Pathology of the lower urinary tract Flashcards
Structural/congenital defects of the lower urinary tract
Bladder
- diverticuli
- exstrophy
- vesicouretral reflux
Ureter
- double/bifid ureter
- uteropelvic junction anomalies
Diverticuli
Outpouching of bladder wall, 1 - 10 cm in diameter
Congenital –> Focal failure of development of normal musculature
- Urinary tract obstruction during fetal development
Acquired –> Secondary to Obstruction - marked muscle thickening of the bladder wall
- Most often secondary to prostatic enlargement
- Multiple with narrow necks located between hypertrophied muscle bundles.
Complications
- urinary stasis – leads to infections
- infections
- calculi
- vesicoureteric reflux
- malignancy
Exstrophy
Developmental failure of the anterior wall of the abdomen –> bladder communicates to the exterior
Complications
- infection
- ulceration
- increased risk of adenocarcinoma
Treatment
- after surgical correction, long term survival
Vesicoureteral reflux
Most common and most serious = incompentence of the vesicoureteral valve
- congenital –> absence or shortening of the intravesicle portion of the ureter - prevents compression of ureter during micturation
- acquired –> can result from bladder atony in adults, due to spinal cord injury
- bladder infection can accentuate vesicoureteral reflux
Complications
- pyelonephritis
- renal scarring
Congenital/structural defects of the ureter
Double/bifid ureter –> usually no clinical significance
Ureteropelvic junction obstruction
- congenital
- M>F
- most common cause of hydronephrosis in children
Causes of obstruction
- urinary calculi (stones) –> deposition of minerals (calcium phosphate, uric acid, calcium oxalate)
- –> can be extremely painful and cause obstruction
- –> various treatments
- blood clots
- strictures
- neoplasms
Inflammation/infections
- UTI/infectious cystitis
- interstitial cystitis
- malakoplakia
- polypoid cystitis
Cystitis
- causes
- symptoms
Causes
- bacterial –> vast majority = enterobacteriaciea, esp. e coli
- fungal (candida, crypto, etc), can occur in immunosuppressed patients
- parasitic –> shistosomiasis (middle east/egypt) is associated with increased risk of squamous cell carcinoma
- anticancer tx –> cytotoxic drugs (cyclophosphamide) and radiation
Symptoms
- urinary frequency
- pain localized to bladder - suprapubic
- dysuria - pain or burning on urination
- systemic symptoms may be present = fever, chills, malaise
- untreated UTIs may lead to pyelonephritis
Most are sporadic –> if underlying cause exists, needs to be corrected
- prostatic enlargement
- cystocele of the bladder
- calculi
- tumors
Cystitis - morphology
Grossly = RED
- hyperemia
- exudates
- hemorrhage
- ulcerations
Microscopic
- inflammatory cells
- edema
- reactive epithelial changes
- acute –> neutrophils
- chronic –> lymphocytes + plasma cells
Interstitial cystitis
Form of chronic cystitis - etiology unknown
- Urine is sterile. Many patients have autoimmune diseases. (not infectious)
- Trauma, structural defects, infections, immunologic derangements may play a role
- Affects women»_space; men.
- Usually highly incapacitating and difficult to treat.
Symptoms:
- frequency, nocturia, urgency, suprapubic pressure
- pelvic pain on bladder filling, relieved by voiding***
Pathology –> Non-specific
- chronic Inflammation
- edema
- ulceration
- fibrosis.
Malacoplakia
Mass lesion, typically in bladder or kidney, but can be seen elsewhere
- chronic bacterial infection, mostly by E. coli or occasionally proteus
- more common in immunosuppressed transplant patients –> can’t clear infection
Gross –> yellow, raised mucosal plaques
Histology
- foamy macrophages
- giant cells
- lymphocytes
- rounded mineralized inclusions (calcium phosphate) = Michaelis Gutmann bodies
Polypoid cystits
Polypoid inflammatory lesion of the bladder –> results from irritation (most commonly from indwelling catheter)
Microscopically
- broad, bulbous polypoid projections
- marked submucosal edema and inflammatory cells
Confused with papillary urothelial carcinoma - both clinically and histologically
Neoplasms
Malignant
- urothelial carcinoma = 90% –> all others are rare
- squamous cell carcinoma
- adenocarcinoma
- small cell carcinoma
- sarcomas
Benign - all are rare
- papilloma
- benign spindle cell tumors
Uncertain
- PUNLMP
Urothelial carcinoma - epidemiology + risk factors
- male >female
- most patients are between 50 and 80 years of age at diagnosis
- bladder carcinomas account for 3% of cancer deaths in the USA
Risk factors
- smoking
- exposure to aniline dyes (textile, printing, plastic and rubber industries)
- chronic irritation (calculi, diverticula, parasites, chronic cystitis)
- analgesic abuse nephropathy
Tumors tend to recur multiple times - usually at different location
- over time, may become less differentiated and more aggressive
Urothelial carcinoma
- flat lesions
Flat lesions
- hyperplasia - thickening
- atypia - reactive
- dysplasia - low grade
- carcinoma in situ - high grade lesion of urothelium that is flat = most important lesion
- –> flat by definition
- –> high grade cytology = very ugly cells, lots of mitoses
- –> confined to mucosa
- –> precursors to invasive carcinoma
Urotherlial carcinoma - papillary lesions
- papilloma
- papillary neoplasm of low malignant potential - PUNLMP
Papillary lesions = finger like projections above the surface of the epithelium + fibrovascular cores
Papilloma –> rare, benign, typically younger patients, does not recur
- normal looking urothelium arranged on delicate fibrovascular stalks
Papillary neoplasm of low malignant potential (PUNLMP)
- thickened epithelium
- no atypia, at most nuclear enlargement
- at most rare mitoses at base
- no invasion
- potential for recurrence
Urothelial carcinoma - papillary lesions
- papillary carcinoma, low grade
- papillary carcinoma, high grade
Papillary carcinoma, low grade
- branching papillae, lined by cells in orderly arrangement
- nuclei uniformly enlarged with mild variation in size, shape and chromatin pattern
- scattered mitoses at all levels
- recurrence common
- invasion is rare - no mets
Papillary carcinoma, high grade
- overtly malignant - marked atypia analogous to CIS
- numerous mitotic figures including atypical ones at all levels
- overall disorderly arrangement with irregularly clustered cells + fused papillae
- dyscohesive single cells
- recurrence common –> invasion of stroma common - mets possible
Invasive urothelial carcinoma
Cells penetrate basement membrane into lamina propria
- may occur in association with CIS (flat) or high grade papillary urothelial carcinoma
- no clear prognostic difference between the two
Urothelial carcinoma staging
Based on the depth of invasion and the presence of mets
Tis: Flat CIS Ta: non-invasive papillary T1: Invision of lamina propria T2: Invasion of muscularis propria T3: Invasion into perivesicle fat T4: Direct spread to adjacent organs
Urothelial carcinoma
- symptoms
Symptoms - painless hematuria
- an elderly patient, especially male, with even one episode of hematuria should have a malignancy work up because of the high incidence of malignancy in the > 65 male age group
Urothelial carcinoma
- diagnosis
- treatment
Diagnosis
- urine cytology –> pretty good sensitivity for high grade tumors, but misses low grade
- cystoscopy –> good for papillary lesions, less sensitive for CIS
- combining both gives good sensitivity for low/high grade lesions
TX
Resection
- Transurethral (TURBT) –> Non-invasive, or lamina propria invasion
- Cystectomy (partion or radical) –> Muscularis propria invasion
Topical therapy
- Bacille Calmette-Guerin (BCG)
- Intravesicle chemotherapy
Systemic chemotherapy
- High-stage tumors
Squamous cell carcinoma
Rhabdomyosarcoma
Squamous cell carcinoma - Rare in US - strongly associated with schistosoma hematobium infections
Rhabdomyosarcoma - most common bladder tumor in kids
