A growth of abnormal cells within or surrounding the spinal cord is generally referred to as a spinal cord tumor or a spinal tumor. This term represents a diverse group of growths classified based on their origin and precise anatomical position. The specific medical name depends heavily on the tissue type from which the cells multiply and the exact compartment of the spinal column where the mass is located.
Classification Based on Location
Spinal tumors are fundamentally classified by their relationship to the dura mater, a tough, protective membrane that surrounds the spinal cord. This system divides them into three distinct anatomical categories: extradural, intradural-extramedullary, and intramedullary. These distinctions often determine the tumor’s likely origin, common type, and required surgical approach.
Extradural tumors are found outside the dura mater, typically developing within the bony vertebrae or the space between the dura and the vertebral bone. These tumors account for the majority of all spinal neoplasms (approximately 55% of cases). Since they are located in the bone or surrounding tissues, growths in this region are most often metastatic lesions that have spread from a primary cancer site elsewhere in the body.
Intradural tumors are located inside the dura mater, within the cerebrospinal fluid-filled space of the spinal canal. This category is further subdivided based on the tumor’s relationship to the spinal cord itself. Intradural-extramedullary tumors grow inside the dura but remain outside the actual spinal cord tissue, often arising from the nerve roots or the meningeal lining.
Intradural-extramedullary tumors are the second most common grouping, making up about 40% of all spinal tumors. The least common, but often most challenging to treat, are intramedullary tumors, which grow directly within the substance of the spinal cord itself. These tumors arise from the support cells within the spinal cord tissue and comprise only about 5% of all spinal tumors.
Common Primary Tumor Types
When a tumor originates from cells within the spine or spinal cord, it is termed a primary tumor, and its specific name reflects the cell type of origin. The most common primary tumors fall into the intradural-extramedullary category, which includes meningiomas and schwannomas. A meningioma is a slow-growing mass that arises from the meninges, the layers of tissue that cover the spinal cord.
Meningiomas are typically benign and are significantly more common in women, often found in the thoracic spine region. Schwannomas, also frequently benign, originate from Schwann cells, which form the protective myelin sheath around the nerve roots as they exit the spinal cord. These tumors are sometimes referred to as neurofibromas, which are similar nerve sheath tumors but arise from a different mixture of cell types.
The primary tumors that grow directly within the spinal cord tissue, the intramedullary group, are most often ependymomas and astrocytomas. An ependymoma arises from ependymal cells, which line the central canal of the spinal cord where cerebrospinal fluid flows. This type is considered the most common primary tumor found inside the spinal cord in adults, frequently occurring near the bottom tip of the cord known as the conus medullaris.
Astrocytomas develop from astrocytes, which are star-shaped glial cells that provide structural and metabolic support to neurons in the central nervous system. While ependymomas are more common in adults, astrocytomas are the most frequent intramedullary tumor seen in children. The names of these primary tumors are derived directly from the specific neuroglial cells that undergo abnormal, uncontrolled division.
Distinguishing Primary and Metastatic Tumors
Tumors are also classified by their origin, differentiating between primary and metastatic growths. Primary spinal tumors begin within the spinal column or spinal cord tissue itself. While medically significant, these tumors are relatively uncommon in the general population.
Metastatic spinal tumors are far more prevalent, representing the vast majority of spinal masses. A metastatic tumor is the result of cancer cells traveling from a primary site elsewhere in the body to the spine, typically via the bloodstream. These secondary tumors are most frequently found in the bony vertebrae, placing them in the extradural location.
The most common cancers that spread to the spine originate from the lung, breast, and prostate. Metastatic disease accounts for up to 90% of all masses discovered on spinal imaging. The distinction between a primary and metastatic tumor is a fundamental step in diagnosis because it completely changes the prognosis and the required treatment strategy.
Recognizing the Associated Symptoms
The symptoms associated with a spinal tumor are primarily caused by the growth compressing or irritating the spinal cord and the nerves. The most common initial sign is back pain that can be localized to the area of the tumor. This pain often does not improve with rest, a characteristic that differentiates it from mechanical back pain, and may also intensify at night, sometimes waking the individual from sleep.
As the tumor grows, it begins to affect neurological function, leading to changes in sensation and motor control. Sensory changes often manifest as numbness, tingling, or a pins-and-needles sensation in the arms, legs, or torso, depending on the tumor’s height in the spine. Progressive muscle weakness in the limbs is also a common complaint, potentially causing difficulty walking, loss of balance, or frequent falls.
In more advanced cases, pressure on the spinal cord can disrupt the normal signaling pathways to the lower body organs. This compression can result in dysfunction of the pelvic organs, leading to issues such as urinary incontinence, difficulty emptying the bladder, or loss of bowel control. Any new or worsening combination of persistent back pain and these neurological symptoms warrants prompt medical evaluation.