Neurofibromatosis

Neurofibromatosis is a genetic conditions, also known as von Recklinghausen's disease. It is abbreviated as NF.

It comes in two flavours:

1. Neurofibromatosis type 1 - NF1 (peripheral).
2. Neurofibromatosis type 2 - NF2 (central).

Neurofibromatosis type 1

• Autosomal dominant.

Diagnosis

Features (need 2/7 to diagnose):

1. Two or more neurofibromas or one plexiform neurofibroma.
   • May give rise to a malignant peripheral nerve sheath tumour.
2. Café-au-lait spots.
3. Freckles in axilla or inguinal area.
4. Optic nerve glioma.
5. Iris hamartomas (Lisch nodules).
6. Sphenoid dysplasia or typical long-bone abnormalities (e.g. bowing).
7. First-degree relative with NF1.

Mnemonic

CAFE SPOT:

• Café-au-lait spots.
• Axillary or inguinal freckling.
• neuroFibroma (two or more) or plexiform neurofibroma (one).
• Eye hamartomas (Lisch nodules).
• Skeletal abnormalities, e.g. sphenoid dysplasia, leg bowing.
• Positive family history.
• Optic Tumour (optic nerve glioma).

Others

• Pancreatic neuroendocrine tumour.
• Gastrointestinal stromal tumour.

Possible association

• Gangliocytic paraganglioma.

Neurofibromatosis type 2

• Caused by mutations in the NF2 gene; this gene is also known as merlin.

Diagnosis

Features (need 1/3 to diagnose):

1. Bilateral CNVIII masses on imaging.
2. Unilateral CNVIII mass + first-degree relative with NF2.
3. First-degree relative with NF2 and 2/4 of the following:
   1. Meningioma (meningothelial meningioma).
   2. Glioma.
   3. Schwannoma.
   4. Juvenile cataract.

Mnemonic MISME:

• Multiple Inherited Schwannomas.
• Meningiomas.
• Ependymomas.

See also

• Soft tissue lesions.
• Neurocutaneous syndromes.
• Berry aneurysm.