Neurofibromatosis

Question 1

what are the differences between type 1 and type 2 fibromatosis?

Answer 1

NF1 associated with problems with body as a whole (you only have 1 body), whereas NF2 associated with ear problems (you have 2 ears)

Question 2

What are cafe au lait spots?

Answer 2

irregular brown ( hyperpigmented ) macules

Question 3

what are neurofibromas

Answer 3

gelatinous small violaceous nodules which appear at puberty and may become papillomatous

Question 4

define neurofibromatosis?

Answer 4

autosomal dominant genetic disorder affecting cells of neural crest origin-> results in development of multiple neurocutaneous nodules

Question 5

explain the aetiology of neurofibromatosis?

Answer 5

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

Question 6

summarise the epidemiology of neurofibromatosis?

Answer 6

No gender or racial predilection

NF1: 1 in 2500

NF2: 1 in 35,000

Question 7

what are the presenting symptoms of type 1 neurofibromatosis?

Answer 7

Skin lesions

Learning difficulties (40%)

Headaches

Disturbed vision (due to optic gliomas)

Precocious puberty (due to lesions of the pituitary gland from an optic glioma involving the chiasm)

Speech difficulties

Compromised social interactions

Question 8

what are the presenting symptoms of type 2 neurofibromatosis?

Answer 8

Hearing loss

Tinnitus

Balance problems

Headache

Facial pain

Facial numbness

Question 9

what are the signs of type 1 neurofibromatosis on physical examination?

Answer 9

• 5+ café au lait maculesof > 5 mm (prepubertal)
• 5+ café 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) – use a slit lamp
• Spinal scoliosis
• Short stature

Question 10

what are the signs of type 2 neurofibromatosis on physical examination?

Answer 10

Few or no skin lesions

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

Question 11

what are the appopriate investigations for neurofibromatosis?

Answer 11

Full body examination for skin lesions

Ophthalmological assessment

Audiometry

MRI brain and spinal cord - for vestibular schwannomas, meningiomas and nerve root neurofibromas

PET scan - for vestibular schwannomas, meningiomas and nerve root neurofibromas

Biopsy – histological features of a neurofibroma

Genetic testing – to confirm the mutation