Neurofibromatosis

Epidemiology

 

NF1 / Von Recklinghausen 

- most frequent of these disorders 

- 1/3000 - 1/4000. 

 

NF2

- VIII nerve schwannomas

- nil musculoskeletal manifestations

 

Aetiology

 

AD

- 50% due to new mutation

 

Gene protein neurofibromin

 

Diagnosis

 

Young children 

- multiple café-au-lait spots that appear in the first year of life.

 

The NIH Consensus Development Conference Statement

- diagnostic criteria for NF1 are met in an individual who has two or more of the following:

 

1.  Six or more café-au-lait spots over 5mm in prepubertal individuals and over 15mm in postpubertal individuals

2.  Two or more neurofibromas of any type or one plexiform neurofibroma

3.  Freckling in the axillary or inguinal region

4.  Optic glioma

5.  Two or more Lisch nodules (iris hamartomas)

6.  A distinctive osseous lesion such as sphenoid dysplasia or thinning of the long bone cortex with or without pseudarthrosis

7.  A first degree relative (parent, sibling, or offspring) with NF1 by the above criteria.

 

Clinical Features

 

Café au lait

 

< 2 normal

6 or more > 0.5cm, smooth edges

Aid early suspicion of NF1

 

Neurofibroma

 

Cutaneous

- raised over the skin

- bluish in colour

- increase in number ofter puberty and with pregnancy

- nil malignant potential

- develop from small cutaneous nerves

 

Plexifom

- bag of worms feeling

- usually develop from major nerves

- potential to become malignant

 

Axilllary / Inguinal Freckling

 

Aids early diagnosis

- second most common feature in children

- 80%

 

Lisch Nodules

 

Hamartomas in iris

- 90% patients over 6

 

Optic Glioma

 

&0% found in NF1

- usually benign and small

- can sometimes rapidly increase in size

 

Elephantiasis

 

Dermatological manifestation

- large soft tissue masses

- rough, raised vilous skin

 

Verrucous Hyperplasia

- skin overgrowth

- velvety, soft papillary

 

Issues

 

Malignancy

- 30 - 50 years

- large deep lesion

- increasing in size

- apin

 

Neurofibrosarcoma NF Leg MRI Coronal T2Neurofibrosarcoma NF Leg MRI Axial T1

 

Congenital Tibial Pseudoarthosis

- normally 1 per 140 000

- 3% of NF1

- see article

 

Spinal Deformities / Kyphosis / Scoliosis

- 30% have spinal deformity

- dystrophic and non dystrophic

- recommend earlier fusion at curves > 35o

- higher incidence of pseudoarthrosis

- all require MRI prior as high incidence of intraspinal lesions

- see Paediatrics / Spine / Scoliosis / Other / Neurofibromatosis