Most tumors associated with NF1 are benign (non-cancerous) skin tumors, which grow on nerves throughout the body.
Neurofibromas (NFs) are the most common type of tumor in people with NF1. The two major types of neurofibromas are:
- Dermal (sub-cutaneous) neurofibromas are small, nodule-like tumors that grow on or just under the surface of the skin. They can be painful, itchy, disfiguring or tender when touched, but they have no known potential to become cancerous. Dermal neurofibromas may also be asymptomatic.
- Plexiform neurofibromas are larger tumors that develop inside the body and tend to wrap in and around nerves, blood vessels and other structures in the body. They can be deep inside the body or closer to the skin. Plexiform neurofibromas can cause pain, numbness, weakness, and disfigurement. These tumors do have a small chance of becoming a cancer. Plexiform neurofibromas may also be asymptomatic.
Malignant peripheral nerve sheath tumors (MPNSTs)
These are cancerous tumors that grow on the nerve sheath, the cells surrounding the nerve. Learn more about malignant peripheral nerve sheath tumors from the Johns Hopkins Peripheral Nerve Surgery Center.