What is the gaze palsy produced by compression of the tectum and what is it known as?
Parinaud syndrome consists of a 1) deficiency in upward-gaze, 2) pupillary light-near dissociation (pupils respond to near stimuli but not light) and 3) convergence-retraction nystagmus.
What is the differential for this mass in this patient?
Differential includes a pineal parenchymal tumour (e.g. pineocytoma), germ cell tumour and metastasis. In this age group a metastasis should be included high on the list.
Centred within the pineal region is a T1 isointense, T2/FLAIR hyperintense mass measuring 18 x 20 x 16 mm in orthogonal planes. The mass contains a single focus of susceptibility artefact on the EPI sequence. There is no evidence of restricted diffusion to indicate high cellularity. The mass demonstrates fairly homogeneous enhancement except for several tiny foci of non enhancement. The lesion obstructs the aqueduct with resultant hydrocephalus of the third and lateral ventricles. FLAIR signal hyperintensity surrounding the lateral ventricles is consistent with transependymal CSF spread.The lesion appears separate from the tectal plate. There is potential extension into the posterior aspect of the third ventricle. A right ventricular drain is noted within the lateral ventricle. No further regions of abnormal intracranial enhancement is identified.