Spinal tanycytic ependymoma associated with neurofibromatosis type 2--case report.

An 18-year-old girl with a 5-year history of neurofibromatosis type 2, consisting of bilateral acoustic tumors and a meningioma at the planum sphenoidale, presented with an intramedullary mass at the T-1 level, and underwent total removal of the tumor. Histological examination showed that the tumor consisted of markedly elongated spindle-shaped cells, which were immunopositive for S-100 protein and glial fibrillary acidic protein. Ultrastructural examination showed microvilli-lined lumina and prominent intercellular junctions, which were characteristic ependymal features. These findings were compatible with the diagnosis of tanycytic ependymoma. This rare subtype of ependymoma appears to arise through inactivation of NF2, in addition to some typical ependymomas.