Mechanisms of symptoms: (a) increased intracranial pressure from hydrocephalus; (b) direct compression of brainstem, cerebellum; (c) endocrine dysfunction.

Headache most common symptom at onset.

Dorsal midbrain compression: (a) Parinaud syndrome (paresis of upgaze, convergence-retraction nystagmus, light-near pupillary dissociation); (b) Sylvian aqueduct syndrome (Parinaud syndrome plus paralysis of downgaze or horizontal gaze); (c) lid retraction (Collier sign); (d) ptosis; (e) fourth nerve palsy (diplopia, head tilt).

Direct cerebellar compression: ataxia, dysmetria.

Endocrine dysfunction rare: diabetes insipidus, precocious puberty in boys.

Brain MRI with gadolinium.

Additional staging investigations: complete spine MRI, CSF cytology. High levels of α-fetoprotein or β-human chorionic gonadotropin in CSF or serum indicate presence of malignant germ cells.

Surgical excision of tumor for tissue diagnosis, debulking.

Postoperative evaluation for CSF seeding with contrast MRI of whole spine, CSF tumor markers and cytology prior to starting adjuvant therapy.