Facts to Know About
Neurofibromatosis type 2 (NF2)

Contents:

Contributed by Jonathan Kantor.


Manifestations and symptoms

NF2 occurrs in 1 person out of 40,000 to 50,000. If you have it, you're born with it. You don't get it later.  The most common manifestation of Neurofibromatosis type 2 (NF2) is bilateral (both-sided) acoustic neuromas. Their symptoms are the same as for other AN patients.

90% of NF2 patients also have ocular abnormalities, causing blurred or loss of vision. Cataracts at a young age are common, and often an early symptom. They are somewhat more difficult to remove than conventional cataracts.  It is therefore important that an affected person or relatives at risk be followed regularly by an opthamologist who is familiar with NF2 and the resulting ocular abnormalities.

50% of all NF2 cases also have spinal lesions, causing pain.  Most of these lesions never result in serious problems, but in some cases they can have very debilitating affects.

Though manifestations and symptoms can differ greatly for different NF2 patients, NF2 often follow similar paths in affected family members.

Schwannomatosis is a similar disorder in which affected individuals have similar manifestations to NF2 except that they do not have bilateral Acoustic Neuromas.


Difference with other Acoustic Neuromas

Acoustic Neuromas grow differently for NF2 patients as opposed to other AN patients, making treatment more challenging:


Heredity of NF2


Methods of Treatment

The usual progression of the disorder usually results in total deafness. In order to preserve hearing as long as possible, it may be best not to intervene unless the tumors are large enough. It is therefore important to determine which of the tumors is growing more rapidly (and it may not be the larger one). However, as the tumor grows, it becomes more difficult and less likely to preserve hearing and other nerve functions with surgery. It is therefore a difficult judgement call to decide, when to intervene, and with which treatment option.

Since AN tumors grow differently for NF2 patients, it is vital that the surgeon has NF2 experience as opposed to regular AN’s.  Hearing has been known to be preserved when the tumor(s) is very small. Preserving facial nerve function is very common in small to medium tumors. Size is not however a guarantee that nerve function will be preserved.

Other than surgery, Gamma Knife until recently was the only other method of treatment. Gamma Knife is a high, accurate and very concentrated form of radiation which has produced excellent results in regular AN’s. Because the tumor is more involved with the nerve in NF2, the high dose and concentration of the radiation may affect the nerve more than in AN cases. The results in hearing, and facial nerve preservation to a lesser extent, are usually less favorable than in for other AN treatments. Indications are that FSR may be better at hearing preservation in NF2 cases, but there are no definitive long term studies available. Dr. Noren at the New England Gamma Knife Center is nor experimenting with fractionated Gamma Knife in order to improve the results on hearing preservation.

FSR ppears to be better at hearing preservation in NF2 cases than Gamma Knife, but there are no definitive long term studies available. Far too often NF2 results are lumped in with studies on other AN cases treated. NF2 patients must be vigilant in determining what any radiosurgeon’s results have been in NF2 cases only. Of the two most commonly known radiosurgeons treating AN’s one claims to have treated many and does not find any differences whereas the other has never specified what his results have been in NF2 cases.


Testing for Manifestations

MRI's are the most precise form of finding AN’s as well as other lesions. They should be done both with and without enhancement. Affected individuals should have regular MRI's to follow the progress of the disorder or any re-growth after treatment. After the first diagnosis, if there are no indications for immediate intervention, annual MRI’s are commonly suggested.As the situation stabilizes, more time can elapse between MRI’s. Initially after treatment, MRI's are advisable every 6 months for at least 18 months. If stable then they may be redone every year or two.

If a person is known to have NF2 it is important to have a spinal MRI as well. If negative it need not be redone for many years. If positive your neurologist should indicate when and if it should be redone.

Simple hearing test that should be done about the same time as the MRI’s. This is a non-invasive simple test that takes about 30 minutes. Hearing tests may be normal even with the presence of AN’s. If the tumors are small enough, they may not as yet have affected hearing. In some cases, tumors may grow substantially before hearing is affected. Audiograms are therefore not the definitive test of determining whether or not one is affected. They are however appropriate in following the progress of AN’s.

Auditory brainstem response (ABR) also known as Brainstem evoked auditory response (BAER) is one of the oldest tests available. Again it is non-invasive and takes about 30 minutes. It is highly accurate in finding problems but does not tell us what the problem is. Positive results are an indication that further investigation is needed. It is also useful in measuring the progress of problems. MRI’s can sometimes find tumors that have not yet affected the ABR results.

An experienced opthamologist may detect ocular abnormalities before other symtoms appear. Individuals at risk (those who have NF2 affected relatives) are advised to ask their eye doctor if he is familiar with the condition; if not, he must be told what to look for.


Related links


Experienced NF2 doctors

Here is a list of experienced NF2 doctor, that NF2 AN patients can use as a starting point for their research. It is not complete.

Dr. James E Raisis

Neurosurgeon

Seattle Ear Clinic

800-377-4075

Prof. Ramsden

Neurosurgeon

Manchester MRI

Dr. Robert Rand

Neurosurgeon

UCLA

Dr. Jame Rappaport

Neuro-otologist

Jewish General, Montreal

lcampane@ent.jgh.mcgill.ca

Dr. Guy Rouleau

Neuro-Geneticist/NF2 Clinic

Montreal General

mi32@musica.mcgill.ca

Dr. Spencer

Neurosurgeon

Yale New Haven

Dr. Charles Tator

Neurosurgeon

Toronto Western

Dr. Warmath

Neurosurgeon

Kaiser Permanente, Denver

Dr. Jeffrey Williams

FSR

Johns Hopkins Univ

jw@jhu.edu

Dr. Robert Young

Neurosurgeon

Northwestern Seattle

Dr. B Gartzam

OTO ABI

UIHC. Iowa

Dr. Arnold Menezes

Neurosugeon ABI

UIHC. Iowa

Dr. Jay Rubenstein

OTO ABI

UIHC. Iowa