Overview
Neurofibromatosis (NF) is an autosomal dominant neurocutaneous disorder that causes lesions in the skin, soft tissues, bone, and nervous system due to the formation of neurofibromas (nerve tumours). It has two subtypes:
- NF1 – defect in NF1 gene on chromosome 17 and more common
- Also known as Von Recklinghausen’s disease
- NF2 – mutation on chromosome 22
Epidemiology
- NF1 makes up the majority of cases (97%) and NF2 makes up 3%
- Vestibular schwannomas are often a predominant problem in NF2
Presentation
Patients may have the following:
- Dermatological features:
- Café-au-lait spots
- Axillary/groin freckles
- Cutaneous/subcutaneous neurofibromas
- Central nervous system:
- Eye features:
- Reduced visual acuity
- Lisch nodules (iris hamartomas) – yellow/brown projections from the iris surface
- Skeletal:
- Scoliosis
- Pectus excavatum/carinatum
- Associated phaeochromocytoma
Differential Diagnoses
Tuberous sclerosis
- Hypopigmented macules – ash leaf spots
- Shagreen patches – irregular elevated skin-colour patch usually on the lower back
- Facial angiofibromas – red/brown papular rash on the face
- Ungual fibromas
- Retinal hamartomas
Investigations
- MRI and/or CT if symptomatic tumours are seen
- Not routinely performed if there are asymptomatic tumours
- Shows evidence of and extent of lesions
- Consider genetic testing
Management
Care involves generally monitoring progress and intervening when tumours cause problems due to pressure or suggest malignancy. Symptomatic lesions can be surgically removed but can recur.
Neurofibromas that grow near important structures or obstruct vision need urgent management
Complications and Prognosis
Complications
- Brain tumours – more common in NF2
- Leukaemia
- Peripheral sheath malignancies
Prognosis
- Most people with NF1 live long and healthy lives but it does decrease life expectancy
- It is difficult to assess prognosis as the phenotype can vary significantly
- NF2 generally has a worse prognosis
