Figure 4

Three phenotypic variants of trisomy 19 ependymomas. Clear cells, indicative of clear cell ependymoma, a subgroup of trisomy 19 ependymoma (HE: A, 250× and B, 60×); PNET-like appearance, because tumoral cells almost devoid of cytoplasm, presence of rounded nuclei and nuclei-free regions not always centered on vessels (HE: E, 190×; F, 60×; I, 375×; J, 90×; M, 130× and N, 30×); and oligo-astrocytoma appearance, due to large eosinophilic tumoral cells and presence of chicken-wire vessels (HE: Q, 125× and R, 60×). Ependymal nature confirmed by GFAP positivity of end-feets (D, 125×; H, 60×; L, 160×; P, 375× and T, 375×) and intra-cytoplasmic EMA dots (C, 160×; G,160×; K, 250×, O, 250× and S, 500×). Pictures A, B, C and D correspond to tumor A1; pictures E, F, G and H to tumor A2; pictures I, J, K and L to tumor A4; pictures M, N, O and P to tumor A3, pictures Q, R, S and T to tumor A8.