Primary skeletal muscle tumors can be benign (rhabdomyoma) or malignant (rhabdomyosarcoma). Secondary tumors involved with metastatic spread include lymphosarcoma, hemangiosarcoma, and adenocarcinomas. Local tumors (fibrosarcoma, osteosarcoma, mast cell tumors) can invade adjacent muscle. Lipomas can also invade intermuscular tissue spaces.
Clinical signs include localized swelling and lameness Overview of Lameness in Small Animals Clinical signs of musculoskeletal disorders include weakness, lameness, limb swelling, and joint dysfunction. Motor or sensory neurologic impairment may develop secondary to neuromuscular lesions... read more . Diagnosis is confirmed by biopsy and histologic evaluation of the samples. Treatment is by surgical excision or limb amputation; chemotherapy and radiation may be used depending on the tumor type.
Also see pet health content regarding muscle tumors in dogs Muscle Tumors Myopathies are diseases that primarily cause damage to muscles or muscle tissues. They may be present at birth or occur due to nutritional imbalances, injury, metabolic disturbances, cancer... read more and muscle tumors in cats Muscle Tumors Myopathies are diseases that primarily cause damage to muscles or muscle tissues. They may be present at birth (congenital) or occur due to nutritional imbalances, muscle injury, ingestion of... read more .