About Hypothalamic Hamartomas

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About Hypothalamic Hamartomas



What is a hypothalamic hamartoma (HH)?

What are the symptoms of a hypothalamic hamartoma?

How are hypothalamic hamartomas diagnosed?

How common are hypothalamic hamartomas?

What are the treatment options for hypothalamic hamartomas?

What are the risks of treatment for hypothalamic hamartoma?


What is a hypothalamic hamartoma (HH)?

Hypothalamic hamartomas (HH) are rare, benign (noncancerous) tumors of the hypothalamus, a region of your brain that regulates many of your body’s systems. Hypothalamic hamartomas affect children from infancy through adulthood and commonly cause seizures, precocious (early) puberty, hormonal imbalances, and cognitive and behavioral problems.

Hypothalamic hamartomas are usually diagnosed during evaluation of patients for epilepsy or precocious puberty.


What are the symptoms of a hypothalamic hamartoma?

The symptoms of hypothalamic hamartoma (HH) include:

  • seizures
  • precocious (early) puberty
  • hormone imbalances
  • cognitive impairment
  • behavioral problems
  • emotional difficulties

Seizures caused by a hypothalamic hamartoma usually begin in infancy, most often as brief and frequent gelastic (or laughing) seizures. You may not be able to tell the difference between a gelastic seizure and normal laughter.

The difficulty in identifying gelastic seizures usually delays the diagnosis of epilepsy and of the hypothalamic hamartoma. Even doctors can have difficulty recognizing gelastic seizures because they are rare and affected children generally develop normally.

Between the ages of 4 and 10 years old, you may notice the seizures becoming more disabling, with the emergence of different seizure types, such as:

  • complex partial seizures (diminished or altered consciousness with involuntary but coordinated movements)
  • generalized convulsions (involuntary shaking, twitching, and disorganized movements)
  • drop or atonic seizures (brief loss of muscle tone leading to falls)

In this stage, your child may display signs of progressive cognitive impairment, worsening school performance, and the following behavioral problems:

  • tantrums
  • rage attacks
  • social isolation

Some children with a hypothalamic hamartoma may have endocrine (hormonal) disturbances. Central precocious puberty (early puberty) is the most common sign of these disturbances, and may be the only symptom of hypothalamic hamartoma that your child has.

Not all people with a hypothalamic hamartoma have the same symptoms or the same age of onset. While you might notice gelastic seizures in your newborn, it is also possible that seizures will not develop until later in life. Seizures caused by a hypothalamic hamartoma generally do not respond to medication.


How are hypothalamic hamartomas diagnosed?

Your neurological symptoms, magnetic resonance imaging (MRI), and neurological tests are examined if a hypothalamic hamartoma is suspected. Early detection can improve the likelihood of successful treatment, especially for children who have worsening seizures or whose learning skills or behavior have begun to deteriorate.

MRI is used to locate your hypothalamic hamartoma and confirm your diagnosis. Hypothalamic hamartomas can be small and difficult to detect, so interpretation by a doctor that specializes in neuroradiology is desirable. Electroencephalography (EEG) may also be used to identify seizure patterns that suggest a hypothalamic hamartoma.


How common are hypothalamic hamartomas?

Hypothalamic hamartomas are rare, and occur at a rate of 1 in every 200,000 people.


What are the treatment options for hypothalamic hamartomas?

Surgical Removal

Our neurosurgeons are one of just a few groups in the world with significant experience using the transcallosal approach to remove hypothalamic hamartomas. This approach uses the natural gap between the two hemispheres of your brain to create an avenue to access and remove the tumor.

We also use more traditional subtemporal or orbitozygomatic approaches if they offer the best chance of success. This surgery begins on the side of your head and passes under your brain and above the base of your skull to reach the lesion.

Less-invasive endoscopic surgery can be considered when the size and exact anatomical positioning of the lesion allows.

Laser Generated Stereotactic Thermoablation

Laser generated stereotactic thermoablation is a new minimally invasive technology that uses energy in the form of light to destroy tumors or damaged tissue. The energy from the laser causes the temperature of the target tissue—in this case your hypothalamic hamartoma—to rise, destroying it.

Computerized safety mechanisms automatically turn the laser off if it approaches brain tissue surrounding the tumor. Magnetic resonance images (MRI) are also used further improve the accuracy of the procedure and guide the placement of the laser.

Gamma Knife Radiosurgery

Gamma Knife radiosurgery uses many beams of radiation that converge on a single point to shrink tumors. Each individual beam is not powerful enough to destroy healthy tissue, but at the point where the beams meet sufficient energy is concentrated to destroy tumor cells.


What are the risks and advantages of the treatment options?

Surgical Removal

Varying degrees of risk to your memory and endocrine and cognitive function are present and depend on the size and location of your hypothalamic hamartoma and the point of connection to your hypothalamus. These risks must be assessed on an individual basis after thorough review of your medical history and images.

Surgical removal can result in immediate improvement in your symptoms. The primary purpose of surgery is to eradicate your seizure activity, but improvement in your behavior and cognitive function can also result.

It may not be possible to remove all of your hypothalamic hamartoma due to involvement of vital surrounding structures. Leaving some tissue behind does necessarily mean your symptoms will persist, provided your tumor has been completely disconnected from your hypothalamus.

Surgery to remove a hypothalamic hamartoma results in total cessation of seizures in 50% of those treated and a more than 90% reduction in seizures in another 30% of those treated. Therefore, about 80% of patients obtain substantial control of their seizures after surgery.

Stereotactic Laser Thermoablation

This technology has been used to treat hypothalamic hamartomas since 2012; early results indicate that it is slightly less risky than traditional surgical removal, owing to the fact that the laser used can be maneuvered more precisely than traditional surgical instruments.

Gamma Knife

The risks of Gamma Knife treatment for your hypothalamic hamartoma depend mostly on the size and location of your tumor. Your doctors will work with you, taking into account your medical history and treatment preferences, to determine if you are a candidate.

Treating hypothalamic hamartomas with Gamma Knife is challenging because of their proximity to your optic nerve. A balance must be struck between a dose of radiation high enough to destroy the tumor, yet low enough to spare your optic nerve and avoid visual loss.

You can expect a gradual improvement of your symptoms over the 2 to 3 years after the procedure, but seizure activity can decrease in as little as 6 months.

Overall, 40% of patients we have treated are eventually seizure free after Gamma Knife treatment, with another 20% showing significant improvement.


How can we help?

For more information, please call 1-800-BARROW1 (227-7691) or (602) 406-7585.

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Barrow Neurological Institute
350 W. Thomas Road
Phoenix, AZ 85013
(602) 406-3000