Meningioma of the spine

A tumor arising in the sheaths of the spinal cord (meninges spinalis) is defined as a spinal meningioma because the spinal cord is located in the spinal canal.

Meningiomas are the second most common tumor of this localization, and most of them (95%) are benign. [1]

Epidemiology

Spinal meningiomas account for 25-30% of primary spinal tumors. They most commonly appear in the thoracic spine (65-80% of cases), in the cervical spine in 14-27% of patients, and in the lumbar spine in no more than 4-5% of cases.

Spinal meningiomas form in middle age and old age and are almost three times more common in women than in men.

Causes of the spinal meningiomas

Although such neoplasms are referred to spinal cord tumors, they do not affect brain tissue (being extramedullary, i.e. Extracerebral). Their location is in the dura mater spinalis (dura mater spinalis), so experts call these tumors intradural. The term "spinal meningiomas" is also used.

The causes of their formation are abnormal growth of cells of the spinal cord sheaths. As a rule, pathologic proliferation occurs not so much in the upper (dura mater) sheath, but in the middle - spider sheath (arachnoidea mater spinalis) with attachment to the dura mater. The spinal cord spider sheath consists of loose connective tissue (arachnoid endothelium) and is separated from the dura mater by the subdural space and from the underlying soft shell (pia mater spinalis) by the subarachnoid space filled with cerebrospinal fluid (liquor).

But what causes the abnormal growth of spider web cells, which are involved in cerebrospinal fluid resorption, is unknown. [2]

Risk factors

It has been established that the risk of developing spinal meningioma is increased with exposure to ionizing radiation (radiation therapy), genetic predisposition, as well as in the presence of gene mutation-driven neurofibromatosis type II, which can be inherited or occur spontaneously, increasing the likelihood of benign brain and spinal cord tumors.

A higher prevalence of meningiomas is seen in women and obese people. [3]

Pathogenesis

Despite the uncertainty of the etiology of meningiomas, their pathogenesis is attributed to mutations in some genes, in particular those encoding the tumor suppressor protein merlin; the protein survivin, an inhibitor of apoptosis (programmed cell death); platelet-derived growth factor (PDGF), which is found in platelets and may act as a systemic regulator of cellular function; vascular endothelial growth factor (VEGF); and others.

In addition, sex hormone receptors have been found in some meningiomas, leading researchers to speculate that they are involved in the growth of these tumors. [4]

There are three grades of malignancy of spinal meningioma cells (determined by histologic examination):

• Grade I is a benign meningioma;
• Grade II - atypical meningioma;
• Grade III - anaplastic or malignant meningioma (most often of metastatic origin).

Symptoms of the spinal meningiomas

Usually spinal meningiomas grow very slowly and do not manifest themselves for many years. But when their size increases, there is compression of the spinal cord tumor or compression of spinal roots. This disrupts the conduction of nerve impulses from the brain to the peripheral nervous system, causing various neurological symptoms - motor and sensory disorders.

First, there may be pain in the back: in the segment of the spine where the tumor has formed. For example, meningioma of the cervical spine (C1-C4) is manifested by pain in the occipital part of the head and neck, as well as decreased sensitivity (tactile, temperature, pain); paresthesia (numbness) of the shoulder girdle of the trunk; spinal-generated movement disorders - difficulty in movements of the upper extremities and gait disturbances. [5]

This tumor mass is mostly found in the middle spine - meningioma of the thoracic spine (Th1-Th12). Its first signs may be manifested by sensory disturbances in the chest area, spasticity and muscle weakness in the extremities with difficulty in movements, including reflex movements.

Meningioma of the lumbar spine (L1- L5) leads to impaired function of the pelvic organs: bladder and bowel. [6]

Complications and consequences

The main complications and consequences of spinal meningiomas are spastic (flaccid paresis) of the lower limbs or tetraparesis, that is, loss of motor functions of all limbs.

If the tumor is localized in the cervical region, hemiparaplegic Broun-Sekar syndrome develops.

Meningiomas may undergo calcification with increased pressure on the spinal cord. Extradural spread of the tumor and/or its malignization significantly worsens the condition of patients. [7]

Diagnostics of the spinal meningiomas

Spinal meningiomas cannot be detected without imaging, so instrumental diagnosis comes first: MRI with intravenous contrast, myelography followed by CT (computed tomography), X-ray of the spine and spinal cord.

For laboratory tests, not only standard clinical blood tests are taken, but also biochemical analysis of the liquor. [8]

Differential diagnosis

Differential diagnosis should exclude the presence of intervertebral disc protrusion, spinal osteoarthritis (spondylosis), amyotrophic lateral sclerosis (ALS), spinal syringomyelia, spinal form of multiple sclerosis, arachnoid cysts, as well as tumor masses with similar symptoms (neurinoma, angioma, angioblastoma, astrocytoma, etc.).).

Treatment of the spinal meningiomas

Small asymptomatic meningiomas are monitored by imaging (CT scan or MRI).

In cases of spinal meningiomas that cause motor and sensory disorders, such an option as medication is not considered by experts, and the main method is surgical treatment - removal of the tumor to decompress the spinal cord.

This surgery is complex because it requires a laminectomy - removing part of the vertebrae to gain access to the tumor, and then (after the tumor is resected) spinal fusion surgery to stabilize the spine.

In some cases, corticosteroids may be prescribed before surgery to reduce the size of the tumor.

If the meningioma is anaplastic or malignant, radiation therapy is used after resection. [9]

Prevention

There are no recommendations regarding the prevention of spinal meningioma formation.

Forecast

There is a direct dependence of the outcome of spinal meningiomas on the degree of malignancy of their cells, and the prognosis in anaplastic or malignant tumors cannot be considered favorable.

At the same time, removal of grade I meningiomas is achieved in most cases (with minimal mortality), and if the tumor can be completely removed, about 80% of people are cured. However, after ten years or more, an average of 9-10% of patients experience recurrences.