A spinal tumor is an abnormal mass of tissue within or surrounding the spinal cord and/or spinal column. These cells grow and multiply uncontrollably, seemingly unchecked by the mechanisms that control normal cells. Spinal tumors can be benign (non-cancerous) or malignant (cancerous). Primary tumors originate in the spine or spinal cord, and metastatic or secondary tumors result from cancer spreading from another site to the spine.
Spinal tumors may be referred to by the region of the spine in which they occur. These basic areas are cervical, thoracic, lumbar and sacrum. Additionally, they also are classified by their location in the spine into three major groups: intradural-extramedullary, intramedullary and extradural.
The most common of these types of 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 the delicate nature of fine neural structures in that area may complicate treatment.
These tumors grow inside the spinal cord, most frequently occurring in the cervical (neck) region. They typically derive from glial or ependymal cells that are found throughout the interstitium of the spinal cord. Astrocytomas and ependymomas are the two most common types. They are often benign, but can be difficult to remove. Intramedullary lipomas are rare congenital tumors most commonly located in the thoracic spinal cord.
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. Estimates indicate that at least 30 percent and as high as 70 percent of patients with cancer will experience spread of cancer to their spine.
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 multiple myeloma, lymphoma, melanoma and sarcoma, as well as cancers of the gastrointestinal tract, kidney 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 non-skeletal metastases and the presence and/or severity of spinal-cord compression.
Pediatric spinal tumors :
Primary spinal tumors are rare in children and are challenging to treat. Incidence and outcome vary by subtype, a listing of which can be quite broad but include the following:
- osteoid osteoma.
- Ewing sarcoma.
- Eosinophilic granuloma.
- Aneurysmal bone cyst.
- Mesenchymal chondrosarcoma.
- Giant-cell tumor of bone.
- Fibrous dysplasia.
Unlike adults, children have not achieved complete skeletal growth, which doctors must take into account when considering treatment. Other factors to consider are spinal stability, surgical versus nonsurgical interventions and preservation of neurological function.
Incidence and Prevalence :
Intracranial (brain) tumors account for 85 to 90 percent of all primary central nervous system (CNS) tumors. Primary tumors arising from the spinal cord, spinal nerve roots and dura are rare compared to CNS tumors that arise in the brain. Overall prevalence is estimated at one spinal tumor for every four intracranial lesions. About 10,000 Americans develop primary or metastatic spinal cord tumors each year.
Intramedullary tumors are rare, accounting for only five to 10 percent of all spinal tumors. Benign tumors such as meningiomas and neurofibromas account for 55 to 65 percent of all primary spinal tumors. Meningiomas most frequently occur in women between the ages of 40 and 70. Metastatic spinal tumors are the most common type of malignant lesions of the spine, accounting for an estimated 70 percent of all spinal tumors.
The cause of most primary spinal tumors is unknown. Some of them may be attributed to exposure to cancer-causing agents. 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. However, the more common tumors associated with this disorder affect the nerves related to hearing and can inevitably lead to loss of hearing in one or both ears.
Von Hippel-Lindau disease:
his rare, multi-system 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.
Non-mechanical 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 the following:
- Loss of sensation or muscle weakness in the legs, arms or chest.
- 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 or other spinal deformity resulting from a large, but benign tumor.