Neurofibroma is a type of tumor that affects nerve cells but is not a form of cancer. It usually affects nerves that are located either inside the skin or immediately under it. These benign tumors develop in the nerves on the periphery of the body. The origin of neurofibroma is in the fibroblasts, Schwann cells and perineural cells, all of which are part of the nerve sheath.
The most vulnerable nerve to neurofibroma is the vestibulocochlear nerve, which has the duty to link the inner ear and the brain, relaying sounds and data needed for balance. The tumors start from the sheaths and spread inside the nerves, damaging its fibers.
It is a condition with two types: single neurofibromas and multiple ones. Multiple tumors are caused by a genetic disease known as neurofibromatosis type I or the von Recklinghausen disease.
The tumors usually expand very slowly and don't cause any kind of pain. Sometimes, they have no symptoms at all, but this depends on their extent and the location.
Neurofibromas disrupt normal nerve tissues by adding other cells around them, such as blood vessels and inflammatory cells. The tumor consists of a mix of the cells that protect nerve fibers (named Schwann cells), the fibers themselves, blood vessels, inflammatory white blood cells, fibroblasts, loose material called extra cellular matrix and various other connective tissues. The inflammatory cells (also known as mast cells) sometimes produce histamine, causing itchiness or pain.
Scientists classify neurofibromas into four distinct types: diffuse neurofibromas, cutaneous (or dermal) neurofibromas, intramuscular neurofibromas and plexiform neurofibromas.
The first type, diffuse neurofibromas, affect the entire skin layer, starting from its surface until the fascia, which is the base of the skin. These tumors rarely continue beyond the skin and their limit of growth is the fascia.
A rare type of tumor is diffuse neurofibromas. They are named diffuse because their edges are not well defined and it's not easy to tell where one ends. Diffuse neurofibromas have a soft texture and usually develop on the scalp. The tumors can also affect the trunk, where they also cause the skin to lose its normal color. They can be compared to large patches of discolored skin, similar to coffee stains. The condition starts at an early age and sometimes expands in time.
Cutaneous neurofibromas can be a minor or severe condition. While some people have a very low number of tumors, in rare cases many of them are present. It appears to be a genetic trigger for this, since the vulnerability to very large numbers of cutaneous neurofibromas often affects people from the same family.
Like their name suggests, intramuscular neurofibromas grow inside the muscles. Even if only tiny nerves are usually affected, this type can generate serious pain. Although removing the tumors leaves a scar, it is sometimes done for pain relief. They can be confused with another type, the plexiform neurofibromas growing in rows.
Approximately half of neurofibromatosis type I patients develops plexiform neurofibromas. These have the same cell structure as the dermal neurofibromas but are usually located deeper inside the body, on large nerves. However, they can also affect peripheral nervous terminations at skin level. The main difference between plexiform and dermal neurofibromas is the additional extracellular matrix between the nervous fibers.
This type of neurofibromas are usually present since birth, so they are a congenital condition. In many cases, there are no symptoms at all or they don't appear for a long time. The tumors can expand but it is not clear which factors influence it. Usually, the growth happens at a young age, with no effect from puberty. It can also continue to expand during adulthood.
It is possible to use surgery to eliminate a neurofibroma but it should only be done after careful consideration. There are many factors that must be weighted, such as the age of the patient, the tumor's location and if complications are possible. Sometimes a neurofibroma can be in a location that is vulnerable to injury or it can cause serious pain or other problems.
Dermal neurofibromas are sometimes removed for cosmetic reasons, if the patient thinks they are unpleasant. However, surgery is also an option if they cause other types of problems or grow in size. If the patient chooses surgery for aesthetic reasons, he should be aware that a scar will appear. There is a high risk that a cutaneous neurofibroma will develop in the same location, but this typically takes a long time. The surgical procedure is quite delicate and specialized doctors have a much higher chance to remove the tumors completely. Plastic surgeons or surgeons who are specifically trained to eliminate neurofibromas are the best.
Since the tumor can't be removed without sectioning a nerve, an experienced doctor must consider if this is a safe thing to do. Cutting it can sometimes lead to weakness or significant impairment to the area.
If a large number of neurofibromas are present, eliminating all of them is a complex problem. Doctors can use electrodessication, a procedure that is able to neutralize a large amount of tumors without actually removing them. It is based on electro cautery, by inserting a probe into the area and burning the growth. This almost always results in a scar.