Nerve Sheath Tumor in Dogs

Nerve sheath tumors are tumors that grow from the myelin sheath that covers the peripheral and spinal nerves. This type of tumor affects the nervous system of the body, as it compromises the functioning ability of the peripheral and/or spinal nerves that form the peripheral nervous system and which reside or extend outside the central nervous system (CNS). Over 80 percent of such tumors affect the forelimbs of dogs. Any breed and gender may be affected.

Symptoms and Types

• Progressive and chronic lameness in forelimb (common symptom)
• Muscle wasting
• Decreased muscle tone
• Uncoordinated movements
• Limb weakness

Causes

The exact cause is not known.

Diagnosis

You will need to give your veterinarian a thorough history of your dog's health, including a background history and onset of symptoms. Your veterinarian will conduct a complete physical examination with laboratory tests, including complete blood count (CBC), biochemistry profile, and urinalysis. The results of these routine laboratory tests are usually within normal ranges. The cerebrospinal fluid (CSF), the protective and nourishing fluid that circulates around the brain and spinal cord, will also be tested, but the findings are usually non-specific. For confirmation of the diagnosis your veterinarian may need to take biopsy samples from the nerve sheaths using ultrasound guidance. Radiographic studies, including x-rays, magnetic resonance imaging (MRI), and computed tomography (CT-scan) will provide further information for a solid diagnosis. MRI is the most specific test for diagnosis of this disease.