Malignant Schwannoma of the Spinal Cord

Tumors of the Spinal Cord

The spinal cord is the part of the central nervous system that transmits messages between the brain and the rest of the body through bundles of nerves enclosed in sheaths and protected by the bony spine. Tumors or abnormal growth of cells may grow anywhere around or within the spinal cord and depending on the size, location and extent of these growths, can affect many bodily functions.

Most tumors of the spinal cord are benign or not life threatening, except when there are complications. They are usually localized and can be removed surgically. However, there are a few malignant tumors (cancerous), most of which are secondary tumors or cancer cells that have spread from a distant (primary) site. They are also more common in young and middle-aged adults than in children.

Primary tumors of the spinal cord are very rare, and they may grow within the sheath or dura that covers the cord or within the spinal cord itself. Nerve sheath tumors (those that develop from the cells surrounding the nerves) account for about 25 percent of tumors in the spinal cord, and only 2.5 percent of these are malignant. The two types of nerve sheath tumors are shwannomas and neurofibromas. An overview of malignant schwannomas of the spinal cord is given below.

What is Malignant Schwannoma?

Schwann cells are cells that cover the nerve fibers involved in conducting nervous impulses in the body. Malignant schwannomas are rare nerve sheath tumors formed from the Schwann cells. They comprise only about one percent of these types of tumors. They are usually slow growing and homogenous.

Causes of schwannomas are unknown but several possible factors that can lead to their formation are genetic abnormalities, viruses, exposure dangerous chemicals and radiation, immune disorders and others. Males and females are equally prone to them, and as previously mentioned they are more prevalent in young and middle-aged adults.

Malignant schwannomas may be graded according to their size and extent of spread. Grade I tumors are small, localized and slow growing, and they can progress to Grade IV, which are bigger, more invasive and difficult to treat.

Signs, Symptoms and Diagnosis of Spinal Schwannoma

Depending on the size, extent and location of the tumor along the spinal cord, signs and symptoms may vary. Symptoms may progress slowly as the tumor grows and impinges on the spine and nerves coming from the spine.

Many schwannomas develop in the neck area and may affect the motor and sensory functions of the arms, legs and structures below the neck. Tumors that are located in the lower parts of the spine may affect fewer structures below the level of involvement. Signs and symptoms may include:

• Motor deficits like weakness or paralysis of the arms and/or legs
• Sensory deficits like pain or numbness below the level of involvement
• Sensitivity to temperature
• Bowel and bladder paralysis, leading to incontinence or loss of control
• Spasticity or contracture of muscles, muscle wasting

Diagnosis is established from the patient’s history, physical and neurologic examination, and laboratory examinations including:

• Computed Tomography (CT) scan
• Magnetic Resonance Imaging (MRI)
• Magnetic Resonance Spectroscopy (MRS)
• Angiography (or arteriogram)
• CSF analysis
• Needle biopsy
• Blood and urine exams

Treatment and Prognosis of Malignant Schwannoma

Standard treatment modes include surgery, chemotherapy and radiation. Depending on the size, location and extent of the tumor, surgical removal of the tumor aims to decompress the spinal cord which is affected by the mass.

Complete removal will result in improvement in the motor and sensory deficits brought about by the tumor. However, if the tumor has spread or is deemed inoperable, radiation may be done to shrink the tumor and reach sites that cannot be operated on. Chemotherapy may also be given to kill cancer cells. These treatment modalities may be done repeatedly and in combination as needed.

Risks of surgery include bleeding and paralysis resulting from excision of part of the spinal cord and nerves. Radiotherapy and chemotherapy have their own side effects owing to the fact that these procedures affect both cancer cells and healthy cells. These result in nausea, vomiting, hair loss, fatigue, weakness, digestive problems, and others. These side-effects are temporary and may be decreased by giving the patient a period of rest between sessions of radio- and chemotherapy.

Aside from these, patients who suffer from the effects of the tumor and its treatment are also given physical therapy and occupational therapy to be able to return to normal function. Supportive and palliative care may also be given in advanced cases.

Much research is still being done to find ways of preventing and treating brain and spinal cord tumors. Among these are the development of vaccines, immune therapy, and biological markers.

Effectiveness of treatment and prognosis depend on the stage of the disease, early diagnosis, age and the general health of the patient, aside from the character of the tumor itself.

References

National Institute of Neurological Disorders and Stroke, “Brain and Spinal Tumors: Hope Through Research”, https://www.ninds.nih.gov/disorders/brainandspinaltumors/detail_brainandspinaltumors.htm#166993060

Mayo Clinic, “Spinal Cord Tumors”, https://www.mayoclinic.org/spinal-cord-tumors/types.html