spinal cord tumors

BACKGROUND

Spinal cord tumors are rare in cats and dogs. The most common spinal cord tumors are lymphoma in cats and meningioma in dogs. The majority of cats with spinal lymphoma are FeLV positive. Other spinal cord tumors include intradural-extramedullary spinal cord tumor of young dogs (also known as nephroblastoma and ependymoma) and glial tumors such as astrocytomas, oligodendroglioma, and choroid plexus tumors. The spinal cord can also be affected by extension of peripheral nerve tumors into the spinal canal. Spinal cord tumors cause neurologic dysfunction with clinical signs being dependent on their location along the spinal cord. Metastasis is rare.

DIAGNOSIS

Survey and contrast radiographs (myelogram) are important to rule out other causes of neurologic disease, such as intervertebral disk disease and vertebral tumors. The contrast pattern on the myelogram is used to classify spinal cord tumors as extradural, intradural-extramedullary, or intramedullary. Meningiomas and peripheral nerve sheath tumors are the most common intradural-extramedullary spinal cord tumors. Advanced imaging is also useful for the localization of spinal cord tumors. MRI is preferred but CT scans, particularly when combined with a myelogram, can also be useful.

CLINICAL STAGING

For cats, palpation of external lymph nodes, blood tests (including FeLV and FIV), thoracic radiographs, and abdominal ultrasound are recommended for clinical staging because of the high risk of multicentric lymphoma. Metastasis is uncommon in dogs with spinal cord tumors, but abdominal ultrasound and thoracic radiographs should be considered.

TREATMENT

Treatment options depend on tumor location, extent of the tumor, and suspected tumor type. Surgery has two possible aims: surgical excision of the tumor and/or palliative decompression of the spinal cord by removing overlying bone. Surgical excision of spinal cord tumors can be complicated by adhesions and their friable nature. Radiation therapy is recommended for incompletely excised spinal cord tumors, extensive and inoperable tumors, and cats with spinal lymphoma. Cats with spinal lymphoma should also receive chemotherapy.

PROGNOSIS

The prognosis for cats with spinal cord tumors in guarded. The median survival time for cats with spinal cord lymphoma treated with radiation therapy and chemotherapy is 125 days and this is significantly better than corticosteroids alone, chemotherapy alone, or the combination of surgical decompression and corticosteroids. The prognosis is better for non-lymphoid spinal cord tumors with a median survival time of 180 days for surgically excised meningiomas.

The prognosis for dogs is guarded to good. The overall median survival time following surgical excision or decompression of meningiomas is 240 days. The prognosis is worse for dogs with spinal cord tumors at the cervicothoracic or lumbrosacral junction, ventrally located tumors, and when the spinal cord is damaged during tumor excision. The median survival time following treatment of intradural-extramedullary spinal cord tumors with surgery and radiation therapy is 17 months.

To be udated