Approximately 10% of spinal tumors are intramedullary. Ependymoma is the most common type of intramedullary tumor in adults (21). The remainder are other types of gliomas. Intramedullary lesions disrupt cord function by invasion and infiltration.
Extramedullary tumors may be extradural or intradural in location. Among the primary extramedullary tumors, neurofibromas and meningiomas are relatively common, often benign, and either intradural or extradural. Carcinomatous metastases, lymphomatous or leukemic deposits, and myeloma are most often extradural lesions. Tumor involvement may lead to pathological fracture or direct cord compression. Spinal cord dysfunction may be the result of ischemia secondary to tumor causing arterial or venous obstruction.
Vertebrae are a common location for primary and metastatic neoplasm. Primary neoplasms of the spine may present as benign lesions, such as the osteoid osteoma, osteoblastoma, or spinal osteochondroma, and are often found in patients between 10 and 40 yr of age. Typically, the tumor forms a nidus and grows by creating a surrounding zone of sclerosis or becoming expansile. More often these tumors are found in the neural arch and pedicle than in the vertebral body.
Multiple myeloma and lymphoma represent the more aggressive lesions of the spine and are permeative in presentation. Multiple myeloma and lymphoma can grow through the vertebrae in a diffuse manner and cause marrow replacement. The weakened bone is prone to form compression fractures that can narrow the central canal and recesses, and be the source of radicular symptoms or focal or referred pain. Multiple myeloma is one of the most common primary bone tumors and most often involves the spine. Lymphoma is often found in the spine as a metastasis in up to 30% of patients with primary systemic disease. Although in fewer than 5% of cases, lymphoma presents as a primary bone lesion. Metastases to the spine occur in 10-40% of cancer patients and the most common primary sites are lung, breast, prostate, and kidney neoplasms.
History The symptoms of spinal tumors may develop insidiously. Pain is commonly the presenting symptom and generally precedes the neurological symptoms. Pain is often conspicuous with extradural lesions. The pain can be radicular and can be aggravated by stretching, coughing, or straining (22). Commonly discomfort may be localized to the back or may be felt in the extremities. Neoplasms of the spine can also compress and irritate the dura to create referred pain such as headaches. Motor deficits, paresthesias, and numbness in the legs are also associated with tumors of the spine. Invasion of the posterior elements can cause focal tenderness but neurological symptoms are often absent. Lesions that are destructive to the bone of the spine can cause pathological fractures that result in cord compression. Tumor causing cord compression or epidural extension along the nerve root can create spinal pain, myelopathy, and/or radiculopathy. Primary benign lesions, such as osteoid osteoma, are often symptomatic at night and present with spinal stiffness, torticollis, and scoliosis. Therefore, because of the varied presentations, the most obvious cause of the pain or neuropathy from tumors and metastases may not be specific.
Physical Examination On physical evaluation a segmental lower motor neuron deficit or dermatomal sensory change (or both) are sometimes found at the level of the lesion. An upper motor neuron deficit and sensory disturbance may be demonstrated below the level of the lesion. The deep tendon reflexes can be hyperreflexic. If hyperreflexic symptoms and other upper motor neuron signs, such as clonus or a positive Babinski test, are found the cervical and thoracic spine should be evaluated to exclude a spinal cord lesion. Palpation of the spinous processes can localize the vertebrae that are affected by tumor.
Diagnostic Imaging Plain film radiographs are commonly unremarkable. In the setting of metastatic disease the films may show evidence of sclerotic, lytic, or permeative bony destruction. CT scans and CT myelography help to reveal the site of cord compression and gross bony change.
MRI with gadolinium enhancement is better for the evaluation of cord involvement and its surrounding soft tissues. At times intramedullary and extramedullary lesions may be differentiated only by MRI. The size, shape, and extent to which the normal anatomy is compromised can also be characterized on MRI, which is also the best tool for evaluating the response to therapy.
Other tests may include evaluation of the CSF, which can reveal greatly increased protein with normal cell count and glucose levels.
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