Common conditions

Neurofibromatosis

There are two types of Neurofibromatosis:

Neurofibromatosis type 1 (NF1)

Neurofibromatosis type 2 (NF2)

 

Neurofibromatosis type 1

The neurofibromatoses can be distinguished according to type and distribution of hamartomatous lesions. Neurofibromatosis type 1 (NF1) is a common and well known disorder first described by von Recklinghausen in 1849.

 

Epidemiology

  • Incidence: 1/2500-1/4000
  • Male= Female
  • There is considerable phenotypic variability between members of the same family.

 

Clinical presentation

Patients with NF1 usually present in childhood with café-au-lait patches or in adulthood with neurofibromas.

 

Physical Signs

  • NF1 Diagnostic Criteria [ ]=% of individuals with features
  • Patients must have 2 or more of the following:
    • Café-au-lait patches 6 or more 5mm prepubertal, >15mm in an adult) [>99%]
    • Axillary or inguinal freckling [85%]
    • Neurofibromas (2 or more cutaneous/ subcutaneous) [>99%]
    • Plexiform neurofibromas (1 or more) [30-50%]
    • Lisch nodules (benign iris hamartomas see on slit lamp) (2 or more) [95%]
    • Optic pathway glioma [15% total, 5% symptomatic]
    • Bony dysplasia (Sphenoid wing/ long bone or pseudarthrosis) [2%]
    • First degree relative with NF1

 

Complications

  • Mild cognitive impairment [30-60%]
  • Scoliosis [11%]
  • Malignant peripheral nerve sheath tumours [8-13% lifetime risk]
  • Cerebral gliomas [2%]
  • Raised blood pressure may be due to benign essential hyper-tension, renal artery stenosis or phaeochromocytoma [2%]

 

Neurofibromatosis type 2 (NF2)

Neurofibromatosis type 2 (NF2) is a much rarer condition and characterised by the formation of VIIIth cranial nerve vestibular schwannomas.

 

Epidemiology

  • Incidence: 1/40 000-1/100 000

 

Clinical presentation

  • Typically bilateral vestibular schwannomas, deafness and tinnitus

 

Physical signs

  • Neurological features secondary to CNS tumour
  • Deafness
  • Cataracts (juvenile)
  • CALS: 4% of patients have >3, 0% of patients have >6
  • In contrast to NF1, plexiform neurofibromas, axillary freckling and lisch nodules are rare

 

Complications

  • CNS tumours and surgical sequelae