Schwannomatosis

Schwannomatosis is the rarest form of neurofibromatosis and has only recently been identified as a separate condition. 

This genetic condition affects less than 1 in every 40,000 people and causes the development of tumours called schwannomas to form on nerves on the spine and other peripheral nerves. Occasionally they may form in the brain as well. 

Signs of Schwannomatosis usually occur in adulthood, over the age of 30, although they can occur at any age.

Unlike neurofibromas found in people with NF1, schwannomas are typically located deeper inside the body. They are often slow growing, causing chronic and debilitating pain and may compromise function.

Most tumours are not cancerous as is the case for the other neurofibromatoses (NF1, NF2). 

DIAGNOSTIC CRITERIA

Schwannomatosis is more complicated than the other forms of NF and so it follows that diagnosis is not so easy either. The diagnostic criteria for this condition is still open for discussion, however, suggested guidelines were put forward in 2005. This condition is generally diagnosed clinically as the genetic basis for the condition remains somewhat uncertain.

To receive a diagnosis of Schwannomatosis someone must be over 30 years of age and meet one of the two criteria paths below:

Discussions have revealed that perhaps these criteria are not quite adequate and so the below has also been proposed as additional diagnostic criteria:

HEALTH IMPLICATIONS

SIGNS AND SYMPTOMS

Symptoms usually begin between the ages of 30 and 60, though they can start at any age. 

The most common symptom is chronic pain, which can occur anywhere in the body and often does not relate to a tumour, but other signs can include:

• Numbness  
• Tingling 
• Weakness 
• Headaches 
• Vision changes, and  
• Swollen areas under the skin where tumours have formed. 

Unlike NF2 this condition is solely a condition of Schwannoma development. Also, unlike NF2 tumours on the hearing nerves (vestibular schwannomas) do not develop on both sides. When a vestibular schwannoma does develop it is rare and unilateral (one side only). 

MONITORING YOUR CONDITION

Scans will assist specialists with monitoring the location, size and effects of tumours. These can include:

• MRI 
• CT scans

TREATMENT

Treatment will always depend on the signs and symptoms present for each person affected. Like the other forms of NF, there is no cure for Schwannomatosis.