Computed tomography and magnetic resonance imaging findings in primitive neuroectodermal tumours in adults.

Primitive neuroectodermal tumours (PNET) are highly malignant, undifferentiated supratentorial neoplasms arising from germinal matrix cells of the primitive neural tube. PNET occur primarily in young children; they are extremely rare in adults. PNET frequently seed within the central nervous system and may be multicentric at the time of diagnosis. Previous reports of the neuroradiological findings refer solely to PNET in children. We describe the computed tomography (CT) and magnetic resonance imaging (MRI) appearances in five adult patients with pathologically proven PNET. In our series, PNET were mostly seen as rather large, heterogeneous masses with cystic and necrotic areas, intratumoral haemorrhage and focal calcification. The prominent contrast enhancement on both CT and MRI scans reflects the increased vascularity of PNET.