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Mucous retention cysts of the maxillary antrum
The pathogenesis and radiographic appearance of mucous retention cysts of the maxillary antrum are presented. Criteria are offered to differentiate these lesions radiographically from other soft tissue growths or shadows encountered within the antrums. Of the 1,469 orthopantomographs that were surveyed, 75 (5.1%) showed mucous retention cysts, the majority of which were single and situated on the floor of the antrum. They occurred twice as often in men as in women.
M
u c o u s
r e te n tio n
c y s t s
o f t h e
R. W. T. Myall, BDS, FDS
m a x illa r y
a n tr u m
A s h a n d R a u m 8 a n d M illh o n a n d B r o w n 5 c o n
P. B. Eastep, DMD
s id e r e d th e s e n o n s e c r e t o r y c y s ts a s p s e u d o c y s t s
J. G. Silver, BDS, LDS, Vancouver, British Columbia
f o r m e d b y f l u i d a c c u m u la t io n i n t is s u e s p a c e s ; t h is e x p la in e d t h e i r la c k o f a w e l l - f o r m e d lin in g . M i l l s , 9 h o w e v e r , c o n s id e r e d a l l c y s t s o f th e a n tr a l m u c o s a to
b e s e c re to ry ,
w h e re a s
c o r r e la
t io n s w i t h ly m p h a n g ie c t a s is le d K a d y m o v a 10 t o p r o p o s e t h e t e r m ly m p h a n g ie c t a t ic c y s t . I n 1 9 6 3 , T h e m o s t c o m m o n le s io n o f t h e m a x i l l a r y a n tru m th e
f o u n d i n r o u t i n e p e r ia p ic a l r a d io g r a p h s is b e n ig n
m u c o s a l c y s t.
Its
in c id e n c e
v a r ie s
f r o m a b o u t 2 % i n a s t u d y c o n d u c t e d b y H a ls t e a d 1 t o 9 . 6 % i n o n e p e r f o r m e d b y P a p a r e lla . 2 I t is s e e n a s a r a d io p a q u e a r e a o f u n i f o r m d e n s it y t h a t c a n b e m is t a k e n f o r o t h e r s o f t t is s u e le s io n s o f t h e a n tru m .
M ucous
r e t e n t io n
c y s ts
a re
u s u a lly
a s y m p t o m a t i c , b u t t h e y a r e s a id t o c a u s e n o n s p e c if ic a n d b iz a r r e s y m p t o m s o c c a s io n a lly t h a t m u s t b e d i f f e r e n t ia t e d f r o m o t h e r f o r m s o f f a c ia l p a in .
P a p a r e lla 2 in t r o d u c e d t h e t e r m
b e n ig n m u c o s a l
c y s t o f t h e m a x i l l a r y a n t r u m ; t h is t e r m h a s g a in e d g e n e r a l a c c e p ta n c e . 11 I t is g e n e r a lly a g r e e d t h a t p r e v io u s in f e c t i o n is i n v o l v e d i n t h e f o r m a t io n o f t h e c y s t s . M i l l s 9 s u g g e s te d t h a t i n f e c t io n o f t h e t u b e r o a c in o u s d u c t s r e s u lt s
in
b lo c k a g e ,
w ith
m u ltic y s tic
spaces
e v e n t u a lly f o r m i n g i n t h e s u b e p i t h e lia l c o n n e c t i v e t is s u e . T h e s e s p a c e s t h e n c o a le s c e t o f o r m a la r g e c y s t w i t h n o in n e r e p it h e l ia l l i n i n g a n d e x p a n d a w a y f r o m th e b o n y w a ll. S p o n t a n e o u s d is c h a r g e , f o l l o w e d b y f u r t h e r o c c lu s io n a n d t h e n r e fill,
m ay
cause
th e p ro c e s s
to
be
r e p e a te d .
W o r t h a n d S t o n e m a n 12 a g re e d t h a t b lo c k a g e o f
Pathogenesis and histopathology
o n e o r m o r e s e r o m u c in o u s d u c t s o r g la n d s m a y e v e n t u a lly f o r m t h e c y s t b u t c o n s id e r e d t h e e x a c t
C o n f u s io n o v e r t h e n o m e n c la t u r e o f th e s e c y s t ic
o r i g i n t o b e o b s c u r e . I s k h a k i 13 i m p l i e d t h a t a l
le s io n s c a n b e a t t r ib u t e d
le r g y m a y b e o f s ig n if ic a n c e i n th e s e in f la m m a
to
u n c e r t a in t y a b o u t
t h e i r o r i g i n . M c G r e g o r 3 b e lie v e d t h e m t o b e d e
t o r y p r o c e s s e s . K w a p is a n d W h i t t e n 14 s u g g e s te d
r iv e d
th a t
fro m
th e
s u b e p it h e lia l c o n n e c t iv e
tis s u e
s t r o m a a n d c o in e d th e t e r m , m e s o t h e lia l c y s t . O t h e r a u t h o r s d e f in e d c y s t s w i t h
s e v e r e p e r id u c t a l in f la m m a t io n
a lt e r s
th e
d u c t a l i n t e g r i t y a n d c o n s e q u e n t ly t r a n s ie n t s u b -
a n e p it h e l ia l
a t m o s p h e r ic p r e s s u r e s ta te s s u c h a s s n e e z e s e x -
li n i n g a s s e c r e t o r y o r in c lu s io n , a n d t h o s e w i t h
p e l l m u c u s i n t o t h e s o f t tis s u e s . W i t h f u r t h e r m u
o u t l i n i n g a s n o n s e c r e t o r y o r r e t e n t io n c y s t s . 4 7
c u s a c c u m u la t io n i n t h e s e lo c a liz e d a r e a s , a f u l l
1338 ■ JADA, Vol. 89, December 1974
blow n cy st w ould app ear. M acro sco p ically , th e in ta c t m ucous reten tio n cy st d isplays a sm o o th , b lue, slightly co m p res sible su rface th a t ap p e a rs ex trem ely thin. H is tologically, th e a tta c h m e n t to th e antral walls is a resu lt o f the c y s t’s origin from th e serous glands d eep to th e p seu d o stratified ciliated col u m n a r epithelium o f the antru m . T h e internal surface is co n to u red irregularly, and c h a ra c teristic straw colored fluid is fo u n d w ithin the lum en. In th e su b m u co sa, a thin fib ro u s layer interm esh ed w ith ly m p h o cy tes m ay be found. N o in n er lining ex ists, b u t th e suggestion o f a conn ectiv e tissu e sy n cy tiu m m ay be p resen t. T h e yellow fluid w ithin th e lum en is prim arily eosinophilic m aterial in te rsp e rse d w ith m u c u s11 b u t inflam m atory cells, p articu larly lym pho cy te s, have been no ted . L in d sa y 4 p ro p o sed that this clear fluid sim ulates an in flam m atory ex u date b ecau se o f its high specific g rav ity , high p ro tein c o n te n t, and ability to coag u late. T h e fluid, h o w ev er, is sterile.
Radiographic assessment O ften m ucous re te n tio n cy sts a re first d etected through routine m axillary periapical radio g rap h s, w hich display a w ell-differentiated radiopaque are a w ithin th e sin u s,5 b o u n d ed by an air shadow (Fig 1). T h e y are uniform ly d en se, sp h erical, and o f various sizes, and th e sm ooth c u rv ed b o rders a re w ell defined but n o t co rtic a te d . T h e re is no evid en ce of ad jacen t re so rp tiv e o r pro d u ctiv e bony changes. O f p a rtic u la r im p o rtan ce is the p e rsiste n c e o f th e thin rad io p aq u e line o f the an tral co rtex itself. A lthough th e m ajority o f cysts are single, m ultiple u n ilateral o r b ilateral cysts h av e been re p o rte d . K w apis an d W h itte n 14 o b serv ed no additional p a th o sis in th e an tru m , al though P ap arella2 d escrib ed radio g rap h ic evi dence o f sinusitis in 68% o f th e p atien ts w ith di agnosed cy sts, w ho su b se q u e n tly w ere reev alu ated w ith additional rad io g rap h s. P eriapical rad io g rap h s m ay show p art o f the lesion only and no air sp ace; th u s, su pplem en tal stan d ard and lateral occlu sal rad io g rap h s and ex trao ral projectio n s m ay be n eed ed to su b stan tia te first im p ressio n s. T h e s e view s h av e th e ad vantag e o f covering a g re a te r a re a an d , hen ce, including th e all-im p o rtan t co n trastin g air sh ad ow . M o st in v estig ato rs have u sed th e W a te r’s (occipitom ental) view and lateral skull p ro jec tion as a basis fo r diagnosis. P o y to n and Stone-
Fig 1 ■ Top, appearance of mucous retention cyst on intraoral periapical radiograph when it is bounded by air shadow. Bot tom, same lesion cannot be discerned in absence of air shadow.
m an 6 pointed out th at the W a te r’s view is useful since both antrum s are seen and c a n be co m pared. T h e ad v e n t of panoram ic rad io g rap h ic te c h niques perm itting an overall view o f m axillary an tru m sp aces, to g eth er with m inim al su p erim position o f neighboring stru c tu re s, offers som e ad v an tag es o v er the lateral and W a te r’s p ro jec tions (Fig 2). T h e reliability o f p an o ram ic radiog rap h y in th e diagnosis o f m axillary a n tru m p ath osis has been d iscussed recently by L y o n .15 M es ial and lateral w alls and th e flo o r and ro o f o f the a n tru m are easily definable an d , as in th e W a te r’s view , co m parison o f an tru m s is p o ssib le. T h e m ain disad v an tag e o f pan o ram ic film s arises from th e ir dynam ic p rojection tec h n iq u e — dis to rtio n levels m ay reach 30% in th e third m olar re g io n .16,17 T h e m ost com m on antral lesion th a t req u ires differentiation from a reten tio n c y st is m ucositis. T his inflam m atory lesion is believed to be c au sed by p ro d u cts o f pulpal o r perio d o n tal disMyall—Eastep—Silver: MUCOUS RETENTION CYSTS ■ 1339
Fig 2 ■ Orthopantomograph shows retention cyst in right maxillary antrum.
mucous
Fig 3 ■ Two areas of mucositis related to bony changes adja cent to retained premolar root and apex of palatal root of dis eased first molar.
e a se th a t p e n e tra te th e an tral flo o r an d reach th e m u co sa, causin g it to th ick en lo c a lly .12 U n like an tritis in w hich th e c o m p lete an tral lining m ay sw ell, m u co sitis is localized . M u co sitis can be a sy m p to m a tic , w ith m inim al o r n o bo n e ch an g e a p p a re n t; its only sign m ay be a soft tis su e sh ad o w a d ja c e n t to th e floor. D iag n o sis o f m u co sitis d e p e n d s on th e d ete rm in a tio n o f an in fectiv e so u rc e , e ith e r pulp al o r p erio d o n tal; th e re fo re , ch an g es in th e lam ina d u ra and p e rio d o n tal ligam ent should be so u g h t o r, in th e ir a b se n c e , a n o n v ital p u lp (Fig 3). T re a tm e n t o f the infection u su ally elim inates th is d om elike lesion, a lth o u g h o ssificatio n m ay o c c u r if ch ro n ic in flam m ato ry c o n d itio n s a re p re se n t; th is so m e tim es re su lts in th e d ev elo p m en t o f tra b e c u la r stria tio n s w ithin th e sw elling. A n ato m ic v a ria tio n o f th e an tra l w alls an d neig h b o rin g stru c tu re s m ay c o n fu se th e d iag n o stician , b u t v asc u la r g ro o v es w ithin are a s o f in c re a se d rad io p acity 1340 ■ JADA, Vol. 89, December 1974
d e n o te an an a to m ic ra th e r th a n a pathologic p h e n o m enon. O d o n to g en ic , d e n tig ero u s, p erio d o n ta l, o r fissu ral cy sts differ from a m ucous rete n tio n cy st in th a t th ey h av e a bony p erip h e ra l c o rte x th a t cau ses disp lacem en t o f th e an tral floor. Benign o r m alignant n e o p lasm s, in trinsic to th e an tru m , m ay p re se n t a rad io g rap h ic p ictu re v ery sim ilar to th a t o f a re te n tio n c y st. C arefu l sc ru tin y of th e o sse o u s an tral lining fo r p o ssible in te rru p tio n s o r irreg ularities an d in dications o f alv eo lar bo n e chan g es p ro v id es th e clue fo r differen tial diagnosis. D en ta l cy sts u su ally h av e a thin bony co rtical lining a b o u t th e ir b o u n d aries. N e o plasm s o f a m alignant n a tu re do n o t in v ariably p re se n t signs o f bone d e stru c tio n , and soft tis su e lesions c a n n o t be distinguished from th eir rad io g rap h ic im ages alo n e w hen u n acco m p an ied by o sseo u s changes. It has b een suggested th a t m ucous c y sts are insignificant clinically an d o f only rad iographic in te re s t.7 In m o st in stan c es this is tru e , b u t o c casionally a seem ingly insignificant lesion p ro v es to be highly significant, and diagnosis b ecom es o f th e first im p o rtan ce. Serial rad io g rap h y show s th a t m ucous re te n tion cy sts m ay in c rea se in size gradually. O th e r re te n tio n c y sts will p e rsist w ith o u t ch an g e in size fo r a long perio d a n d , finally, d isap p e ar spon ta n e o u sly . H e n c e , a cy st d isc o v ered fo rtu ito u s ly m ay re q u ire no o th e r tre a tm e n t th an seq u en tial rad io g rap h ic review .
Materials and methods F o r th e stu d y , 1,469 o rth o p an to m o g rap h s w ere su rv ey ed in d ep en d en tly by us using tw o sets o f
Table 1 ■ Age distribution of patients with and without mucous retention cysts. Ages P a fie n ts
0-20
21-30
31-40
41-50
51-60
61 and o ver
T o ta l
W ith c y s ts W ith o u t c ysts T o ta l
19 386 405
33 624 657
11 141 152
6 109 115
4 74 78
2 60 62
75 1,394 1,469
r a d io g r a p h ic c r i t e r i a f o r m u c o u s r e t e n t io n c y s t s
Table 2 ■ Sex distribution of patients with and w ithout
o f th e
mucous retention cysts.
m a x illa r y
a n tru m .
The
fir s t s e t w a s
a
r o u n d , o v o i d , o r d o m e - s h a p e d s h a d o w o f u n i
P a tients
M en
W om en
T otal
f o r m d e n s it y w i t h i n th e m a x i l l a r y a n t r u m w h o s e b a s e is c o n t in u o u s w i t h t h e f l o o r o r w a l l . S e c
W ith c y s ts W ith o u t c y s ts Total
50 723 773
25 671 696
75 1,394 1,469
o n d , th e fr e e
X2 = 5.674; 0 . 0 2 > / ’ > 0 . 0 1 .
s u r fa c e
o f th e
le s io n
s h o u ld
be
s m o o t h a n d s h a r p ly d e f in e d a n d a d ja c e n t t o a n a i r s h a d o w . T h e r e s h o u ld b e n o o s s e o u s c o r t e x . I f r a d io g r a p h ic
c h a n g e s a t t r ib u t a b le
to
p e r i
a p ic a l o r a d v a n c e d p e r io d o n t a l d is e a s e e x is t e d
Table 3 ■ D istribution and site of origin of cysts w ithin the m axillary antrums.
w i t h i n t h e a d ja c e n t b o n e , t h e y w e r e r e g a r d e d a s t h e p r o b a b le
c a u s e o f th e
s o f t t is s u e
shadow .
A l l o r t h o p a n t o m o g r a p h s s h o w in g e v id e n c e o f m u c o u s r e te n tio n c y s ts w e r e n o te d . T h e s e w e r e th e n
r e v ie w e d
b e fo re
d is c u s s io n
w it h
an
o ra l
r a d i o lo g is t ; t h i s le d t o a f i n a l d ia g n o s is . A l t h o u g h s u c h r a d io g r a p h ic i n f o r m a t io n o n l y g iv e s a p r e s u m p t iv e
d ia g n o s is , i t
was
c o n s id e r e d
n e it h e r
n e c e s s a r y n o r d e s ir a b le t o u n d e r t a k e h is t o p a t h
No. D is trib u tio n w ith in a n tru m s S in g le M u ltip le U n ila te ra l B ila te ra l S ite o f o rig in Nasal w a ll F loor L a te ra l w a ll A n te rio r and p o s te rio r w a lls Roof
63 12 67 8 2 43 24 6 1
Total n u m b e r o f cys ts , 75.
o lo g ic c o n f i r m a t i o n o f th e s e le s io n s . S u b s e q u e n t r a d i o g r a p h i c r e e x a m in a t io n , h o w e v e r , w a s u n d e rta k e n .
W o r t h a n d S t o n e m a n 12 w e r e d is c o u n t e d f r o m t h e s t u d y . T h e p r e c is e c r i t e r i a t h e y p r e s e n t e d w e r e used
and,
w h e re
p o s s ib le ,
c l i n i c a l t e s ts
w e re
m a d e t o s u b s t a n t ia t e t h e d ia g n o s is . M o s t r e t e n t i o n c y s ts w e r e s in g le ( 8 4 % ) a n d s it u a t e d o n th e
Results
f lo o r o f th e m a x illa r y O f t h e 1 ,4 6 9 o r t h o p a n t o m o g r a p h s s u r v e y e d , 7 7 3 w e re o f m e n a n d 696 o f w o m e n . M u c o u s re te n t i o n c y s t s w e r e p r e s e n t i n 7 5 r a d io g r a p h s ( 5 . 1 % ) . T h e d is tr ib u tio n
o f m u c o u s r e t e n t io n
c y s ts b y
a g e is p r e s e n t e d i n T a b le 1 a n d w a s n o t s t a t is t i c a l l y s i g n if ic a n t . T a b le 2 s h o w s t h e d i s t r i b u t i o n b y s e x , a n d t h is w a s s t a t is t ic a lly s ig n if ic a n t ( 0 .0 2 > P > 0 . 0 1 ) . A l t h o u g h th e m a j o r i t y o f le s io n s w e r e u n ila t e r a l a n d s in g le , o c c u r r in g o n th e f l o o r o f t h e in v o l v e d a n t r u m , t h e r e w a s a m u l t i p l i c i t y o f
a n tru m
( 5 7 .3 % ) ; h e n c e ,
i n t r a o r a l r a d io g r a p h s o f t e n w i l l s h o w
th e s e le
s io n s . F u r t h e r i n t r a o r a l o r e x t r a o r a l v ie w s s h o u ld b e t a k e n i f t h e d ia g n o s is is e q u iv o c a l, s in c e th e s e s h a d o w s m u s t b e d if f e r e n t ia t e d f r o m m u c o s it is , o d o n t o g e n ic c y s t s , a n d b e n ig n o r m a l ig n a n t n e o p la s m s . A n t r i t i s , a n o t h e r a n d e v e n m o r e c o m m o n c o n d itio n
c a u s in g
m ucosal
t h ic k e n in g ,
is
un
l i k e l y t o b e e v id e n t i n in t r a o r a l r a d io g r a p h s b e c a u s e a n y s o f t t is s u e s h a d o w m a y e s c a p e r e c o g n itio n
u n le s s
th e
r a d io g r a p h
show s
som e
a ir
s p a c e t o p r o v id e t h e n e c e s s a r y c o n t r a s t .
s ite s a n d d i s t r i b u t io n s ( T a b le 3 ).
O n c e a s o f t t is s u e s h a d o w h a s b e e n r e v e a le d w it h in
th e
a n tru m , it m u s t be p ro v e d
d o u b t t h a t i t is n o t m a lig n a n t .
Discussion
beyond
D e s tr u c tio n
of
b o n e w i l l m a k e d ia g n o s is o f m a lig n a n c y m o r e o b v io u s , b u t t h e a b s e n c e o f o s s e o u s c h a n g e d o e s
T h e 5 . 1 % in c id e n c e o f m u c o u s r e t e n t io n c y s t s
n o t p r e c lu d e th e p o s s i b i l i t y o f m a lig n a n c y . S u s
in
p e c te d
t h is
cases
s u rv e y
is
o f s p e c ia l s ig n if ic a n c e
o f m u c o s i t is ,
as
d e s c r ib e d
s in c e
r e c e n t ly
by
m a lig n a n c y
L o n g -te rm
m akes
b io p s y
m a n d a to ry .
r a d io g r a p h ic f o l l o w - u p is a d v o c a t e d
Myall—Eastep—Silver: MUCOUS RETENTION CYSTS ■ 1341
f o r a ll l o c a liz e d s o f t t is s u e le s io n s o f t h e m a x i l
g r o u p s s u r v e y e d a n d w e r e t w i c e a s c o m m o n in
la r y a n tru m .
m e n a s in w o m e n .
W h e n t h e c a s e h is t o r ie s o f p a t ie n t s w i t h m u c o u s r e t e n t i o n c y s t s w e r e r e v i e w e d , 11 ( 1 4 .6 % ) w e r e f o u n d t o h a v e s y m p t o m s t h a t m ig h t b e r e la t e d t o t h e le s io n s . L o c a liz e d d u l l p a in in th e a n t r a l m a x i l l a r y r e g io n w a s r e p o r t e d b y e ig h t. U n ila te r a l h e a d a c h e w a s n o te d in
o n e p a t ie n t
a n d g e n e r a liz e d in t r a o r a l m a x i l l a r y d is c o m f o r t in a n o th e r. A
s in g le p a t ie n t h a d b lo o d - t in g e d r h i n -
o r r h e a a n d n a s a l c o n g e s t io n . F o r n o n e o f th e s e p a t ie n t s , h o w e v e r ,
was
i t p o s s ib le
to
say u n
e q u iv o c a l ly t h a t h is s y m p t o m w a s r e la t e d d ir e c t l y t o t h e m u c o u s r e t e n t io n c y s t . O t h e r p a p e r s h a v e s u g g e s te d a v a r i e t y o f s y m p t o m s p o t e n t i a l l y a t t r ib u t a b le t o m u c o u s r e t e n t io n c y s t s . H e a d a c h e a n d d u l l p a in in t h e a n t r a l o r d e n t o a lv e o la r r e g io n o n t h e s a m e s id e a r e a m o n g t h e m o s t c o m m o n s u g g e s t io n s , w h e r e a s s e ro u s n a s a l d is c h a r g e , s in u s it is , a n d s o r e t h r o a t s a ls o h a v e b e e n b la m e d o n th e s e le s io n s . R e p o r t s o f m a la is e , lo w - g r a d e f e v e r , d iz z in e s s , a n d f a t ig u e 11, 18 a d d t o t h e l i s t , b u t i n n o in s t a n c e d id o u r o w n f in d in g s p a p e rs
c o n fir m in
w h ic h
th e s e s u g g e s tio n s n o r d id t h e th e s e a p p e a r e d
g iv e
p o s it iv e
s u p p o r t . I n l i g h t o f th e s e f a c t s i f s e e m s u n w is e t o r e l a t e t h e p r e s e n c e o f m u c o u s r e t e n t io n c y s ts p o s it iv e ly w it h a n y p a r tic u la r s y m p to m s .
Sum m ary T h e p a t h o g e n e s is a n d r a d io g r a p h ic a p p e a r a n c e o f m u c o u s r e t e n t io n c y s t s o f t h e m a x i l l a r y a n t r u m a r e r e v i e w e d . T h e f e a t u r e s t h a t d is t in g u is h th is
e n tity
fro m
m u c o s it is , o d o n t o g e n ic c y s t s ,
a n d n e o p la s m s a r e d is c u s s e d . In
a s tu d y ,
1 ,4 6 9 o r t h o p a n t o m o g r a p h s w e r e
s c r u t in iz e d b y t h r e e in d e p e n d e n t o b s e r v e r s f o r e v id e n c e o f th e s e le s io n s . A n in c id e n c e o f 5 . 1 % w a s fo u n d , a n d th e m a jo r ity o f m u c o u s re te n t i o n c y s t s w e r e s in g le a n d s it u a t e d o n th e f l o o r o f t h e a n t r u m s . T h e c y s t s w e r e f o u n d i n a ll a g e
1342 ■ JADA, Vol. 89, December 1974
The authors thank Dr. H. M. Worth for his assistance with the final radiographic diagnosis of the mucous retention cysts and his guidance and helpful criticism during the preparation of this manuscript. The protocol for this paper was part of a research project un dertaken by a fourth-year student, Mr. David Catherall, and sup ported by a Dean’s Fund Summer Student Fellowship. Dr. Myall, Dr. Eastep, and Dr. Silver are in the department of oral medicine, Faculty of Dentistry, University of British Colum bia, Vancouver 8, British Columbia, Canada. 1. Halstead, C.L. Mucosal cysts of the maxillary sinus: report of 75 cases. JADA 87:1435 Dec 1973. 2. Paparella, M.M. Mucosal cyst of the maxillary sinus. Arch Otolaryngol 77:650 June 1963. 3. McGregor, G.W. The formation and histologic structure of cysts of the maxillary sinus. Arch Otolaryngol 8:505 Nov 1928. 4. Lindsay, J.R. Nonsecreting cysts of the maxillary sinus mu cosa. Laryngoscope 52:84 Feb 1942. 5. Millhon, J.A., and Brown, H.A. Cysts arising from the mu cosa of the maxillary sinus as seen in the dental roentgenogram. Am J Orthod 30:12 Jan 1944. 6. Poyton, H.G., and Stoneman, D.W. Benign cysts of the max illary antrum. J Can Dent Assoc 27:289 May 1961. 7. Skillern, R. The accessory sinuses of the nose, ed 2. Phila delphia, J. B. Lippincott Co., 1916, p 136. 8. Ash, J.E., and Raum, M. An atlas of otolaryngologic path ology. Armed Forces Institute of Pathology, 1949, p 149. 9. Mills, C.P. Secretory cysts of the maxillary antrum and their relation to the development of antrochoanal polypi. J Laryngol 73:324 May 1959. 10. Kadymova, M.l. [Lymphangiectatic (false) cysts of the maxillary sinuses and their relationship to allergy.] Vestn Otorinolaringol 28:58 July-Aug 1966. 11. Killey, H.C., and Kay, L.W. Benign mucosal cysts of the maxillary sinus. Int Surg 53:235 April 1970. 12. Worth. H.M., and Stoneman, D.W. Radiographic interpre tation of antral mucosal changes due to localized dental infec tion. J Can Dent Assoc 38:111 March 1972. 13. Iskhaki, Y.B. On the morphogenesis of cysts of the maxil lary sinus. Zh Ushn Nos Gorl Bolezn 27:36 May-June 1967. 14. Kwapis, B.W., and Whitten, J.B. Mucosal cysts of the max illary sinus. J Oral Surg 29:561 Aug 1971. 15. Lyon, H.E. Reliability of panoramic radiography in the diagnosis of maxillary sinus pathosis. Oral Surg 35:124 Jan 1973. 16. Christen, A.G., and Segreto, V.A. Distortion and artifacts encountered in Panorex radiography. JADA 77:1096 Nov 1968. 17. Kite, O.W., and others. Radiation and image distortion in the Panorex X-ray unit. Oral Surg 15:1201 Oct 1962. 18. Wright, R.W. Round shadows in the maxillary sinuses. Laryngoscope 56:455 Aug 1946.
M
u c o u s
r e te n tio n
c y s t s
o f t h e
R. W. T. Myall, BDS, FDS
m a x illa r y
a n tr u m
A s h a n d R a u m 8 a n d M illh o n a n d B r o w n 5 c o n
P. B. Eastep, DMD
s id e r e d th e s e n o n s e c r e t o r y c y s ts a s p s e u d o c y s t s
J. G. Silver, BDS, LDS, Vancouver, British Columbia
f o r m e d b y f l u i d a c c u m u la t io n i n t is s u e s p a c e s ; t h is e x p la in e d t h e i r la c k o f a w e l l - f o r m e d lin in g . M i l l s , 9 h o w e v e r , c o n s id e r e d a l l c y s t s o f th e a n tr a l m u c o s a to
b e s e c re to ry ,
w h e re a s
c o r r e la
t io n s w i t h ly m p h a n g ie c t a s is le d K a d y m o v a 10 t o p r o p o s e t h e t e r m ly m p h a n g ie c t a t ic c y s t . I n 1 9 6 3 , T h e m o s t c o m m o n le s io n o f t h e m a x i l l a r y a n tru m th e
f o u n d i n r o u t i n e p e r ia p ic a l r a d io g r a p h s is b e n ig n
m u c o s a l c y s t.
Its
in c id e n c e
v a r ie s
f r o m a b o u t 2 % i n a s t u d y c o n d u c t e d b y H a ls t e a d 1 t o 9 . 6 % i n o n e p e r f o r m e d b y P a p a r e lla . 2 I t is s e e n a s a r a d io p a q u e a r e a o f u n i f o r m d e n s it y t h a t c a n b e m is t a k e n f o r o t h e r s o f t t is s u e le s io n s o f t h e a n tru m .
M ucous
r e t e n t io n
c y s ts
a re
u s u a lly
a s y m p t o m a t i c , b u t t h e y a r e s a id t o c a u s e n o n s p e c if ic a n d b iz a r r e s y m p t o m s o c c a s io n a lly t h a t m u s t b e d i f f e r e n t ia t e d f r o m o t h e r f o r m s o f f a c ia l p a in .
P a p a r e lla 2 in t r o d u c e d t h e t e r m
b e n ig n m u c o s a l
c y s t o f t h e m a x i l l a r y a n t r u m ; t h is t e r m h a s g a in e d g e n e r a l a c c e p ta n c e . 11 I t is g e n e r a lly a g r e e d t h a t p r e v io u s in f e c t i o n is i n v o l v e d i n t h e f o r m a t io n o f t h e c y s t s . M i l l s 9 s u g g e s te d t h a t i n f e c t io n o f t h e t u b e r o a c in o u s d u c t s r e s u lt s
in
b lo c k a g e ,
w ith
m u ltic y s tic
spaces
e v e n t u a lly f o r m i n g i n t h e s u b e p i t h e lia l c o n n e c t i v e t is s u e . T h e s e s p a c e s t h e n c o a le s c e t o f o r m a la r g e c y s t w i t h n o in n e r e p it h e l ia l l i n i n g a n d e x p a n d a w a y f r o m th e b o n y w a ll. S p o n t a n e o u s d is c h a r g e , f o l l o w e d b y f u r t h e r o c c lu s io n a n d t h e n r e fill,
m ay
cause
th e p ro c e s s
to
be
r e p e a te d .
W o r t h a n d S t o n e m a n 12 a g re e d t h a t b lo c k a g e o f
Pathogenesis and histopathology
o n e o r m o r e s e r o m u c in o u s d u c t s o r g la n d s m a y e v e n t u a lly f o r m t h e c y s t b u t c o n s id e r e d t h e e x a c t
C o n f u s io n o v e r t h e n o m e n c la t u r e o f th e s e c y s t ic
o r i g i n t o b e o b s c u r e . I s k h a k i 13 i m p l i e d t h a t a l
le s io n s c a n b e a t t r ib u t e d
le r g y m a y b e o f s ig n if ic a n c e i n th e s e in f la m m a
to
u n c e r t a in t y a b o u t
t h e i r o r i g i n . M c G r e g o r 3 b e lie v e d t h e m t o b e d e
t o r y p r o c e s s e s . K w a p is a n d W h i t t e n 14 s u g g e s te d
r iv e d
th a t
fro m
th e
s u b e p it h e lia l c o n n e c t iv e
tis s u e
s t r o m a a n d c o in e d th e t e r m , m e s o t h e lia l c y s t . O t h e r a u t h o r s d e f in e d c y s t s w i t h
s e v e r e p e r id u c t a l in f la m m a t io n
a lt e r s
th e
d u c t a l i n t e g r i t y a n d c o n s e q u e n t ly t r a n s ie n t s u b -
a n e p it h e l ia l
a t m o s p h e r ic p r e s s u r e s ta te s s u c h a s s n e e z e s e x -
li n i n g a s s e c r e t o r y o r in c lu s io n , a n d t h o s e w i t h
p e l l m u c u s i n t o t h e s o f t tis s u e s . W i t h f u r t h e r m u
o u t l i n i n g a s n o n s e c r e t o r y o r r e t e n t io n c y s t s . 4 7
c u s a c c u m u la t io n i n t h e s e lo c a liz e d a r e a s , a f u l l
1338 ■ JADA, Vol. 89, December 1974
blow n cy st w ould app ear. M acro sco p ically , th e in ta c t m ucous reten tio n cy st d isplays a sm o o th , b lue, slightly co m p res sible su rface th a t ap p e a rs ex trem ely thin. H is tologically, th e a tta c h m e n t to th e antral walls is a resu lt o f the c y s t’s origin from th e serous glands d eep to th e p seu d o stratified ciliated col u m n a r epithelium o f the antru m . T h e internal surface is co n to u red irregularly, and c h a ra c teristic straw colored fluid is fo u n d w ithin the lum en. In th e su b m u co sa, a thin fib ro u s layer interm esh ed w ith ly m p h o cy tes m ay be found. N o in n er lining ex ists, b u t th e suggestion o f a conn ectiv e tissu e sy n cy tiu m m ay be p resen t. T h e yellow fluid w ithin th e lum en is prim arily eosinophilic m aterial in te rsp e rse d w ith m u c u s11 b u t inflam m atory cells, p articu larly lym pho cy te s, have been no ted . L in d sa y 4 p ro p o sed that this clear fluid sim ulates an in flam m atory ex u date b ecau se o f its high specific g rav ity , high p ro tein c o n te n t, and ability to coag u late. T h e fluid, h o w ev er, is sterile.
Radiographic assessment O ften m ucous re te n tio n cy sts a re first d etected through routine m axillary periapical radio g rap h s, w hich display a w ell-differentiated radiopaque are a w ithin th e sin u s,5 b o u n d ed by an air shadow (Fig 1). T h e y are uniform ly d en se, sp h erical, and o f various sizes, and th e sm ooth c u rv ed b o rders a re w ell defined but n o t co rtic a te d . T h e re is no evid en ce of ad jacen t re so rp tiv e o r pro d u ctiv e bony changes. O f p a rtic u la r im p o rtan ce is the p e rsiste n c e o f th e thin rad io p aq u e line o f the an tral co rtex itself. A lthough th e m ajority o f cysts are single, m ultiple u n ilateral o r b ilateral cysts h av e been re p o rte d . K w apis an d W h itte n 14 o b serv ed no additional p a th o sis in th e an tru m , al though P ap arella2 d escrib ed radio g rap h ic evi dence o f sinusitis in 68% o f th e p atien ts w ith di agnosed cy sts, w ho su b se q u e n tly w ere reev alu ated w ith additional rad io g rap h s. P eriapical rad io g rap h s m ay show p art o f the lesion only and no air sp ace; th u s, su pplem en tal stan d ard and lateral occlu sal rad io g rap h s and ex trao ral projectio n s m ay be n eed ed to su b stan tia te first im p ressio n s. T h e s e view s h av e th e ad vantag e o f covering a g re a te r a re a an d , hen ce, including th e all-im p o rtan t co n trastin g air sh ad ow . M o st in v estig ato rs have u sed th e W a te r’s (occipitom ental) view and lateral skull p ro jec tion as a basis fo r diagnosis. P o y to n and Stone-
Fig 1 ■ Top, appearance of mucous retention cyst on intraoral periapical radiograph when it is bounded by air shadow. Bot tom, same lesion cannot be discerned in absence of air shadow.
m an 6 pointed out th at the W a te r’s view is useful since both antrum s are seen and c a n be co m pared. T h e ad v e n t of panoram ic rad io g rap h ic te c h niques perm itting an overall view o f m axillary an tru m sp aces, to g eth er with m inim al su p erim position o f neighboring stru c tu re s, offers som e ad v an tag es o v er the lateral and W a te r’s p ro jec tions (Fig 2). T h e reliability o f p an o ram ic radiog rap h y in th e diagnosis o f m axillary a n tru m p ath osis has been d iscussed recently by L y o n .15 M es ial and lateral w alls and th e flo o r and ro o f o f the a n tru m are easily definable an d , as in th e W a te r’s view , co m parison o f an tru m s is p o ssib le. T h e m ain disad v an tag e o f pan o ram ic film s arises from th e ir dynam ic p rojection tec h n iq u e — dis to rtio n levels m ay reach 30% in th e third m olar re g io n .16,17 T h e m ost com m on antral lesion th a t req u ires differentiation from a reten tio n c y st is m ucositis. T his inflam m atory lesion is believed to be c au sed by p ro d u cts o f pulpal o r perio d o n tal disMyall—Eastep—Silver: MUCOUS RETENTION CYSTS ■ 1339
Fig 2 ■ Orthopantomograph shows retention cyst in right maxillary antrum.
mucous
Fig 3 ■ Two areas of mucositis related to bony changes adja cent to retained premolar root and apex of palatal root of dis eased first molar.
e a se th a t p e n e tra te th e an tral flo o r an d reach th e m u co sa, causin g it to th ick en lo c a lly .12 U n like an tritis in w hich th e c o m p lete an tral lining m ay sw ell, m u co sitis is localized . M u co sitis can be a sy m p to m a tic , w ith m inim al o r n o bo n e ch an g e a p p a re n t; its only sign m ay be a soft tis su e sh ad o w a d ja c e n t to th e floor. D iag n o sis o f m u co sitis d e p e n d s on th e d ete rm in a tio n o f an in fectiv e so u rc e , e ith e r pulp al o r p erio d o n tal; th e re fo re , ch an g es in th e lam ina d u ra and p e rio d o n tal ligam ent should be so u g h t o r, in th e ir a b se n c e , a n o n v ital p u lp (Fig 3). T re a tm e n t o f the infection u su ally elim inates th is d om elike lesion, a lth o u g h o ssificatio n m ay o c c u r if ch ro n ic in flam m ato ry c o n d itio n s a re p re se n t; th is so m e tim es re su lts in th e d ev elo p m en t o f tra b e c u la r stria tio n s w ithin th e sw elling. A n ato m ic v a ria tio n o f th e an tra l w alls an d neig h b o rin g stru c tu re s m ay c o n fu se th e d iag n o stician , b u t v asc u la r g ro o v es w ithin are a s o f in c re a se d rad io p acity 1340 ■ JADA, Vol. 89, December 1974
d e n o te an an a to m ic ra th e r th a n a pathologic p h e n o m enon. O d o n to g en ic , d e n tig ero u s, p erio d o n ta l, o r fissu ral cy sts differ from a m ucous rete n tio n cy st in th a t th ey h av e a bony p erip h e ra l c o rte x th a t cau ses disp lacem en t o f th e an tral floor. Benign o r m alignant n e o p lasm s, in trinsic to th e an tru m , m ay p re se n t a rad io g rap h ic p ictu re v ery sim ilar to th a t o f a re te n tio n c y st. C arefu l sc ru tin y of th e o sse o u s an tral lining fo r p o ssible in te rru p tio n s o r irreg ularities an d in dications o f alv eo lar bo n e chan g es p ro v id es th e clue fo r differen tial diagnosis. D en ta l cy sts u su ally h av e a thin bony co rtical lining a b o u t th e ir b o u n d aries. N e o plasm s o f a m alignant n a tu re do n o t in v ariably p re se n t signs o f bone d e stru c tio n , and soft tis su e lesions c a n n o t be distinguished from th eir rad io g rap h ic im ages alo n e w hen u n acco m p an ied by o sseo u s changes. It has b een suggested th a t m ucous c y sts are insignificant clinically an d o f only rad iographic in te re s t.7 In m o st in stan c es this is tru e , b u t o c casionally a seem ingly insignificant lesion p ro v es to be highly significant, and diagnosis b ecom es o f th e first im p o rtan ce. Serial rad io g rap h y show s th a t m ucous re te n tion cy sts m ay in c rea se in size gradually. O th e r re te n tio n c y sts will p e rsist w ith o u t ch an g e in size fo r a long perio d a n d , finally, d isap p e ar spon ta n e o u sly . H e n c e , a cy st d isc o v ered fo rtu ito u s ly m ay re q u ire no o th e r tre a tm e n t th an seq u en tial rad io g rap h ic review .
Materials and methods F o r th e stu d y , 1,469 o rth o p an to m o g rap h s w ere su rv ey ed in d ep en d en tly by us using tw o sets o f
Table 1 ■ Age distribution of patients with and without mucous retention cysts. Ages P a fie n ts
0-20
21-30
31-40
41-50
51-60
61 and o ver
T o ta l
W ith c y s ts W ith o u t c ysts T o ta l
19 386 405
33 624 657
11 141 152
6 109 115
4 74 78
2 60 62
75 1,394 1,469
r a d io g r a p h ic c r i t e r i a f o r m u c o u s r e t e n t io n c y s t s
Table 2 ■ Sex distribution of patients with and w ithout
o f th e
mucous retention cysts.
m a x illa r y
a n tru m .
The
fir s t s e t w a s
a
r o u n d , o v o i d , o r d o m e - s h a p e d s h a d o w o f u n i
P a tients
M en
W om en
T otal
f o r m d e n s it y w i t h i n th e m a x i l l a r y a n t r u m w h o s e b a s e is c o n t in u o u s w i t h t h e f l o o r o r w a l l . S e c
W ith c y s ts W ith o u t c y s ts Total
50 723 773
25 671 696
75 1,394 1,469
o n d , th e fr e e
X2 = 5.674; 0 . 0 2 > / ’ > 0 . 0 1 .
s u r fa c e
o f th e
le s io n
s h o u ld
be
s m o o t h a n d s h a r p ly d e f in e d a n d a d ja c e n t t o a n a i r s h a d o w . T h e r e s h o u ld b e n o o s s e o u s c o r t e x . I f r a d io g r a p h ic
c h a n g e s a t t r ib u t a b le
to
p e r i
a p ic a l o r a d v a n c e d p e r io d o n t a l d is e a s e e x is t e d
Table 3 ■ D istribution and site of origin of cysts w ithin the m axillary antrums.
w i t h i n t h e a d ja c e n t b o n e , t h e y w e r e r e g a r d e d a s t h e p r o b a b le
c a u s e o f th e
s o f t t is s u e
shadow .
A l l o r t h o p a n t o m o g r a p h s s h o w in g e v id e n c e o f m u c o u s r e te n tio n c y s ts w e r e n o te d . T h e s e w e r e th e n
r e v ie w e d
b e fo re
d is c u s s io n
w it h
an
o ra l
r a d i o lo g is t ; t h i s le d t o a f i n a l d ia g n o s is . A l t h o u g h s u c h r a d io g r a p h ic i n f o r m a t io n o n l y g iv e s a p r e s u m p t iv e
d ia g n o s is , i t
was
c o n s id e r e d
n e it h e r
n e c e s s a r y n o r d e s ir a b le t o u n d e r t a k e h is t o p a t h
No. D is trib u tio n w ith in a n tru m s S in g le M u ltip le U n ila te ra l B ila te ra l S ite o f o rig in Nasal w a ll F loor L a te ra l w a ll A n te rio r and p o s te rio r w a lls Roof
63 12 67 8 2 43 24 6 1
Total n u m b e r o f cys ts , 75.
o lo g ic c o n f i r m a t i o n o f th e s e le s io n s . S u b s e q u e n t r a d i o g r a p h i c r e e x a m in a t io n , h o w e v e r , w a s u n d e rta k e n .
W o r t h a n d S t o n e m a n 12 w e r e d is c o u n t e d f r o m t h e s t u d y . T h e p r e c is e c r i t e r i a t h e y p r e s e n t e d w e r e used
and,
w h e re
p o s s ib le ,
c l i n i c a l t e s ts
w e re
m a d e t o s u b s t a n t ia t e t h e d ia g n o s is . M o s t r e t e n t i o n c y s ts w e r e s in g le ( 8 4 % ) a n d s it u a t e d o n th e
Results
f lo o r o f th e m a x illa r y O f t h e 1 ,4 6 9 o r t h o p a n t o m o g r a p h s s u r v e y e d , 7 7 3 w e re o f m e n a n d 696 o f w o m e n . M u c o u s re te n t i o n c y s t s w e r e p r e s e n t i n 7 5 r a d io g r a p h s ( 5 . 1 % ) . T h e d is tr ib u tio n
o f m u c o u s r e t e n t io n
c y s ts b y
a g e is p r e s e n t e d i n T a b le 1 a n d w a s n o t s t a t is t i c a l l y s i g n if ic a n t . T a b le 2 s h o w s t h e d i s t r i b u t i o n b y s e x , a n d t h is w a s s t a t is t ic a lly s ig n if ic a n t ( 0 .0 2 > P > 0 . 0 1 ) . A l t h o u g h th e m a j o r i t y o f le s io n s w e r e u n ila t e r a l a n d s in g le , o c c u r r in g o n th e f l o o r o f t h e in v o l v e d a n t r u m , t h e r e w a s a m u l t i p l i c i t y o f
a n tru m
( 5 7 .3 % ) ; h e n c e ,
i n t r a o r a l r a d io g r a p h s o f t e n w i l l s h o w
th e s e le
s io n s . F u r t h e r i n t r a o r a l o r e x t r a o r a l v ie w s s h o u ld b e t a k e n i f t h e d ia g n o s is is e q u iv o c a l, s in c e th e s e s h a d o w s m u s t b e d if f e r e n t ia t e d f r o m m u c o s it is , o d o n t o g e n ic c y s t s , a n d b e n ig n o r m a l ig n a n t n e o p la s m s . A n t r i t i s , a n o t h e r a n d e v e n m o r e c o m m o n c o n d itio n
c a u s in g
m ucosal
t h ic k e n in g ,
is
un
l i k e l y t o b e e v id e n t i n in t r a o r a l r a d io g r a p h s b e c a u s e a n y s o f t t is s u e s h a d o w m a y e s c a p e r e c o g n itio n
u n le s s
th e
r a d io g r a p h
show s
som e
a ir
s p a c e t o p r o v id e t h e n e c e s s a r y c o n t r a s t .
s ite s a n d d i s t r i b u t io n s ( T a b le 3 ).
O n c e a s o f t t is s u e s h a d o w h a s b e e n r e v e a le d w it h in
th e
a n tru m , it m u s t be p ro v e d
d o u b t t h a t i t is n o t m a lig n a n t .
Discussion
beyond
D e s tr u c tio n
of
b o n e w i l l m a k e d ia g n o s is o f m a lig n a n c y m o r e o b v io u s , b u t t h e a b s e n c e o f o s s e o u s c h a n g e d o e s
T h e 5 . 1 % in c id e n c e o f m u c o u s r e t e n t io n c y s t s
n o t p r e c lu d e th e p o s s i b i l i t y o f m a lig n a n c y . S u s
in
p e c te d
t h is
cases
s u rv e y
is
o f s p e c ia l s ig n if ic a n c e
o f m u c o s i t is ,
as
d e s c r ib e d
s in c e
r e c e n t ly
by
m a lig n a n c y
L o n g -te rm
m akes
b io p s y
m a n d a to ry .
r a d io g r a p h ic f o l l o w - u p is a d v o c a t e d
Myall—Eastep—Silver: MUCOUS RETENTION CYSTS ■ 1341
f o r a ll l o c a liz e d s o f t t is s u e le s io n s o f t h e m a x i l
g r o u p s s u r v e y e d a n d w e r e t w i c e a s c o m m o n in
la r y a n tru m .
m e n a s in w o m e n .
W h e n t h e c a s e h is t o r ie s o f p a t ie n t s w i t h m u c o u s r e t e n t i o n c y s t s w e r e r e v i e w e d , 11 ( 1 4 .6 % ) w e r e f o u n d t o h a v e s y m p t o m s t h a t m ig h t b e r e la t e d t o t h e le s io n s . L o c a liz e d d u l l p a in in th e a n t r a l m a x i l l a r y r e g io n w a s r e p o r t e d b y e ig h t. U n ila te r a l h e a d a c h e w a s n o te d in
o n e p a t ie n t
a n d g e n e r a liz e d in t r a o r a l m a x i l l a r y d is c o m f o r t in a n o th e r. A
s in g le p a t ie n t h a d b lo o d - t in g e d r h i n -
o r r h e a a n d n a s a l c o n g e s t io n . F o r n o n e o f th e s e p a t ie n t s , h o w e v e r ,
was
i t p o s s ib le
to
say u n
e q u iv o c a l ly t h a t h is s y m p t o m w a s r e la t e d d ir e c t l y t o t h e m u c o u s r e t e n t io n c y s t . O t h e r p a p e r s h a v e s u g g e s te d a v a r i e t y o f s y m p t o m s p o t e n t i a l l y a t t r ib u t a b le t o m u c o u s r e t e n t io n c y s t s . H e a d a c h e a n d d u l l p a in in t h e a n t r a l o r d e n t o a lv e o la r r e g io n o n t h e s a m e s id e a r e a m o n g t h e m o s t c o m m o n s u g g e s t io n s , w h e r e a s s e ro u s n a s a l d is c h a r g e , s in u s it is , a n d s o r e t h r o a t s a ls o h a v e b e e n b la m e d o n th e s e le s io n s . R e p o r t s o f m a la is e , lo w - g r a d e f e v e r , d iz z in e s s , a n d f a t ig u e 11, 18 a d d t o t h e l i s t , b u t i n n o in s t a n c e d id o u r o w n f in d in g s p a p e rs
c o n fir m in
w h ic h
th e s e s u g g e s tio n s n o r d id t h e th e s e a p p e a r e d
g iv e
p o s it iv e
s u p p o r t . I n l i g h t o f th e s e f a c t s i f s e e m s u n w is e t o r e l a t e t h e p r e s e n c e o f m u c o u s r e t e n t io n c y s ts p o s it iv e ly w it h a n y p a r tic u la r s y m p to m s .
Sum m ary T h e p a t h o g e n e s is a n d r a d io g r a p h ic a p p e a r a n c e o f m u c o u s r e t e n t io n c y s t s o f t h e m a x i l l a r y a n t r u m a r e r e v i e w e d . T h e f e a t u r e s t h a t d is t in g u is h th is
e n tity
fro m
m u c o s it is , o d o n t o g e n ic c y s t s ,
a n d n e o p la s m s a r e d is c u s s e d . In
a s tu d y ,
1 ,4 6 9 o r t h o p a n t o m o g r a p h s w e r e
s c r u t in iz e d b y t h r e e in d e p e n d e n t o b s e r v e r s f o r e v id e n c e o f th e s e le s io n s . A n in c id e n c e o f 5 . 1 % w a s fo u n d , a n d th e m a jo r ity o f m u c o u s re te n t i o n c y s t s w e r e s in g le a n d s it u a t e d o n th e f l o o r o f t h e a n t r u m s . T h e c y s t s w e r e f o u n d i n a ll a g e
1342 ■ JADA, Vol. 89, December 1974
The authors thank Dr. H. M. Worth for his assistance with the final radiographic diagnosis of the mucous retention cysts and his guidance and helpful criticism during the preparation of this manuscript. The protocol for this paper was part of a research project un dertaken by a fourth-year student, Mr. David Catherall, and sup ported by a Dean’s Fund Summer Student Fellowship. Dr. Myall, Dr. Eastep, and Dr. Silver are in the department of oral medicine, Faculty of Dentistry, University of British Colum bia, Vancouver 8, British Columbia, Canada. 1. Halstead, C.L. Mucosal cysts of the maxillary sinus: report of 75 cases. JADA 87:1435 Dec 1973. 2. Paparella, M.M. Mucosal cyst of the maxillary sinus. Arch Otolaryngol 77:650 June 1963. 3. McGregor, G.W. The formation and histologic structure of cysts of the maxillary sinus. Arch Otolaryngol 8:505 Nov 1928. 4. Lindsay, J.R. Nonsecreting cysts of the maxillary sinus mu cosa. Laryngoscope 52:84 Feb 1942. 5. Millhon, J.A., and Brown, H.A. Cysts arising from the mu cosa of the maxillary sinus as seen in the dental roentgenogram. Am J Orthod 30:12 Jan 1944. 6. Poyton, H.G., and Stoneman, D.W. Benign cysts of the max illary antrum. J Can Dent Assoc 27:289 May 1961. 7. Skillern, R. The accessory sinuses of the nose, ed 2. Phila delphia, J. B. Lippincott Co., 1916, p 136. 8. Ash, J.E., and Raum, M. An atlas of otolaryngologic path ology. Armed Forces Institute of Pathology, 1949, p 149. 9. Mills, C.P. Secretory cysts of the maxillary antrum and their relation to the development of antrochoanal polypi. J Laryngol 73:324 May 1959. 10. Kadymova, M.l. [Lymphangiectatic (false) cysts of the maxillary sinuses and their relationship to allergy.] Vestn Otorinolaringol 28:58 July-Aug 1966. 11. Killey, H.C., and Kay, L.W. Benign mucosal cysts of the maxillary sinus. Int Surg 53:235 April 1970. 12. Worth. H.M., and Stoneman, D.W. Radiographic interpre tation of antral mucosal changes due to localized dental infec tion. J Can Dent Assoc 38:111 March 1972. 13. Iskhaki, Y.B. On the morphogenesis of cysts of the maxil lary sinus. Zh Ushn Nos Gorl Bolezn 27:36 May-June 1967. 14. Kwapis, B.W., and Whitten, J.B. Mucosal cysts of the max illary sinus. J Oral Surg 29:561 Aug 1971. 15. Lyon, H.E. Reliability of panoramic radiography in the diagnosis of maxillary sinus pathosis. Oral Surg 35:124 Jan 1973. 16. Christen, A.G., and Segreto, V.A. Distortion and artifacts encountered in Panorex radiography. JADA 77:1096 Nov 1968. 17. Kite, O.W., and others. Radiation and image distortion in the Panorex X-ray unit. Oral Surg 15:1201 Oct 1962. 18. Wright, R.W. Round shadows in the maxillary sinuses. Laryngoscope 56:455 Aug 1946.