proof. Plese provide your nswers when returning your proof fter checking, either on this form or on seprte sheet. Q1 Q2 Reference 2 is provided in the list ut not cited in the text. Plese supply cittion detils or delete the reference from the reference list. Figures 1 nd 17 re of dmged, plese provide the etter qulity figures. Plese return your checked proof to: Pulictions Deprtment, The British Institute of Rdiology, 36 Portlnd Plce, London W1B 1AT, UK Do not hesitte to contct us if you hve ny queries Tel +44 (0) Fx +44 (0) pulictions@ir.org.uk Dentomxillofcil Rdiology

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