Ganglioglioma with a tanycytic ependymoma as the glial component

Abstract

We studied a cystic ganglioglioma (GG) located in the right frontal lobe of the brain. Interestingly, the fibrillary spindle glial cells were often arranged in a fascicular pattern, and the generally uniform, round-to-oval delicate 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 contained granular or microvesicular structures positive for epithelial membrane antigen. Ultrastructural investigation revealed that the glial cells were ependymal in nature; intracytoplasmic lumina and intercellular microrosettes lined with cilia and microvilli, as well as long zonulae adherentes, were evident. In addition, chromogranin A-positive granular staining, neurosecretory-granule-like structures, and parallel arrays of microtubules were sometimes associated with the blood vessels. We considered the present case to be an unusual example of GG with an ependymoma, more precisely a tanycytic ependymoma, as the glial component; to our knowledge, the existence of ependymoma as the main glial component of this particular tumor has not been described before. The occurrence of NFTs, which has been reported in several cases of GG, was an additional, unusual feature.

Angiocentric Glioma

“…However, retrospectively this seems to be inadequate, because the rare examples of supratentorial tanycytic ependymomas reported in the literature were enhancing lesions on MRI and did not show the distinct perivascular growth pattern of angiocentric glioma. 10,15,28,30 The very strong immunolabeling for GFAP, vimentin, and S100B is less characteristic (in our experience) for common ependymoma but is reminiscent of radial glia cells in human fetal brain which have been postulated to be candidate stem cells of ependymoma. 35 Furthermore, angiocentric glioma tumor cells infiltrating the cerebral cortex showed a conspicuous radial orientation.…”

Tanycytic ependymoma arising from the right lateral ventricle: A case report and review of the literature

“…Electron microscopy (EM) can aid in distinguishing TEs from other tumors if diagnosis is in doubt. EM of these tumors shows characteristic ependymal features including intracytoplasmic intermediate filaments, prominent intercellular junctions, numerous slender surface microvilli, and microvilli‐lined lumina, but no basement membrane in aggregated tumor cells 4,6,8,15 …”

Supratentorial tanycytic ependymoma

“…It tends to be paucicellular, has a somewhat fascicular architecture, and is generally well differentiated with rare mitoses. 4,10,13,14 The perivascular pseudorosettes are inconspicuous and ependymal rosettes typically absent. 1,3,4,10,11,[13][14][15] As the light microscopy picture is similar to astrocytoma, tanycytic ependymoma is often misinterpreted as being piloid astrocytoma, 1,3,4,10,11,13,14,16 however, the EM characteristics are confirmed as ependymal.…”

“…4,10,13,14 The perivascular pseudorosettes are inconspicuous and ependymal rosettes typically absent. 1,3,4,10,11,[13][14][15] As the light microscopy picture is similar to astrocytoma, tanycytic ependymoma is often misinterpreted as being piloid astrocytoma, 1,3,4,10,11,13,14,16 however, the EM characteristics are confirmed as ependymal. 1,4,10,11 Despite tanycyte concentration being highest in the third ventricle, tanycytic ependymomas demonstrate a propensity for the spinal cord, 1,3,4,8,11 in keeping with other ependymomas.…”

“…Following surgical resection, the 51-year old man remained well at 14 months post operatively. 10 There is insufficient prognostic evidence available exclusively on tanycytic ependymoma, although the prognosis of ependymoma depends on age, extent of resection, and localisation. 11,17 The prognosis is better in adults and those with spinal tumours, with complete or near complete resection as an independent prognostic factor.…”