Neurofibromatosis, type 2 (NF2), is characterized by
benign tumors that grow on the cranial and spinal nerves.
There are few visible signs of NF2, and this type of
neurofibromatosis rarely occurs in children. However,
there are symptoms that can indicate the presence of
NF2 often causes slow-growing, benign tumors to grow
along the eighth nerve, which leads from the brain to
the inner ear. The tumors, called acoustic neuromas
or vestibular schwannomas, can lead to ringing in the
ear(s); balance problems; and gradual hearing loss in
one or both ears.
Other schwannomas, so named because they develop from
the schwann cells that protect nerve cells, develop
elsewhere in the body. The dumbbell-shaped spinal cord
schwannoma is a particularly troublesome, yet common,
tumor that forms in people with NF2. As the tumor grows
along the spinal cord, it can cause numbness, tingling,
pain, and weakness in various parts of the body. If
left untreated, the tumors may even cause paralysis.
A person with NF2 can also develop cataracts at a relatively
early age but these cataracts may be asymptomatic. Usually,
cataracts are found in people over 50, but in patients
with NF2, “juvenile cataracts” can form
much sooner. Cataracts are a clouding of the eye’s
lens and on occasion make distance vision difficult
or cause problems with glare.
How is NF2 Diagnosed?
NF2is generally a clinical diagnosis. Although genetic
tests are available for NF2, the detection rate is only
between 65 percent and 70 percent. Many NF2 patients
are the first person in their family with the condition.
The most useful imaging modality for NF2 is magnetic
resonance imaging (MRI). It is the mainstay for diagnosis
and screening for central nervous system tumors and
spinal cord tumors that commonly occur with this disorder.
Typically, NF2 patients will have an annual MRI study
of the head, but screening for spinal cord tumors may
be done less frequently. Some doctors may recommend
MRIs of the spine only when symptoms occur.