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A.TIS
B.TIB
C.MI
D.THI
18.A52-year-oldmalepresentsforultrasound-guidedfineneedleaspirationbiopsyofapainlessright
necklump.Whichofthefollowingismostlikelytobepresentinthefineneedleaspirate?
A.Malignantcells
B.Mycobacteriumtuberculouslymphadenitis
C.Colloid
D.Hemosiderin-ladenmacrophages
AnswersandExplanations
1a.AnswerB.Thyroglossalductcyst(TDC)isthemostcommoncongenitalneckmass.Itislocatedin
themidline(75%)orslightlyoffmidline(25%)intheanteriorneck.MostTDCsarelocatedeitheratthe
levelof(15%)orimmediatelybelow(65%)thehyoidbone. Theymostcommonlypresentasagradually
enlargingpainless massin themidlineofthe neckinchildrenoryoung adults.AnuncomplicatedTDC
may appear as an anechoic, well-circumscribed cyst with increased through transmission or can be
pseudosolid in appearance with homogenous low-level internal echoes because of the presence of
proteinaceous fluid content, cholesterol crystals, and keratin. TDCs with previous infection or
hemorrhagemayappearasheterogeneouscomplexcystswithinternalechoes.
The 2nd branchial cleft cyst (BCC) usually presents as a cystic neck mass posterolateral to the
submandibulargland,lateraltocarotidspace,andanteriortosternocleidomastoid.Most2ndBCCsareat
orimmediatelycaudaltotheangleofmandible.Asuppurativelymphnodeusuallypresentsasapainful
neckmasswithskinerythema,fever,poororalintake,andelevatedwhitebloodcellcount.Cysticnodal
metastasesaremostcommonlyfrom squamouscarcinoma oftheupperaerodigestivetractandpapillary
carcinomaofthethyroid. Thenodesareoftenmultipleandonultrasoundusuallyshowasolidcomponent
withabnormalvascularity.
1b. Answer B. The presence of a normal thyroid gland should be confirmed during a preoperative
ultrasound of a TDC because if the ectopic thyroid tissue in a TDC is the patient’s only functioning
thyroid tissue, then a resection of the ectopic thyroid with the cyst will cause hypothyroidism.
Preoperativeidentificationofnormalthyroidglandonultrasoundissufficienttoexcludethediagnosisof
ectopic thyroid tissueandhelps toavoid thyroid scintigraphy, whichshould be minimized,ifpossible,
especiallyinpediatricpatients.
ThepresenceofasolidvascularcomponentinaTDCshouldraisethesuspicionofthyroglossalduct
carcinoma.Fine needle aspiration (FNA) can be performed to confirm the diagnosis preoperatively.
ThyroglossalductcarcinomaisanuncommoncomplicationofTDC,occurringin<1%ofcases.
References:AhujaAT,WongKT,KingAD,etal.Imagingforthyroglossalductcyst:thebareessentials.ClinRadiol2005;60(2):141–148.
HertzbergBS,MiddletonWD.Ultrasound:therequisites,3rded.Philadelphia,PA:Elsevier,2016:229–230.
KutuyaN,KurosakiY.Sonographicassessmentofthyroglossalductcystsinchildren.JUltrasoundMed2008;27(8):1211–1219.
2.AnswerB. Comet-tail artifactis a formofreverberation artifact.Identificationofaprominent(>1
mm) comet-tail artifact posterior to a linear echo within a thyroid nodule is a key imaging feature of
colloid.AnarticlebyMalhietal.showedthatsmall(<1mm)comet-tailartifactsmaybeseenposterior
toechogenicfociinmalignantnodules.
Acoustic shadowing is produced distal to a highly attenuating object such as a calcification.
Microcalcifications in thyroid nodules are often too small to produce a posterior acoustic shadow.
Increased through transmission occurs posterior to a weakly attenuating material. Whereas increased
through transmission may be seen posterior to a colloid cyst, it would not be expected to be seen
posterior toanechogenicfocus ofcolloid.Refractionartifact occurswhen the ultrasoundbeamtravels
throughtwoadjacentmaterialswithdifferentinherentsoundpropagationvelocities. Thisartifactresults
inmisplacementofobjectsontheimage.
References:FeldmanMK,KatyalS,BlackwoodMS.USartifacts.RadioGraphics2009;29(4):1179–1189.
Frates MC, Benson CB, Charboneau JW, et al. Management of thyroid nodules detected at US: Society of Radiologists in ultrasound
consensusconferencestatement1.Radiology2005;237(3):794–800.
Malhi H, Beland MD,CenSY,et al.Echogenic fociin thyroidnodules:significance of posterior acoustic artifacts. AJR AmJ Roentgenol
2014;203(6):1310–1316.
3.AnswerA.Benignorreactivecervical lymphnodestendtohaveanovalshapewhereasmalignant
lymphnodestendtoberoundwithashort-axis-to-long-axisratio>0.5. Thereisnoconsensusforacutoff
short-axis diameter for cervical lymph nodes. Both malignant and reactive lymph nodes may become
enlarged.Anechogenichilumthatiscontiguouswiththesurroundingperinodalfatisconsideredabenign
appearance.Anechogenichilummaynotbeseeninsmallerlymphnodes<5mm.Occasionally,malignant
nodeswillhaveanechogenichilum,sothisfeatureshouldnotbeconsidereddiagnosticofabenignlymph
node in andof itself.Hilar vessels are expected inbenign or reactive lymph nodes. Malignant lymph
nodesmayshowperipheralvascularity.
Reference: Ying M, Bhatia KSS, Lee YP, et al. Review of ultrasonography of malignant neck nodes: greyscale, Doppler, contrast
enhancementandelastography.CancerImaging2013;13(4):658–669.
4.AnswerD.Thislesionisanechoicwithposterioracousticenhancement,whichtellsusthatthelesion
is cystic,a benignpattern. Thereisnosolid or nodular component. According toboth SRU consensus
statementand 2015 ATAguidelines, fine needle aspirationis notnecessary for entirelycystic lesions.
MRIandPET-CTdonotplayaroleinfurthercharacterizationofthyroidnodules.
References: Frates MC, Benson CB, Charboneau JW, et al. Management of thyroid nodules detected at US: Society of Radiologists in
ultrasoundconsensusconferencestatement1.Radiology2005;237(3):794–800.
HaugenBR,AlexanderEK,BibleKC,et al. 2015 AmericanThyroid Association Management Guidelines for Adult Patientswith Thyroid
NodulesandDifferentiatedThyroidCancer:TheAmericanThyroidAssociationGuidelinesTaskForceonThyroidNodulesandDifferentiated
ThyroidCancer.Thyroid2016;26(1):1–133.
5a.AnswerB.TheAmericanCollegeofRadiologyformedtheIncidentalThyroidFindingsCommittee
to provide guidance on managing thyroid nodules detected on medical imaging (other than dedicated
thyroidultrasound) thatwerepreviouslyunsuspected. Thecommittee recommendations werepublished
ina white paper in February 2015. The goals of the committee were todetermine whichincidentally
detectedthyroidnodulesshouldundergothyroidultrasound,toreducethecostsandrisksassociatedwith
follow-up ultrasoundandthyroid FNA (fineneedleaspiration), andtoachieve consistencyinreporting
andmanaging ofincidental thyroid nodules and providing guidance toradiologists whoare concerned
aboutnotreportingorrecommendingadditionalworkupforincidentalthyroidnodulesthatlaterproveto
beclinicallyimportant.
It is knownthat thyroid nodules are very common, foundin upto50% of patientswithoutclinical
historyofthyroiddisease,andmajorityofthesenodulesaremultiple.Upto25%ofpatientswillhavean
incidentallydetectedthyroidnodulewhenundergoingCT andMRI studies(which includethe thyroid).
Malignancy rates vary basedon how the nodule wasdetected. In large population-based studies, most
incidentallydetectedthyroidnodulesonultrasoundarefoundtobebenign(themalignancyratewas1.6%
inpatientswith 1 or morenodules). On the otherhand, when the nodulepresentswith focal uptakeon
18
FDG-PETscans,asmanyas33%to35%aremalignant.Althoughautopsystudieshaveshownthatthe
background rate of papillary thyroid cancer is as high as 36% of thyroid glands, most are welldifferentiated small (<1 cm) papillary thyroid carcinomas with an excellent prognosis. Other studies
showedthatthyroidcancers<2cmalsohaveanindolentcourse,with99.9%10-yearsurvivalrates.
A 3-tiered system was adoptedfrom Duketo guide the evaluation ofincidentallydetected thyroid
nodulesbasedonthepatient’sageandimagingfindings.Withthissystem,furtherevaluationwiththyroid
ultrasoundisconsideredforthreegroups:(1)noduleswithcertainimagingfeaturesassociatedwithhigh
risk (suspicious adenopathy, local invasion,and PETavidity), (2) nodules ≥1 cm inpatients age<35
years, and (3) nodules ≥ to 1.5 cm in patients age ≥35 years of age. Studies have shown that the
applicationofthesecriteriacoulddecreasetherateofthyroidultrasoundrecommendationsbyabout46%
(compared toa 1-cmsize cutoff) anddecrease the rate ofultrasound-guided biopsies by35%. The3tieredsystemhasa13%false-negativerate,butwhenincludingallthyroidcancers,thisaccountsforonly
1.2%ofallthyroidmalignancies.
References: HoangJK,LangerJE,MiddletonWD,etal.Managing incidentalthyroid nodulesdetectedon imaging: whitepaperoftheACR
incidentalthyroidfindingscommittee.JAmCollRadiol2015;12(2):143–150.
RumackCM,WilsonSR,CharboneauWJ.Diagnosticultrasound,4thed.Philadelphia,PA:ElsevierHealthSciences,2011:712–715.
5b.AnswerD.Accordingtothewhitepaperonincidentallydetectedthyroidnodulesproposedbythe
Incidental Thyroid Findings Committee, in patients within the general population with normal life
expectancyandwithoutsuspiciousimagingfindings,itisthepatientageandnodulesizethatdeterminethe
need for additional workup. Further workup with thyroid ultrasound is recommended for patients <35
yearsoldwithincidentallydetected nodulesmeasuring≥1cmintheaxialplane. Forpatientsage35 or
older, the size cutofffor further evaluation is raised to1.5 cm. In this scenario, becausethe patient is
above35yearsofageandthenodulemeasuresunder1.5cm,nofurtherworkupisrecommended.Patients
with limited life expectancy and comorbidities do not need further evaluation of incidental thyroid
nodulesunlessitiswarrantedclinicallyorrequestedbythepatientorreferringphysician. Theneedfor
nodulebiopsy isbasedonresultsofthethyroidultrasoundunlessthenoduleisfound tobe18FDG-PET
avidinwhich caseabiopsyisrecommendedregardless oftheultrasoundappearanceinpatientswitha
normallifeexpectancy.
Reference: HoangJK,LangerJE,MiddletonWD,et al. Managingincidental thyroid nodulesdetected onimaging: white paper oftheACR
incidentalthyroidfindingscommittee.JAmCollRadiol2015;12(2):143–150.
6a.AnswerD.Theultrasoundimagerevealsanenlarged,heterogenousthyroidlobewithinnumerable
small hypoechoic foci termed micronodulation very characteristic of Hashimoto thyroiditis (HT).
MicronodulationisahighlysensitivesignofHT.Itiscausedbythyroidglandinfiltrationanddestruction
of thyroid follicles by lymphocytes and plasma cells. An associated fibrotic reactionthen creates the
appearanceofechogenicbandsintheglandinmoreadvanceddisease.Othersonographicfeaturesoften
presentarecentralcompartmentadenopathy(usuallyinferiortothethyroidgland)andnodularcontourof
thethyroidgland.Vascularityofthethyroidisvariable,butisoftenincreased.
HTis the mostcommoncauseofhypothyroidismintheUnitedStates. Theonsetofhypothyroidism
symptomsisofteninsidiousincludingfatigue,dryskin,weightgain,andconstipation. Thecondition,as
withothercauses ofthyroiditis, hasa strongfemalepredominance,presenting inyoung tomiddle-aged
women with painless thyromegaly. Serology usually confirms positive autoantibodies to anti-TPO
(antithyroidperoxidase)andanti-Tg(antithyroglobulin).
Gravesdiseaseisanautoimmunediseaseofthethyroidglandalsooftenassociatedwiththyromegaly,
parenchymal coarsening, and diffuse hypoechogenicity due to the presence of large intraparenchymal
vessels and lymphocytic infiltration. Unlike in HT, the patients are hyperthyroid. The marked thyroid
hypervascularity that is seen in Graves’ on color Doppler has been termed “thyroid inferno.”
MicronodulationisnottypicalofGravesdisease.Radiation-inducedhypothyroidismisincorrectbecause
the thyroid is usually small and is preceded byahistory of radioiodineablation or external beam. de
Quervain thyroiditis is a type of subacute thyroiditis that typically presents with painful, hypoechoic,
hypovascularlesionsinthethyroidthatcanappearmass-likeordiffuse. Theconditionisaccompaniedby
hyperthyroidismatfirst,followedbyahypothyroidintervalbeforereturningtonormal.
References:HertzbergBS,MiddletonWD.Ultrasound:therequisites,3rded.Philadelphia,PA:Elsevier,2016:237–238.
RumackCM,WilsonSR,CharboneauWJ.Diagnosticultrasound,4thed.Philadelphia,PA:ElsevierHealthSciences,2011:741–746.
SholoshB,BorhaniAA.Thyroidultrasoundpart1:techniqueanddiffusedisease.RadiolClinNorthAm2011;49(3):391–416.
6b.AnswerC.Primarythyroidlymphomaisararecauseofmalignancyaccountingfor<5%ofthyroid
malignancies.Mostthyroidlymphomasarenon-Hodgkinlymphomatype,arisingdenovoinapatientwith
preexistingHashimotothyroiditisorsecondarilyinvolvingthethyroidingeneralizedlymphoma.Patients
with Hashimoto thyroiditis have a relative risk of 67 of developing primary thyroid lymphoma. The
transformationfrom Hashimotothyroiditis toprimary thyroidlymphoma occursinabout 0.5% ofcases.
Although most patients with thyroiditis do not proceed to lymphoma, most cases of primary thyroid
lymphomadoariseinabackgroundofthyroiditis,whichaccountsforapproximately60%to90%thyroid
lymphomacases.
Thyroid lymphoma typically presents in older patients with a rapidly enlarging neck mass and
obstructivesymptomssuchasdysphagiaanddyspnea.Onultrasound,lymphomatoustissuewillappearas
large,solid,veryhypoechoicpseudocysticmasses.Posterioracousticenhancementofthelesionisuseful
in suggesting the diagnosis. The diagnosis is established and distinguished from anaplastic thyroid
carcinomawithfineneedleaspirationbiopsyandflowcytometry.
References: Rumack CM, Wilson SR, Charboneau WJ. Diagnostic ultrasound, 4th ed. Philadelphia, PA: Elsevier Health Sciences,
2011:724–726.
SteinSA,WartofskyL.Primarythyroidlymphoma:aclinicalreview.JClinEndocrinolMetab2013;98:3131–3138.
7. Answer B. The ultrasound image shows an enlarged, diffusely coarsened and heterogenous
appearanceoftheparotidglandwithinnumerablesmall2to3mmhypoechoiclesions. Thesehypoechoic
lesionsrepresentareasofnonobstructivesialectasisthatcanbeseenonsialography. Thesesonographic
findingsarecharacteristicofSjögrensyndrome,anautoimmunediseasethatcauseschronicinflammation
ofjoints, salivary glands, and lacrimal glands resultingin gland enlargementand dysfunction. Patients
experiencedrymucousmembranes(drymouthanddryeyes). Theconditionismorecommoninwomen
andinvolvestheparotidglandmorefrequentlythanitdoesthesubmandibulargland.Inearlystages,the
parotid gland may appear normal on ultrasound. End-stage disease is characterized by gland atrophy.
Ultrasoundisusedtomonitorpatientsfordevelopmentoflymphoma,forwhichtheyareprone.
Thedifferentialdiagnosisfortheultrasoundappearanceincludessarcoidosis,acutesialadenitis,and
granulomatoussialadenitis,whichcan causediffuseheterogenousenlargementoftheparotidglands,but
without numerous smallhypoechoic foci associatedwith Sjögren disease. Acute sialadenitisis painful
andcanbe associatedwith clinical signs ofinfection,abscess formation,or calculusformation,which
canbereadilyidentifiedonsonography.
Lymphoepithelial cysts,Warthin tumor,andpleomorphicadenoma are benignentitiesthatpresentas
focal parotid lesions. Lymphoepithelial cysts present as multiple cysts in those affected with human
immunodeficiency virus infection. On ultrasound, Warthin tumor and the more common pleomorphic
adenoma present as circumscribed hypoechoic lesions with posterior acoustic enhancement. Both can
showinternalcystic changeandseptations. Warthintumorsare multiple or bilateral in10% to15%of
patients.
References:HertzbergBS,MiddletonWD.Ultrasound:therequisites,3rded.Philadelphia,PA:Elsevier,2016:246.
HowlettDC.Highresolutionultrasoundassessmentoftheparotidgland.BrJRadiol2014;76:271–277.
OnkarPM,RatnaparkhiC,MitraK.High-frequencyultrasoundinparotidglanddisease.UltrasoundQ2013;29(4):313–321.
8a. Answer C. The ultrasound reveals diffuse parenchymal microcalcifications throughout a mildly
diffuselyenlargedthyroidglandwithoutafocalordominantmass,typicalofthismoreaggressivesubtype
ofpapillarythyroidcancer.Associatedmalignant-appearingcervicallymphadenopathyindicatesthemore
aggressivenatureofthisdisease.
Diffusesclerosingvariantofpapillarythyroidcarcinomaisanuncommon,moreaggressivevariantof
papillary thyroid carcinoma. The thyroid cancer is manifested by numerous microcalcifications
infiltratingtheglandinadiffuseorregionalpatternwithoutformingadominantmass.Pathologically,the
gland reveals extensive fibrosis and numerous psammoma bodies. It is more common in females and
affects youngerpatients,eveninthe pediatricpopulation. Thisvariant hasahigherincidenceoflymph
node metastases but has a similar prognosis to conventional papillary thyroid carcinoma due to
aggressivetreatmentprotocols.Biopsyshouldbedirectedtoanareacontainingmicrocalcificationsand
lymphadenopathy.
Multinodulargoiter(choice A)isincorrectbecausetherearenofocalthyroid nodules. Thetypical
appearanceseeninmultinodulargoiteristhatofmultiplecloselyapposedsolidnoduleswithoutnormal
interveningthyroidparenchyma.
Althoughdifferentiating tiny,bright,nonshadowing foci ofmicrocalcificationsfrom colloid crystals
canbe difficult,thelackof surrounding cystic spaces(whichare often perceived with high-resolution
transducers) and comet-tail artifact suggestthe presence ofmicrocalcifications. Choice B is incorrect.
Psammomabodies,which correspondtothemicrocalcificationsseen onultrasound,representthe most
important and specific feature of papillary thyroid cancer. Cervical adenopathy will be absent in the
presenceofbenigncolloidcysts.
Metastaticdiseasetothethyroidisquiterareandwouldnotshowmicrocalcifications(ChoiceD).On
ultrasound,metastasesusuallyappearassolidhypoechoicnodule(s)orcandiffuselyreplacethethyroid
gland.Adenopathy can be present. Patients usually have a known diagnosis of malignancy at the time
thyroid metastases are discovered because these often occur late in the disease process. Renal cell
carcinomaisthemostcommonmalignancytometastasizetothethyroid.
Chroniclymphocyticthyroiditiscancausethyromegalyandaheterogeneous,coarsenedappearanceof
theparenchymabutisnotassociatedwithmicrocalcifications.Mildcervicaladenopathyischaracteristic,
but the nodes are not frankly malignant appearing;usually, multiple mildlyenlarged hypoechoiclymph
nodesarelocatedinthecentralcompartmentbelowthethyroidgland.ChoiceEisincorrect.
References: Oyedeji F, Giampoli E, Ginat D, et al. The sonographic appearance of benign and malignant thyroid diseases and their
histopathologycorrelate.UltrasoundQ2013;29:161–178.
PillaiS,GopalanV,SmithRA,etal.Diffusesclerosingvariantofpapillarythyroidcarcinoma—anupdateofitsclinicopathologicalfeaturesand
molecularbiology.CritRevOncolHematol2015;94(1):64–73.
RumackCM,WilsonSR,CharboneauWJ.Diagnosticultrasound,4thed.Philadelphia,PA:ElsevierHealthSciences,2011:716–720.
8b.AnswerE.Spongiformcompositionreferstothereplacementofatleast50%ofanisoechoicnodule
bymicrocystswithinterveningsepta,resemblingaspongeorhoneycomb.Noduleswiththisappearance
are benignwitha veryhighspecificity(99.7% to 100%).Onhistopathology, theyrepresent colloidor
hyperplasticnodules.
Most thyroid cancers arewelldifferentiated,with papillarycancerbeing themost commonthyroid
malignancy, constituting75% to90%ofall cases.Varioussonographic features ofthyroid cancer have
beenstudied tohelptriagenodulesforFNA biopsybydistinguishingsuspiciousfrom benignnodules.
The sonographic features that are most specific for malignancy include extension beyond the thyroid
capsule, malignant-appearingadenopathy (especially when lymph nodes contain microcalcifications or
cystic degeneration), and the presence of microcalcifications (up to 95% specific). Other features of
malignancy include solid and hypoechoic composition, marked hypoechogenicity (the nodule is
hypoechoicrelativetothestrapmuscle),thickandincompletehalo,spiculatedorlobularmargin,tallerthan-wide shape,refractiveedgeshadowing,andinterruptedperipheralcalcifications. Increasedcentral
intranodular flow oncolor Doppler and macrocalcifications have also beenassociatedwith increased
risk. Strain elastography, which measures nodule stiffness,has alsobeen very promisingin identifying
malignant nodules. Themore ofthesesuspiciousfeatures are present ina givennodule, thehigher the
likelihoodofmalignancy,particularlypapillarythyroidcarcinomabutalsomedullarycarcinoma.
Recently,awhitepaperfromtheAmericanCollegeofRadiologyTI-RADScommitteehasproposed
recommendationsonriskstratificationofthyroidnodulesonthebasisoftheirultrasoundappearance.The
basis of the classificationsystementails assigning numeric points for various sonographic features of
thyroidnodules;the moresuspiciousthefeature,the morepointsare addedtothesum. Noduleswith a
totalscoreofatleast3pointsareassignedaTI-RADS level3or higherwherenodule sizedetermines
correspondingrecommendationsforFNAbiopsyorfollowup.
References:BonavitaJA,MayoJ,BabbJ,etal.Patternrecognitionofbenignnodulesatultrasoundofthethyroid: whichnodulescanbeleft
alone?AJRAmJRoentgenol2009;193(1):207–213.
DesserTS,KamayaA.Ultrasoundofthyroidnodules.NeuroimagClinNorthAm2008;18(3):463–478.
MoonWJ,JungSL,LeeJH,etal.Benignand malignant thyroidnodules:USdifferentiation—multicenterretrospective study 1. Radiology
2008;247(3):762–770.
Nachiappan AC, MetwalliZA,Hailey BS, et al. The thyroid: review of imaging features and biopsy techniques with radiologic-pathologic
correlation.RadioGraphics2014;34(2):276–293.
OyedejiF,GiampoliE,GinatD,etal.Thesonographicappearanceofbenignandmalignantthyroiddiseasesandtheirhistopathologycorrelate.
UltrasoundQ2013;29:161–178.
TesslerF,MiddletonW,GrantE, et al. ACR ThyroidImaging,ReportingandDataSystem(TI-RADS):WhitePaperoftheACRTI-RADS
Committee.JAmCollRadiol2017;14(5):587–595.
9a. AnswerA. Theultrasound images show four oval hypoechoic nodules, two located deep to the
midgland of both thyroid lobes and two others near the lower poles. The appearance, location, and
delayed retention of radiotracer on technetium-99m sestamibi scan are characteristic of multigland
parathyroid enlargement. Primary hyperparathyroidism is caused by autonomous production of
parathyroidhormone(PTH)byasingleadenomain80%to90%ofcases,bymultipleglandenlargement
in10%to20%casesandcarcinomain<1%ofcases.Onthecontrary,secondaryhyperparathyroidism,as
presentinthispatient,isseeninthosewithchronicrenalfailureinwhichchronichypocalcemialeadsto
compensatory multigland parathyroid hyperplasia. Less common causes of secondary
hyperparathyroidism include osteomalacia, rickets, and malabsorption. Hyperplasia usually affects all
four glands asymmetrically, whereas multiple adenomas may involve two or possibly three glands.
Becausedistinguishinghyperplasia fromadenoma isdifficult pathologically andbecausethepattern of
glandenlargementisinconsistent,whenmorethanoneparathyroidglandisenlarged,itissimplyreferred
toasmultipleglanddisease.
Parathyroid carcinoma(choiceB)isa rarecauseofprimary hyperparathyroidismthatisassociated
with higher levels of serum calcium and an enlarged parathyroid gland. Histologic and sonographic
distinctionfromparathyroidadenomaisdifficult,andthediagnosisisusuallymadebythesurgeonwhena
firm, adherentparathyroidglandhasinvasive features or when the postoperative histologyreturnswith
atypiaorcarcinoma.Whenparathyroidcarcinomaisinitiallydiagnosed,itpresentsasasolitarymass,not
as multigland enlargement.Sonographic features that raise suspicion ofparathyroid carcinoma include
size >2 cm, lobular contour, taller-than-wide shape, internal cystic component, heterogenous internal
architecture,andgrossinvasionofadjacentstructures.Whenthesearepresent,itisimportanttonotifythe
surgeonsothatanenblocresectionwiththeipsilateralthyroidglandcanbeperformed.
Parathyromatosis(choiceC)isanuncommonconditionwherehyperplasiaofpreexistingparathyroid
rests are stimulated by the metabolic derangements associated with renal failure (secondary
hyperparathyroidism) or more commonly present with recurrent hyperparathyroidism after spillage of
parathyroid tissueatthe time ofparathyroidectomy. Growth ofthe scatteredimplantsintheanterior or
deeper aspect of the neck results in multifocal ectopic parathyroid tissue. They have the same
sonographicappearanceofatypicalenlargedparathyroidgland,butthelocationisatypicalfromnormal
parathyroid location.Fineneedleaspirationwithdetectableparathyroidhormonelevelassay wouldbe
diagnostic. Thyroidcarcinoma(choiceD)isincorrect,becauseunlikethyroidcancer,thesehypoechoic
nodulesareextrathyroid.
References:JohnsonNA,CartySE,TublinME.Parathyroidimaging.RadiolClinNorthAm2011;49(3):489–509.
RumackCM,WilsonSR,CharboneauWJ.Diagnosticultrasound,4thed.Philadelphia,PA:ElsevierHealthSciences,2011:761–762.
TublinME,YimJH,CartySE.Recurrenthyperparathyroidismsecondarytoparathyromatosisclinicalandimagingfindings.JUltrasoundMed
2007;26(6):847–851.
9b.AnswerD.In oneseriesof102patientswithpersistentorrecurrentprimary hyperparathyroidism
whounderwentreoperation,themostcommoncauseoffailedparathyroidsurgerywasfailuretoremove
ectopicparathyroidtissuein53% ofthe patients. Regrowth ofresected tumor(choice B)wasfoundin
only 3% of cases and tissue missed in normal position during previous surgery (technical failure)
occurred in 7% of patients (choice A). Although recurrent or incompletely resected parathyroid
carcinoma (choice C) can cause residual or recurrent hyperparathyroidism, parathyroid cancer is
uncommon(<1%ofcases).
Ectopic locationof a parathyroid glandisencountered in approximately3%ofpatients. The most
common location for ectopic superior parathyroid adenomas is retrotracheal. Other sites of ectopic
parathyroid tissue include the carotid sheath, intrathyroidal, mediastinal, and low neck. Patient
positioningandoptimalprobeselectionandscanningtechniquearecriticalforsonographiclocalization.
Supernumeraryparathyroidglands(morethan4)arepresentin2%to9%ofindividuals.
References:JohnsonNA,CartySE,TublinME.Parathyroidimaging.RadiolClinNorthAm2011;49(3):489–509.
HertzbergBS,MiddletonWD.Ultrasound:therequisites,3rded.Philadelphia,PA:Elsevier,2016:239–242.
ShenW,DürenM,MoritaE,etal.Reoperationforpersistentorrecurrentprimaryhyperparathyroidism.ArchSurg1996;131(8):861–869.
10a. Answer A. The sonographic features of progressive hypoechoic, hypovascular patches in the
thyroid gland associated with painis characteristic of de Quervainthyroiditis. Theclassic presenting
clinical symptoms include thyrotoxicosis and neck pain following a viral illness. The other options
providedarepainlessconditions.InGravesdisease,incontrasttodeQuervainthyroiditis,thethyroidis
usually hypervascular, and involvementis almost always diffuse although both present clinicallywith
hyperthyroid symptoms. Although thyroid cancer and lymphoma both usually present with focal
hypoechoiclesions,patientsarenotthyrotoxic.Patientswiththyroidlymphomamaydevelopcompressive
symptomsandhypothyroidismwithdiffuseinvolvement. Therelativelyrapidprogressionofthethyroid
gland involvement is very unusual in differentiated thyroid cancer but can be relatively rapidly
progressive inaggressive thyroid lymphoma. FNA biopsymay be necessary to exclude malignancy in
difficultcases.
De Quervain thyroiditis (subacute granulomatous thyroiditis) is a self-limited thyroid condition
believed tobe caused bya viral-induced transient autoimmune responselasting weeks tomonths. Itis
associatedwithatriphasicclinicalcoursecharacterizedbyreleaseofpreformedthyroidhormonecausing
hyperthyroidismbecauseofthyroidfollicledestruction,thenhypothyroidismoncethethyroidhormoneis
depleted, and, finally, the return to a euthyroid state once the thyroid follicle regenerates and thyroid
synthesis resumes. De Quervain thyroiditis is the most common cause of a painful thyroid gland.
Clinically, the thyroid can be enlarged, painful to palpation, and associated with fever and elevated
erythrocyte sedimentation rate. The imaging appearance reflects the extent of thyroid involvement.
Sonographically,theglandshowshypoechoic,hypovascularill-definedpatchesduetothyroiddestruction
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