A spinal tumor is abnormal tissue that grows within or surrounding the spinal cord and spinal column. These tumors can be benign (noncancerous) or malignant (cancerous). Primary tumors originate in the spine or spinal cord and metastatic (secondary) tumors result from cancer spreading from another site to the spine.
Spinal tumors are divided according to location into three major groups: intradural-extramedullary, intradural-intramedullary, and extradural.
- Intradural-extramedullary: These tumors develop in the spinal cord’s arachnoid membrane (meningiomas), in the nerve roots that extend out from the spinal cord (schwannomas and neurofibromas) or at the spinal cord base (filum terminale ependymomas). Although meningiomas are often benign, they can be difficult to remove and may recur. Nerve root tumors are also generally benign, although neurofibromas may become malignant over time. Ependymomas at the end of the spinal cord can be large, and treatment may be complicated by the delicate nature of fine neural structures in that area.
- Intramedullary: These tumors grow inside the spinal cord or individual nerves, most frequently occurring in the cervical (neck) region. They typically derive from glial or ependymal cells that are found throughout the spinal cord. Astrocytomas and ependymomas are the two most common types.
- Extradural: These lesions are typically attributed to metastatic cancer or schwannomas derived from the cells covering the nerve roots. Occasionally, an extradural tumor extends through the intervertebral foramina, lying partially within and partially outside of the spinal canal.
Metastatic spinal tumors
The spinal column is the most common site for bone metastasis. Common primary cancers that spread to the spine are lung, breast and prostate. Lung cancer is the most common cancer to metastasize to the bone in men, and breast cancer is the most common in women. Other cancers that spread to the spine include gastrointestinal tract, lymphoma, melanoma, kidney, sarcoma and thyroid.
Prompt diagnosis and identification of the primary malignancy is crucial to overall treatment. Numerous factors can affect outcome, including the nature of the primary cancer, the number of lesions, the presence of distant metastases and the presence and/or severity of spinal cord compression.
The cause of most primary spinal tumors is unknown. Spinal cord lymphomas, which are cancers that affect lymphocytes (a type of immune cell), are more common in people with compromised immune systems. There appears to be a higher incidence of spinal tumors in particular families, so there is most likely a genetic component. In a small number of cases, primary tumors may result from presence of these two genetic diseases:
- Neurofibromatosis 2: In this hereditary disorder, benign tumors may develop in the arachnoid layer of the spinal cord or in the supporting glial cells (neurofibromas/schwannomas).
- Von Hippel-Lindau disease: This rare, multisystem disorder is associated with benign blood vessel tumors (hemangioblastomas) in the brain, retina and spinal cord and with other types of tumors in the kidneys or adrenal glands.
Nonmechanical back pain, especially in the middle or lower back, is the most frequent symptom of both benign and malignant spinal tumors. This back pain is not specifically attributed to injury, stress or physical activity. However, the pain may increase with activity and is often worse at night. Pain may spread beyond the back to the hips, legs, feet or arms and may worsen over time, even when treated by conservative, nonsurgical methods that can often help alleviate back pain attributed to mechanical causes.
Depending on the location and type of tumor, other signs and symptoms can develop, especially as a malignant tumor grows and compresses on the spinal cord, the nerve roots, blood vessels or bones of the spine. Impingement of the tumor on the spinal cord can be life-threatening in itself. Additional symptoms can include:
- Loss of sensation or muscle weakness in the extremities
- Difficulty walking, which may cause falls
- Decreased sensitivity to pain, heat and cold
- Loss of bowel or bladder function
- Paralysis that may occur in varying degrees and in different parts of the body, depending on which nerves are compressed
- Scoliosis, kyphosis or other spinal deformity resulting from a large but benign tumor
A thorough medical examination with emphasis on back pain and neurological deficits is the first step. Radiological tests are required for an accurate and positive diagnosis.
- X-Ray: Application of radiation to produce a film or picture of a part of the body and can show the structure of the vertebrae and the outline of the joints. X-rays of the spine are obtained to search for other potential causes of pain (i.e. tumors, infections, fractures, etc.). X-Rays are not very reliable in diagnosing tumors.
- Computed tomography scan (CT or CAT scan): A diagnostic image created after a computer reads x-rays and can show the shape and size of the spinal canal, its contents and the structures around it. Very good at visualizing bony structures.
- Magnetic resonance imaging (MRI): A diagnostic test that produces three-dimensional images of body structures using powerful magnets and computer technology that can show the spinal cord, nerve roots, and surrounding areas as well as enlargement, degeneration and tumors.
After radiological confirmation of the tumor, the only way to determine whether the tumor is benign or malignant is to examine a small tissue sample (biopsy) under a microscope. If the tumor is malignant, biopsy also helps determine the cancer’s type, which provides information that helps determine treatment options.
Staging classifies neoplasms (abnormal tissue) according to the extent of the tumor, assessing bony, soft tissue, and spinal canal involvement. A whole body scan utilizing nuclear technology may be ordered as well as a CT scan of the lungs and abdomen for staging purposes. The above findings and results from laboratory tests are compared with the patient’s symptoms to confirm diagnosis.
Nonsurgical treatment options include observation, chemotherapy and radiation therapy. Tumors that are asymptomatic or mildly symptomatic and do not appear to be changing/progressing, may be observed and monitored with regular MRIs. Some tumors respond well to chemotherapy and others to radiation therapy. However, there are specific types of metastatic tumors that are inherently radio-resistant (i.e. gastrointestinal tract and kidney), and in those cases, surgery may be the only viable treatment option.
Indications for surgery vary and depend on the type of tumor. Primary spinal tumors may be removed through complete en bloc resection for a possible cure. In patients with metastatic tumors, treatment is primarily palliative, with the goal of restoring or preserving neurological function, stabilizing the spine, and alleviating pain. Generally, surgery is considered only as an option for patients with metastases who are expected to live 12 weeks or longer and the tumor is resistant to radiation or chemotherapy. Indications for surgery include intractable pain, spinal cord compression and the need for stabilization of impending pathological fractures. Tumors that occur within the spinal cord itself can be biopsied and microsurgically removed. DNS surgeons have significant experience in these delicate neurosurgical procedures.