Neurinoma tumour. Light micrograph of a section through tissue from a neurinoma, a benign (non- cancerous) tumour of nervous tissue. The tumour forms from the myelin sheath that surrounds nerve fibres. Any nerve can be affected by a neurinoma. Although benign, the growth of the tumour can put pressure on the nerve, leading to tingling or even paralysis in the area that the nerve supplies. Surgical removal of the growth is the treatment in such cases.