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Rhabdomyosarcoma in Dogs

Rhabdomyosarcomas are malignant, aggressive, easily metastasizing (spreading) tumors. They arise from striated muscles (banded - not smooth, muscles of the skeletal and cardiac musculature) in adults, and from embryonic stem cells in juveniles. These tumors are often found in the larynx (voice box), the tongue, and in the heart. Aggressive and widespread metastasizing can occur in the lungs, the liver, the spleen, the kidneys, and the adrenal glands.

The condition or disease described in this medical article can affect both dogs and cats. If you would like to learn more about how this disease affects cats please visit this page in the PetMD pet health library.

Symptoms and Types

• Large, diffuse, soft tissue mass, generally of the skeletal muscle
• May spread into the primary muscle (forming multiple nodules)
• If tumor is in the heart there may be signs of right-sided congestive heart failure

Causes

• Idiopathic (unknown)

Diagnosis

Your veterinarian will perform a complete physical exam, including a chemical blood profile, a complete blood count, a urinalysis, and an electrolyte panel. You will need to provide a thorough history of your dog's health leading up to the onset of symptoms. While a cytologic (microscopic) examination of a fine-needle aspirate sample may reveal cancer, a definitive diagnosis can only be made with a surgical biopsy (tissue sample).