Neurofibromatosis

Question 1

Define Neurofibromatosis?

Answer 1

An autosomal dominant genetic disorder affecting cells of neural crest origin, resulting in the development of multiple neurocutaneous tumours

Question 2

What is Type 1 Neurofibromatosis (von Recklinghausen’s disease) characterised by?

Answer 2

Peripheral and spinal neurofibromas 
Multiple cafe au lait spots 
Freckling (axillary/inguinal)
Optic nerve glioma 
Lisch nodules (on iris)
Skeltal deformities 
Phaeochromocytomas 
Renal artery stenosis

Question 3

What is Type 2 Neurofibromatosis characterised by?

Answer 3

Schwannomas (often bilateral vestibular schwannomas)
Meningiomas
Gliomas
Cataracts

Question 4

What is the aetiology of Neurofibromatosis?

Answer 4

Associated with multiple mutations in tumour suppressor genes NF1 (type 1) and NF2 (type 2)

Question 5

What do we ask about in a history for Neurofibromatosis?

Answer 5

Positive family history (however, 50% are caused by new mutations)

Question 6

What are the presenting symptoms of Type 1 Neurofibromatosis?

Answer 6

Skin Lesions
Learning difficulties (40%)
Headaches 
Disturbed vision 
Precocious puberty

Question 7

What is the Disturbed Vision due to in Neurofibromatosis?

Answer 7

Optic gliomas

Question 8

What is Precocious puberty due to in Type 1 Neurofibromatosis?

Answer 8

Lesions of the pituitary gland from an optic glioma involving the chiasm

Question 9

What are the presenting symptoms of Type 2 Neurofibromatosis?

Answer 9

Hearing Loss 
Tinnitus 
Balance problems 
Headache 
Facial pain
Facial numbness

Question 10

What are the signs of Type 1 Neurofibromatosis on physical examination?

Answer 10

5+ cafe au lait macules of > 5 mm (prepubertal)
5+ cafe au lait macules of > 15 mm (post-pubertal)
Neurofibromas (may appear as cutaneous nodules or complex plexiform neuromas)
Freckling in armpit or groin
Lisch nodules (hamartomas on the iris)
Spinal scoliosis

Question 11

What are the signs of Type 2 Neurofibromatosis on physical examination?

Answer 11

Few or no skin lesions

Sensorineural deafness with facial nerve palsy or cerebellar signs (if the schwannoma is large)

Question 12

What investigations do we do for Neurofibromatosis?

Answer 12

Opthalmologial assessmne t
Audiometry 
MRI brain and spinal cord 
Skull X-Ray (sphenoid dysplasia in NF1)
Genetic testing

Question 13

Why do we do a MRI brain and spinal cord for Neurofibromatosis?

Answer 13

For vestibular schwannomas, meningiomas and nerve root neurofibromas