Neurofibromatosis type 1 (cutaneous manifestations)

Cutaneous manifestations of neurofibromatosis type 1 (NF1), or von Recklinghausen disease, are the heralding features of this multisystem neurocutaneous disorder, which is the most common phakomatosis.

Nowadays genetic testing permits the laboratory diagnosis of NF1 in as many as 95%, although in the majority of patients the diagnosis remains based on clinical manifestations .

For a general discussion of the underlying condition, please refer to the article on neurofibromatosis type 1.

Clinical presentation

As is the case with many phakomatoses, NF1 results in a variety of abnormalities of variable severity. To make the clinical diagnosis two or more of following are required :

• >6 cafe au lait spots evident during one year
• two or more neurofibromas or one plexiform neurofibroma
• optic nerve glioma
• distinctive osseous lesion (such as sphenoid wing dysplasia or thinning of long bone cortex with or without pseudoarthrosis)
• two or more iris hamartomas (Lisch nodules)   
• axillary or inguinal freckling
• primary relative with NF1 with above criteria

Radiographic features

• cutaneous and subcutaneous neurofibromas: benign peripheral nerve sheath tumors
  • presented as small soft tissue skin nodules on radiological images