Posterior Fossa Tumors Clinical Presentation

Updated: Apr 03, 2018
  • Author: Hassan Ahmad Hassan Al-Shatoury, MD, PhD, MHPE; Chief Editor: Brian H Kopell, MD  more...
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The clinical presentation depends on the site of the tumor, biological behavior and aggressiveness of the tumor, and the rate of growth. At the time of presentation, the patient may be very ill from severe headache or frequent vomiting due to associated hydrocephalus.

Symptoms may be caused by focal compression of the cerebellum or brain stem centers and increased intracranial pressure.

Symptoms due to focal brainstem compression include cranial nerve dysfunction, which  commonly involves the nuclei or tracts of the third, fourth, or sixth cranial nerves, resulting in ocular palsies and diplopia and long tract signs (hemiparesis).

Symptoms due to focal compression of the cerebellum include characteristic eye findings and vermian syndrome. Truncal ataxia is a common finding in midline tumors, such as medulloblastomas, ependymomas, and vermian astrocytomas. It is manifested by a tendency to fall frequently and a widely based gait.

Hemi-cerebellar syndrome involves limb ataxia, nystagmus, and dysmetria. Tumors that occur in the cerebellar hemisphere, such as metastases, cerebellar astrocytomas, or cystic hemangioblastomas, may present by ataxia of the contralateral limbs. Nystagmus usually occurs late in the disease. Vertical nystagmus suggests a lesion in the anterior vermis, periaqueductal region, or craniocervical junction. Horizontal nystagmus implies involvement of the cerebellar hemisphere.

Intracranial hypertension causes the following 8 symptoms:

  • Headache  is the most common symptom in patients with posterior fossa tumors. Associated neck pain, stiffness, or head tilt suggest tonsillar herniation into the foramen magnum. Headache is insidious and intermittent. It is most severe in the morning or after a nap because of increased intracranial pressure from recumbency and hypoventilation during sleep. Headache manifests in children as irritability and difficulty to be handled.

  • Vomiting may be due to generalized intracranial hypertension or irritation of the vagal nuclei in the medulla oblongata or area postrema of the fourth ventricle; it usually occurs in the morning. Vomiting sometimes relieves headache.

  • Strabismus is secondary to sixth nerve palsies from intracranial hypertension. Third nerve palsies may also occur.

  • Blurring of vision due to papilledema

  • Meningismus

  • Dizziness

  • Macrocephaly in children

  • Hydrocephalus

Young age, moderate to severe hydrocephalus, transependymal edema, the presence of cerebral metastases, and tumor pathology (medulloblastoma and ependymoma) on presentation may predict postresection or persistent hydrocephalus. [7]