T om ographic aspects of xanthogranulom atous
pyelonephritis and related com plications
Department
of Imagery Diagnosis, Paulist School of Medicine, Federal University of Siio Paulo - Siio Paulo, Brazil
T h e a u th o rs p re se n t th e ir e xp e rie n ce in vo lvin g se ve n p a tie n ts w ith h isto p a th o lo g ic d ia g n o sis o f xa n th o g ra n u lo m a to u s p ye lo n e p h ritis w h o w e re su b m itte d to p re o p e ra tive co m p u te d to m o g ra p h y (C T ). T h e re su lts a re th e fo llo w in g : a ) sto n e s (8 6 p e rce n t o f th e ca se s), b ) in cre a se in re n a l vo lu m e , c) h yd ro n e p h ro sis, d ) d e n sity m e a su re m e n ts (fro m 1 4 to 2 9 H U ), e ) e n h a n ce m e n t fo u n d in a ll ca se s, f) e xtra re n a l in vo lve m e n t (a ll ca se s). C T h a s sh o w n to b e a re lia b le m e th o d in ch a ra cte rizin g xa n th o g ra n u lo m a to u s xye lo n e p h ritis a n d e xtra re n a l in vo lve m e n t.
U N IT E R M S : P ye lo n e p h ritis. C o m p u te d T o m o g ra p h y.
IN T R O D U C T IO N
X
a n th o g ra n u lo m a to u sa ty p ic a l v a rie ty o f a c h ro n icp y e lo n e p h ritisre n a l in fe c tio n(X G P )w h ic his a n is u su a lly u n ila te ra l a n d fre q u e n tly a sso c ia te d w ithu rin a ry o b stru c tio n a n d sto n e s 1 3 .1 5 . B e fo re u ltra so n o g ra p h y
(U S ) a n d c o m p u te d to m o g ra p h y , (C T ) p re o p e ra tiv e
d ia g n o sis w a s n o t c e rta in in 4 4 -6 4 p e rc e n t o f a ll c a se s,
d u e e sp e c ia lly to u n c h a ra c te riz e d sy m p to m s, a n d
la b o ra to ry e x a m s th a t sh o w e d n o a lte ra tio n s5
. 1 3 . 1 6 . IX . R a d io g ra p h ic e x a m s su c h a s e x c re to ry u ro g ra m (E U ) a n d
a n te g ra d e p y e lo g ra p h y (A P G ) a llo w th e d ia g n o sis o f a
re n a l m a ss w ith o r w ith o u t fu n c tio n a l e lim in a tio n ;
h o w e v e r, th e y d o n o t in d ic a te th e d e g re e o f in fla m m a tio n
c a u se d b y th e d ise a se13
• A lth o u g h it is re la tiv e ly ra re (8 2 0
A d d re s s fo r c o rre s p o n d e n c e : G iu s e p p e D 'Ip p o lito
R u a A lc e u d e C a m p o s R o d rig u e s , 1 6 5 - V .N . C o n c e i9 a o S a o P a u lo /S P - B ra s il- C E P 0 5 4 0 9 -0 0 1
c a se s d e sc rib e d u p to 1 9 9 3 ), th e to m o g ra p h ic a sp e c ts h a v e
a lre a d y b e e n d e sc rib e d a n d h a v e b e e n sa id b y so m e
a u th o rs to b e p a th o g n o m o n ic5. 9 .
T h e re fo re , it is p o ssib le n o t o n ly to d ia g n o se th e
d ise a se , b u t a lso to e v a lu a te its e x tra re n a l e x te n sio n a n d
to d iffe re n tia te th e fo c a l a n d th e d iffu se fo rm s, a llo w in g
fo r p re c ise su rg ic a l p la n n in g . T re a tm e n t c o n sists o f to ta l
n e p h re c to m y in th e d iffu se fo rm a n d a p a rtia l n e p h re c to m y
w h e n o n ly a lim ite d a re a is a ffe c te d II.
T h e p u rp o se o f o u r stu d y is to p re se n t se v e n c a se s,
d e sc rib in g th e ir to m o g ra p h ic a sp e c ts a n d fre q u e n c y , so
a s to h e lp d iffe re n tia te th is d ise a se fro m o th e rs.
M A T E R IA L A N D M E T H O D S
W e re v ie w e d C T stu d ie s o f se v e n p a tie n ts w ith a n
h isto p a th o lo g ic d ia g n o sis o fX G P m a d e b e tw e e n 1 9 9 1 a n d
1 9 9 3 . S ix o f th e se se v e n p a tie n ts w e re fe m a le a n d o n e
w a s m a le , w ith a g e s ra n g in g fro m 1 3 to 7 1 (m e a n a g e - 4 1
y e a rs).
D 'IP P O L IT O , G .; T O K E C H I, D .; S H IG U E O K A , D .C .; A JZ E N , S . - T o m o g ra p h ic a sp e cts o f xa n th o g ra n u lo m a to u s p ye lo n e p h ritis a n d re la te d co m p lica tio n s
1 0 9 2
T a b le 1 . b lu r r in g o f p e r ito n e a l f a t d u e to
P a tie n ts a c c o r d in g to th e p r e s e n c e a n d th e s ite o f s to n e s , d e g r e e o f h y p e r d e n s e th ic k la y e r s , m a s s
h y d r o n e p h r o s is , a n d m e a s u r e m e n ts o f th e le s s d e n s e a r e a o f r e n a l le s io n im a g e s w ith th e a s p e c t o f s o f t tis s u e
o r c ir c u n d a tin g liq u id c o lle c tio n s .
P a tie n t S to n e s C o r a lif o r m S ite D e g r e e o f D e n s ity H e te r o g e n e ity a n d a s y m m e tr ic
S to n e s H y d r o n e p h r o s is ( U H )
e n la r g e m e n t o f p a r a v e r te b r a l
A R + p y e lo u r e te r a l ju n c tio n I V 2 1 -2 5 m u s c le a n d o r s u b c u ta n e o u s
B F S + + p y e lo - c a lix I V 1 7 -2 9 c e llu la r tis s u e w e r e c o n s id e r e d
F L N + p a r e n c h y m a /u r e te r a l I in d ic a tio n s o f a b d o m in a l
J C M + + p y e lo - c a lix I V 1 4 in v o lv e m e n t.
L A C C + u r e te r a l I V 2 2 -2 4
M L F + + p y e lo - c a lix I V
M V S + I V 2 3 -2 5
R E S U L T S
T h e e x a m s w e r e c a r r ie d o u t u s in g th e S o m a to m D R
( S ie m e n s M e d ic a l S y s te m ) , w ith 8 m m w id e c u ts a n d a n 8
o r 1 6 m m in c r e m e n t, b e f o r e a n d a f te r o n e e n d o v e n o u s
in je c tio n o f 1 0 0 -1 5 0 m l io d in e h y d r o s o lu b le c o n tr a s t,
m e a s u r in g d e n s itie s b e f o r e a n d a f te r c o n tr a s t in je c tio n .
T h e to m o g r a p h ic p a r a m e te r s a s s e s s e d w e r e :
a ) p r e s e n c e o f s to n e s a n d th e ir s ite s .
b ) r e n a l d im e n s io n s . W e c o n s id e r e d th e k id n e y
" e n la r g e d " w h e n its lo n g itu d in a l d ia m e te r e x c e e d e d
1 3 c m4 •
c ) d e g r e e o f h y d r o n e p h r o s is , c la s s if ic a tio n I - I V2•
d ) d e n s ity m e a s u r e d in lo w - d e n s ity a r e a s .
e ) p r e s e n c e o f e n h a n c e m e n t a f te r e n d o v e n o u s c o n tr a s t
in je c tio n .
t) e x tr a - r e n a l d a m a g e ( p e r ir e n a l, p a r a r e n a l a n d
a b d o m in a l s ite s ) , w ith p r e s e n c e o f h e te r o g e n e ity o r
F ig u re 1 - In c re a s e o f le ft k id n e y v o lu m e s h o w in g p e rip h e ra l
e n h a n c e m e n t a n d d ila tio n o f th e c o lle c tin g s y s te m w ith c e n tra l c a lc ific a tio n . T h is p a tie n t s h o w e d a n o rm a l in fe rio r s e g m e n t o f th e k id n e y .
U n ila te r a l r e n a l m a lf u n c tio n w a s e v id e n t in a ll
p a tie n ts ; le f t m a lf u n c tio n in 5 (7 1 p e r c e n t) a n d r ig h t in 2
( 2 9 p e r c e n t) . I n s ix c a s e s , k id n e y e n la r g e m e n t w a s
o b s e r v e d w ith g r a d e I V h y d r o n e p h r o s is ( 8 6 p e r c e n t) , w h ile
in o n ly o n e c a s e (1 4 p e r c e n t) th e r e w a s a v o lu m e tr ic
d e c r e a s e w ith h y d r o n e p h r o s is g r a d e I ( F ig . 5 ) . I n s ix ( 8 6
p e r c e n t) , th e r e w e r e s to n e s iI i th e c o lle c tin g s y s te m ; in
tw o ( 2 8 p e r c e n t) , th e r e w e r e s to n e s in th e r e n a l
p a r e n c h y m a ; a n d o n ly o n e p a tie n t (1 4 p e r c e n t) d id n o t
p r e s e n t a n y s to n e s . I n th r e e o f th e s ix p a tie n ts w ith s to n e s in
th e c o lle c tin g s y s te m , th e s to n e w a s c o r a lif o r m ( T a b le I ) .
T h e d e n s ity o f th e lo w - d e n s ity c o m p o n e n t o f th e
le s io n , m e a s u r e d f r o m 1 4 to 2 9 U H , w ith n o f a t o r g a s
-ty p e d e n s itie s b e in g o b s e r v e d . A f te r th e in tr a v e n o u s
in je c tio n o f c o n tr a s t, th e r e w a s a p e r ip h e r a l e n h a n c e m e n t
o f th e a f f e c te d k id n e y ( F ig . 10 ) , a s w e ll a s e x tr a r e n a l
F ig u re 2 - L e ft re n a l s ite o c c u p ie d b y a la rg e c o lle c tio n o f m u ltilo c i liq u id w h ic h e x te n d e d to th e p e rire n a l p o s te rio r p a ra re n a l a n d d o rs a l w a ll s ite s . A le ft e n la rg e m e n t o f th e p s o a s m u s c le c a n b e o b s e rv e d .
s a o P a u lo M e d ic a l J o u rn a l/R P M 1 1 4 (1 ): 1 0 9 1 -1 0 9 6 , 1 9 9 6 D 'IP P O L IT O , G .; T O K E C H I, D .; S H IG U E O K A , D .C .; A J Z E N , S . - T o m o g ra p h ic a s p e c ts o f
T a b le 2
P a tie n ts a cco rd in g to p re se n ce a n d site o f e xtra re n a l in vo lve m e n t
P a tie n t p e rire n a l p o ste rio r p a ra re n a l a b d o m in a l w a ll
A R + +
B F S + + +
F L N + + +
JC M + +
L A C C + + +
M L F + +
M V S + + +
D IS C U S S IO N
T a b le 3
F re q u e n cy o f o b se rve d to m o g ra p h ic sig n s
X G P w a s d e s c rib e d in 1 9 1 6 b y S c h lo g e n h a u fe r, w h o c a lle d it s ta p h y lo m y c o s is d u e to its re s e m b la n c e to a c tin o m y c o s is a n d to th e p re s e n c e o f s ta p h y lo c o c c i 1 7 .T h e te rm X G P w a s u s e d b y O b e rlin g , in 1 9 3 5 , d u e to its y e llo w c o lo r a n d to its g ra n u lo m a to u s c h a ra c te ris tic . X G P c a n b e d e fin e d a s a ra re fo rm o f a c h ro n ic re n a l in fe c tio n w ith d a m a g e e x te n d in g to p e rire n a l a n d p o s te rio r p a ra re n a l s ite s in a ll c a s e s . In 4 c a s e s (5 7 p e rc e n t), th e a b d o m in a l w a ll w a s in v o lv e d (T a b le 2 ). T h e re w e re n o s ig n s o f in v o lv e m e n t o f re tro p e rito n e a l g a ry lia , d a m a g e to o th e r a b d o m in a l o rg a n s , o r fis tu la e . A ll th e c a s e s w e re c la s s ifie d a s X G P o f th e d iffu s e fo rm , w ith o n e e x c e p tio n , w h ic h , d u e to th e d a m a g e o f th e s u p e rio r s e g m e n t o f th e k id n e y , w a s c o n s id e re d to b e a s e g m e n te d fo rm (F ig . 1). O b s e rv e d to m o g ra p h ic s ig n s a n d th e ir re la tiv e a n d a b s o lu te fre q u e n c y a re lis te d in T a b le 3 .
F ig u re 3 - X G P "b e a r cla w " a sp e ct. T h e rig h t kid n e y is e n la rg e d w ith liq u id co lle ctio n s a n d p re se n ts in te n se p e rip h e ra l e n h a n ce m e n t. In fla m m a tio n to th e p e rire n a l site ch a ra cte rize d b y b lu rrin g o f fa t a n d th e liq u id co lle ctio n .
d iffu s e o r s e g m e n te d d a m a g e , c h a ra c te riz e d b y th e d e s tru c tio n o f p a re n c h y m a a n d th e a c c u m u la tio n o f m a c ro p h a g e s c o n ta in in g lip id s a s s o c ia te d w ith in tra re n a l, p e rip y e lic a n d p e rire n a l fib ro s islH• T h e re is a n a s s o c ia tio n
o f X G P w ith a lip o m a to u s d e g e n e ra tio n th a t s u b s titu te s n e c ro tic re n a l tis s u e , w h ic h o rig in a te s in th e re n a l s in u s a n d s p re a d s to th e p e rire n a l s ite , w h e re it is e n c a p s u la te d b y th e re n a l fa s c ia l. 9 .
X G P c a n b e c la s s ifie d a s d iffu s e , s e g m e n te d o r fo c a l, a ll s h o w in g s im ila r c lin ic a l m a n ife s ta tio n s6
• In th e d iffu s e
fo rm th e k id n e y is u s u a lly e n la rg e d a n d d is to rte d b y th e p re s e n c e o f m u ltip le liq u id c o lle c tio n s w h ic h c o rre s p o n d to d ila te d c a lix o r p a re n c h y m a l d e s tru c tio n fo c i fille d w ith p u ru le n t m a te ria l. T h e s e a lte ra tio n s a re fre q u e n tly a s s o c ia te d w ith e x tra re n a l e x te n s io n o f th e in fla m m a tio n a n d p e ris in u s fib ro s is6• S e g m e n te d X G P is fo rm e d b y tw o
o r m o re in fla m m a to ry m a s s e s th a t c o m m u n ic a te w ith a c a lix o r a d u p lic a te d u n it, w h ic h u s u a lly is n o t d ila te d , a lth o u g h if d o e s c o n ta in s m a ll o b s tru c tiv e s to n e s c lo s e to th e p a p illa6 . T h e fo c a l fo rm s h o w s th e s a m e a lte ra tio n s a s th e s e g m e n te d fo rm , a lth o u g h th e re is n o c o m m u n ic a tio n w ith th e c o lle c tin g s y s te m a n d w ith a s o -c a lle d fo c a l x a n th o g ra n u lo m a to u s in fla m m a tio n6. H . 13.In o u r s tu d y , w e
o b s e rv e d s ix c a s e s o f th e d iffu s e fo rm a n d o n e c a s e o f th e s e g m e n te d fo rm ; a ll w e re tre a te d w ith c o m p le te n e p h re c to m y .
X G P p a th o g e n e s is is n o t y e t fu lly u n d e rs to o d , a lth o u g h th e in fe c tio n a n d o b s tru c tio n o f th e u rin a ry tra c t (1 3 a re c o n s id e re d to b e e s s e n tia l fo r th is to o c c u r). O th e r fa c to rs th a t s e e m to c o n trib u te to its in s ta lla tio n a re th e a lte ra tio n o f lip id m e ta b o lis m , im m u n ity a n d ly m p h a tic d ra in a g e , in a d d itio n to d ia b e te s a n d re n a l p a p illa ry
100% (7/7)
100% (7/7)
F re q u e n cy
86% (6/7)
86% (6/7)
14% (1/7)
86% (6/7)
100% (7/7)
S ig n s
E n la rg e m e n t o f kid n e y
H yd ro n e p h ro sis g ra d e IV
g ra d e I
L ith ia sis
T h ick liq u id co lle ctio n s
P e rip h e ra l e n h a n ce m e n t a fte r co n tra st in je ctio n
E xtra re n a l in vo lve m e n t
D 'IP P O L IT O , G .; T O K E C H I. D .; S H IG U E O K A , D .C .; A JZ E N , S . - T o m o g ra p h ic a sp e cts o f xa n th o g ra n u lo m a to u s p ye lo n e p h ritis a n d re la te d co m p lica tio n s
1094
n e c r o s is 1 5 .T h e in c id e n c e o f X G P is v a r ia b le , o c c u r r in g a t
a n y a g e , w ith th e d e s c r ip tio n o f a c a s e a t4 8 d a y s o f a g e ! l.
l! l; h o w e v e r , it is m o r e f r e q u e n t in w o m e n in th e ir f if tie s
a n d s ix tie s 1 2 .
C lin ic a l m a n if e s ta tio n s a r e c o lic p a in in th e lo w e r
b a c k ( 8 4 p e r c e n t) 1 3 , f e v e r ( 5 5 p e r c e n t) , m a c r o s c o p ic
h e m a tu r ia (2 4 p e r c e n t) , w e ig h t lo s s (1 0 p e r c e n t) 1 2 a n d a
p a lp a b le m a s s in th e lo w e r b a c k ( 3 9 p e r c e n t) ( 3 , 1 3 , 1 4 ,
1 8 ) ; a ll th e s e s y m p to m s m a y b e a c u te o r s u b a c u te a n d o c c u r
w ith o u t a p r e v io u s h is to r y o f u r in a r y tr a c t in f e c tio n 5 .
L a b o r a to r y e x a m s m a y b e a s n o n - s p e c i f ic a s th e
c lin ic a l m a n if e s ta tio n s , w ith a n o r m a l u r o c u ltu r e in 4 0
p e r c e n t o f th e p a tie n ts , e s p e c ia lly d u e to th e r e n a l e x c lu s io n
f o u n d in th e s e c a s e s 1 0 . O n th e o th e r h a n d , p o s itiv e
u r o c u ltu r e m o r e f r e q u e n tly in d ic a te s th e p r e s e n c e o f E .
c o li ( 4 9 - 6 7 p e r c e n t) , P . m ir a b ilis ( 2 6 - 3 1 p e r c e n t) , S . a u r e u s
( 1 9 p e r c e n t) a n d P . a e r u g in o s a ( 2 0 p e r c e n t) l3 . 1 4 .1 6 .l! l.
O th e r la b o r a to r y a lte r a tio n s f o u n d a r e in c r e a s e d E S R
( 1 0 0 p e r c e n t) , le u k o c y to s is ( 7 0 p e r c e n t) , a d e c r e a s e in
h e m a to c r it ( 6 7 p e r c e n t) , a n d c r e a tin in e a lte r a tio n s ( 4 6
p e r c e n t) 1 4 . 1 6 .l! l.
I m a g e r y d ia g n o s is s u c h a s E U , A P G , U S a n d
a n g io g r a p h y s u g g e s t X G P , a lth o u g h th e r e a r e s o m e
lim ita tio n s w h ic h a r e e s p e c ia lly d u e to th e e x tr a r e n a l
e x te n s io n o f th e d is e a s e ( I ) .
E U m a y s h o w r e n a l e x c lu s io n ( 7 1 - 9 6 p e r c e n t) ,
n e p h r o m e g a ly ( 1 0 0 p e r c e n t) , lith ia s is ( 7 1 - 8 2 p e r c e n t) a n d
f o c a l d ila tio n o f th e c o lle c tin g s y s te m ( 9 p e r c e n t) 3 . 1 3 .1 4 .
A P G is u s e d f o r c a s e s in v o lv in g r e n a l e x c lu s io n , a n d
d e m o n s tr a te s th e le v e l o f o b s tr u c tio n , w h ic h is m o r e
f r e q u e n tly lo c a te d a t th e u r e te r o p y e lic ju n c tio n l3 . 1 5 .
Figure 4 - E x tra re n a l in v o lv e m e n t o f X G P . E n la rg e m e n t a n d h e te ro g e n e ity o f th e p s o a s a n d p a ra v e rte b ra l m u s c le s to th e le ft s h o w in g liq u id c o lle c tio n s a s s o c ia te d w ith la rg e th ic k e n in g o f p o s te rio r p a ra re n a l fa s c ia .
Figure5 - D o tte d c a lc ific a tio n s a n d v o lu m e tric re d u c tio n o f k id n e y s im ila r to re n a l tu b e rc u lo s is . T h e re is a n e n la rg e m e n t a n d
h e te ro g e n e ity o f th e a b d o m in a l d o rs a l w a ll.
U ltr a s o n o g r a p h y h a s , a s its m o s t im p o r ta n t lim ita tio n ,
a n in a d e q u a te r e tr o p e r ito n e a l a s s e s s m e n tlO . I t is in te r e s tin g
to m e n tio n th a t s o m e a u th o r s h a d d if f ic u ltie s in d e s c r ib in g
th e p y e lo c a lix d ila tio n in X G P p a tie n ts l3 . O n th e o th e r
h a n d , it is v e r y e a s y to d ia g n o s e th e p r e s e n c e o f liq u id
c o lle c tio n s a n d r e n a l s to n e s , w h ic h e v e n a llo w s f o r a
s u g g e s tio n o f th e ty p e o f liq u id .
T h e r e a r e tw o d e s c r ib e d u ltr a s o n o g r a p h ic p a tte r n s
in d if f u s e X P G . I n m o s t c a s e s th e k id n e y is e n la r g e d , w ith
s m o o th c o n to u r s , a n d a r c h ite c tu r a lly d is a r r a y e d d u e to th e
p r e s e n c e o f s e v e r a l liq u id m a s s e s w h ic h h a v e a te n d e n c y
to jo in a n d , in th e s e c a s e s , c h a r a c te r iz e s to a d ila te d
c o lle c tin g s y s te m w ith d e b r is , c o r r e s p o n d in g to p u r u le n t
m a te r ia ! . S to n e s a r e f r e q u e n tly id e n tif ie d , e x c e p t in th o s e
c a s e s in w h ic h th e r e is p e r ip y e lic f ib r o s is th a t m a y m im ic
th e p o s te r io r a c o u s tic s h a d o w s p r o d u c e d b y c a lc if ic a tio n s6 ,
I n a n o th e r le s s f r e q u e n t a n d n o n - s p e c if ic f o r m o f
p r e s e n ta tio n , th e r e n a l s ite is n o te d to h a v e b e e n o c c u p ie d
b y a n e x te n s i v e h e te r o g e n e i c f o r m a ti o n th a t is
p r e d o m in a n tly liq u id . T h e s e g m e n te d f o r m is v e r y s im ila r
to th e f ir s t f o r m d e s c r ib e d , a lth o u g h p a r t o f th e a f f e c te d
k id n e y is p r e s e r v e d 6 . D if f ic u lty in d ia g n o s is o c c u r s in th e
f o c a l f o r m , b e c a u s e its p r e s e n ta tio n in th e u ltr a s o n o g r a m
is o f te n u n d is tin g u is h a b le f r o m a s o lid o r c y s tic k id n e y '
n e o p la s m o r e v e n f r o m a n a b s c e s s6
.7•
F in a lly , it is im p o r ta n t to r e m e m b e r th a t a n g io g r a p h y ,
w h e n u s e d to d is tin g u is h a n X G P f r o m a r e n a l c a r c in o m a ,
o n ly d o e s s o in 2 5 - 7 5 p e r c e n t o f th e c a s e s , th o s e w ith a
h y p o v a s c u la r ( 5 0 p e r c e n t) o r a n a v a s c u la r ( 2 5 p e r c e n t)
p a tte r n , d if f e r e n t f r o m w h a t is u s u a lly f o u n d in th e
h y p e r n e p h a n a 1 3 , T h is p r e s e n ta tio n d e p e n d s o n th e q u a n tity
o f n e o v a s c u la r iz a tio n o f g r a n u la tio n tis s u e7 ,
Magnetic
resonance
has not shown any significant
advances
up to this moment
in the diagnosis
of XGP,
and is not able to provide
any information
beyond that
given by CT
(9).However,
it is important
to remember
that the low toxicity
of the paramagnetic
contrast,
as
well as the possibility
of receiving
orthogonal
images
in three planes, may make MR useful for those patients
who are allergic to iodine or need more detailed surgical
planning.
In our study, CT showed a constant pattern similar
to those described
by other authorsl2. 13.14.We observed a
diffuse increase in renal volume in most of the patients
6.7,
except for one who presented
the segmented
form of the
disease. In this case, besides being enlarged,
the kidney
kept its usual form, and peripheral enhancement was noted
that may correspond to compressed residual parenchyma or
to a capsule of inflammatory tissueS (Fig.
1).It is important to observe that the radial distribution
of the liquid cavities
which were found in the kidney
resembles the distribution
of the collecting system and has
the aspect of a "bunch
of grapes"
or a "bear claw" as
described
by some authors 12.13(Figs.
2and
3).The density measures
obtained
(14-29UH) do not
differ significantly
from those found by Goldman
et al.
(10 -15UH)S, if we remember that all these rates indicate
a thick
liquid
and that different
calibrations
of the
equipment used may lead to small differences. On the other
hand, we emphasize
that in no case did we find densities
similar to fat, as was suggested
by Acunas et al., who
considered
this infrequent I.
It was not surprising
to find a frequent
extrarenal
extension
of XGP that was drained
in all studied cases
and easily identified
in several retroperitoneal
sites and
dorsal wall (Fig.
4).The importance
in defining extrarenal
damage
resides
in adequate
surgical
planning,
thus
avoiding
any undesirable
fistulae'2.'3,
which has even
suggested a classification
of the XGP through CT in: State
I when the disease is restricted
to renal parenchyma,
in
State II when there is perirenal involvement,
and in State
III when
there
is peri
and pararenal
involvement3.
Therefore, it may be interesting
to define a State IV when
there is damage to the abdominal
wall.
Despite the characteristic
aspect of the XGP in the
CT, a differential
diagnosis
with hypernephroma,
renal
tuberculosis
(Tb), and pyohydronephrosis
must be made.
Hypernephroma
may be similar to XGP in its focal form
when studied by the US and CT, and, even more, 50 when
in its cystic form, although this is relatively rare in adults.
In these cases, a more crude type calcification
with a
coraliform
aspect may help in the diagnosis
of XGPI3.16.
When this is not possible and there are no retroperitoneal
ganglia in the tomographic
exam (rare in XGP) or other
malignity
signs
(e.g.
hepatic
metastases),
selective
arteriography
may be useful if it demonstrates
an avascular
pattern therefore ruling out the blastomatose
origin of the
process. On the other hand, a hypo or hypervascular
pattern
may be found in XGP and hypernephroma's.
Renal Tb usually evolves with a decrease
in renal
volume and with calcifications
somewhat
different from
XGP which are more pointed in shape. When XGP leads
to renal reduction, differential
diagnosis
with Tb may be
extremely difficult as in one of the studied cases (Fig. 5).
Finally, pyohydronephrosis
is considered
by many
authors to be an initial stage or a precursor
of XGP9, and
has a very similar pattern.
Other differential diagnoses, which are more rare that
should be remembered,
are lipoma and liposarcoma,
in
which XGP coexists with an intense gradual replacement
of granulation
tissue for adipose
tissue of an unknown
origin'.
C O N C L U S IO N
Although
some authors
suggest
that preoperati ve
diagnosis through imagery exams should not be done in
I
any case, but cannotjustify
this3, we believe that, according
to the results found in our study and literary review, that
computed
tomography
is a method
which
allows
identification
of very characteristic
signs
indicating
a
preoperative diagnosis ofXGP. These signs are: a) increase
in renal volume;
b) hydronephrosis;
c) renal/ureteral
lithiasis;
c) collections
of thick
fluid;
d) peripheral
enhancement
after
contrast
injection;
f) extrarenal
in vol vement
of peri renal,
posterior
pararenal
and
abdominal wall sites.
D 'IP P O L IT O , G .; T O K E C H I, D .; S H IG U E O K A , D .C .; A J Z E N , S . - T o m o g ra p h ic a s p e c ts o f
x a n th o g ra n u lo m a to u s p y e lo n e p h ritis a n d re la te d c o m p lic a tio n s
1096
RESUlVlO
O s a u to re s a p re s e n ta m a s u a e x p e rie n c ia e m 7 p a c ie n te s c o m d ia g n 6 s tic o a n c H o m o p a to l6 g ic o d e P ie lo n e frite X a n to g ra n u lo m a to s a (P X G ) s u b m e tid o s a to m o g ra fia c o m p u ta d o riz a d a (T C ) p re -o p e ra t6 ria . O s p a ra m e tro s e s tu d a d o s e s e u s re s u lta d o s fo ra m : a ) p re s e n c ;:a d e c a lc u lo s e m 8 6 % d o s c a s o s , b ) v o lu m e re n a l fre q u e n te m e n te a u m e n ta d o , c ) h id ro n e fro s e , d ) m e d id a s d e d e n s id a d e v a ria n d o e n tre 1 4 e 2 9 H U , e ) p re s e n c ;:a d e re a lc e e m to d o s o s c a s o s , f) c o m p ro m e tim e n to e x tra -re n a l, ta m b e m p re s e n te e m to d o s o s c a s o s . A T C d e m o n s tro u s e r u m m e to d o b a s ta n te fid e d ig n o n a c a ra c te riz a c ;:a o d a P X G e s u a e x te n s a o e x tra -re n a l.
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