Schwannomatosis

About SWN

Schwannomatosis (SWN) is the least common and most recently identified form of NF. The term schwannomatosis is an umbrella term for several genetic conditions that cause the development of benign tumors to grow on nerves. Some types of SWN affects 1 in 20,000 people, with NF2-related schwannomatosis (NF2) the most common type of SWN. Excluding NF2, the other types of SWN affect just 1 in 70,000 individuals.

Schwannomatosis is a type of NF in which individuals develop tumours, called schwannomas, on nerves in the central nervous system (brain and spine) and on peripheral nerves, which are the nerves throughout the rest of the body. Most tumours are not cancerous as is the case for the other neurofibromatoses.

There are at least three genes, NF2, LZTR1, and SMARCB1 that are known to cause schwannomatosis, and there may be additional genes discovered in the future. These genes are thought to help regulate cell growth and division. If these genes are not functioning properly, the cells may multiply excessively and form tumours.

This page focuses on the less common forms of SWN.

CLICK HERE to learn more about NF2-related schwannomatosis, or NF2.

Signs and symptoms

Signs of schwannomatosis usually occur in adulthood, between the ages of 20 and 40, although they can occur at any age.

Schwannomas are typically slow growing and located deep inside the body.

The most common symptom is chronic pain, which can occur anywhere in the body and often may not relate to a tumour.

The intensity and frequency of pain varies significantly among individuals who are affected, and, in some cases, the size of the tumour does not necessarily relate to the intensity level of the pain.

Schwannomatosis is a variable condition. While most people with schwannomatosis experience some degree of pain that requires medical management, a small number of people have only mild pain. Some people with schwannomatosis develop many tumours throughout their body, while others may have only one or two tumours during their lifetime.

In addition, a small subset of individuals develop tumors along the hearing/balance nerves (called vestibular schwannoma or VS).

Although pain is the most common symptom, other signs can include:

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