A large neurofibroma growing on a man's hand. A neurofibroma is a benign tumour which grows from the fibrous covering of a peripheral nerve. They are normally symptomless, except when they develop from the sheath of a nerve root, when pain and compression of the spinal cord may occur. Numerous, widespread neurofibromas occur in a congenital disese known as neurofibromatosis or von Recklinghausen's disease.