Brain, ependymoma

Ependymomas are tumours with ependymal differentiation and are classified as WHO grade II. Both children and adults are affected, although infratentorial ependymomas are more common in children. Ependymomas may arise anywhere in the CNS, but typically within the ventricles. Microscopically, ependymomas show architectural features of perivascular pseudorosettes and occasionally true ependymal rosettes (with an empty central lumen); nuclei are generally monomorphic with stippled chromatin. Tumour cells are immunoreactive for GFAP and EMA (in a dot-like pattern or along the luminal surface of a rosette). Prognosis of ependymomas is variable and does not correspond well to traditional histologic grading. A molecular classification of ependymomas has been proposed that divides ependymomas among 3 compartments (supratentorial, infratentorial, spinal) with 3 molecular subgroups each; this system seems to correspond better to biologic behaviour (see reference in Related Content).