Neurofibromatosis type 2 (NF2)

NF2 is a rare inherited condition in which benign tumours grow on nerves inside the skull and the spine. They are called schwannomas because they arise from the cells that form the nerve sheath; in current classifications the condition is named NF2-related schwannomatosis. These tumours do not invade tissue and do not spread, but they grow in a tight space and press on whatever lies next to them: the hearing nerve, the facial nerve, the brainstem, the spinal cord. That is the defining feature of the condition — the harm comes from where the tumours sit, not from any malignancy. The cause cannot be removed, but the tumours are monitored, and many of them go for years without needing anything done. Despite the similar name, NF2 has little in common with neurofibromatosis type 1: different genes, different problems.

How it usually begins

In almost everyone with NF2, tumours grow on the nerves leading from the inner ear, so the first complaints involve hearing and balance. They most often start in the late teens or after twenty.

• Hearing declines gradually, usually in one ear first. People notice it not as loss of volume but as loss of clarity: in a quiet room hearing seems fine, but in a café or a meeting speech turns into noise. The phone ends up permanently against the "good" ear.
• Ringing, buzzing or whistling in the ear (tinnitus). This is often the very first complaint, long before hearing loss becomes obvious.
• Unsteadiness. Not attacks of spinning, as in inner ear disease, but a constant sense that walking has become less sure — particularly in the dark, on uneven ground, or with the eyes shut in the shower.
• Sudden loss of hearing in one ear also happens, and it needs attention the same day rather than a wait to see whether it settles.

In children the condition often starts differently: with a squint, clouding of the lens, lumps on the skin or difficulty lifting the foot — the ears may stay quiet for years. So in a child with an unexplained cataract or several skin lumps it is worth asking about hearing problems in the family.

Where else the tumours grow

NF2 is not confined to the inner ear. Tumours appear in several places at once, and the pattern of symptoms depends on what has ended up compressed.

• The membranes around the brain. Meningiomas cause headaches, seizures, sometimes weakness of an arm or a leg and changes in behaviour.
• The facial nerve. One side of the face weakens: the eye does not close, the corner of the mouth droops, speech becomes indistinct. A separate problem is that an eye which cannot close dries out, so lubricating drops and protection are needed or the cornea suffers.
• The spinal cord and its roots. Schwannomas and ependymomas cause back or neck pain, numbness, weakness in the arms and legs and difficulty passing urine.
• Peripheral nerves. A firm, tender lump under the skin of an arm or leg, sometimes with weakness of the hand or foot.
• Skin and eyes. Flat plaques with darker, slightly hairy skin, and lumps under the skin; in young people, early clouding of the lens and changes in the retina.

How the diagnosis is made

The key investigation when NF2 is suspected is an MRI scan of the brain with contrast, including dedicated views through the internal auditory canals. That is how small schwannomas are seen at the earliest stage. An ordinary CT scan will not do the job: it misses a small tumour in the auditory canal, and a negative CT rules nothing out. If the problem is unexplained hearing loss, the scan to ask for is MRI.

• Audiometry shows how much and in what way hearing has been affected, and a speech discrimination test explains what the person experiences in a noisy room.
• MRI of the whole spine is done once the diagnosis is confirmed: spinal tumours stay silent for a long time.
• An eye examination with the pupil dilated covers the lens, the retina and the state of the cornea if there is facial weakness.
• Genetic testing confirms the change in the NF2 gene and allows relatives to be assessed. One important caveat: in around a third of people the change is mosaic — present in the tumour but not in all blood cells. A blood test can then come back negative in someone who clearly has the condition, and the sample has to be taken from removed tumour tissue instead.

When urgent help is needed

Call an ambulance — in Spain, Italy, Portugal, Poland and Ukraine on the single European number 112 — if:

• a seizure occurs, especially a first-ever one;
• one side of the face, or an arm and leg on one side, suddenly becomes weak or numb;
• a headache worsens abruptly and comes with vomiting, double vision, increasing drowsiness or confusion — this is how raised pressure inside the skull shows itself;
• both legs become weak, numbness spreads up from the trunk, or passing urine becomes impossible — these point to compression of the spinal cord, and here it is a matter of hours;
• swallowing becomes difficult, food goes down the wrong way, or the voice turns hoarse and nasal.

A same-day appointment is needed if hearing in one ear disappears over hours or days, if balance is suddenly disturbed, if double vision appears, or if an eye stops closing.

What doctors can offer

There is no treatment that removes the cause, so the question is never simply whether to take the tumour out, but which choice costs least right now.

• Watching. Many schwannomas grow very slowly or stay still for years. If hearing is preserved and the tumour is small, scheduled MRI scans and audiometry make more sense than surgery.
• Surgery. Needed when a tumour presses on the brainstem, obstructs the flow of fluid from the ventricles of the brain, or grows quickly. An experienced surgeon works to preserve the facial nerve and, where possible, hearing. Part of a tumour is sometimes deliberately left behind rather than risk damaging the nerve.
• Stereotactic radiosurgery halts the growth of a small tumour precisely, without an incision. In NF2 it is used more cautiously than for a single sporadic schwannoma: in someone with this gene, irradiated tissue causes more trouble later, so the decision is made by a team.
• Drug treatment. For growing vestibular schwannomas, medicines that block the tumour's blood vessel formation are used. They are given by drip, can shrink the tumour and in some people improve speech understanding. The benefit lasts while treatment continues, and treatment itself requires monitoring of blood pressure, protein in the urine and wound healing.

Hearing: what to arrange in advance

This is the part that is easy to put off and later regretted. Hearing in NF2 usually does decline, and preparing for that is worth more than any single operation.

• Hearing aids help while the hearing nerve is intact, and they are better fitted early rather than once speech has become impossible to follow.
• A cochlear implant is an option if the hearing nerve is undamaged — for instance when hearing was lost to the tumour itself but the nerve was preserved during surgery.
• An auditory brainstem implant bypasses a damaged nerve and delivers the signal directly to the brainstem. The sound is not like natural hearing, but it allows environmental sounds to be told apart and makes lip reading considerably easier.
• Lip reading and sign language are easier to learn while you can still hear: progress is faster and the skill stays. It is worth asking about them straight after the diagnosis, not several years on.
• Balance. Vestibular rehabilitation exercises help, as do a night light in the hallway, a grab rail in the shower, and care in water: underwater, with no visual reference, it is easy to lose all sense of direction.

Monitoring, family and everyday life

NF2 is caused by a change in a single gene and is passed on in a dominant pattern: the chance of passing it to each child is one in two, 50 % in every pregnancy. In roughly half of people the parents are unaffected and the change arose afresh. In the mosaic form the condition is usually milder and the risk to children is lower than usual, though only a geneticist can put a figure on it.

Relatives of someone with NF2 are offered assessment: genetic testing, or where that is not available, periodic MRI and hearing checks from childhood. This is a condition where finding it early has a direct effect on how much hearing is kept.

After that, life follows the monitoring schedule: MRI of the head and spine at whatever interval the doctor sets, audiometry, and eye and neurology reviews. Between appointments it helps to write changes down — whether the telephone has become harder, whether numbness has appeared, whether walking has changed. Those small details are forgotten in the consulting room, and they are exactly what shows the trend.

The condition affects everyday matters worth thinking about early: driving with poor balance or double vision, working in noisy surroundings, safety at home, support when tiredness and low mood set in. Psychological support here is not a luxury: gradual hearing loss combined with regular scans wears down even the calmest people.

Online consultation

With NF2 many questions arise not in the clinic but at home: what the MRI report actually means, whether to wait or push for surgery, when to see an ear specialist, what to do about an eye that keeps drying out, how to explain at work that a different desk is needed. In an online consultation a doctor can go through your situation, help pull scattered reports into a coherent picture, and point you to whoever should be seen next.

It is a convenient way to discuss test results and to work out what needs an urgent visit and what can wait for the routine review. If any of the signs in the urgent section are present, though, the place to start is emergency care, not an online appointment.

This material is for information only and does not replace medical advice.