Neurofibromatosis

Question 1

What is a neurofibroma

Answer 1

A benign tumour derived from peripheral nerve elements

Question 2

What is neurofibromatosis

Answer 2

An autosomal dominant condition characterised by the presence of multiple neurofibromas, in combination with other dermatological manifestations (over 5 cafe au lait spots)

Question 3

What are the two types of neurofibromatosis

Answer 3

Type 1 (von Recklinghausen’s disease)

• Defective gene on chromosome 17

Type 2

• Defective gene on chromosome 22
• Variable penetrance
• Cutaneous signs seen less often

Question 4

What are the features of a neurofibroma

Answer 4

Pedunculated nodules

Can result in severe deformity if arising from deeper nerve

Question 5

What are the complications of neurofibromata

Answer 5

Pressure effects - eg. spinal cord and nerve root compression

Deafness with involvement of the VIIIth CN

Sarcomatous transformation - only occurs in type I neurofibromatosis (5-13% cases)

Intra-abdominal effects - obstruction, chronic GI bleeds

Skeletal changes - can cause kyphoscoliosis, cystic changes and pseudoarthrosis

Question 6

What is pseudoarthrosis

Answer 6

False joint.

Refers to an area of unhealed bone that has motion like a joint but is not a true joint.

Typically the result of trauma and non-union of 2 fractured ends of a long bone.

Question 7

How would you treat a patient with a single neurofibroma

Answer 7

Non-surgical:

• Leave alone if asymptomatic and patient does not want treatment

Surgical:

• Indicated only if malignant growth suspected

Question 8

What is a specific complication of surgical excision of a neurofibroma

Answer 8

Local regrowth is common post-excision

Neurofibromata cannot be surgically detached from the underlying nerve

Question 9

What nerve cells do neurofibromas consist of

Answer 9

Schwann cells