Clinical features

The most usual presentation of medulloblastoma is with a short history of features of raised intracranial pressure - listlessness, vomiting and early morning headache.

As the majority of tumours arise in the fourth ventricle, many patients present with obstructive hydrocephalus. Unsteadiness, falls and double vision follow, and develop over a few days.

Examination is often normal. If signs are present, they are usually related to the obstructive hydrocephalus (e.g., impaired horizontal gaze or diplopia due to a sixth nerve palsy, papilloedema) rather than the tumour itself (e.g., ataxia, nystagmus, head tilt, dysmetria). Neck stiffness due to tonsillar herniation is common.

Physical examination should include a thorough neurological assessment with particular attention to cerebellar function (gait, coordination, Romberg test, finger-to-nose testing), a cranial nerve examination (especially extraocular movements for sixth nerve palsy due to increased intracranial pressure), and a fundoscopic examination for papilloedema.

Reference

1. Orr BA. Pathology, diagnostics, and classification of medulloblastoma. Brain Pathol. 2020 May;30(3):664-678