Urinary bladder pathology radiology

nice presentation for md student with imaging appoaches.

1. Imaging of Urinary bladder pathology Dr. Pradeep Kumar MD Radiodiagnosis

2. Introduction Fourth most common malignancy in men. Tenth most common in female Occur 3- 4 times more frequently in male. Upto 47% of cancer related death can be avoided so early diagnosis is important Survival of the patients with bladder cancer is longer than those with most other cancers.

3. Pathologic features About 90% of bladder tumors are urothelial in origin ( ie , transitional cell carcinomas). Squamous cell carcinomas account for 6%–8% Adenocarcinomas are rare and typically represent urachal cancer. Up to 25% of urothelial cancers have a mixed histology.

4. Risk factors Cigarette smoking in 50%–60% of men and one-third of women. occupational exposure to chemical carcinogens such as aniline dyes therapeutic irradiation of neighboring organs use of alkylating agents although it is rare. genetic predisposition to the development of urothelial tumors in some families. Risk factors for squamous cell cancer include long-term catheterization, nonfunctioning bladder, urinary tract calculi, and chronic infection by Schistosoma hematobium

5. Pathologic features Urothelial tumors are classified not invading muscle (superficial or papillary). Approximately 80%–85% of urothelial tumors invading muscle ( nonpapillary ) Approximately 20%–25% of bladder cancers are muscle invasive and includes squamous and adenocarcinoma.

6. Clinical staging most commonly present with painless hematuria (80%–90% of cases). CT/ Cystoscopy Some institutions perform computed tomographic (CT) urography for triage prior to cystoscopy, whereas others use cystoscopy as the first line of investigation. Magnetic resonance (MR) imaging of the pelvis is usually performed for T (tumor) staging once bladder cancer has been diagnosed.

7. TNM Staging Tumor Tx Primary tumor cannot be evaluated T0 No primary tumor Ta Noninvasive papillary carcinoma Tis Carcinoma in situ T1 Tumor invades connective tissue under the epithelium (surface layer) T2 Tumor invades muscle T2a Superficial muscle affected (inner half) T2b Deep muscle affected (outer half) T3 Tumor invades perivesical fat T3a Tumor is detected microscopically T3b Extravesical tumor is visible macroscopically T4 Tumor invades the prostate gland, uterus, vagina, pelvic wall, or abdominal wall

8. N – Regional Lymph Nodes NX: Regional lymph nodes cannot be assessed N0:No regional lymph node metastasis N1:Metastasis in a single lymph node in the true pelvis ( hypogastric , obturator , external iliac, or presacral ) N2:Metastasis in multiple regional lymph nodes in the true pelvis ( hypogastric , obturator , external iliac, or presacral ) N3: Metastasis in a common iliac lymph node(s)

9. M- Metastasis M0: No distant metastasis M1a: Non regional lymph nodes M1b: Other distant metastasis

10. Imaging Consideration USG Superficial bladder tumors may be seen as mass lesions of intermediate echogenicity . May be sessile or papillary, the latter being easier to detect, sometimes down to 2-3 mm diameter. Tumor may be seen infiltrating the bladder wall and extending through it in advanced cases

11. IVU Both IVU and ultrasound will fail to diagnose a substantial proportion of cases (with a detection rate as low as 26%). May demonstrate tumor but is more important in diagnosing alternative pathologies (renal cell carcinoma, calculi etc ). It has also been used to access upper urinary tract for detection of synchronous or metachronous lesion In some institution it has been used as a yearly surveillance investigation for detecting these lesion. However, its use is being controversial.

12. Computed Tomography CT urography has a sensitivity and specificity of over 90% for the diagnosis of bladder cancer in patients with hematuria. Despite these encouraging results, CT urography cannot be used as a replacement for diagnostic cystoscopy in most patients with suspected bladder cancer.

13. It is possible to visualize bladder wall enhancement and thickness on nephrographic phase CT scans. Virtual cystoscopy has been performed with the installation of 300–500 mL of air or carbon dioxide into the bladder lumen via a catheter. Some small series have shown CT cystoscopy to have a sensitivity of over 90%.

14. MR Imaging Requires high spatial resolution, thin sections (3 mm), and a large matrix. More accurate staging than CT :high soft-tissue contrast resolution, which allows clear differentiation between bladder wall layers. Better depict intramural tumor invasion as well as extravesical extension. Allows differentiation between muscle-invasive and non-muscle-invasive disease No ionizing radiation.

15. Local staging of bladder cancer: a multiparametric approach with conventional and functional sequences is useful. Multiparametric MRI: combination of T1- and T2-weighted images and functional MRI techniques, including DCE imaging and DWI. Axial spin-echo (SE) T1-weighted images with a large FOV : for evaluating the perivesical fat planes for extravesical tumor infiltration, pelvic lymphadenopathy, and bone metastases.

16. Dynamic Contrast Enhanced MR Imaging . The usefulness of dynamic contrast-enhanced T1-weighted MR imaging is debatable, with some studies showing that it is a useful technique and others showing that it is of no additional value The bladder tumor, mucosa, and submucosa enhance early (20sec), but the muscle layer maintains its hypointensity and enhances late (60 sec)

17. Diffusion-weighted MR Imaging Role of diffusion-weighted imaging in bladder cancer is evolving and has not yet been fully established. Provides both qualitative and quantitative information that reflects changes at the cellular level concerning tumor cellularity and cell membrane integrity. For most bladder tumors, increased cellular density manifests as increased signal intensity on diffusion-weighted images with a reduced apparent diffusion coefficient (ADC) at quantitative analysis

18. Positron Emission Tomography Positron emission tomography (PET) with 2-[fluorine-18]fluoro-2-deoxy-d-glucose is considered to be of lesser value in the local staging of bladder cancer due to urinary excretion of the radiotracer

19. The most common site of nodal metastasis is the obturator nodes . Conventional CT and MR imaging cannot help identify metastases in lymph nodes less than 10 mm. According to recent published reports, diffusion-weighted imaging has shown promise in differentiating benign from malignant lymph nodes

20. Treatment Non-Muscle-invasive Disease Non-muscle-invasive tumors are usually treated with TURBT. in patients with bulky Ta lesions or T1 tumors, the current trend is to perform repeat TURBT 2–6 weeks after the first TURBT. adjuvant intravesical chemotherapy ( eg , with mitomycin C or gemcitabine) or immunotherapy (with bacille Calmette-Guérin [BCG]). Muscle-invasive Disease For muscle-invasive tumors, radical cystectomy is the established treatment with meticulous extended bilateral lymphadenectomy, since extent of lymphadenectomy is associated with survival.

21. Post-treatment Surveillance Because of the high rate of local recurrence, patients with non-muscle-invasive bladder cancer must be followed up after treatment Cystoscopy, urine cytology, and imaging of the upper tract with retrograde ureteroscopy are usually performed annually. muscle-invasive bladder cancer, guidelines for post-cystectomy surveillance include urine cytology, chest radiography, and abdominopelvic imaging every 3–6 months for the first 2 years.

22. Rare malignancies Urachal carcinoma Less than 0.5% of bladder cancer. Overwhelmingly adenocarcinoma Vast majority arise in the urachus immediately adjacent to the bladder vault and extends superiorly in the perivesical space towards the umbilicus and inferiorly to the bladder. Considerable extra vesical component and the position in the bladder vault should suggest the urachal rather than bladder carcinoma. Are often mucinous and two third show dystrophic calcification which may be punctate or curvilinear. Three fifth of the cases also show cystic degeneration with mucinous component

23. Mimics of urinary bladder carcinoma Inflammatory pseudotumor Pathogenesis: Unclear Can be locally aggressive and mimic malignancy Imaging: Usually solitary bladder mass ( exophytic or polypoid ) 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).

24. Malacoplakia Rare granulomatous inflammation which can involve any organ, urinary tract commonest. Multiple, polypoid , vascular, solid masses or circumferential wall thickening. Can invade perivesical space and even cause bladder obstruction, A/w VUR and hydroureteronephrosis. bone destruction. (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 thickening.

25. eosinophilic cystitis

26. Schistosomiaisis 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.

27. Leiomyoma Leiomyoma is the most common mesenchymal tumor of the bladder. Leiomyomas occur equally in men and women with a wide age range of 22–78 years. Imaging features include either a smooth indentation of the bladder wall or an intraluminal mass. They are smooth, solid, homogeneous masses. Cystic components indicate degeneration. MR imaging is superior in demonstrating the submucosal origin of the tumor and the preservation of the muscle layer and also most specific for tissue characterization .Typically, leiomyomas exhibit intermediate signal intensity on T1-weighted images and low signal on T2.

28. Leiomyosarcoma Leiomyosarcoma is the most common nonepithelial malignant bladder tumor in adults. age range is wide at 25–88 years with a male-to-female ratio of 3:1 necrosis is common in leiomyosarcomas, which tend to be poorly circumscribed, invasive masses with a mean size of 7cm . Consequently, they are more heterogeneous on T2-weighted images and demonstrate nonenhancing areas secondary to necrosis.

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