Hypothalamic Hamartomas

By Meg Marinis, Director of Medical Research Oct 27, 2011
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What's bad about being a fourteen-year-old girl? Braces. Acne. Confusing hormones. Being too young and not old enough. 

…Try life-debilitating seizures preceded by fits of extreme rage.

That's what poor fourteen-year-old Charissa Bayer has had to face as she battles a hypothalamic hamartoma – a non-cancerous tumor that has sat on her hypothalamus (a part of the brain that sits right above the brain stem) since birth.

Besides being hard to say and spell, the hypothalamus holds a very important role in our bodies.

For such a tiny size, the hypothalamus controls many tasks -- its main job is to maintain our body's status quo. Vital measurements such as blood pressure, body temperature, fluid and electrolyte balance, and body weight all factor into a value called the "set-point." The hypothalamus monitors the set-point, managing necessary changes in the body if the set-point drifts from its normally fixed state.

The hypothalamus also regulates behaviors that involve eating, drinking, general arousal, rage, aggression, embarrassment, escape from danger, pleasure, and copulation. So what does this all mean? Well, here's one example: sensory inputs (taste, smell, gut distension) inform the hypothalamus if we feel hungry, full, or smell something insanely delicious.

So, what happens when a 'hamartoma' is found in the hypothalamus?

As said above, a hamartoma is a benign growth. However, when one is located in the hypothalamus, the symptoms can be severe. They may include:

- Intense seizures.
- Precocious (early) puberty.
- Cognitive impairment.
- Emotional and behavioral difficulties.

Do most of the seizures look like Charissa's? Well, these patients usually tend to suffer from a type of seizure called a 'gelastic' (laughing) seizure. These seizures may first present during infancy and can appear to be brief and almost resemble normal child-like laughter, or sometimes they present as fits of uncontrollable crying. But the parents, knowing their kids, can soon tell the difference. This laughing or crying is often followed by a full-on seizure, like the one that Charissa had in the episode. And regardless of the seizure's presentation, the seizures consistent with a hypothalamic hamartoma are frequently quite difficult to control.

Are all hypothalamic hamartomas as difficult to remove as Charissa's?

Well, we should remember, Charissa's lesion sat off to one side of the brain more than the other, so the unique location of this tumor already indicated difficulties. And initially, doctors may recommend anti-convulsant medications. Yet due to disappointing results, many doctors agree to surgical resection, stereotactic radiation, radiofrequency ablation, and vagal nerve stimulation. But in general, if surgical treatment has been chosen, meticulous planning must be done due to the risks that include infection, bleeding, hydrocephalus, stroke, and death. Risks specific to the hypothalamus involve eating disorders, aggression, trouble with regulating sodium balance in the body, level of consciousness and wakefulness difficulties, and memory disturbances.

In the past, the traditional method to remove these types of tumors would entail an approach from the temple or near the cheek, but several surgeons found that the technique did not enable them to resect the entire tumor, thereby completely eliminating the terrible seizures.

So, how did Dr. Shepherd remove Charissa's tumor? In the last decade or so, a few surgical centers have embraced the trans-callosal/trans-forniceal approach. In this method, surgeons perform a small craniotomy on the top of the patient's head and proceed between the two hemispheres of the brain, carefully traveling a longer distance to the tumor in the hypothalamus at the bottom of the brain. Once they reach the tumor, they resect it through the roof of the third ventricle. Currently, this method has shown better results in the ability to remove the entire mass and free the patient of such devastating seizures.