Neural cyst of the ovary with central nervous system microvasculature.

A case of a monodermal teratoma of the ovary composed solely of mature neuroglial elements is described. The cyst lining comprised ependymal cells surrounded by white matter which itself was resting on mesothelial cells. Astrocytes, oligodendrocytes, microglia and neurofilament-positive fibres were seen, but no neuron cell bodies were present. Immunohistochemical stains showed positivity for glial fibrillary acidic protein in ependymal, subependymal and the white matter regions while S-100 protein positivity was restricted to the white matter. Vessels within neuroectodermal tissue, but not those within the mesodermal tissue, stained positively for anti-glucose transporter protein, a marker shown to be present in vessels with barrier functions. We conclude that this is a rare case of monodermal teratoma consisting of purely mature brain tissue with a microvasculature exhibiting blood-brain barrier characteristics.