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A JR :16 9, N ove mb er 1 99 7 1339

Im ag ing o f R ena l H yda tid C ys ts

P ic to ria l E ssay

V incen zo M iga le ddu1 , M auriz io Con ti1 , G iu lio C esa re C ana lis1 , Rena ta Senarega2 , Fab io P re to le s i3 , Ca rlo M artin o li3 ,

L oren zo E . D erc hi3

Hyda tid d isease is a pa tho log ic co n -

dition caused by the cys t stage of

in fes ta tio n by the ta pew orm Ech i -

nococ cus granu losus . The adu lt fo rm of the

parasite l ive s in the in tes tina l trac t o f ca -

n in es , w hereas sheep , ca ttle, an d hum ans ar e

in te rm ed ia te h osts . T he d is ea se is re la tiv e ly

f requen t in co untries w h ere sheep and ca ttle

fa rm ing is comm on and is endem ic to m ost

par ts o f A sia , South Am erica , northe rn and

eas te rn A frica , A us tra lia a nd N ew Z ealand ,

a nd c ou nt rie s su rro un din g the M editerrane an

S ea [1 ]. P a tho log ica lly , th e cys t is a c av ity

con ta in ing c lea r flu id su r rou nded by a w a ll

w ith tw o d is tin ct la ye rs : a n in ne r, n uc lea ted ,

g erm in ative m em brane and an ou te r, n on nu -

c lea ted layer m ade of innum erab le de l ica te

lam ina tio ns. T he ho st su rro unds the lesion

with a th ird layer : an in flamm atory reac tion

c ontain ing f ib ro bla sts , g ian t ce lls , an d mono -

nuc lea r an d eos in oph ilic in filtra tes th at, in o ld

c ys ts , be com es a th ick fib rou s cap su le an d is

ca lled a pericy st. T he hyda tids are l iv ing o r-

g an ism s th a t g row w ith s low p rog res s iv e e n -

la rgement and unde rgo s truc tu ra l c ha nge s ,

w ith deve lopm ent o f m any daugh ter cys ts

with in t he c av it y of the large paren t le sio n .

P resen ce o f the p a ras ite e lic its an imm une

re sp on se . G iven th e ir h ig h sen s itiv ity , th e in -

d ire c t h em oagg lu tin a tion a nd la tex agg lu tina -

tion te s ts a re o ften used fo r in it ia l sc ree n in g .

Spec i f ic conf irmation of reac t ive se rum can

be ob ta ine d w ith im m unoe lec tro p ho re s is to

d e te c t a n tibo dy aga ins t A rc-S . a genus-spe -

c ific an tig en iso la ted from un i locu la r hyda t id

cys t flu id . H ow eve r , in tact cys ts m ay pro -

d uce a low leve l o f an tig en ic s tim u la tio n , an d

up to 30% o f hepa tic le s io n s a nd 50 % o f lun g

h yda tid s can be se ro lo g ica lly ne ga tiv e [2 ].

M o s t h yd a tid cys ts o ccu r in the live r ( 59%) ,

fo llow ed in freq uen cy by the lun g (2 7% ) and

o th e r o rga ns [1 ]. In vo lvem en t o f the k id ne y is

ra re (3% ) [3 ]. R e na l le s io ns a re th e resu lt o f

hematogeneous sp re ad , a re c omm on ly so li-

tary , and a re lo ca ted a t th e u ppe r o r low e r po le

o f the k id n ey . C lin ica lly , re na l le s io ns a re u su -

a lly as ym p tom atic ; w hen p res en t, sym p tom s

ar e tho se o f a sp ace -o ccu py ing ren a l les ion

w ith pa lp ab le m ass , p a in , a nd hem a tu ria .

C om plic atio ns inc lud e infe ctio n a nd r up tu re ,

either in the ren a l s inu s o r in pe nneph ric tis -

su es . R up tu re of th e cy st in to th e ren a l s inu s

causes p assage o f h yd a tid m a te ria l in to the

ur ine [3 -5] .

P la in F ilm s

En l a r g emen t o f the ren a l s ha dow , usua lly

a t on e po le , ca n be th e on ly fin d ing v is ib le o n

p la in fi lm o f th e abdom en . H ow eve r, c a lc if i-

ca tion s can be f req uen tly enco un tered and

have bee n re po r ted o n p la in f ilm s in a bo u t

20 -30% of cases [3 , 4 ] . Th eir p atte rn is n o t

sp ecific , rang ing from th in , e g gshe ll- like in -

vo lvem en t o f th e o u te r w a ll, to a dense , re ticu -

la r app earan ce (F ig . 1 ). A cru shed eggshe ll

pa ttern , a t tim es confused w ith neop lastic o r

t ub er cu lo us c al ci fi ca ti on s, h as b een de sc r ib ed

a fte r co llap se o f a ca lc if ie d h yda tid c ys t. A

f ron tal v iew o f c a lc if ic p la qu es on th e wa ll o f

the c ys t g ives rise to a la cy pa tte rn . C om p le te

ca lc if ica tio n o f th e w a ll o f a n h yda tid cy s t ca n

F ig . 1 .-65-year -o ld m an w ith la rg e hyda t id cys t o f

l ow e r po le o f rig ht k idn ey c au sing m ed ia l d isp la ce -

m en t o f asc en ding co lo n. R ad iog ra ph sh ow s th in c al-

c ifica tio ns loca ted w ith in w all o f d au gh te r cys ts ,

p ro du cin g r etic ula r appearance .

R ece ive d Ja nu ary iO , i99 7: a cce pte d a fte r re vis ion A pri l 21 , i 997 .

1 I st it ut o d i R a di ol og ia , U n iv er si t# {2 2 4}i S assa ri, V ia le S an P ie tro , iO , 0 7i0 0 S ass ari, Ita ly .

2 Se rv iz io d i R ad io lo gia , O sp ed ale d i S es tri L eva nte (G E), V ia A . T erz i, 4 3/A , i 6039 Se s tr i L e v an t e (G e n ov a ), I ta l y.

3 Is t it u t o d i R a d io l og i a, U n i ve r si t# { 22 4 }i G eno va , V ia le B ene de tto X V, 161 32 G eno va , I ta ly . A dd ress co rre spo nd en ce to LE . D erch i.

A JR i9 97 ;i69 :i3 39 -i342 036 i-803X /97 /i69 5 -i339 © A m eric an R oe ntg en R ay S oc ie ty

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F ig . 2 .-6 i-y ear -o ld w om an w ith re na l co lic .A , Urog r am re vea ls in fe rio r d isp lacem en t o f u pp er ca lic es o f le ft k idn ey b y m ass with f e wf a in t c a lc if ic a ti o ns ( arrows) .

B , Con tra s t-en ha nce d CT sca n show s he te rog en eo us cy s tic le s io n o n m ed ia l a sp ect o f k idn ey . In te rna l ca lc if i-

c a tion s a re c lea r ly v is ib le .

M iga leddu et a I.

1340 A JR :16 9 , N o vem ber 1 997

be con s ide re d an in d ica tion o f q u ie scence . o r

pe rha p s dea th , o f th e parasi te [5 . 61 .

IV U ro grap hy

C lo sed hyda tid s. w itho ut com municat ion

with the ca lice a l sys tem . presen t as space-oc-

cup y ing m asses tha t cause com pression and

d isplacement of c alices (Figs. 2A . 3A . and

4A ) . T he y have no pathognomoni c features at

u ro g ra p hy . an d on ly d e te c tio n of a th ick , d ense

w all s ur ro un din g a he te ro geneous cen te r at

neph ro tom ogra p hy can sugge s t, in an endem ic

a re a , the d ia gno s is o f the disease . O pen cy s ts

h av e a co mm un ica tio n b etw een the hyda t id

an d the calicea l sys tem , so th at con tras t m ed ia

can en ter them . Th ese cy sts u su ally hav e a

m ott led ap pearan ce be cau se con tras t medium

i ns inua tes among th e d au gh te r cy sts c on ta ine d

w ith in the la rge r lesion . M ore ra rely , con tra st

m edium flow s around the tigh tly packed cy st

con ten t and th e cy st w a ll, an d a cre scen t s ign

can re su lt . A c resc en t app earanc e c an also be

en co un te red in the so -ca lled pseudo c lo se d

typ e o f h yda tid c ys t in w h ich co n tra s t m ed ium

in te rpo ses be tw een th e ou te r w a ll o f the cys t

an d th e ca lice al ep i the lium [5 , 6 ]. A fte r ru ptu re

of th e cy st in to the co llec ting sys tem , hy datid

mater ia l can be see n as irre gu la r f illin g de fec ts

w ith in th e re na l p elv is and urete r tha t m ay

cause obs truc tion [7 , 8] .

Sonog r a phy

T he typ ica l fin d in g of a ren al cyst w ith a

m ultilocu la te ap pearance , con ta in in g in te rna l

flo ating echo es an d curv ilin ea r in tern al sep ta , is

ob served in m o st cases (F ig . 5) . In te rna l echoes

a re re la ted to p res en ce o f hook le t s , sco lices,

and b ro od cap su le s w ith in the h yda tid flu id , th e

so -ca lle d “h yd atid sand .” S ep ta c an b e attr ib-

u te d to de tac hed m em b ra ne s , to th e w a lls o f th e

d augh te r cys ts tha t d eve lo p w ith in the larg er

on e, o r to bo th o f these find ing s. H ow ev er , th e

d iagno sis o f hy da tid d isease on sonogram s is

no t a lw ays s tra ig h tfo rw ard . In fa c t, in th e

early s tages of deve lopm en t, hyda tid cys ts can

F ig . 3 -30 -year-o ld m an w ith a c u te p a n cr e at it is .

A , U rog ram reve a ls b o th com p res s io n an d cra n ia l d isp lacem en t o f in fe rio r c a lice s by la rge hyda t id cy s t. C ra n ia lly , no te ca lc ifica tio ns o f w a lls o f la rge r c ys t , w he re as cau -

da ily , sm alle r d au gh te r le sio ns a re w ell de line ate d.

B , Sag i t ta l son og ram o fle f t k id ne y (K ) revea ls h ig hly re fle ctive ca lc ific su rfa ce o f cy s t ( arrows) w ith p os te rio r a co ust ic s ha do w. C alipe rs ind ica te a pp rox im ate s iz e o fle sio n (10 cm ).

C , C T scan show s en la rg em en t o f low e r p o le o f le ft k idn ey ca used by he te roge ne ou s m ass. W ith in le s io n , no te b o th irreg u la r c a lc ific a t ion s a nd cys ts w ith p e r iph e ra l c a l-

c ific a tion o f ou te r w alls .

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A JR :1 69 , N o vem ber 19 97 1341

Fig. 4 -33 -year-old m an w ith right rena l pa in.

A , R ad iog rap h re vea ls la rge h yda tid cys t on u pp e r

po le of righ t k idn ey , ca us ing com pre ss ion a nd d is -

p lacem en t o f up pe r ca lices . T hin ca lc if ica tio ns a re

ap pre cia ted o n cran ia l c on tou r ( arrows) .

B , S ag itta l s on og ram show s so lid h ype re cho ge n ic

ma s s ( a r r owheads ) w ith a ne cho ic a re as con s is ten t

w ith flu id a t p e riph e ry . p = r en al p e lv is .

p resen t as sim ple . anech o ic les io ns [91. an d

even if the w alls o f p aras itic cy sts a re sligh tly

th ic ke r th an th ose of sim p le sero us cy sts. a pro-

spec tiv e d iagn osis o f h yd atid ren al cy st m ay b e

dif ficu lt w h en a c om p le t el y ane cho ic les ion is

de tec ted . D augh te r cysts deve lop at la te r s tages

and m ake the d iagnos is eas ie r. H ow ev er. th in

sep ta and calc itica tions of the w all can be en-

coun te red a lso in sim ple se ro us rena l cysts .

w he rea s a m u ltilo cu late pa ttern can be o b-

serv ed a lso in m ultilo cu lar cyst ic nep hrom as

a nd . ra rely . in re na l c e ll ca rc in om as . A d ia gn o -

s is o f h yd atid d isease can be suspec ted on ly in

endem ic area s o r w hen lab ora to ry tes ts a re p os -

i tive fo r p re se nce o f in fes ta tio n [3 -6] . W all ca l-

c ific ations p resen t a s h yp erecho gen ic areas

w ith p os te rio r acou stic shadow (F ig . 3B ). In

som e ca ses . d aug hte r cysts . m em b ran es. and

hyda t id san d can fill in com ple tely th e pa ren t

lesion w ith echog en ic m a ter ia l a nd m ake the

lesion appear as a so l id tum o r (F ig . 6A ). T he

c or re ct d ia gn os is m ay be su spe cted w hen res id -

u al cys tic spaces can be recogn ized w ith in th e

m ass. usual ly a t the pe rip hery (F ig . 4B ).

T he sonog rap h ic ap pea ran ce o f a m ultiloc -

u late hyd atid renal cys t tha t rup tured in to th e

co llec ting sy sten i h as be en rep orted (101 .

w ith d ire ct com munic ation betw een the cyst

and th e rena l pelv is and iden tification of hy-

da tid m ate ria l a t th e ure te rope lv ic jun ction .

C T

In CT stud ies . h yda tid cysts presen t a s le -

s ion s w ith a hete rog en eou s structura l p attern

tha t is re la ted to p resence of the daugh te r

cys ts an d to the ir num be r. In fa c t. su ch le s io ns

give ris e to tw o typ ica l fin d in gs: m ultip le in -

te rna l sep ta . p ro duced b y th e ir w alls , and a

ty p ic al rose tte p atte rn re la te d to the fact th at

flu id w ith in daughter cy sts h as low e r den sity

than tha t o f the p aren t lesion (F ig . 7 ). W all

c alc ific atio ns c an b e ea sily iden tified (F ig s.

2B and 3C ). T he p rop er w all o f th e c ys t is no t

vascu larized and doe s not enhance afte r in je c-

tion o f co n tra s t m ateria l. T he increase in den-

s ity at th e per iphery o fthe les io n th a t h a s b een

des c rib e d in the lite ra tu re a fte r in jec tion o f

con tras t m ate ria l can b e re la ted to enhance-

m en t o f th e p er icys t. Th is f ind ing co rre la tes

with t he h yp e rv a sc u la r rim tha t is v isib le d ur-

in g th e cap illary venous p ha se a t a ng io gra ph y

I I I ]. Lesion s w ith so lid appearance can be en -

cou n te red . L ack of in terna l co n trast enhance-

m en t a llow s one to c la ss ify th em a s

hyperdense cystic les ions and to avo id m is in -

te rp retin g them as tum o rs (F igs. 6B and 6C ).

F ig . 5 .-6 5-y ear -o ld w om an w ith r en al c olic .

Sagittal onog ram of h yd atid cy st o f lo we r pole

o f l e ftk i dn e y s h ow s ty pic al f lu id -fil le d le sio n

w i t h m u l t i lo c u l a t edi n t e r n ala p p e a ra n c e d u e t o

p re se nc e o f m a n y d a ug ht er c ys ts . Lo w- g ra de

h y d r o ne p h r o si s i s a s s o c ia t e d . k = l e ft k id n e y.

CT find ing s o f h yda tid renal cy sts are no t

pa thognom onic . A s w ith so nograp hy . p rob -

lem s in d iffe ren tia tin g su ch le sions from cys tic

re na l tu mo rs and from o the r com plicated ren al

cy s ts ex is t . F ur the rm ore . C T ha s low er se n s i-

tiv ity th an so nog rap hy in revea ling th in sep ta

or hy da tid san d 14-71 . E p idem io log ic c rite ria

and labora to ry tests a re o f bas ic im po rtan ce

and can he lp d irec t th e d iagn osis tow ard the

presence of parasitic d isease w h en im ag ing

find ings a re n onspecific . H ig h -de ns ity ren a l

cys ts have been re la ted to the presen ce of com -

plicated f lu id w ith in the le sion due to h ig h p ro -

te in co n ten t. o ld hem orrhage . o r ge la tin ou s o r

v is co us m ate ria l. In hyd a t id d ise ase , s uch fin d -

ing s c an be rela ted to c om p le te fill in g in o f th e

cys t b y h yd atid sand o r m em branes . H yda tid

d ise ase m us t b e added to th e p os sib le d iffe re n-

tia l d iag n os is lis t o f h yp e rd e nse ren a l cy s ts , a t

le as t in a c lin ica l se tting w he re the d ise a se is o f

h ig h p re va le nce [1 2 ].

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F ig . 6-53 -year-o ld m an w ith acu te pancrea titis .

A, Axia l son og ram o f sm all h yda tid cy s t o f righ t k idn ey (k ) p rese n t ing w ith so lid a pp ea ran ce ( a r r owheads ) .

B , CT scan w ith ou t c on tra s t en han cem en t revea led les ion as sm a ll, h ig h ly a tten ua tin g m ass o f la te ra l a sp ect o f k id ne y ( a r r owhead) .

C , A fte r c on tra st e nh an ce me nt, c ys t a pp ea rs h yp od en se to re na l p ar en ch ym a ( a r r owhead) .

l iver le sions under sono graph ic gu idan ce has

been re p o rte d to be a sa fe a nd e ffec tive p ro -

cedure [ 1 4] . S on o gr ap hy se em s to be cons id -

Re fe rences

M iga leddu et a l.

1342 AJR:169 , N ovem be r 1 997

M R Im ag ing

MR im ag in g ha s th e c ap ab ili ty to re ve al

accura tely rena l lesions and to iden tify thecomplex in te rna l s truc tu re o f hy da tid cys ts .

F ive cases o f rena l lesions ha ve be en re po rted

in a re v iew on the M R im ag in g fin d in gs in

p a tie n ts w ith ab dom in a l ech in o coc co s is [13] .

W ith the ex cep tio n of w all ca lc if ica tion s , the

sam e d iag nos tic c rite ria o f ren a l h yda tid cys ts

used fo r C T and sonog raphy can be used a lso

w ith th is M R im aging [13].

Conc lus ion

A lth o ugh p la in film s of the abdom en ca n

sh ow c alcific atio ns o f th e cy s t w a lls a nd

F ig . 7 .-78-year-o ld w om an w ith ja und ice d ue to ch o -

la ng ioca rc inom a. C T revea ls la rg e ech in ococ ca l cys t

o f low e r po le o f le ft k idn e y . M ass has con tra s t e n -

h an ce me nt o f w all a nd ro se tte s tru ctu ra l pa tte rn w ith

p res en ce o f pe rip he ra l d au gh te r cy sts w ith flu id d en -

s ity lo we r tha n th at o f pa re nt le sion .

urography can show hyda tid cy s ts a s sp ace -

o ccu pying renal m asses . son ograph y an d

C T are th e m os t us e fu l te ch n iqu es in pa -

tien ts w ith re na l e ch ino co cco s is , b o th w hen

eva lua tion o f a suspec ted hyd a tid cys t is

needed and w hen an o cca s ion a l re na l m ass

is e nco un tered du rin g s tu d ies pe rfo rm ed fo r

unre la ted reasons . D ete c tio n o f a cy stic le -

s io n w ith in te rn a l s ep ta t ion s an d sa nd o r, a t

C T , id e n tif ica tion o f w a ll calcificat ion s o r

presen ce o f the rose tte sign a llow , in th e

prop er c lin ica l se ttin g , the co rrec t d iag no s is

in m ost cases.

Su rge ry , w ith pa rtia l o r to ta l ne ph re c tom y

ac co rd in g to lo ca tion a nd s iz e o f the le s io n ,

is the tre a tm en t o f cho ic e fo r p a tien ts w ith

ren a l h yd a tido s is [4 ]. A lth o ugh pun c tu re o fhy da tid cys t ha s been con s ide re d a po ss ib le

so u rce o f a naphy lac tic rea c tio n s and sp rea d

of the paras i te , percu taneous t rea tmen t of

ered th e bes t-su ited procedure to gu ide

therapy w ith need le asp ira tion o f the cy st

content fo l lowed b y in jec tio n o f a lco ho l o r

h ype rto n ic sa lin e a lso in p a tien ts w ith ren a l

loca t ion of th e disea se [9] .

I. Marsden PD. The c estodes. In Beeson PB .

McDe rmo t t W , eds . Tex tbook o f , ne di ci ne . Phila-

d elp hia : S au nd er s. 1975 :510 -511

2. Schantz PM . Echinococcosis/hydatidosis. In :

Go ld sm ith R . H e yn em an D . ed s . Trop ica l i ned i -

c ine a nd paras i to logv . Ea st N o rw alk . C T: A pp le -

t on & L an ge , 1 98 9: 50 3- 50 9

3. O’Lea r y P . A five -year s tudy o f hum an hydatid

d is ease in T urk ana d istr ic t, K eny a. East A fr M ed J

1976 ;53 :540 -544

4 . G ogus 0 , Be du k Y , T op ukcu Z . R ena l hyda tid

d is ease . B rJ U ro l 1991 :68 :466 -469

5. A rag on a F , D i C a nd io G , S erre tta V . F io ren tin i L .

R e n a l hyda tid d ise ase : rep ort o f 9 c ase s and dis -

cus s ion of uro log ic d iagn ost ic p roc ed ure s. Urol

Radio! 1984 :6 :182 - 186

6 . P a lm er P ES , R eeder M M. P aras itic d ise ase of th e

ur ina ry trac t . In : P o llac k HM . e d . C lin ica l u ro g-

raphv . P hila delph ia: S aund ers . 199 0:9 99 -10 19

7 . Be gg s I. The rad io lo gy o f h yd atid d ise ase . AJ R

1985;145:639-648

8 . G is la nz V . L oza no F , J im enez J. R ena l hyd atid

cy sts : c om munic atin g w ith co lle cting sys tem .

Ai R 1979:135:357-361

9 . O ne r A . D em irc in G , A khan 0 , O ner K . R ena l

hydatid cys t de tec ted in a ch ild du rin g th e cou rse

o f a cu te p os tg lo m eru lo co cc al g lo m er ulo ne ph ritis .

Nephron 1995 :69 :193 -194

1 0 . B ad ea R , A nd re ica M , H u ta nu I, M iu N . Echi-

no coccus cyst rup tured in to th e ren al pelv is : u l-

tra sou nd fin din gs. Eu r J U ltrasound 1995:2 :

293-296

1 1 . B a ltaxe H A , F lem ing R i. T he ang iog ra ph ic ap -

pearance of hy da tid d isease . Rad io logy 1970; 97:

599-604

12 . D unnick NR , K orobk in M , S ilv erm an PM , F os-

ter W L J r. C om puted tom ograph y of h ig h d en si ty

r ena l cysts. J C om put A ss ist Tom ogr 1984 ;8 :

458-461

13 . K a lo v id ou ris A , G ou liam os A , V la cho s L , e t a l.

M RI of abd om ina l hy datid d isease . Abdom Im ag-

i,Ig 1994 :19 :489 -494

14 . F ilic e C , P iro la F, B ru ne tti E , e t a l. A new thera-

peu tic approach fo r hy da tic liver cysts: a sp ira tion

and a lco ho l in je ctio n und er son ograph ic gu idan ce.

Gastroen te ro !ogv 1990;98:I 3 6 6 - 1 3 68