What is Neoplastic Arachnoiditis, Know its Causes, Symptoms, Treatment, Risk Factors

Arachnoiditis when associated with neoplasm it is known as neoplastic arachnoiditis.¹ It is mainly caused by long standing infection or due to presence of underlying inflammatory diseases. Neoplastic arachnoiditis presents itself initially as stinging sensation with a burning type of pain often associated with other neurological issues. In some cases, the neoplastic changes are preceded by formation of scar tissue, leading to disruption in functioning of the spinal nerves which causes pain and extreme discomfort in the areas supplied by the affected nerves. Neoplastic arachnoiditis happens when the arachnoid infection becomes malignant.

Neoplastic arachnoiditis starts as general arachnoiditis which gradually spreads to other areas. It generally affects the lower extremities and the back. Neoplastic arachnoiditis generally begin with the following symptoms:

• Pain and discomfort in the lower extremities and the back
• Numbness, weakness, tingling and burning sensation in legs ²
• Episodes of severe shooting pain and electric shock-like sensation in the lower legs
• Muscle cramps and spasms with twitching in legs
• Sexual dysfunction ³
• Change in urinary and bowel pattern
• Limitation of daily activities.

As the malignancy advances, the cancer cells spread to the neighboring area and can harm the surrounding tissues, muscles and organs.

Neoplastic arachnoiditis is a rare condition that affects women more than men. This is likely due to the higher incidence of administration of epidural injection in women during child birth. The exact incidence rate of malignancies in cases on arachnoiditis is yet unknown. It is a rare condition and in large number of episodes it goes undiagnosed or misdiagnosed.

Neoplastic arachnoiditis occurs when general arachnoiditis develop malignancies. The most common causes include the following:

• Repetitive trauma of the spine
• Long Standing Mechanical Injury or Repetitive Physical Trauma Causing Neoplastic Arachnoiditis: This is most often seen in patients who has undergone repetitive back surgery or in cases of post-surgical complications. This is also seen in association with invasive spinal surgeries and multiple lumbar puncture procedures.
• Chemical Reactions in the Nerves: Certain agents such as dye used in myelogram can lead to irritation in the nerves and can damage the nerves over a period of time. These are dyes that are used in certain radiographic imaging. The use of these dyes has been stopped due to the side effects caused by them. Administration of epidural injection can also lead to inflammation of the arachnoid in some cases.
• Infectious Diseases That Can Cause Neoplastic Arachnoiditis: Certain infectious diseases (bacterial, viral or fungal) causes inflammation of the arachnoid. This includes infectious diseases such as meningitis and tuberculosis.
• Chronic Back Issues can lead to Neoplastic Arachnoiditis: Chronic back conditions such as chronic degenerative disease of the disc and advanced spinal stenosis results in compression or impingement of the spinal nerves causing infection in the arachnoid and leading to neoplastic arachnoiditis if not treated on time.
• Other Causes such as improper catheter insertion, spinal taps and epidural disc prolapse over a period of time can also lead to neoplastic arachnoiditis.

The risk factors of neoplastic arachnoiditis include:

• Infections caused by bacteria, virus, fungi or parasites
• Other non-infectious condition such as intrathecal haemorrhage, post-surgical complications, adverse reaction to contract agent used on myelographic studies, reaction to steroids and anaesthetics.
• Pre-existing cancerous conditions such as non-Hodgkin lymphoma, melanoma, breast cancer, lung cancer, choroid plexus carcinoma, medulloblastoma, glioblastoma multiforme, ependymoma etc.

Diagnosis of neoplastic arachnoiditis is done by a cancer specialist or an oncologist. This condition also needs interventions by a neurologist. Diagnosis includes obtaining detailed case history followed by a physical examination. Investigative procedures include MRI and CAT scan which give us an in-depth understanding of the spread of the cancer. Plain x-ray in such condition does not provide adequate information about the condition and thus is not very helpful. Other confirmatory studies include EMG or electromyograms, which helps is assessment of the nerve functioning and electrical impulses.

Once the arachnoiditis reaches the neoplastic stage, it is managed as any other cancer. Treatment modality for neoplastic arachnoiditis includes:

• Regular chemotherapy sessions
• Radiation therapy may be considered depending on the condition
• Surgical intervention is also helpful in some cases. However, it has been seen that surgical intervention often leads to scar tissue formation and fibrosis.
• Other treatment modality for neoplastic arachnoiditis includes conservative management of symptoms. This includes oral medications for management of pain and chronic discomfort; anti-inflammatories and muscle relaxants may be considered.
• Opioids can also be considered to treat neoplastic arachnoiditis; but it must be administered cautiously to avoid dependencies and addiction.
• Intervention by a pain management specialist and a chiropractor may be beneficial too in treating neoplastic arachnoiditis.
• In early stages, physical therapy can help in improving function.
• Cancer patients often develop depression and emotional disturbances. Psychotherapy and counseling is advised in such cases. The family members of the affected individual should be advised to provide emotional strength to the patients for overcoming the situation.

The exact line of treatment for neoplastic arachnoiditis is not discovered at present. There are a number of studies and clinical researches being carried out with the support of governmental and private funding organizations to understand the benefit of steroid injection and electrical stimulation in management of arachnoiditis.

Neoplastic arachnoiditis is a rare malignant condition that affects the neurological system secondary to inflammation of the arachnoid mater. It is the membrane that covers and provides protection to the brain and spinal cord. Inflammation within the arachnoid mater affects the nerve root directly or indirectly. Over a period of time, when exposed to constant irritation or in cases of delayed healing, the condition may develop into a malignant condition and may spread to the surrounding area. It can lead to limitation of movement leading to restricted physical activities. Hence, one must seek medical help as soon as symptoms of arachnoiditis surfaces not delay the treatment since delaying the treatment might transform arachnoiditis to neoplastic arachnoiditis which is cancerous.

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• What is Arachnoiditis, Know its Symptoms, Causes, Treatment, Risk Factors, Epidemiology, Diagnosis
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• What is Arachnoiditis Ossificans & How is it Treated?
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• Postmyelographic Arachnoiditis: Causes, Symptoms, Treatment, Prognosis