Vestibular Schwannoma is a benign (non-cancerous) tumor. It is the second most common tumor inside the head. The tumor forms from the Shwann cells that line the balance nerve fibers that connects the inner ear to the brain.
The tumor does not spread, but it does grow. As it enlarges, it infiltrates into the remaining balance and hearing nerves, causing disequilibrium and hearing loss. It can ultimately push on the brain or other nerves in the area if it gets large. In most cases, these tumors grow slowly over many years, but sometimes the rate of growth changes and becomes rapid.