Schwannomatosis: Symptoms, Causes, Treatment

What are the symptoms of schwannomatosis?

Schwannomatosis is a rare genetic disorder characterized by the development of multiple non-cancerous (benign) tumors called schwannomas on nerves throughout the body. The main symptoms of schwannomatosis include:

• Chronic pain: This is the most common symptom and can vary in severity. Pain may be localized or widespread, often in areas where tumors are growing along nerves.
• Numbness and tingling: This can occur in the area where the schwannomas are affecting nerve function.
• Muscle weakness: Some patients may experience weakness in the muscles served by affected nerves.
• Loss of sensation: In some cases, there may be a loss of feeling in areas of the body where nerves are impacted.
• Tumor-related complications: While the tumors themselves are benign, they can grow and press on nerves or other structures, causing discomfort or additional neurological symptoms.

Unlike other related conditions like neurofibromatosis type 1 (NF1) or type 2 (NF2), schwannomatosis does not usually involve tumors on the vestibular (hearing) nerve, so hearing loss is uncommon.

The disorder typically appears in adults, and symptoms usually begin between the ages of 25 and 30 .

What are the causes of schwannomatosis?

Schwannomatosis is caused by genetic mutations, but it is distinct from other neurofibromatosis disorders, like NF1 and NF2. The primary causes of schwannomatosis include:

• Genetic mutations: Mutations in two main genes, SMARCB1 and LZTR1, are associated with the development of schwannomatosis. These gene mutations affect the production of certain proteins that regulate cell growth. When these proteins malfunction, benign tumors (schwannomas) can form along nerves.
• Sporadic (non-inherited) mutations: Many cases of schwannomatosis occur without a family history. These are caused by new mutations in the affected individual and are not passed down from parents.
• Inherited mutations: In some cases, schwannomatosis can be inherited in an autosomal dominant pattern. This means a person with a mutation in either the SMARCB1 or LZTR1 gene has a 50% chance of passing it on to their offspring.

Unlike neurofibromatosis type 2 (NF2), schwannomatosis does not typically involve mutations in the NF2 gene and rarely affects hearing, as vestibular schwannomas (tumors on the auditory nerve) are uncommon in this condition.

Schwannomatosis typically affects adults, with symptoms usually emerging later in life compared to other neurofibromatosis disorders.

What is the treatment for schwannomatosis?

The treatment for schwannomatosis primarily focuses on managing symptoms, especially chronic pain, as there is no cure for the condition. Treatment options include:

• Pain management: Chronic pain is the most common and debilitating symptom. Treatment may involve:
• Medications: Pain relievers, anticonvulsants (such as gabapentin), and antidepressants (such as amitriptyline) are often used to manage nerve-related pain.
• Nerve blocks: Injections to block pain signals in the affected nerves can provide temporary relief.
• Neuropathic pain treatments: Some patients benefit from medications specifically targeting nerve pain, such as pregabalin or duloxetine.
• Surgical removal of tumors: If schwannomas cause severe pain, neurological deficits, or are growing in problematic locations, surgical removal of the tumors may be necessary. However, surgery can be complicated, and there is a risk of nerve damage or recurrence of tumors.
• Radiation therapy: In certain cases, radiation therapy may be used to reduce tumor size or slow tumor growth, although this is less common due to potential risks.
• Physical therapy: Some individuals with muscle weakness or nerve dysfunction may benefit from physical therapy to improve mobility and function.
• Psychological support: Chronic pain and the challenges of managing a long-term condition like schwannomatosis can take a toll on mental health. Counseling, support groups, and cognitive behavioral therapy (CBT) can help individuals cope with the emotional impact.

Since schwannomatosis is rare and challenging to treat, care is often managed by a multidisciplinary team, including neurologists, pain specialists, surgeons, and genetic counselors.