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Neurocutaneous Disorders

Neurofibromatosis
»	What are the two main forms of neurofibromatosis?
»	Outline the diagnostic criteria for NF-1.
»	Where is the gene for NF-1 located? What protein does it encode?
»	What is the earliest skin sign of NF-1?
»	What is Crowe’s sign? When does it develop?
»	When do peripheral neurofibromas appear in NF-1?
»	What is a plexiform neurofibroma?
»	What are Lisch nodules?
»	What is the most common central nervous system (CNS) tumor occurring in NF-1?
»	How common is intellectual impairment in NF-1?
»	What are the most common skeletal abnormalities in NF-1?
»	How frequently should patients with NF-1 be assessed? What should this assessment include?
»	What are the diagnostic criteria for NF-2?
»	Where is the gene for NF-2? What is the gene product?
»	What are the most common presenting symptoms of NF-2?
»	What are the skin signs of NF-2?
»	What is the ocular sign of NF-2?

What is a plexiform neurofibroma?

Fig. 5.3 Soft baglike lesion of a plexiform neurofibroma.

It is a diffuse, elongated neurofibroma occurring along the course of a nerve, usually the trigeminal or upper cervical nerves. Present in 30% of patients with NF-1, these lesions are mostly congenital. They are often disfiguring, associated with overlying skin hypertrophy, hyperpigmentation, and increased hair (Fig. 5-3).