Figure 2 Surgical and histologic images

(A, B) Intraoperative view confirming the hemorrhagic component of the lesion (A) and documenting the floor of the fourth ventricle free of disease at the end of tumor removal (B). (C–E) Histologic examination showed monomorphic cells with regular round nucleus and dispersed chromatin; tumor cells of the perivascular area were arranged radially around the vessels, forming perivascular pseudorosettes, with prominent perivascular immunoreaction for glial fibrillary acid protein (D) and epithelial membrane antigen (E). Mitoses and necrosis were absent. Diagnosis: WHO grade II ependymoma.