Neurofibroma
Definition
Neurofibromas are benign tumors of peripheral nerves. They arise from the cells that form and support the nerve sheath — Schwann cells, fibroblasts, and perineural cells. These tumors infiltrate the nerve and disrupt the sheaths of individual fibers. The most commonly affected nerve is the vestibulocochlear nerve. Neurofibromas can be single or multiple. When multiple, they are associated with neurofibromatosis type I, a genetic disorder also known as von Recklinghausen disease.
Causes/Risk Factors
The cause of solitary neurofibromas is unknown. Neurofibromatosis type I, which causes the multiple form, is inherited as an autosomal dominant trait.
Symptoms
Symptoms depend on the location and size of the tumor(s). These tumors typically present as a painless, slow-growing mass. The patient may feel an electric-like shock (the Tinel sign) when light pressure is applied to the tumor. If a motor or sensory nerve is involved, the associated function may be affected.
Diagnosis
Neurofibromas have a characteristic appearance on MRI (magnetic resonance imaging). A biopsy of the tumor taken during surgery enables positive diagnosis.
Treatment
Surgery is the treatment of choice for neurofibromas; however, it is complicated by the fact that these tumors are often interwoven in the nerve structure.
Neurofibromas of the skull base can be directly approached through the expanded endonasal approach (EEA). This state-of-the-art, minimally invasive surgical procedure uses the nose as a natural corridor to reach these lesions. There are no incisions in the skin of the face or head.
Because of the risk of damaging the nerve during surgery, tumors that are not causing symptoms may be left alone.
Prevention
There are no guidelines for preventing neurofibromas. Early detection and treatment may help to prevent some damaging effects of these tumors.