Neurofibromatosis Program

Diagnosing Neurofibromatosis

Only a physician can formally diagnose neurofibromatosis type 1, or NF1. To make a diagnosis of NF1, an individual must have two or more of the following:

• Six or more café-au-lait macules (brown skin spots)
• Freckling in the axilla (armpit) or groin
• Two or more neurofibroma tumors of any type or one plexiform neurofibroma (a larger, more extensive tumor)
• Optic pathway glioma (a tumor of the optic pathway in the eye)
• Two or more iris Lisch nodules or choroidal abnormalities (bright, patchy spots in the eye)
• Osseous lesions (bony lesion), such as sphenoid dysplasia (abnormal growth) of the bone behind the eye, or dysplasia or pseudarthrosis of the tibia (long bone in the leg) or other long bones
• A pathogenic NF1 variant revealed by genetic testing
• A parent with NF1 based on the criteria above

Neurofibromatosis type 2, or NF2, is typically diagnosed by a neurologist or geneticist based on the presence of clinical findings documented during a clinical examination, MRI imaging and medical history discussion. While this disorder has been called NF2, NF experts are transitioning to call it NF2-related schwannomatosis. The diagnostic criteria for NF2 include the following:

• Bilateral vestibular schwannomas (affecting both ears)
• Or a first-degree relative with NF2, PLUS:
  • Unilateral (affecting one ear) vestibular schwannoma OR
  • Any two of the following
    • Meningioma
    • Glioma (for example, spinal ependymoma)
    • Neurofibroma
    • Schwannoma
    • Juvenile cataracts
  • OR unilateral vestibular schwannoma PLUS any two of the following:
    • Meningioma
    • Glioma
    • Neurofibroma
    • Schwannoma
    • Juvenile cataracts
  • OR multiple meningiomas (two or more) PLUS:
    • Unilateral vestibular schwannoma, OR
    • Any two of the following:
      • Glioma
      • Neurofibroma
      • Schwannoma
      • Juvenile cataracts