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What Are the Neurofibromatosis Types?

There two major types of neurofibromatosis. Neurofibromatosis type I causes light brown (café-au-lait) spots in the groin and underarms, benign tumors under the skin, and tumors in the brain (on the cranial nerves or involving the spinal cord). Neurofibromatosis type II causes benign tumors of the nerves that affect hearing and balance.
There two major types of neurofibromatosis. Neurofibromatosis type I causes light brown (café-au-lait) spots in the groin and underarms, benign tumors under the skin, and tumors in the brain (on the cranial nerves or involving the spinal cord). Neurofibromatosis type II causes benign tumors of the nerves that affect hearing and balance.

Neurofibromatosis is a rare genetic disorder that has neurological and skin (cutaneous) manifestations. The syndrome typically causes benign (noncancerous) nerve tumors and growths in other parts of the body, including the skin. 

There are two major types: 

  • Neurofibromatosis type I (NF1) 
    • Shows at birth or during early childhood
    • Characterized by multiple light brown (café-au-lait) spots clustered in the groin and underarms and benign tumors under the skin
    • Enlargement and deformity of bones and curvature of the spine (scoliosis) may be present
    • Tumors in the brain, on the cranial nerves, or involving the spinal cord may also occur
  • Neurofibromatosis type II (NF2)
    • Appears during childhood, adolescence, or early adulthood
    • Characterized by benign tumors of the nerves that transmit sound impulses and balance signals from the inner ears to the brain
    • Tumors commonly affect both the hearing on both sides and the balance (vestibulocochlear) nerves

What Are Symptoms of Neurofibromatosis?

Symptoms of neurofibromatosis can range from mild to severe. 

Symptoms of neurofibromatosis type I (NF1) include: 

  • Skin
    • Light brown (café au lait) spots
    • Bumps on the skin (dermal neurofibromas)
    • Freckling
  • Eyes
    • Glaucoma
    • Tumors on the optic pathway 
    • Tumors on the iris, the colored part, of the eye (Lisch nodules)
  • Bony malformations
    • Nonunion of bone (pseudoarthrosis)
    • Bowed tibia (lower leg bone)
    • Defect of the base of the skull (sphenoid wing dysplasia)
  • Vascular (vein)
  • Nervous system
    • Brain tumors called gliomas
  • Peripheral nervous system
    • Neurofibroma
    • Malignant peripheral nerve sheath tumor (MPNST)
  • Other signs of NF1 

Symptoms of neurofibromatosis type II (NF2) include: 

  • Vestibular schwannomas (also called acoustic neuromas), which can cause: 
  • Other tumors including multiple meningiomas, peripheral schwannomas, and ependymomas
  • A few café au lait spots and/or dermal schwannomas (rare)
  • Cataracts or other eye problems

What Causes Neurofibromatosis?

Both neurofibromatosis type I (NF1) and neurofibromatosis type II (NF2) are caused by genetic mutations of certain genes believed to function as tumor-suppressors. 

Some people inherit the mutated gene from a parent, and in other people, the mutation occurs for unknown reasons (spontaneous mutation).


 

How Is Neurofibromatosis Diagnosed?

Both neurofibromatosis type I (NF1) and neurofibromatosis type II (NF2) have specific diagnostic criteria. 

The diagnostic criteria for neurofibromatosis (NF) type 1 includes two or more of the following:

  • Six or more café au lait spots
  • Two or more dermal neurofibromas (or at least one plexiform NF)
  • Bone lesions
  • Family history of NF1
  • Lisch nodules
  • Freckles in armpit) or groin
  • Optic pathway glioma

A diagnosis of neurofibromatosis (NF) type 2 is confirmed (definite) if a person has bilateral (on both sides) vestibular schwannomas (also called acoustic neuroma).

There is a probable diagnosis of NF2 in patients who have a family history of NF2 AND unilateral vestibular schwannomas or any 2 of the following tumor types: meningioma, glioma, schwannoma, juvenile posterior subcapsular lenticular opacity, or juvenile cortical cataract.

What Is the Treatment for Neurofibromatosis?

There is no known treatment or cure for neurofibromatosis type 1 or 2. 

Treatments for both types are aimed at management of the condition and relief of symptoms and may include: 

  • Pain medication 
  • Surgical removal of growths 
  • Radiation therapy to reduce growths
  • Regular monitoring 
    • Children:
      • Height, weight, head circumference, evidence of normal sexual development, and signs of learning disability and/or behavioral issues should be checked
      • Skin examination for growths and spots
      • Screening for scoliosis, blood pressure, vision, hearing loss, unusual growth patterns, and early or late onset of puberty 
      • Blood tests, X-rays, and other tests may be ordered if needed
      • Healthy children should be examined at six or 12-month intervals
    • Adults:
      • Examination of the skin for growths or spot
      • Screening for scoliosis, blood pressure, vision, and hearing loss
      • Screening for new or enlarging mass or any new symptoms 
      • Standard physical examinations annually

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References
Image Source: iStock Images

https://www.aans.org/en/Patients/Neurosurgical-Conditions-and-Treatments/Neurofibromatosis

https://www.hopkinsmedicine.org/neurology_neurosurgery/centers_clinics/neurofibromatosis/