Schwannomas are non-cancerous tumours on nerve coverings and are characteristic of the rare conditions Neurofibromatosis Type 2 and Schwannomatosis.
The clinical problems of Schwannomatosis overlap with Neurofibromatosis Type 2 (NF2). Both conditions are associated with schwannomas.
In Schwannomatosis, schwannomas occur infrequently on the hearing and balance nerve (vestibular schwannoma) and are only found on one side. In NF2, bilateral vestibular schwannomas are the hallmark of the condition. Single meningiomas (tumours on the coverings on the nervous system) occur in some patients with Schwannomatosis but may be multiple in NF2. Ependymomas (spinal cord tumours) and eye problems do not occur in Schwannomatosis but are found in NF2.
What are schwannomas?
Schwannomas are benign tumours of the nervous system. They originate in the nerve sheath (the cells covering and protecting the nerve). Anyone can develop a single schwannoma but if you develop multiple schwannomas then you will probably have either Schwannomatosis or NF2. Examining the tumours under the microscope reveals that they are made up of multiple schwann cells. They are different from neurofibromas which have a mixture of cells in them. Neurofibromas are a sign of Neurofibromatosis Type 1.