Spinal Tumors

EXTRADURAL TUMORS

Extradural tumors are usually metastases to the vertebrae that subsequently invade the epidural space (see Plate 2-21). Almost any neoplasm can spread to the spine, but spinal metastases most commonly occur from a primary tumor in the lung, breast, or prostate. The tumor metastasizes through the arterial circulation or Batson’s venous plexus, although direct extension from lung cancer or lymphoma is possible. Primary bone tumors, such as osteogenic sarcoma and giant cell tumor, are also seen, as are benign hemangiomas of bone. In most cases, pain is the first symptom of a vertebral tumor. Spinal cord compression, with associated symptoms, usually develops late and may be slowly progressive, but a rapidly growing tumor may cause acute neurologic deterioration secondary to infarction of the spinal cord.

A patient with a known primary cancer in whom spinal pain develops must be assumed to have a metastasis. A bone scan reveals a lesion earlier than plain radiographs but may fail to reveal neoplasms without increased blood flow or new bone formation. Furthermore, bone scanning is not informative about thecal sac compression Spinal magnetic resonance imaging (MRI) is the preferred imaging modality and has largely replaced computed tomography (CT) myelography. Epidural tumor deposits are often multiple, so the entire spine should be imaged.

Epidural tumors must be treated before serious spinal cord dysfunction develops, but treatment is controversial. High-dose corticosteroids should be administered, and the lesion irradiated if the primary lesion is known. If there is no known primary tumor, if the tumor is known not to be radiosensitive, or if the neurologic status is rapidly deteriorating, surgical decompression should be done. Radiation therapy is usually administered postoperatively.

INTRADURAL TUMORS

Intradural extramedullary tumors include the benign meningiomas and nerve sheath tumors (neurilemmomas) and the neurofibromas associated with neurofibromatosis. Local and radicular pain is an early symptom. A spinal cord deficit results from compression of the spinal cord, usually develops gradually, and leads to sensory complaints, weakness, and sphincter disturbances. Plain radiographs are not helpful in diagnosis unless a neurilemmoma has caused widening of the intervertebral foramen by extending through it in the shape of a dumbbell (see Plate 2-22). MRI allows the entire thecal sac and adjacent bone and soft tissue to be studied (see Plates 2-22 and 2-23). CT myelography is sometimes helpful. These tumors can be completely resected. Nerve roots in the thoracic region may be sectioned to provide better exposure, but damage to radicular arteries must be avoided.

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