Supratentorial ectopic ependymoma.

BACKGROUND: Ependymomas usually arise from the ventricular surface. METHODS: We report an 11-year-old female who presented with a supratentorial ectopic ependymoma. RESULTS: The patient presented with a two-month-history of progressive headache, nausea and vomiting. Examination revealed papilledema, horizontal nystagmus, diplopia on upward gaze, and right pronator drift. CT scan showed an enhancing left precentral subcortical lesion measuring 3 cm in diameter with associated edema and mass effect. Its medial border was located 3 cm from the ependymal surface of the ventricle. A firm tumour was dissected from the centrum semiovale white matter, and removed in toto as confirmed on MRI. Pathological examination revealed histological, immuno-histochemical and electron microscopic features consistent with an ependymoma. Spine MRI and bone marrow aspirate, as well as lumbar puncture of cytology failed to show any dissemination. CONCLUSION: From the literature review, this represents an exceptional ependymoma located at the distance from the ventricular system or cisterns. Different pathogenic alternatives are discussed.