Gliomatosis peritonei, light micrograph. Gliomatosis peritonei is characterised by the presence of nodules of mature glial tissue in the peritoneum. It is a rare complication of solid immature ovarian teratomas. Some cases are associated with a mixed germ cell tumour, mature teratoma, or occur in patients with ventriculoperitoneal shunting. The nodules of gliomatosis peritonei are composed of elongated mature glial cells haphazardly arranged in a fibrillary matrix, covered by mesothelial lining. Usually, there is associated chronic inflammation and fibrosis. Haematoxylin and eosin stained section. Magnification: x100 when printed at 10 centimetres wide.