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.