概述
Plexiform neurofibroma also is called PN or PNF. It is a type of noncancerous tumor called neurofibroma that forms in or around a nerve. Neurofibromas grow on the protective covering around the nerve, called the nerve sheath. When a neurofibroma grows on several nerve bundles, it's called a plexiform neurofibroma.
The tumor grows along the nerve and can spread into nearby tissues such as skin, fat, bone and muscle. Plexiform neurofibroma is most often seen in people with a condition caused by a change in genes that affects how nerve cells grow and develop, called neurofibromatosis type 1 (NF1). Up to half of the people with NF1 develop plexiform neurofibromas.
Plexiform neurofibromas are different from other nerve tumors because they spread out in a networklike pattern. These tumors are known for their distinctive "bag of worms" texture, which means they feel like a bundle of tangled cords or threads. This is a classic sign of a plexiform neurofibroma.
Plexiform neurofibromas are most common in childhood and adolescence. Some people may notice swelling or a soft lump under the skin. These tumors often grow in the head, neck, trunk, arms or legs, but they can appear anywhere in the body.
Treatment depends on the size, location and symptoms of the plexiform neurofibroma. Most plexiform neurofibromas grow slowly and are not life-threatening. But some can cause serious symptoms depending on the size or location or if they become cancerous.
症状
Plexiform neurofibromas can cause different symptoms based on where they grow, how big they are, and how they press on nearby nerves and tissues. Some people have no symptoms at first. Others may notice changes in how their bodies look, feel or move.
Common signs and symptoms of plexiform neurofibroma include:
- Pain. Ongoing pain, which may be moderate to severe, is common in people with plexiform neurofibroma. Pain from plexiform neurofibroma can make it difficult to do daily activities and affect movement.
- Swelling or soft lumps. Tumors can cause growths that can be seen or felt under the skin. These may grow over time and may be soft, spongy or thickened.
- Changes in appearance. Tumors in visible areas such as the face or limbs can cause disfigurement, leading to emotional or social concerns.
- Movement changes. Tumors pressing on nerves or muscles can make it harder to walk, grasp objects or perform everyday tasks.
- Vision changes. Tumors near the eyes or the optic nerve can cause blurred vision, drooping eyelids or other changes in how the eyes look or work.
- Numbness or tingling. These symptoms may occur when the tumor interferes with how a nerve works — either by pressing on it or growing into it.
- Bladder or bowel changes. Plexiform neurofibromas near the pelvis or lower spine can affect the nerves that control the bladder and bowel. This can lead to symptoms such as urgency, frequent urination, leakage or trouble emptying, as well as constipation or stool leakage.
- High blood pressure. Some tumors may affect nearby structures or organs in a way that leads to high blood pressure, especially if they press on blood vessels or involve the kidneys or adrenal glands.
- Emotional changes. Children may feel anxious, sad or lonely due to their symptoms, appearance or ongoing pain.
病因
Most plexiform neurofibromas occur in people with a condition called neurofibromatosis type 1 (NF1). NF1 is caused by a change in the NF1 gene, which is located on chromosome 17. This gene typically helps control how cells grow. When it isn't working properly, cells that support nerves may grow too much and form tumors like plexiform neurofibromas.
风险因素
Plexiform neurofibromas are linked to a genetic condition called neurofibromatosis type 1 (NF1). Anyone with NF1 has a risk of developing these tumors. The number, size and location of tumors can vary from person to person.
Having NF1 is the main risk factor for plexiform neurofibroma. Up to 50% of people with NF1 will develop one or more plexiform neurofibromas during their lives.
预防
There is no known way to prevent plexiform neurofibromas. The tumors develop because of a genetic change that is present from birth and cannot be reversed.
Aug. 19, 2025