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RadioGraphics AFIP ARCHIVES 1847
From the Archives of the AFIP
Inﬂammatory and Nonneoplastic
Bladder Masses: Radiologic-Pathologic
CME FEATURE Jade J. Wong-You–Cheong, MD ● Paula J. Woodward, MD ● Maria A.
See accompanying Manning, MD ● Charles J. Davis, MD
test at http://
/rg_cme.html Although the vast majority of bladder tumors are epithelial neoplasms,
a variety of nonneoplastic disorders can cause either focal bladder
masses or diffuse mural thickening and mimic malignancy. Some of
FOR TEST 6 these entities are rare and poorly understood such as inﬂammatory
After reading this
pseudotumor, which produces ulcerated, bleeding polypoid bladder
article and taking masses. These masses may be large and have an extravesical compo-
the test, the reader
will be able to: nent. Bladder endometriosis manifests as submucosal masses with
Describe a group characteristic magnetic resonance imaging features consisting of hem-
of inﬂammatory and
nonneoplastic disor- orrhagic foci and reactive ﬁbrosis. Nephrogenic adenoma has no typi-
ders that can cause cal features, and pathologic evaluation is required for diagnosis. Al-
focal bladder masses
or diffuse bladder
though imaging features of malacoplakia are also nonspeciﬁc, charac-
wall thickening and teristic Michaelis-Gutmann bodies are found at pathologic evaluation.
might be misdiag-
nosed as malignancy.
The various types of cystitis (cystitis cystica, cystitis glandularis, and
Outline the patho- eosinophilic cystitis) require pathologic diagnosis. Bladder infection
genesis and risk fac- with tuberculosis and schistosomiasis produces nonspeciﬁc bladder
tors for these disor-
ders. wall thickening and ulceration in the acute phase and should be sus-
Discuss the imag- pected in patients who are immunocompromised or from countries
ing characteristics where these infections are common. The diagnosis of chemotherapy
features of these enti- cystitis and radiation cystitis should be clinically evident, but imaging
ties. may be used to determine severity and to assess complications. Extrin-
sic inﬂammatory diseases such as Crohn disease and diverticulitis may
be associated with ﬁstulas to the bladder and focal bladder wall abnor-
TEACHING mality. The extravesical ﬁndings allow the diagnosis to be made easily.
Finally, extrinsic masses arising from the prostate or distal ureter may
See last page
cause ﬁlling defects, which can be confused with intrinsic bladder
Abbreviation: H-E hematoxylin-eosin
RadioGraphics 2006; 26:1847–1868 ● Published online 10.1148/rg.266065126 ● Content Code:
1From the Department of Diagnostic Radiology, University of Maryland School of Medicine, 22 S Greene St, Baltimore, MD 21201-1595 (J.J.W.);
and Departments of Radiologic Pathology (P.J.W., M.A.M.) and Genitourinary Pathology (C.J.D.), Armed Forces Institute of Pathology, Washing-
ton, DC. Received July 5, 2006; revision requested August 2 and received August 24; accepted August 24. All authors have no ﬁnancial relationships
to disclose. Address correspondence to J.J.W. (e-mail: firstname.lastname@example.org).
The opinions and assertions contained herein are the private views of the authors and are not to be construed as ofﬁcial nor as representing the views of
the Department of Defense.
1848 November-December 2006 RG f Volume 26 ● Number 6
Pathologic conditions of the bladder can manifest
as a focal bladder mass or diffuse wall thickening.
Focal masses may be neoplastic or may develop
secondary to congenital, inﬂammatory, idio-
pathic, or infectious sources. Clinical, macro-
scopic, and radiologic ﬁndings for these masses
may overlap; thus, histologic evaluation is re-
quired. Some of these entities, such as inﬂamma-
tory pseudotumor, endometriosis, Crohn disease,
and ﬁlling defects such as ureteroceles, have ra-
diologic features suggestive of the diagnosis and
may be ﬁrst suspected by the radiologist.
Figure 1. Normal bladder wall. Diagram shows the
Diffuse bladder wall thickening can develop
urothelium (a), lamina propria (b), muscularis propria
secondary to many nonneoplastic conditions, in- (detrusor muscle) (c), and adventitia (d). (Reprinted,
cluding infection with bacteria or adenovirus; with permission, from reference 1).
schistosomiasis; tuberculosis; inﬂammatory con-
ditions such as cystitis cystica, cystitis glandularis,
or eosinophilic cystitis; and exposure to chemo- der masses or diffuse bladder wall thickening.
therapy (particularly with cyclophosphamide) or The article describes and illustrates the clinical,
irradiation. Although the radiologic characteris- pathologic, and radiologic features of these condi-
tics of these disorders are less speciﬁc, radiologic tions, with emphasis on radiologic-pathologic cor-
evaluation is still of value. relation. Acute bacterial cystitis from infection
These various conditions may affect different will not be discussed.
portions of the bladder wall, so it is important to
be familiar with its histologic layers. The bladder Inﬂammatory Pseu-
wall consists of four layers (Fig 1). The lumen is dotumor (Pseudosarco-
lined by uroepithelium, which comprises three to matous Fibromyxoid Tumor)
seven layers of stratiﬁed ﬂat cells. These cells are An inﬂammatory pseudotumor is a nonneoplastic
ﬂexible and can change shape from cuboidal to proliferation of myoﬁbroblastic spindle cells and
ﬂattened as the bladder distends, hence the term inﬂammatory cells with myxoid components. Pa-
transitional epithelium. The second layer under- tients present most commonly with an ulcerating
neath the epithelium is the lamina propria, which bleeding mass, hematuria, and voiding symp-
is very vascular. Deep to the lamina propria is the toms. Other signs and symptoms include fever
third layer, which consists of bundles of smooth and iron deﬁciency anemia. This condition is
detrusor muscle (muscularis propria). The detru- more common in adults, with the mean age at
sor muscle is a complex network of interlacing diagnosis reported to be 38 years, with a range of
smooth muscle ﬁbers. The inner and outer mus- 15–74 years (2). Inﬂammatory pseudotumors also
cle ﬁbers tend to be oriented in a longitudinal occur in children, and one case in a neonate has
fashion, but distinct layers are usually not dis- been reported (3). The condition may have male
cernible. Fibers from the detrusor muscle merge predominance, as the male-to-female ratio was
with the prostatic capsule or anterior vagina and 11:6 in one series of 17 patients (2).
pelvic ﬂoor muscles. A fourth adventitial layer is Inﬂammatory pseudotumor is an interesting
formed by connective tissue. A serosal covering, entity that has been reported in every organ of the
formed by the peritoneum, is present only over body. Within the bladder, the lesion is locally ag-
the bladder dome. The bladder is suspended gressive and may mimic malignancy clinically, at
within the extraperitoneal space and is sur- cystoscopy, and at imaging. At histologic analysis,
rounded by pelvic fat. the lesions are distinct and show loosely packed
Herein, we review a diverse group of nonneo- spindle cells within a myxoid matrix. The patho-
plastic disorders with inﬂammatory, idiopathic, genesis of inﬂammatory pseudotumor is not clear;
and infectious causes that manifest as focal blad- some have postulated that the lesion develops in
response to infection, inﬂammation, or malig-
nancy, but the causative relationship had not
been proved (4). Accordingly, some authors pre-
RG f Volume 26 ● Number 6 Wong-You–Cheong et al 1849
Figure 2. Polypoid inﬂammatory pseudotumor. (a– c) Coronal T1-weighted (a), gadolinium-enhanced fat-sup-
pressed T1-weighted (b), and T2-weighted (c) magnetic resonance (MR) images show an enhancing polypoid mass
projecting into the bladder lumen (arrow). (d) Photograph of the cut, resected specimen shows a glistening surface,
with adjacent thickening of the bladder wall.
fer the name pseudosarcomatous ﬁbromyxoid tumor,
which is more accurate and also describes the his-
tologic ﬁndings (5). Inﬂammatory pseudotumor,
unlike urothelial carcinoma, has no association
with smoking (5). Lesions are varied in size, rang-
ing from 2 to 8 cm in diameter, and have an
edematous surface and a gel-like consistency at
cystoscopy (6,7). Even though these lesions are
locally aggressive, with an invasive growth pat-
tern, inﬂammatory pseudotumors fail to progress
At imaging evaluation, inﬂammatory pseudo-
tumor usually appears as a single bladder mass,
which may be exophytic or polypoid (Fig 2) and
which may be ulcerated. Intramural solid and
cystic variants may also occur (Fig 3). These
masses tend to spare the trigone; however, large
Figure 3. Cystic inﬂammatory pseudotumor.
Axial contrast material– enhanced computed tomo-
graphic (CT) image shows a predominantly cystic
mass (arrow) arising from the anterior bladder wall.
* bladder lumen.
1850 November-December 2006 RG f Volume 26 ● Number 6
Figure 4. Invasive inﬂammatory pseudotumor.
Transverse ultrasonographic (US) (a), axial con-
trast-enhanced CT (b), and axial gadolinium-
enhanced fat-suppressed T1-weighted MR (c)
images show a large, lobulated mass arising from
the lateral wall of the bladder with signiﬁcant
extravesicular extension (arrows).
lesions may invade through the bladder and may
have a substantial extravesical component (Fig 4),
making differentiation from a malignant process
On CT and MR images, inﬂammatory pseudo-
tumors demonstrate enhancement (Figs 2, 4),
and at color Doppler US, these lesions may show
internal vascularity (7). On T2-weighted MR im-
ages, inﬂammatory pseudotumor may appear het-
Teaching erogeneous, with a central hyperintense compo-
Point nent surrounded by a low-signal-intensity peri-
phery (Fig 5); after administration of contrast
material, the periphery enhances while the central
region enhances poorly (7). The central region
of an inﬂammatory pseudotumor consists of ne-
crotic tissue, and the periphery comprises fasci-
cles of spindle cells in edematous stroma with
myxoid components, vessels, and inﬂammatory
cells (Fig 6). This structure may produce the pat-
tern of ringlike enhancement observed on CT and
MR images that may be suggestive of the diagno-
sis, but histologic conﬁrmation is essential (7). In
young adults, the presence of luminal clot sur-
rounding an enhancing bladder mass may also
suggest this diagnosis (4).
Treatment may consist of surgery, a regimen of
high-dose steroids, radiation therapy, or conser- Figure 5. Inﬂammatory pseudotumor. Axial T2-
weighted MR image shows a lobulated polypoid
mass arising from the anterior wall of the bladder
with central hyperintensity (*) and low peripheral
signal intensity (arrowhead).
RG f Volume 26 ● Number 6 Wong-You–Cheong et al 1851
Figure 6. Inﬂammatory pseudotumor. Photomicro-
Figure 7. Endometriosis. Photomicrograph (original
graph (original magniﬁcation, 100; hematoxylin-eo-
magniﬁcation, 100; H-E stain) shows endometrial
sin [H-E] stain) shows uniform, elongated spindle cells
glands (arrows) surrounded by endometrial stromal
within a background of myxoid stroma. These cells are
cells, deep within the muscularis propria of the bladder.
loosely packed, a feature that helps differentiate this
lesion from a smooth muscle tumor, which has a
densely packed, cellular stroma.
with endometrial deposits or implants more than
5 mm deep into the peritoneum. Bladder endo-
vative management. Because imaging features metriosis is deeply inﬁltrating (8) (Fig 7). Bladder
may overlap, it is critical that the pathologist dis- implants typically occur at the vesicouterine
tinguish inﬂammatory pseudotumor from rhab- pouch. These masses can grow through the
domyosarcoma and myxoid leiomyosarcoma to muscle into the submucosa, producing an obtuse
prevent unnecessary radical surgery. bulge into the bladder lumen. Less frequently,
endometriosis can grow through the mucosa and
Endometriosis produce a polypoid mass (11). A conﬂuent area
The urinary tract is not usually involved by endo- of endometriosis can develop between the bladder
metriosis; however, when it is, the bladder is the and uterus and obliterate the vesicouterine pouch
most common site, with a reported prevalence of (11). Small superﬁcial serosal implants may also
1%–15% in women with endometriosis (8 –10). occur. Most endometriotic lesions are found in
Bladder endometriosis can occur spontaneously the posterior wall of the bladder above the trigone
after direct implantation of endometrium or fol- or at the dome (8,10,12).
lowing pelvic surgery. Bladder endometriosis has There are three main theories regarding the
been reported in only premenopausal women (5). pathogenesis of bladder endometriosis. The ﬁrst
The ectopic endometrium responds to circulating and most widely accepted theory is that endome-
hormones during the menstrual cycle, although in triosis develops in the bladder because of retro-
a less predictable fashion than uterine endome- grade menstruation, which seeds the surface of
trium. Cyclic hematuria is highly suggestive of the bladder serosa. Spread of endometrium to
bladder endometriosis, but it occurs in only 20% distant sites may also occur during surgery, such
of cases (9). Patients may have cyclic pain, dys- as cesarean section. The other theories postulate
uria, urgency, and pain, or they may be entirely that bladder endometriosis arises due to metapla-
asymptomatic. sia of mullerian remnants or direct extension from
Endometriosis can occur in several forms: cys- anterior uterine adenomyosis (12).
tic ovarian endometriotic masses, superﬁcial en-
dometriosis, or deeply inﬁltrating endometriosis
1852 November-December 2006 RG f Volume 26 ● Number 6
Figure 8. Endometriosis. (a) Right posterior oblique view of the bladder obtained during intra-
venous urography shows an irregular, rounded ﬁlling defect along the posterior dome. (b) Longitu-
dinal US image shows a solid homogeneous, hypoechoic mass protruding into the bladder lumen.
Bladder endometriosis can occur in several Fibrosis may be an accompanying feature. Malig-
locations. Superﬁcial and deeply inﬁltrating le- nant transformation of endometriosis to adeno-
sions are much more common in dependent sites carcinoma of the endometrioid and clear cell
in the peritoneal cavity, such as the posterior types is rare (15).
Douglas cul-de-sac, rather than the anterior vesi- Imaging features can be nonspeciﬁc, with the
couterine pouch (8). Endometriosis of the detru- location of the lesions being more helpful than
sor muscle is believed to result from trapping of their imaging appearances at US, CT, and excre-
endometrial cells in the anterior cul-de-sac with a tory urography (Fig 8). Endometriotic bladder
resultant inﬂammatory response and ﬁbrosis, masses are posterior and may be inseparable from
which then obliterates this space (12). Typically, the anterior aspect of the uterus. Images may
bladder endometriosis is inseparable from the show a nonspeciﬁc ﬁlling defect, typically located
anterior uterus, but it does not usually result from posteriorly in the bladder, with variable protru-
direct extension of adenomyosis. In addition, sion into the lumen (16,17). Transvaginal US has
bladder endometriosis has not been observed in been found to be useful in demonstrating the
retroverted uteri because of the absence of a de- depth of endometriotic lesions in the bladder wall
pendent vesicouterine pouch. and the continuity of bladder endometriosis to
The bladder may also be the site of involve- adenomyosis in the anterior myometrium if
ment by endocervicosis and endosalpingiosis, present (14).
conditions that represent ectopic cervical and MR imaging is superior to other imaging mo-
tubal epithelium, respectively. These entities are dalities because of higher contrast resolution, de-
usually grouped with endometriosis and are col- lineation of bladder wall layers, tissue character-
lectively referred to as mullerianosis (13). ization, and multiplanar capability. The typical
At cystoscopy, endometriosis typically appears MR imaging features of bladder endometriosis Teaching
as bluish or reddish-brown submucosal masses. are hemorrhagic foci with high signal intensity Point
Bleeding may occur from the surface of the (representing blood) on fat-suppressed and non–
masses, which range in size from 2 to 4 cm fat-suppressed T1-weighted images (11). Such
(13,14). Endometriotic masses may grow into the foci may occur in areas of ﬁbrosis, which are dark
bladder lumen and mimic a polypoid neoplasm on T1- and T2-weighted images (Fig 9) (11,16).
(13). Bladder endometriosis may also have high signal
Characteristic histologic features are endome- intensity on T2-weighted images. In a series of 16
trial glands and stroma with hemosiderin-laden patients with endometriosis of the bladder, all
macrophages from repeated hemorrhage (Fig 7). patients had ﬁbrotic lesions that contained high-
signal-intensity foci on T1- and T2-weighted im-
RG f Volume 26 ● Number 6 Wong-You–Cheong et al 1853
Figure 9. Endometriosis. (a, b) Axial T1-weighted (a) and fat-suppressed T1-weighted (b) MR images
show high-signal-intensity foci (arrow) within a soft-tissue mass in the vesicouterine space, projecting into the
bladder lumen. (c) Axial T2-weighted MR image shows the lesion is predominantly low signal intensity (ar-
row), a ﬁnding consistent with ﬁbrosis. (d) Axial gadolinium-enhanced fat-suppressed T1-weighted image
shows homogeneous enhancement of the lesion (arrow).
ages (11). When imaging ﬁndings were correlated Nephrogenic Adenoma
with surgical results, MR imaging was reported to Despite its name, a nephrogenic adenoma is not a
have a high speciﬁcity of 98.9% and a high nega- neoplastic mass but rather a benign reactive pro-
tive predictive value of 98.9%, with a moderate cess that occurs in the urothelium. Chronic irrita-
sensitivity of 88% and an accuracy of 97.9% (11). tion by calculi, infection, injury, or previous sur-
The authors reported that the main limitation of gery incites metaplasia of the urothelium, which
MR imaging was in delineating the relationship of develops papillary and tubular growths. A typical
endometriotic masses to the ureteral oriﬁce, a case might be a patient with a history of undergo-
limitation that has surgical implications. ing repeated biopsies for urothelial carcinoma,
Endometriotic masses enhance, either homo- with the reparative process causing a nephrogenic
geneously or peripherally, with contrast material adenoma. Nephrogenic adenomas involve the
(Fig 9) (16). Bladder endometriosis is rarely iso- lamina propria but spare the muscle layer. Irrita-
lated, and in the majority of patients, other foci of tive voiding symptoms or hematuria are the most
endometriosis are present in the pelvis (10). common symptoms (18,19). Patient age ranges
Treatment of symptomatic bladder endometri- from 26 to 80 years; men are three times more
osis consists of partial cystectomy.
1854 November-December 2006 RG f Volume 26 ● Number 6
Figure 10. Nephrogenic adenoma. Anteroposte- Figure 11. Nephrogenic adenoma. Photomicrograph
rior view of the bladder obtained during intravenous (original magniﬁcation, 150; H-E stain) of a bladder
urography shows an irregular lobulated ﬁlling defect biopsy specimen shows a background of chronic inﬂam-
at the base of the bladder. Pathologic evaluation matory cells with tubules lined by cuboidal (straight
showed urothelial carcinoma with an adjacent neph- arrow) or teardrop-shaped (curved arrow) cells. Note
rogenic adenoma. the papillations (arrowheads) on the luminal surface.
likely than women to develop nephrogenic ad-
At cystoscopy, a nephrogenic adenoma may
resemble urothelial carcinoma or chronic cystitis
with multiple polypoid or single sessile growths
(18). It can occur in diverticula or at sites of pre-
vious surgery. Imaging studies reveal polypoid or
sessile masses within the bladder or irregular mu-
cosa, all of which are nonspeciﬁc ﬁndings (Fig
10); the diagnosis can be made only with a histo-
logic evaluation (18,20). At histologic analysis,
the adenoma resembles immature urothelial or
metanephric structures (Fig 11) (5).
Optimal treatment is endoscopic resection.
Although nephrogenic adenomas recur in up to
63% of cases, they are not premalignant (19).
Bladder surveillance is required. Figure 12. Malacoplakia. Photomicrograph (original
magniﬁcation, 150; H-E stain) shows the classic tar-
Malacoplakia get or bull’s-eye appearance of Michaelis-Gutmann
The term malacoplakia signiﬁes soft plaque. Ma- bodies (arrows), which represent calciﬁed intracellular
lacoplakia is a rare chronic granulomatous condi- inclusions within large histiocytes.
tion that can affect any organ, with the urinary
tract being the most common system involved.
Within the urinary tract, the bladder is the most mune diseases, those with acquired immunodeﬁ-
frequently affected organ, with 40% of patients ciency syndrome, or recent transplant recipients.
with malacoplakia having bladder involvement Presenting symptoms include gross hematuria
and 16% renal involvement (21). The disease is and signs of urinary tract infection such as hesi-
found predominantly in women, with a female-to- tancy, dysuria, and frequency. Patients may have
male ratio of 4:1 (21). Patients of any age may variable proteinuria, as well as leukocytes and
develop malacoplakia, but the peak occurrence is erythrocytes in their urine. Malacoplakia is highly
in middle age. The disease is more common in associated with Escherichia coli infection (21), but
patients with diabetes mellitus or in immunocom- infection alone is not thought to be causative. The
promised individuals, such as those with autoim- pathogenesis of malacoplakia is mainly thought
to involve impaired host defenses and defective
phagocytosis. There is an underlying decreased
RG f Volume 26 ● Number 6 Wong-You–Cheong et al 1855
Figure 13. Malacoplakia. (a) Axial CT image shows marked circumferential bladder wall thickening.
(b) Photograph of the cut, resected specimen shows a friable, hemorrhagic mucosal surface and dramatic wall
Figure 14. Malacoplakia. Axial CT images through the upper (a) and lower (b) pelvis show a large, irregu-
larly enhancing mass (arrows in a), which is contiguous with the bladder. Note the diffuse thickening of the
bladder wall (arrow in b).
cyclic guanosine monophosphate/cyclic adenosine Imaging characteristics of malacoplakia are
monophosphate (cGMP/cAMP) ratio (22). Bac- likewise varied. There may be multiple, polypoid,
teria ingested by the macrophages are destroyed vascular, solid masses or circumferential wall
but not completely digested. They persist in the thickening (Fig 13), associated with vesicoure-
phagolysosomes and become mineralized, result- teric reﬂux and dilatation of the upper urinary
ing in the pathognomonic calciﬁed intracellular tract (24). Malacoplakia may be extremely ag-
inclusions, the Michaelis-Gutmann bodies (Fig gressive, invading the perivesical space (Fig 14),
12) (23). and it can even cause bone destruction (25).
Malacoplakia begins in the submucosa with Ring-shaped bladder calciﬁcation representing
overlying normal or hyperplastic epithelium, later adherent calculi has been described after treat-
followed by mucosal ulceration. Its appearance at ment (26). A less common radiologic manifesta-
cystoscopy varies, ranging from soft, ﬂat yellow- tion is that of a predominantly retrovesical mass
brown plaques to nodules, papillary lesions, hem- involving the uterus or an extravesical anterior
orrhagic masses, and necrotic ulcerations. The mass (27).
size of the lesions can range from a few millime-
ters to several centimeters. Plaques can extend
into the distal ureters.
1856 November-December 2006 RG f Volume 26 ● Number 6
Figure 15. Cystitis cystica and cystitis glandularis.
Photomicrograph (original magniﬁcation, 150; H-E Figure 16. Cystitis cystica and cystitis glandu-
stain) shows nests of von Brunn with cystic changes laris. Cystoscopic photograph shows cobblestone
(straight arrow), typical of cystitis cystica, and mucin- appearance of the mucosa with a focal polypoid
ﬁlled goblet cell metaplasia (curved arrow), typical of mass (arrow).
Given the nonspeciﬁc cystoscopic and imaging
appearances of malacoplakia that may simulate
those of neoplasms, biopsy is essential for appro-
priate conservative management. Treatment regi-
mens include antibiotics, ascorbic acid, and a
and Cystitis Glandularis
Cystitis cystica and cystitis glandularis are com-
mon chronic reactive inﬂammatory disorders,
which occur in the setting of chronic irritation
(23). Metaplasia of the urothelium is incited by
Figure 17. Cystitis cystica and cystitis glandularis.
irritants such as infection, calculi, outlet obstruc-
Oblique view of the bladder obtained during intrave-
tion, or even tumor (28). The urothelium then nous urography shows a lobulated contour of the blad-
proliferates into buds (nests of von Brunn), which der, with a nodular ﬁlling defect (arrow).
grow down into the connective tissue beneath the
epithelium in the lamina propria. The buds then
differentiate into cystic deposits of cystitis cystica of the intestinal type only, the association is rare
or into intestinal columnar mucin-secreting (13,28). However, patients with this condition
glands (goblet cells) resulting in cystitis glandu- should be closely monitored.
laris (Fig 15) (13). The histologic features of both Cystitis glandularis and cystitis cystica can oc-
cystitis cystica and cystitis glandularis are usually cur at any age, and there is reported prevalence
present, rather than either in its pure form. Mucin of 2.4% in children with urinary tract infections
may be extravasated into the stroma and may (29). A slight male predominance is reported.
cause these entities to be misdiagnosed as adeno- Symptoms are those of chronic irritation, such as
carcinoma (13). Florid proliferation results in frequency, dysuria, urgency, and hematuria. In
nodular masses in the lamina propria. Atypia and rare cases, mucus may be secreted in the urine.
muscle invasion are not features and, if present, At cystoscopy, the mucosa usually has a cob-
should suggest the diagnosis of adenocarcinoma. blestone pattern. In addition, cystitis glandularis
Cystitis glandularis also occurs in association may develop into a papillary or polypoid mass
with pelvic lipomatosis and is believed to result (Fig 16), a form that mimics carcinoma, with a
from bladder obstruction and chronic infection. predilection for the bladder neck and trigone
Bladder exstrophy is also associated with diffuse (30,31). In young patients, their age should raise
cystitis glandularis. Although there are reports of the suspicion that the lesion might be nonneo-
adenocarcinoma developing in cystitis glandularis plastic, but biopsy is necessary for a deﬁnitive di-
RG f Volume 26 ● Number 6 Wong-You–Cheong et al 1857
Figure 18. Eosinophilic cystitis. (a) Sagittal T1-weighted MR image shows a single, sessile mass (arrow) arising
from the posterior bladder wall; the mass is mildly hyperintense relative to muscle. (b) Sagittal gadolinium-enhanced
fat-suppressed MR image shows enhancement of the mass (arrow) and the adjacent bladder wall.
Masses from cystitis cystica and cystitis glan- may be idiopathic, as no cause is found in 29% of
dularis vary in number and size and manifest as adult patients (34). It is postulated that an anti-
ﬁlling defects at urography (Fig 17) (30 –32). A gen-antibody response occurs in the bladder and
hypervascular polypoid mass has been observed attracts eosinophils, which provoke an inﬂamma-
on CT and MR images, with low signal intensity tory response. In both adults and children, there
reported with T1-weighted sequences. On T2- is a slight male predominance, with a ratio of
weighted images, the lesion was predominantly 1.3:1 reported for adults. The age distribution is
low in signal intensity with a central branching wide, with a mean age of 41.6 – 48 years (34,35).
high-signal-intensity pattern. The hyperintense Hematuria (macroscopic or microscopic) and
area showed the most contrast enhancement and frequency are the most common presenting
corresponded to the vascular stalk (33). The symptoms (35). Other clinical features include
muscle layer should be intact, a feature that dis- irritative voiding symptoms such as dysuria and
tinguishes cystitis cystica and cystitis glandularis pain, as well as urinary retention. Five percent of
from urothelial carcinoma. patients may be asymptomatic, for whom eosino-
Treatment consists of removing the source of philic cystitis is diagnosed incidentally at biopsy
irritation and surgical excision of the area of in- during surveillance for urothelial carcinoma, for
ﬂammation or cystectomy in rare severe cases. example (36). Peripheral eosinophilia is found in
These patients should be monitored carefully be- 0%– 43% of cases and positive urine cultures in
cause of the possible association with adenocarci- 26% (34 –36). Impaired renal function is not un-
noma. common (34).
At cystoscopy, all patients with eosinophilic
Eosinophilic Cystitis cystitis have erythema (36). Other manifestations
Eosinophilic cystitis is another rare chronic in- are polypoid, velvety, or ulcerative lesions and
ﬂammatory disease of the bladder, with only 83 bladder mass or edema in 17% of cases (36). At
reported cases in adults (34). It is characterized histologic analysis, there is transmural inﬂamma-
by an inﬁltrate of eosinophils into the bladder wall tion, with the most intense inﬂammatory change
and associated with variable degrees of ﬁbrosis found in the lamina propria. The inﬂammation
and muscle necrosis (34). Eosinophilic cystitis is typiﬁed by eosinophilic predominance with
can occur in patients with atopy, with peripheral edema. Muscle necrosis may occur, leading to
eosinophilia, or after bladder surgery. Whether it ﬁbrosis and a contracted bladder (34).
represents a distinct entity has been questioned, At radiologic evaluation, single masses are ob-
as eosinophilic inﬁltrates are also seen with other served more frequently than multiple bladder
conditions and the list of associated disorders is masses and may be sessile (Fig 18) (34,36). The
long: adverse reactions to drugs and food, para- bladder wall may appear normal or thickened
sitic or nonparasitic urinary tract infection, uro- (37). A cystic variant with an enhancing wall may
thelial carcinoma, autoimmune disorders, and
eosinophilic enteritis (5,34). Eosinophilic cystitis
1858 November-December 2006 RG f Volume 26 ● Number 6
Figure 19. Cystic eosinophilic cystitis. (a, b) Axial (a) and sagittal reconstructed (b) contrast-enhanced CT im-
ages show a thick-walled cystic mass (arrow) arising from the anterior dome of the bladder. (c) Intraoperative photo-
graph, with the bladder wall retracted (arrowheads), shows the mass (arrow) protruding into the lumen. (d) Photo-
graph of the cut specimen shows a circumferentially thickened wall, as seen on the CT images. (e) Photomicrograph
(original magniﬁcation, 120; H-E stain) shows an intense inﬁltration of eosinophils deep within the muscularis pro-
be seen (Fig 19). MR imaging shows a mass Typically, eosinophilic cystitis runs a benign,
that is hyperintense relative to muscle with T1- self-limiting course following removal of the etio-
weighted sequences, isointense with T2-weighted logic factor, if known. Treatment is conservative
sequences, and enhanced after intravenous ad- initially. Local transurethral resection can be
ministration of contrast material (Fig 18). In the supplemented with a regimen of antihistamines,
ﬁbrotic stage, the bladder is small and contracted, steroids, nonsteroidal anti-inﬂammatory drugs,
and there may be resultant hydronephrosis. Since or antibiotics if there is intercurrent infection. A
clinical and imaging features overlap with those of small percentage of patients may require cystec-
other disorders, particularly neoplasm which may tomy for severe, unremitting symptoms and fail-
coexist with eosinophilic cystitis, biopsy is needed ure to respond to conservative measures (36).
for both children and adults (36).
Tuberculosis of the bladder is an uncommon
bladder disease in Western countries, even
RG f Volume 26 ● Number 6 Wong-You–Cheong et al 1859
RadioGraphics At cystoscopy, early features of bladder tuber-
culosis are cystitis with a thick, chalky, white mu-
cosa; mucosal ulceration; and edema. Later, ﬁ-
brosis causes a contracted bladder. Characteristic
features at biopsy are caseating granulomas and a
positive Ziehl-Neelsen stain. Care must be taken
during biopsy, as a tuberculous bladder is at in-
creased risk of perforation (38). Necrosis can oc-
cur but is rare when bladder tuberculosis is in-
duced by B Calmette-Guerin treatment.
In the acute phase of bladder tuberculosis,
sonographic ﬁndings include irregular mucosal
masses due to coalescing tubercles with ulceration
and edema, diffuse wall thickening, and trabecu-
lation (39). At urography, the bladder mucosa is
irregular (Fig 20), and there may be ureteral stric-
tures and thickening with obstruction, or a ﬁxed
and patulous vesicoureteric junction oriﬁce, re-
sulting in vesicoureteric reﬂux. In the chronic
phase, imaging ﬁndings are a thick-walled con-
tracted bladder from ﬁbrosis (40). The diminu-
tion of bladder volume accounts for symptoms of
frequency. There may be associated calciﬁcation
in the seminal vesicles, but bladder wall calciﬁca-
tion is rare and seen only after healing (32,39,40).
Bladder tuberculosis may be complicated by ﬁstu-
Figure 20. Tuberculosis. Anteroposterior view las or sinus tract formation, although these com-
obtained during intravenous urography shows plications are rare and are demonstrated better on
irregularity of the bladder contour (arrowheads). CT and MR images.
There is also distortion and irregularity of the Treatment consists of antituberculous regi-
renal calices (arrows).
though the genitourinary tract is the second most Schistosomiasis
frequent site of tuberculosis after the lungs. Bladder schistosomiasis is uncommon in the
Worldwide, tuberculosis remains the most com- United States, but it is a major health problem in
mon infectious cause of death. Tuberculosis of developing parts of the world, especially Africa,
the urinary tract almost always begins in the up- and cases are seen in immigrants to the U.S. (41).
per tracts, with the bladder being secondarily in- Genitourinary tract infection is caused by the
volved. Bladder tuberculosis results directly from Schistosoma haematobium species. The larvae (cer-
infection with Mycobacterium tuberculosis or less cariae) are released from snails into water and
often from Bacillus Calmette-Guerin (BCG) treat- penetrate human skin exposed to the infected wa-
ment for urothelial carcinoma. The diagnosis may ter. They travel to the lungs and liver of the hu-
be difﬁcult because of nonspeciﬁc symptoms, man host, where they reside until they mature.
clinical results, and imaging ﬁndings. After maturation, the adult worm pairs travel to
Symptoms are nonspeciﬁc and include dysuria, the pelvic veins, where oviposition occurs. The
urgency, frequency, and hematuria. Tuberculosis eggs are deposited in the bladder wall vessels and
should be considered in patients with refractory incite a granulomatous response that results in
Teaching cystitis, with sterile pyuria, or who originate from polypoid lesions. During this time, eggs are ex-
Point countries where tuberculosis is more common. creted in urine. Adult worms may live for many
Immunocompromised patients with acquired im- years after initial infection. Even after the death of
munodeﬁciency syndrome or recipients of organ the adult worms, large numbers of calciﬁed eggs
transplants are also at higher risk. Urine culture
or cytology may be helpful, but a more rapid and
sensitive assay is the polymerase chain reaction
performed on urine (38).
1860 November-December 2006 RG f Volume 26 ● Number 6
RadioGraphics can be found in the bladder wall (Fig 21) with no
viable eggs in the urine (41). The eggs incite a
chronic inﬂammatory response and ﬁbrosis,
which is an important predisposing factor for
Symptoms of bladder schistosomiasis are non-
speciﬁc and are most commonly dysuria, supra-
pubic pain, microscopic hematuria, and fre-
quency. There may be some white cells in the
urine, in addition to the red cells. The deﬁnitive
diagnosis is made when eggs are found at urine
microscopy. At gross pathologic analysis, the le-
sions are white and raised in the acute phase, but
the polypoid lesions ﬂatten as ﬁbrosis ensues.
Imaging ﬁndings mirror the pathologic course. Figure 21. Schistosomiasis. Photomicrograph (origi-
In the acute phase, nodular bladder wall thicken- nal magniﬁcation, 200; H-E stain) shows schisto-
ing is observed at urography or cross-sectional some ova (arrows) surrounded by numerous lympho-
cytes. These ova are starting to calcify. When extensive
imaging (Fig 22). There may be ureteral dilata-
numbers of ova are present, calciﬁcation can be seen
tion. The chronic phase is characterized by a con- with imaging.
tracted, ﬁbrotic, thick-walled bladder with calciﬁ-
cations. These calciﬁcations are typically curvilin-
ear and represent the large numbers of calciﬁed
eggs within the bladder wall. Distal ureteral calci-
ﬁcation may also be present (Fig 23). A mass may
be secondary to inﬂammation or complicating
carcinoma, typically squamous carcinoma.
For treatment, patients are given praziquantel,
which destroys the adult worms and incites the
eggs to hatch. It has no effect on the chronic ﬁ-
brotic changes in the bladder wall and ureters.
Bladder involvement in Crohn disease consists of
ﬁstulas from inﬂamed small and large bowel.
Teaching Crohn disease is the most frequent cause of ileo-
Point vesical ﬁstula and ileocolovesical ﬁstula (42). En-
terovesical ﬁstulas occur in 1.7%–7.7% of pa- Figure 22. Schistosomiasis. Longitudinal US image
through the bladder shows nodular bladder wall thick-
tients with Crohn disease and are most often from
ening (arrows), an appearance more typical in the acute
the ileum (64% of cases) and colon (21%) (42). phase of infection.
Fistulas are slightly more common in male pa-
tients, with the median patient age being 27 years;
patient age ranges from 10 to 76 years (42). The The bladder is secondarily involved by the ad-
most suggestive symptoms are pneumaturia and jacent bowel inﬂammatory lesions. Transmural
fecaluria, which occur in 68% and 28% of pa- inﬂammation and deep ﬁssures cause ﬁstulas be-
tients, respectively (42). Dysuria and recurrent tween diseased bowel and other viscera such as
urinary tract infections, pain, and fever are the the bladder. Cystoscopy and CT are the most
other most common symptoms (43). Pyuria is useful diagnostic tools (42). At cystoscopy, the
present in 100% of cases, and E coli is the most ﬁstula may be directly visualized, and there may
common bacterial infective agent (43). be pus, feces, and bullous edema in the bladder
(42). At CT, air within the bladder, focal irregu-
larity of the wall (most commonly on the right
side of bladder), and tethering of thickened ad-
jacent bowel are the usual ﬁndings (Fig 24)
RG f Volume 26 ● Number 6 Wong-You–Cheong et al 1861
Figure 23. Schistosomiasis. Anteroposterior radiograph (a) and axial CT image (b) of the bladder shows
curvilinear calciﬁcation in the bladder wall (arrowheads), which also extends to the distal left ureter (arrow).
Calciﬁcation, representing an abundance of calciﬁed ova, is typically seen in the chronic phase of the infection.
Figure 24. Crohn disease with a ﬁstula to the bladder. (a) Contrast-enhanced, coronal CT reformation shows wall
thickening of the distal small bowel (straight arrow) and the adjacent bladder (curved arrow). (b) Collimated radio-
graph obtained during a small bowel contrast study shows an enterovesical ﬁstula (curved arrow), extending from the
abnormal segment of the ileum to the bladder (arrow).
(42,44). The presence of orally administered con- of the bowel or bladder, such as a small bowel
trast material in the bladder is diagnostic of a ﬁs- series or cystography, respectively (Fig 24).
tula between the bowel and bladder. Hydrone- Treatment consists of surgery, with resection
phrosis may also be present. Other signs of pelvic of the abnormal segment of bowel and closure of
Crohn disease, such as ﬁbrofatty proliferation, the bladder defect. The value of medical therapy
inﬁltration of fat, phlegmon, and lymphadenopa- has not yet been established.
thy, should also be present. The diagnosis of a
ﬁstula may also be made with ﬂuoroscopic studies
1862 November-December 2006 RG f Volume 26 ● Number 6
Figure 25. Diverticulitis with a ﬁstula to the bladder. (a) Axial CT image shows diffuse wall thickening of
the sigmoid colon with an adjacent focal, thick-walled, gas-containing abscess (arrowhead). (b) Coronal CT
reformation shows the abscess (arrowhead) immediately adjacent to the bladder. A ﬁstula has formed with gas
within the bladder lumen, as well as diffuse bladder wall thickening (arrow).
Figure 26. Chemotherapy cystitis from cyclophosphamide. (a) Longitudinal US image shows diffuse wall
thickening (arrows). (b) Axial contrast-enhanced CT image shows enhancement of the mucosal surface (ar-
row), as well as diffuse wall thickening. The hyperemic mucosa may ulcerate and cause signiﬁcant hematuria.
Diverticulitis the diagnosis, assuming the contrast material was
Colovesical ﬁstulas and cystitis are not uncom- not excreted by the kidneys.
mon complications of diverticulitis. Patients Deﬁnitive treatment consists of surgical exci-
present with pneumaturia, pain, fever, pyuria, sion of the ﬁstulous tract and diseased segment of
and fecaluria. CT is more sensitive than cystogra- bowel.
phy or contrast enema studies (44). Imaging ﬁnd-
ings include bladder wall thickening with gas in Radiation and
the bladder lumen and adjacent inﬂamed colon Chemotherapy Cystitis
with diverticula and pericolonic fat stranding (Fig Severe hemorrhagic cystitis may develop after
25). Such ﬁstulas typically occur on the left wall chemotherapy or irradiation of the bladder. Che-
of the bladder. The use of rectal or oral contrast motherapy-related cystitis occurs from systemic
agents will opacify the bladder and help conﬁrm or local chemotherapy. Radiation injury may re-
sult from external, interstitial, or intracavitary
RG f Volume 26 ● Number 6 Wong-You–Cheong et al 1863
Figure 27. Radiation cystitis, chronic changes.
Axial CT image shows focal thickening and calciﬁca-
tion of the right posterior bladder wall (straight ar-
row). There is subtle widening of the presacral space
(curved arrow) and fatty inﬁltration of the pelvic
Figure 28. Radiation cystitis with ﬁstula. (a) Collimated anteroposterior view of the bladder obtained during
cystography shows a ﬁstulous communication between the bladder and perivesical space (arrow). (b) Axial CT
image obtained after cystography helps conﬁrm the presence of contrast material posterolateral to the bladder
(arrow). Note the radiation changes within the bones. * Foley catheter balloon.
radiation therapy for bladder or other pelvic ma- result in intraluminal clot, visible at US or CT
lignancy, and the effects may be acute or delayed. (46,47). MR imaging may show inﬂammation
In the acute phase of radiation and chemo- and edema as high signal intensity with T2-
therapy cystitis, there is a hemorrhagic cystitis weighted sequences and can enable the bladder
secondary to denudation of the urothelium, wall to be distinguished from clot (47).
which then becomes covered with ﬁbrinous exu- Beyond 1 year, chronic radiation effects result
dates (23). Patients may have minor symptoms from an obliterative endarteritis in the lamina
related to voiding difﬁculty or gross hematuria, propria, followed by ischemic changes and inter-
dysuria, frequency, and urinary retention. The stitial ﬁbrosis. Symptoms are mostly related to the
most severe radiation injuries cause bladder ne- contracted bladder and consist of frequency, ur-
crosis, incontinence, and ﬁstula formation. Hy- gency, dysuria, hematuria, and incontinence.
peremia, petechiae, hemorrhage, and ulceration Pneumaturia and fecaluria are highly suggestive
may be visible at cystoscopy. At histologic analy- of a ﬁstula. At imaging, a small ﬁbrosed bladder
sis, there is cellular atypia, with mild to moderate with a thick wall and resultant hydronephrosis are
nuclear pleomorphism but no mitoses (45). The seen. Calciﬁcation may be seen in rare cases (Fig
epithelial proliferation may be so marked as to be 27). Other evidence of previous irradiation in-
confused with invasive cancer in the lamina pro- cludes fatty replacement of the pelvic muscula-
pria (45). At imaging, there is an abnormal blad- ture and widening of the presacral space (Fig 27).
der wall with focal or diffuse irregular thickening Gas within the bladder is indicative of a ﬁstula.
(Fig 26), spasticity, and decreased distensibility. Complex ﬁstulas may ensue (Fig 28).
Hypervascularity in the wall and bleeding vessels
1864 November-December 2006 RG f Volume 26 ● Number 6
Figure 29. Cervical cancer invading the posterior wall of the bladder. Axial contrast-enhanced CT (a) and sagittal
T2-weighted MR (b) images show a large, irregular cervical mass invading the posterior wall of the bladder (straight
arrow). There is uterine obstruction with hematometros (curved arrow in b).
Figure 30. Prostate cancer. Anteroposterior view of the bladder obtained during intravenous urography (a)
and axial unenhanced CT scan (b) show an irregular, nodular ﬁlling defect in the base of the bladder (arrow).
Histologic evaluation showed prostatic adenocarcinoma.
Treatment is supportive, with blood transfu- Extrinsic Masses Caus-
sions and bladder irrigation with instillation of ing Bladder Filling Defects
various agents such as alum, silver nitrate, and In addition to the conditions previously de-
formalin. Pelvic vascular embolization may be scribed, a number of other entities can protrude
required, and hyperbaric oxygen has been shown into the bladder and mimic a bladder mass.
to be helpful (46,48). For patients with intrac- These entities include extrinsic masses of pros-
table symptoms, urinary tract diversion or cystec- tatic, uterine (Fig 29), and ovarian origin; ure-
tomy may be the last option. teroceles, extramedullary hematopoiesis; urachal
cysts; paraganglionic tissue; hamartomas; amy-
loidosis; and vascular malformations (5).
RG f Volume 26 ● Number 6 Wong-You–Cheong et al 1865
Figure 31. Benign prostatic hypertrophy. Axial
CT image shows a large, smooth, lobular mass bulg-
ing into the base of the bladder (arrow). Despite its
large size, this “mass” proved to be benign hypertro-
phy of the prostate.
Figure 32. Benign prostatic hypertrophy. Sagittal (a) and coronal (b) T2-weighted MR images show the
central portion of the prostate gland protruding into the bladder base (arrow). In this case, the gland is pre-
dominantly low signal intensity, a ﬁnding that indicates it contains a larger amount of stromal rather than glan-
An enlarged prostate gland may protrude into mass is more diagnostic than its appearance. At
the bladder base and simulate a mass arising from MR imaging, however, benign prostatic hyperpla-
the bladder at imaging. The enlargement is more sia has a characteristic appearance, consisting of
commonly benign than malignant: Malignant round nodules of varying sizes that have high sig-
lesions are more irregular (Fig 30). Benign pros- nal intensity with T2-weighted sequences, as
tatic hyperplasia is common and its prevalence well as a variable amount of low-signal-intensity
increases with patient age, but it is not an indica- ﬁbrosis (49) (Fig 32). The relative proportion of
tion for imaging. However, an enlarged median nodules to stromal reaction depends on the de-
lobe of the prostate that bulges into the base of gree of stromal versus glandular hyperplasia.
the bladder may be incidentally seen and needs to
be distinguished from an intrinsic bladder mass
(Fig 31). At CT or US, the site of origin of the
1866 November-December 2006 RG f Volume 26 ● Number 6
Figure 33. Ureterocele. (a) Longitudinal gray-scale US image shows an anechoic cystic structure (ar-
row) at the ureteral oriﬁce. (b) Transverse color Doppler US image shows an ureteral jet, a ﬁnding that
conﬁrms the cyst is an ureterocele.
Ureteroceles are another common entity that
causes bladder ﬁlling defects. They are secondary
to congenital obstruction of the ureteral meatus,
resulting in saccular dilatation of the intramural
course of the ureter. The ureterocele may be asso-
ciated with a duplicated (80% of cases) or single
collecting system and may insert into the bladder
(“orthotopic” insertion in 17%–35% of cases) or
into an ectopic site such as the urethra or vagina.
One in 4000 children have an ureterocele, and
there is a 4 –7:1 female-to-male ratio. Approxi-
mately 10% of ureteroceles are bilateral (50).
Patients may be asymptomatic, but when
symptoms are manifested, they are varied and
relate to vesicoureteric junction obstruction and
reﬂux. Symptoms and signs include urinary tract
infection, urosepsis, frequency, hematuria, pain,
urinary retention, and stone disease. At cystos- Figure 34. Left posterior oblique radiograph of
copy, the wall of the ureterocele is smooth and the bladder shows a contrast material–ﬁlled ureter
covered by normal epithelium. The wall of the that creates a smooth ﬁlling defect within the blad-
der. As the ureter prolapses into the bladder, the
ureterocele consists of one layer of ureteral epi-
combined walls of the ureter and bladder create a
thelium and one of bladder urothelium, with in- radiolucent rim, the so-called cobra sign (arrow).
tervening connective tissue and muscle (50).
Imaging features of ureteroceles are character-
istic of the entity. At sonography, the classic ap- or distended at urography, with a radiolucent rim
pearance is a ﬂuid-ﬁlled intraluminal lesion aris- referred to as the “cobra sign” (Fig 34). At CT or
ing from the wall of bladder. The ureterocele is MR imaging, the ureterocele is a round ﬂuid-
contiguous with the ureter, and an associated ure- ﬁlled lesion. CT or MR urography allows a more
teral jet helps conﬁrm the diagnosis (Fig 33). As- comprehensive evaluation of the urinary tract
sociated duplicated or dilated upper tracts may be (Fig 35).
present. A ureterocele is a smooth ﬁlling defect of Management depends on symptoms, but treat-
variable size, depending on whether it is collapsed ment usually consists of surgical unrooﬁng of the
ureterocele and control of infection.
RG f Volume 26 ● Number 6 Wong-You–Cheong et al 1867
Figure 35. (a) Axial contrast-enhanced CT image shows a contrast material–ﬁlled ureterocele
(straight arrow) and a dilated, distal left ureter (curved arrow). (b) Coronal three-dimensional CT uro-
gram shows the ureterocele (arrow) and dilated left ureter to excellent advantage.
Conclusions 6. Heney NM, Young RH. A 33-year-old woman
with gross hematuria, case 39 –2003. N Engl
The discovery of a focal bladder mass usually re- J Med 2003;349:2442–2447.
quires pathologic evaluation. Although bladder 7. Sugita R, Saito M, Miura M, Yuda F. Inﬂamma-
neoplasms are common, there are a number of tory pseudotumour of the bladder: CT and MRI
nonneoplastic and inﬂammatory disorders that ﬁndings. Br J Radiol 1999;72:809 – 811.
can manifest as a focal bladder mass and mimic 8. Chapron C, Chopin N, Borghese B, et al. Deeply
inﬁltrating endometriosis: pathogenetic implica-
malignancy. Some of these entities, such as in- tions of the anatomical distribution. Hum Reprod
ﬂammatory pseudotumor, endometriosis, Crohn 2006;21:1839 –1845.
disease, diverticulitis, ureterocele, and benign 9. Batler RA, Kim SC, Nadler RB. Bladder endome-
prostatic hyperplasia, have radiologic features triosis: pertinent clinical images. Urology 2001;57:
highly suggestive of the diagnosis and should be 798 –799.
10. Bazot M, Darai E. Sonography and MR imaging
recognized by the radiologist to prevent unneces- for the assessment of deep pelvic endometriosis.
sary radical surgery. Diffuse bladder wall thicken- J Minim Invasive Gynecol 2005;12:178 –185.
ing has a longer list of differential diagnoses, and 11. Bazot M, Darai E, Hourani R, et al. Deep pelvic
clinical and pathologic correlation is required. endometriosis: MR imaging for diagnosis and pre-
diction of extension of disease. Radiology 2004;
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RadioGraphics RG Volume 26 • Volume 6 • November-December 2006 Jade J. Wong-You–Cheong et al
Inflammatory and Nonneoplastic Bladder Masses:
Jade J. Wong-You–Cheong, MD, et al
RadioGraphics 2006; 26:1847–1868 ● Published online 10.1148/rg.266065126 ● Content Code:
On T2-weighted MR images, inflammatory pseudotumor may appear heterogeneous, with a central
hyperintense component surrounded by a low-signal-intensity periphery (Fig 5); after administration
of contrast material, the periphery enhances while the central region enhances poorly (7).
Because imaging features may overlap, it is critical that the pathologist distinguish inflammatory
pseudotumor from rhabdomyosarcoma and myxoid leiomyosarcoma to prevent unnecessary radical
The typical MR imaging features of bladder endometriosis are hemorrhagic foci with high signal
intensity (representing blood) on fat-suppressed and non--fat-suppressed T1-weighted images (11).
Tuberculosis should be considered in patients with refractory cystitis, with sterile pyuria, or who
originate from countries where tuberculosis is more common. Immunocompromised patients with
acquired immunodeficiency syndrome or recipients of organ transplants are also at higher risk.
Crohn disease is the most frequent cause of ileovesical fistula and ileocolovesical fistula (42).