Neurofibromatosis Type 2: Diagnosing Criteria

00:00 How do we diagnose NF2? Well, it is a genetic condition.

00:04 But like NF1, we often don't do genetic testing.

00:08 It can be helpful and it's done in certain circumstances, but the vast majority of patients with NF2 are diagnosed clinically, based on these criteria.

00:17 The most common clinical criteria to establish a diagnosis of NF2 is the presence of bilateral vestibular schwannomas, just like in our case.

00:26 That should be present by the age of 30.

00:29 And typically, patients with NF2 will have their tumors by 30, and you should see them at that time.

00:35 So a patient who does not have bilateral vestibular schwannomas on MRI imaging by the age of 30, likely does not have or will develop NF2.

00:45 There are other clinical criteria that can be met to establish this diagnosis.

00:49 The presence of a family history of NF2, and a unilateral vestibular schwannoma is sufficient to make the diagnosis.

00:55 The presence of a family history and two other characteristics of NF2, two other characteristic tumors like meningiomas, ependymomas, peripheral nerve schwannomas, gliomas, or this juvenile posterior subcapsular cataract are also consistent with a diagnosis of NF2.

01:14 And then there are some other ways to make this diagnosis a unilateral vestibular schwannoma and two other characteristic tumors, which you can see there, and multiple meningiomas, as well as two other characteristic tumors.

01:25 The point is, it's not just one tumor, because meningiomas and vestibular schwannomas are amongst the four most common benign tumors, brain tumors, that we see.

01:35 These patients have multiple tumors.

01:37 And that raises the suspicion that they're not sporadically acquired, but inherently gained.

01:46 What are some other features that we see in these patients? Well, it's not just tumors. We can see cutaneous lesions.

01:52 And 70% of patients with cutaneous lesions may be a bit high, but if you look, you may find them.

01:58 Neurofibromas can occur but are much less common than in patients with NF1.

02:03 And typically the tumors that we see are schwannomas.

02:06 Neuropathy is common in these patients, and we see both a generalized polyneuropathy that's usually pretty mild and only present on exam, not subjectively reported by patients, as well as manoneuropathies.

02:18 Things like Bell's Palsy or other single nerve dysfunction syndromes.

02:23 Seizures can occur but are rare.

02:25 Intracranial hypertension, too much intracranial pressure is also rare, but can occur particularly in patients with multiple meningiomas.

02:34 And then we can see cranial neuropathies from compression of a tumor or other causes.

02:38 And that can contribute to hearing loss, facial nerve dysfunction like a Bell's Palsy, dysphasia, balance dysfunction, or vagal nerve dysfunction.

02:47 Again, a lot of neurologic symptoms that can be seen in these patients.

02:51 Many of those which are of central nervous system origin.