Posterior fossa tumor

Causes

The posterior fossa is a small space in the skull, found near the brainstem and cerebellum. The cerebellum is the part of the brain responsible for movement, balance, and coordination. The brainstem is responsible for controlling vital body functions, such as breathing.

If a tumor grows in the area of the posterior fossa, it can block the flow of spinal fluid and cause increased pressure on the brain and spinal cord.

Most tumors of the posterior fossa are primary brain cancers. They start in the brain, rather than spreading from somewhere else in the body.

Posterior fossa tumors have no known causes or risk factors.

Symptoms

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

• Drowsiness
• Headache
• Imbalance
• Nausea
• Uncoordinated walk (ataxia)
• 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 problems
• Face muscle weakness
• Hearing loss
• Loss of feeling in part of the face
• Taste problems
• Unsteadiness when walking
• Vision problems

Exams and Tests

Diagnosis is based on a thorough medical history and physical examination, followed by imaging tests. The best way to look at the posterior fossa is with an MRI scan. CT scans are usually not helpful to see that area of the brain.

The following procedures may be used to remove a piece of tissue from the tumor to help with diagnosis:

• Open brain surgery, called a posterior craniotomy
• Stereotactic biopsy

Treatment

Most tumors of the posterior fossa are removed with surgery, even if they are not cancerous. There is limited space in the posterior fossa, and the tumor can easily press on delicate structures if it grows.

Depending on the type and size of the tumor, radiation treatment may also be used after surgery.

Support Groups

You can ease the stress of illness by joining a support group whose members share common experiences and problems. See: Cancer - support group

Outlook (Prognosis)

A good outlook depends on finding the cancer early. A total blockage in the flow of spinal fluid can be life threatening. If tumors are found early, surgery can lead to long-term survival.

Possible Complications

• Cranial nerve palsies
• Herniation
• Hydrocephalus
• Increased intracranial pressure

When to Contact a Medical Professional

Call your health care provider if you have regular headaches that occur with nausea, vomiting, or vision changes.

Alternative Names

Infratentorial brain tumors; Brainstem glioma

References

Maity A, Pruitt AA, Judy KD, Phillips PC, Lustig R. Cancer of the central nervous system. In: Abeloff MD, Armitage JO, Niederhuber JE, Kastan MB, McKenna WG, eds. Abeloff's Clinical Oncology. 4th ed. Philadelphia, Pa: Elsevier Churchill Livingstone; 2008:chap 70.

Brackmann DE, Arriaga MA. Neoplasms of the posterior fossa. In: Flint PW, Haughey BH, Lund VH, et al, eds. Cummings Otolaryngology: Head & Neck Surgery. 5th ed. Philadelphia, Pa: Mosby Elsevier; 2010:chap 177.

Update Date: 2/7/2012

Updated by: Linda J. Vorvick, MD, Medical Director and Director of Didactic Curriculum, MEDEX Northwest Division of Physician Assistant Studies, Department of Family Medicine, UW Medicine, School of Medicine, University of Washington; and Yi-Bin Chen, MD, Leukemia/Bone Marrow Transplant Program, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M. Health Solutions, Ebix, Inc.