Light micrograph of perineural invasion by prostate cancer. Perineural invasion occurs when a tumour invades into and around nerves. In this image, a nerve (central light pink roughly oval structure) is surrounded by prostate cancer tumour cells (light blue-purple). Around the invaded nerve is pink prostate stroma (pink areas making up most of image). Haematoxylin and eosin stained tissue section. Magnification: 200x when printed at 10 centimetres.