Urinary tract neoplasia Flashcards
Are neoplasms of the kidney common in dogs?
- no
- represent 0.5-1.7% of all neoplasms in dogs
Are benign tumours of the kidney common?
- no
Examples of benign tumours of the kidney
- adenoma
- lipoma
- fibroma
- papilloma
Which age groups are neoplasms of the kidney most common in?
- middle-aged to older animals
Is there a breed predilection for kidney neoplasms?
- no
- except for heritable predilection for the development of bilateral, multifocal cystoadenocarcinomas in German Shepherds, generally between 5-11y)
What is the most common renal neoplasm?
Characteristics/description?
- renal carcinoma
- usually unilateral, located at 1 pole of the kidney and well demarcated
- size varies from microscopic to bigger than the normal kidney
- metastasise early to various organs
– opposite kidney
– lungs
– liver
– adrenals
What neoplasm of the kidney arises from vestigial embryonic tissue?
Age most commonly affected?
Breed predilection?
Males or females more commonly affected?
Unilateral or bilateral?
Metastasis?
- nephroblastomas (embryonal nephroma, Wilms’ tumour)
- seen in young animals
- in dogs, most commonly diagnosed <1y/o
- no breed predilection
- males affected twice as commonly as females
- usually unilateral
- grow to immense size, not uncommon to have basically entire abdomen occupied by tumour
- mets can occur to regional LN, liver & lungs
Where can transitional cell carcinomas arise from (i.e. what cell, what organs?)
- from transitional epithelium of the renal pelvis, ureter, bladder or urethra
Other than TCC are primary malignant renal neoplasms common? Give examples of some
- uncommon
- include
– haemangiosarcomas
– fibrosarcomas
– leiomyosarcomas
– SCC
Are the kidneys a common site for mets or multi centric neoplasms?
- yes
Are mets lesions uni or bilateral?
- can be either / both
What is the most common multi centric tumour involving the kidneys?
- lymphosarcoma
– as many as 50% dogs and cats with lymphosarcoma have renal lesions, and in some cases, only the kidneys or kidneys & brain are affected
CS of renal neoplasia
- Haematuria, dysuria, stranguria, and pollakiuria are the most common signs
- Animals with ureteral obstruction and unilateral hydronephrosis may show signs of abdominal pain and have a palpable, enlarged kidney
- Signs of uraemia may be apparent in animals with bilateral ureteral obstruction and hydronephrosis or with urethral obstruction
- The bladder wall may be thickened, and a cord-like urethra or urethral mass(es) may be palpable rectally
Diagnosis of renal neoplasia
- history
- CS
- US
- urinalysis
- radiography (contrast)
- CT
Tx of renal neoplasia
- majority except lymphosarcoma involves surgical removal
– unilateral nephrectomy is usually needed - lymphosarcoma -> combination chemo
– chemo is generally ineffective against renal tumours other than lymphosarcoma
Are neoplasms of the lower urinary tract (ureters, bladder and urethra) common in dogs and cats?
- uncommon in dogs
- rare in cats
Theory for low incidence of neoplasms of the lower urinary tract in cats?
- difference in tryptophan metabolism that results in low urinary concentrations of carcinogenic tryptophan metabolites
Mean age for dogs/cats affected by neoplasms of the lower urinary tract
- 9 y/o
In the lower urinary tract are primary neoplasms more likely to be benign or malignant?
- malignant
What neoplasms are infrequently found in the lower urinary tract?
- papillomas
- leiomyomas
- fibromas
- neurofibromas
- haemangiomas
- rhabdomyomas
- myxomas
What is the most commonly diagnosed primary malignant neoplasm of the lower urinary tract?
- TCC
What neoplasms are found more frequently in the lower urinary tract?
- TCC
- SCC
- adenocarcinomas
- fibrosarcomas
- leiomyosarcomas
- rhabdomyosarcomas
- haemangiosarcomas
- osteosarcomas
Where do transitional cell carcinomas arise? What do they look like?
- solitary or multiple papillary-like projections from the mucosa
- can develop as a diffuse infiltration of the ureter, bladder, prostate and/or urethra
Which breeds are more commonly affected by cystic transitional cell tumours?
- Scottish terriers
What previous therapy has been linked to cystic transitional cell tumours?
- cyclophosphamide
- also may be linked to exposure to herbicides and older-generation insecticides
TCC: mets?
- highly invasive
- mets frequently
- most commonly to regional LN and lungs
CS of lower urinary tract neoplasia
- ureteral and bladder neoplasms can cause chronic obstruction to urine flow with secondary hydronephrosis
- urethral tumours are more likely to cause acute obstructive uropathy
- intractable secondary bacterial UTIs are commonly associated with neoplasms of the bladder and urethra
Diagnosis of lower urinary tract neoplasia
- Hx & CS
- urinalysis: haematuria, may be evidence of secondary infection
- neoplastic cells may be found in sediment, esp with TCC
- veterinary bladder tumour antigen test or the BRAF mutation test can be helpful for bladder tumours in dogs, but false results do occur
- cystourethrogram, retrograde urethrogram or US generally needed to determine the location and extent of the tumour
- biopsy needed for definitive diagnosis
Tx of lower urinary tract neoplasia
- Excision of the tumour, if possible, is the most beneficial therapy
- TCCs are frequently located at the trigone
of the bladder or in the urethra and may necessitate radical
reconstructive surgery of the lower urinary tract - Prognosis is poor for these animals, even with surgery, because
recurrence and metastasis occur rapidly - Radiation therapy and/or chemotherapy with piroxicam, cisplatin,
doxorubicin, vinblastine, chlorambucil, or mitoxantrone will
generally prolong the life of affected animals - Palliative stenting of the urethra is sometimes considered for
tumours of the bladder neck and urethra
Primary causes of urethral obstruction
Intraluminal
– Plugs
– Uroliths
– Sloughed tissue
Mural or extraluminal
– Neoplasms
– Strictures
– Anomalies
– Reflex dyssynergia
Combinations
Perpetuating causes of urethral obstruction
Intraluminal
– Sloughed tissues
– Inflammatory cells and clots
– Increased production of mucoprotein
Mural or extraluminal
– Inflammatory swelling
– Muscular spasm
– Strictures
Combinations
Iatrogenic causes of urethral obstruction
- Tissue damage
– Retrograde flushing solutions
– Catheter trauma
– Catheter-induced foreign body reaction
– Catheter-induced infection - Post surgical dysfunction
What will persistent complete urethral obstruction generally cause classic signs of?
- post-renal failure
What does post-renal urinary tract obstruction result in?
- severe azotaemia
- hyperkalaemia
- metabolic acidosis
Immediate relief of urethral obstruction methods
- urethral catheterisation
- therapeutic cystocentesis
Removal of urethral plugs methods
- restraint
- use of muscle relaxants
- use of reverse flushing solutions
- catheter
Use of reverse flushing solutions
Walpole’s solution (buffered acetic acid)
- pH of 4.5
- acid solutions precipitate proteins
- little or no effect on crystals other than struvite
- little effect on uroliths
- potential for systemic absorption
- local irritant effect (urethritis)
- DO NOT USE
Catheters for urethral plug removal
- Jackson cat catheter
- lacrimal catheter (if v small, e.g. for rabbits)
- Slippery Sam catheter
How to localise urethral obstruction
- best achieved by retrograde positive contrast urethrocystography
- abdo US
Surgical options for urethral obstruction
- Tube cystotomy and urethral stenting
- Perineal urethrostomy (based on Wilson-Harrison technique)
- Prepubic urethrostomy
- Subpubic urethrostomy (transpelvic urethrostomy)
Complications of feline perineal urethrostomy
- haemorrhage
- wound dehiscence
- SC urine leakage
- urinary incontinence
- UTI
- urethral (stoma) stricture
