Ganglioglioma with a tanycytic ependymoma as the glial component

We studied a cystic ganglioglioma (GG) located in the right frontal lobe of the brain. Interestingly, the fibrillary spindle glial cells were often ar ranged in a fascicular pattern, and the generally uniform, round-to-oval de licate nuclei appeared to resemble those of ependymoma; and the neoplastic neurons often contained neurofibrillary tangles (NFTs). The glial component was positive for glial fibrillary acidic protein and occasionally containe d granular or microvesicular structures positive for epithelial membrane an tigen. Ultrastructural investigation revealed that the glial cells were epe ndymal in nature; intracytoplasmic lumina and intercellular microrosettes l ined with cilia and microvilli, as well as long zonulae adherentes, were ev ident. In addition, chromogranin A-positive granular staining, neurosecreto ry-granule-like structures, and parallel arrays of microtubules were someti mes associated with the blood vessels. We considered the present case to be an unusual example of GG with an ependymoma, more precisely a tanycytic ep endymoma, as the glial component, to our knowledge, the existence of ependy moma as the main glial component of this particular tumor has not been desc ribed before. The occurrence of NFTs, which has been reported in several ca ses of GG, was an additional, unusual feature.