Rhabdomyosarcoma of the Urinary Bladder in Cats
Rhabdomyosarcoma is a very rare metastasizing (spreading), and malignant type of tumor. It may derive from stem cells, or originate in the striated muscle that surrounds the developing Müllerian or Wolffian ducts. Müllerian ducts begin as two ducts in the female embryo, developing into the vagina, uterus and oviducts, while Wolffian ducts begin in the male embryo, developing into the tubes that carry sperm from the testicles through the penis (vas deferens).
Rhabdomyosarcoma of the urinary bladder may be reported as botryoid rhabdomyosarcomas due to their tendency to take on the appearance of grape clusters. They often spread to the internal organs and lymph nodes.
Symptoms and Types
- Predominantly consistent with a lower urinary tract infection
- Blood in the urine
- Straining to urinate
- Frequent urination in small quantities
- Urine retention/inability to urinate
Your veterinarian will perform a complete physical exam on your cat, with a blood chemical profile, a complete blood count, a urinalysis and an electrolyte panel. You will need to provide a thorough history of your cat's health leading up to the onset of symptoms. If rhabdomyosarcoma is, in fact, present, the urinalysis will show bloody urine, and a cytologic (microscopic) examination of urine sediment will indicate rhabdomyosarcoma.
The bladder may be internally examined using ultrasound, or double-contrast cystourethrography imaging (which uses an injection of dye into the bladder and urethra to show the structures more distinctly). An intravenous pyelography can also be used for examining the kidney and bladder, to evaluate any trigonal mass, and to assess the ureters (the tubes that carry urine from the kidney to the bladder), and the renal pelvis (the center of the kidney where the urine funnels into the ureters). This method also uses the injection of a dye to visually examine the internal structure of these organs.
A definitive diagnosis can be made from an examination of the diseased tissue (histopathology) using tissue samples (biopsies) obtained from exploratory surgery, or from cystoscopy – an examination of the bladder and ureters, performed by inserting a tube through the urethra.
Surgical removal of the rhabdomyosarcoma is recommended, but it is difficult to perform, since these tumors are highly invasive. If the bladder is also inflamed due to a bacterial infection, antibiotics will be prescribed based on culture and sensitivity tests.
Living and Management
Your veterinarian will schedule follow-up appointments to follow your cat's progress every three weeks during chemotherapy therapy, and every three months after the of course of chemotherapy has ended.