Histologic evaluation
All cases demonstrated features of myxopapillary ependymoma with fibrillary processes arranged around fibrovascular cores with variable amounts of myxoid material (Fig.2.A). One case had focal (10%) features of classic ependymoma. The cases ranged from low to moderate cellularity. 5 cases harbored ≥5 mitoses per 10 high-powered fields (range: 5-9, Fig.2.B), 3 of which also showed necrosis (including two with disseminated disease, Fig.2.C). Microvascular proliferation was identified in one case that had increased mitotic activity and necrosis. An identifiable capsule was present in 4 cases. Leptomeningeal involvement was identified in 4 cases and nerve root involvement was present in 1 case.