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Neoplasia of the bladder is most commmon in dogs, cats and cattle.
Benign tumours
Leiomyoma
- Occur in the smooth muscle of the bladder wall.
- May be single or multiple, well defined white nodular projections.
- If situated at the neck of the bladder, they can disrupt urinary flow.
Papilloma
- Bladder papillomas are uncommon.
- Will often recur following excision.
- Can lead to carcinomas.
Botryoid rhabdomyosarcoma
- Occurs in the bladder and less commonly the urethra of large breed dogs less than 18 months of age.
- Embryonic myoblasts may be the origin.
- Appears as a large fungating mass, usually at the trigone of the bladder.
- Highly infiltrative and metastatic.
Bovine enzootic haematuria
Malignant tumours
Transitional cell carcinoma
- Most relevant in dogs and cats.
- Spreads along and through the bladder wall.
- Destroys the epithelium and invades the muscle layers.
- Metastasis to regional nodes and the lungs occurs in approximately 50% of cases.
- Can also spread to the peritoneum or in a retrograde manner to the soft tissue and bone of the hindlimbs.