This is a case of neurofibromatosis. It is a rare genetic disorder that causes typically benign tumors of the nerves and growths in other parts of the body. Some people with this disorder have barely noticeable neurological problems, while others are affected profoundly. The cause is a genetic mutation in certain genes. In half of cases these are inherited from a person's parents while in the rest, they occur during early development. The tumors involve supporting cells in the nervous system rather than the neurons. There is no known prevention or cure. Surgery may be done to remove tumors that are causing problems.