Neurologist Questions Neurologist

Is there any way possible to have NF2 (neurofibromatosis type 2) without having any vestibular tumors?

Genetic tests for both came back negative. All my tumors (8 of them) are in my head and they consist of both Schwannomas and meningiomas. One geneticist is leaning toward schwannomatosis while another one is leaning towards NF 2.

Female | 51 years old

3 Answers

Neurofibromatosis type 2 (NF2) is a condition that is often characterized by the growth of tumors on the nerves that help control balance and hearing. People with NF2 often develop tumors on the nerves responsible for balance, which are called vestibular schwannomas. These tumors are noncancerous. It is possible to have NF2 without developing any vestibular tumors, but this is rare. People with NF2 may also develop tumors on the spinal cord or brain. Research published in the Journal of Neuro-Otology suggests that there is a 75% chance that someone who has a vestibular tumor will also have vestibular schwannoma. This is one hallmark symptom of NF2. Furthermore, it is estimated that 90% of people with vestibular schwannomas will also have symptoms of NF2. While these numbers do not necessarily mean that there is an absolute connection between vestibular tumors and NF2, they suggest that this may be a distinct possibility.

While there is no definitive way to determine whether someone with vestibular tumors has neurofibromatosis type 2, or NF2, it is generally believed that a person must have two copies of the mutated gene in order to develop vestibular tumors. This is supported by the fact that genetic tests for both vestibular tumors and NF2 came back negative in your case, suggesting that you do not carry either of the mutated genes associated with these conditions.

Furthermore, while vestibular tumors are known to occur in both schwannomatosis patients and those with NF2, they tend to occur at different frequencies. In general, vestibular tumors are more common in individuals with schwannomatosis than in those with NF2; however, there have also been some documented cases of people having vestibular tumors without being diagnosed with either condition.

While there are documented cases of NF2 without vestibular tumors, this is relatively rare. The underlying genetic cause of NF2 is a mutation on the NF2 gene, which codes for a protein called merlin. This protein acts as an important tumor suppressor in many tissues throughout the body, including vestibular tissue. When there is a mutation on the NF2 gene leading to vestibular tumors, this typically indicates that a person has neurofibromatosis type 2 (NF2). However, other factors besides mutations in the NF2 gene can lead to vestibular tumors, including environmental triggers and personal factors like age or gender. Still, given their complicated causes, it may be difficult to definitively diagnose or exclude vestibular tumors in individuals without vestibular tumors.

Given all this information, it seems likely that you may be dealing with vestibular tumors that fall somewhere on the spectrum between schwannomatosis and NF2. While further research is needed in order to provide a more definitive diagnosis, it does seem that you may be facing a unique set of challenges due to your unique medical history and genetic results. Still, with proper treatment and support from your healthcare team and loved ones, you can manage these challenges and continue living a happy and healthy life.
unlikely - there could be other genetic conditions that cause both types of tumors
It is possible to have nf2 without vestibular tumors apparent on imaging, but I am not sure the exact diagnosis matters. The most important aspect is a close follow-up with your medical team so they can handle complications early.