According to the National Canine Cancer Foundation, one out of three dogs will suffer from some form of cancer, and more than half of those dogs will die as a direct result. For any owner, cancer can be a frightening diagnosis. Fortunately, dogs diagnosed with nerve sheath tumors usually have a fairly good prognosis.
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Identification
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The nervous system, like all other areas of the body, is subject to developing a tumor. A tumor that occurs on a nerve is referred to as a nerve sheath tumor. These tumors are a type of soft tissue tumor that evolve from myelin. Myelin is the layer of tissue surrounding the nerve. Tumors that affect the nervous system may go by many different names, including peripheral nerve sheath tumors, Schwannomas, fibrosarcomas and hemangiopericytomas.
Symptoms
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One common symptom of a nerve sheath tumor is a lameness of either the front or hind legs. This is often accompanied by pain that may be mild to severe. The dog may whine or refuse to move, both of which can be an indication of pain. Some dogs may have a palpable tumor, meaning that the tumor can be felt―or even seen―beneath the skin. Additional symptoms may include a loss of muscular movement or paralysis of certain muscles, such as the facial muscles (due to a tumor in the nerves of the neck) or leg muscles (due to a tumor in the leg nerves).
Diagnosis
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Since these tumors affect the nerves and muscular movement, it may be difficult to come to the right diagnosis. The affected canine will undergo a series of tests including a urinalysis, an electrolyte panel and several blood tests such as a complete blood count and a blood chemical profile. If nothing turns up during these tests, additional tests will be run, including a CT scan or an MRI, an electromyogram or an ultrasound, to rule out other potential neurological diseases.
Treatment
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Once a tumor has been identified, surgical removal is often the first option. If the nerve sheath tumor is located on one of the limbs, amputation may be vital due to the rare but highly metastatic nature of some nerve sheath tumors. If the tumor is located on the spinal cord, a laminectomy may be necessary. A laminectomy is an operation in which a section of vertebral bone is removed. Radiotherapy may also be beneficial in some cases. Approximately 72 percent of these dogs will require a second surgery, because these tumors have been known to regrow.
Prognosis
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As with any cancer, the prognosis can be rather guarded. Dogs whose tumor is located closer to the paw in the leg have a greater chance of survival in comparison to dogs whose tumor is located in the spinal cord. The average survival time for a canine with a nerve tumor is approximately two years. Overall, metastasis is rare though highly invasive when it does occur. Therefore, most dogs have a relatively good prognosis as long as metastasis does not occur.
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