Introduction and Extradural Tumors

Tumors of the spine, their treatment and prognosis are varied. Spinal tumors are categorized to allow for a better understanding and anticipation of treatment options and outcomes. Spinal tumors are described as: extradural, intradural/extramedullary and intradural/intramedullary. Extradural tumors are within the spine but outside the sac (dura) that holds the spinal cord, nerve roots and spinal fluid. Intradural tumors are within the dural sac and can either be extramedullary (outside the spinal cord) or intramedullary (within the spinal cord).

The majority of extradural tumors represent metastases, or cancerous tumors that have travelled from other parts of the body. Kidney, breast, prostate and lung cancers will commonly travel to the bony spine. Metastatic spine tumors can cause pain (from bony destruction, fracture or instability) or neurological dysfunction from compression of the spinal cord or nerve roots. Treatments for these tumors are aimed at preserving spinal stability, reducing/eliminating pain and maintaining neurological function. Common treatment modalities include surgery and radiation therapy. The typical goals of surgery are to confirms diagnosis, eliminate any compression of the spinal cord or nerve roots, and maintain stability by correcting deformity or restoring structural integrity. Complete surgical removal of tumors to the bony spine is rarely possible or practical. As such, radiation therapy is often used in conjunction with surgery to eliminate remaining tumor tissue or at least slow its progression. Such therapy can be delivered in multiple small doses over the course of several weeks (radiotherapy) or sometimes in much larger doses given just a few times or even once. Finally, there are some emerging options whereby a small catheter is inserted within the tumor to deliver a laser strong enough to heat and kill tumor tissue (laser interstitial thermal therapy-LITT) or one that delivers radiation directly (intraoperative radiation therapy-IORT).

There are also primary tumors that affect the extradural bony spine. These are considerably less common than metastatic tumors and tend to be seen more commonly in children and young adults. There are several types of these tumors that are benign but can cause problems by being locally destructive or invasive (for example, hemangiomas, giant cell tumors and osteoblastomas). These are most often treated surgically to eliminate their destructive tendencies. Malignant tumor types (osteosarcomas and Ewing’s sarcoma) are often treated with multiple modalities including surgery, radiation and chemotherapy.

Intradural Tumors

Intradural tumors (found in the dural sac) are less common than those affecting the extradural/bony spine. Intradural tumors are categorized as intramedullary (inside spinal cord) or extramedullary (outside spinal cord). Intradural/extramedullary are mostly comprised of two types: meningiomas and nerve sheath tumors. Meningiomas arise from cells attached to the sac enclosing the spinal cord and spinal fluid—the dura. These tumors are overwhelmingly benign but can cause neurological dysfunction or pain if they compress the spinal cord or nerve roots. Surgical resection is the mainstay of treatment, however, radiation therapy can be utilized to treat spinal meningiomas that are incompletely resected or unresectable (or the rare meningioma exhibiting unusual or malignant features). Nerve sheath tumors (Schwannomas and neurofibromas) arise from cells that serve as layers of insulation to nerve fibers outside the spinal cord. The majority of these tumors are benign as well but, like meningiomas, can cause problems if they are large enough to compress the spinal cord or other nerve roots. Surgery is also the chief treatment for symptomatic nerve sheath tumors. Finally, metastases can also occur in the intradural/extramedullary space. This is not particulary common and treatment is dependent upon tumor type and extent of disease in the spine and elsewhere.

Lastly, intramedullary tumors occur within the spinal cord itself and are comprised mainly of astrocytomas, ependymomas and hemangioblastomas. Most of these tumors are lower grade (less aggressive in nature) and some, like hemangioblastomas and myxopapillary ependyomomas, will behave in a benign nature. Surgical intervention is the most common initial treatment with the goals of making a definitive diagnosis and obtaining improvement or relief of symptoms. The risk of intramedullary tumor progression is likely determined by two factors: tumor type and extent of surgical resection. Generally speaking, tumors with more benign features lend themselves to more complete resection and therefore better long-term outcome. The opposite being true for tumors with more aggressive or malignant features.

If one is diagnosed with a spine tumor, no matter the type, it is important that they follow up with a specialist to determine the best treatment options.