From the Archives of the AFIP Dysuria

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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
                and distinguishing
                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:

                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

RadioGraphics                     Introduction
                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
                                                                             after resection.
                                                                                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-
                enoma (19).
                   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).
                       cystitis glandularis.

                   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
                cholinergic agonist.
                              Cystitis Cystica
                          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-
                pria (*).

                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
                   squamous carcinoma.
                      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.

                                  Crohn Disease
                   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
                                                                         musculature (arrowheads).

                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-
                dular hyperplasia.

                   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;
                                                                                  232:379 –389.
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                This article meets the criteria for 1.0 credit hour in category 1 of the AMA Physician’s Recognition Award. To obtain
                credit, see accompanying test at
RadioGraphics   RG     Volume 26 • Volume 6 • November-December 2006                               Jade J. Wong-You–Cheong et al

                Inflammatory and Nonneoplastic Bladder Masses:
                Radiologic-Pathologic Correlation
                  Jade J. Wong-You–Cheong, MD, et al
                  RadioGraphics 2006; 26:1847–1868 ● Published online 10.1148/rg.266065126 ● Content Code:

                Pages 1611
                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).

                Page 1612
                Because imaging features may overlap, it is critical that the pathologist distinguish inflammatory
                pseudotumor from rhabdomyosarcoma and myxoid leiomyosarcoma to prevent unnecessary radical

                Page 1613
                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).

                Page 1615
                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.

                Page 1618
                Crohn disease is the most frequent cause of ileovesical fistula and ileocolovesical fistula (42).

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