A benign peripheral nerve tumor can cause symptoms if it presses on the nerve in which it is growing or on nearby nerves, blood vessels or tissues. As the tumor grows, it may be more likely to cause symptoms, but even small tumors can sometimes cause symptoms. Symptoms depend on the location of the tumor and which tissues it affects. Symptoms may include:  Swelling or a lump under your skin Pain, tingling or numbness Weakness or loss of function in the affected area Dizziness or loss of balance  Causes The cause of benign peripheral nerve tumors usually isn't known. Some are passed down in families. The most common type of benign peripheral nerve tumor is a schwannoma. A schwannoma typically starts in a single bundle inside the main nerve, shifting the rest of the nerve. Another common type is a neurofibroma. A neurofibroma also often forms inside the nerve. Sometimes it grows from several nerve bundles. Perineuriomas are rare and can grow from inside or outside the nerve. Tumors outside a nerve can cause problems when they press on the nerve. Other benign tumors that form outside nerves are soft lumps of slow-growing fat cells called lipomas and ganglion cysts.                  By Mayo Clinic Staff By Mayo Clinic Staff  Benign peripheral nerve tumor care at Mayo Clinic 
benign peripheral nerve tumor can cause symptoms presses nerve growing nearby nerves  blood vessels tissues  tumor grows  may likely cause symptoms  small tumors can cause symptoms  symptoms depend location tumor tissues affects  symptoms may include:  swelling lump skin pain  tingling numbness weakness loss function affected area dizziness loss balance  causes cause benign peripheral nerve tumors isn't known  passed down families  common type benign peripheral nerve tumor schwannoma  schwannoma typically starts single bundle inside nerve  shifting rest nerve  common type neurofibroma  neurofibroma forms inside nerve  grows nerve bundles  perineuriomas rare can grow inside nerve  tumors nerve can cause problems press nerve  benign tumors form nerves soft lumps slow-growing fat cells called lipomas ganglion cysts                   mayo clinic staff mayo clinic staff  benign peripheral nerve tumor care mayo clinic 
peripheral nerve tumors benign