Symptoms:

Symptoms occur very early with posterior fossa tumors and may include:

• Ataxia (uncoordinated gait)
• Drowsiness
• Headache
• Imbalance
• Nausea
• Vomiting

Symptoms from posterior fossa tumors also occur when the tumor damages local structures, such as cranial nerves. Symptoms of cranial nerve damage include:

• Dilated pupils
• Eye deviations
• Facial muscle weakness
• Hearing loss
• Loss of sensation of part of the face
• Taste disturbances
• Unsteadiness when walking
• Visual field deficits

Signs and tests:

Diagnosis is based on thorough history and physical examination, followed by imaging tests. The best way to look at the posterior fossa is with an MRI.

Posterior craniotomy (open brain surgery) or stereotactic biopsy (using special instruments to get a small piece of the tumor) can be used to obtain tissue for diagnosis.

Tumors of the posterior fossa usually require surgical removal, even if they are benign (noncancerous). This is because of the delicate structures in the area that can be compressed by any abnormal growth and the frequency of symptoms associated with the tumors.