Ependymoblastoma: a histological, immunohistological and ultrastructural study of five cases

Abstract

Five ependymoblastomas were studied by means of routine histological techniques, immunohistology and electron microscopy. The tumours were characterized histologically by medium sized, poorly differentiated cells with round or oval nuclei frequently in mitosis and by ependymoblastic rosettes. Reactions for cytokeratin and neurofilament were negative and tubular material positive for glial fibrillary acidic protein was scanty. All five tumors demonstrated positivity for vimentin and S-100 protein. Electron microscopy showed poorly differentiated cells with high nucleo-cytoplasmic ratio and scanty cytoplasmic organelles. Sparse rosettes were present and the cells were united by junctional complexes. Frequent rudimentary or incomplete cilia, a few basal bodies and a few short intercellular glial-like filaments were seen. Features differentiating ependymomas and anaplastic ependymomas from ependymoblastomas are discussed and the need for a definite category separating ependymoblastomas from the former tumours is emphasized.

Ependymoblastoma in an adult: a diagnostic challenge on cytology

“…Immunohistochemical profile revealed S-100 and Vimentin positivity in all cases reviewed by Cruz-Sanchez et al 9 12 The authors observed that, in contrast to medulloblastomas, vimentin reactivity in ependymoblastomas was present in most cells throughout the tumour and its intensity was stronger, indicating a later stage of maturation in the latter group. GFAP was found to be absent or only sparsely positive in few tumour cells 12.…”

“…The histological diagnostic feature of ependymoblastoma is its dense cellularity with numerous distinctive multi-layered rosettes formed by concentric arrangement of cellular rings around small round lumina 3 5 9. The tumour cells are poorly differentiated, oval to spindle shaped with ill-defined cytoplasm and wispy polar processes 5.…”

“…The tumour cells are poorly differentiated, oval to spindle shaped with ill-defined cytoplasm and wispy polar processes 5. Features which identify these tumours as embryonal are the small cell size, uniform appearance and round or ovoid nuclei showing frequent mitoses 9. The structure of ependymoblastic rosette corresponds to the later phase of neural tube development characterised by multilayering of cells and abundant mitotic activity in juxtaluminal position 5 9…”

Ependymoblastoma with cystic change in a child

“…[1][2][3][4][5][6][7][8][10][11][12][13][14]16,17,[19][20][21][22][23][24][25][26][27][28][29][30] In our study, we described a 4-year-old girl diagnosed with ependymoblastoma and reviewed the relevant literature. Comparison of these data are possible only to a limited degree, since ependymoblastomas are very rare tumors and have been reported either as single case reports, frequently with no or only scant data on treatment and follow-up, or as part of larger reports on PNETs, and the outcomes usually were not separately elaborated.…”

Tumours of the Central Nervous System

“…According to the current concept (McLendon and Gray, 2006), it is a rather rare embryonal tumour characterised by the presence of ependymoblastic rosettes. Ependymoblastomas are characterised by the presence of microvilli, typical cilia and blepharoplasts, and zonulae adherentes (adhesive plaque junctions); thus ependymoblastoma cells resemble those embryonal cells that are already committed to ependymal differentiation (Langford, 1986;Cruz-Sanchez et al, 1988;.…”