Fig. 14

Primitive neuroectodermal tumour (PNET) involving the pineal gland in a 3-year-old boy. Well-circumscribed, tumour arising from the pineal gland (arrow), which has mostly intermediate signal as well as high signal foci on sagittal T1-weighted image (a) and intermediate, low and high signal on axial T2-weighted image (b). The pineal tumour demonstrates heterogeneous contrast enhancement on sagittal T1-weighted image (c). The tumour causes obstructive hydrocephalus by exerting localised mass effect and compression of the quadrigeminal plate, cerebral aqueduct and third ventricle