Hypothalamic Hamartoma

A hamartoma is a benign (non-cancerous) growth made up of an abnormal mixture of cells and tissues. A hypothalamic hamartoma is a tumor-like formation on the hypothalamus, the area at the base of the brain that controls the production and release of hormones by the pituitary gland. These hormones regulate a wide array of bodily functions, from growth and metabolism to sexual development and the body’s reaction to stress.

While hypothalamic hamartomas do not grow or spread to other parts of the brain or body, they can sometimes place pressure on the brain resulting in health problems that include seizures, early puberty, and cognitive impairment.

Hypothalamic hamartomas emerge during the development of the embryo and fetus and are present at birth. In most cases, their cause is not known.

In some cases, genetic disorders can be found. Pallister-Hall syndrome, for example, is a genetic condition that can present with deformities of the hands and feet and other anatomical anomalies, including hypothalamic hamartoma.

The specific genetic mutation associated with Pallister-Hall syndrome has been identified (a defect of the GLI3 gene), and research is ongoing to learn whether other cases of hypothalamic hamartoma also have a genetic association. If they do, it is likely due to sporadic (not inherited) gene mutations. In the majority of cases, the person with hypothalamic hamartoma is the only one in the family to have the condition.

Symptoms of hypothalamic hamartoma may include:

• Gelastic seizures (episodes of laughing with no apparent trigger)
• Other types of seizures, including seizures with altered awareness, with stiffening of the limbs, or with shaking
• Problems with concentration, memory and learning
• Sudden episodes of rage, often with no apparent provocation
• Early puberty (known as central precocious puberty, occurring before age 8 in girls or age 9 in boys, sometimes as early as infancy)
• Bedwetting or frequent urination
• Extreme thirst or lack of thirst
• Delays in motor development, problems with balance and coordination
• Poor social skills

Gelastic seizures in infancy are often the first sign of hypothalamic hamartoma. These particular seizures sometimes go unrecognized, or undiagnosed, until other symptoms arise.

Endocrinologists most often encounter patients with hypothalamic hamartoma when they develop endocrine problems, most often early puberty. In some children, puberty may be the first recognized symptom.

Your doctor will usually begin with a physical exam and with questions about any symptoms you may have noticed. Height and weight will be charted to look for changes in growth patterns. The doctor will also check to make sure there are no abnormalities in pubertal development. If your child has experienced seizures, he or she will be evaluated by a neurologist.

If signs indicate the possibility of hypothalamic hamartoma, additional tests may include:

• Blood and urine tests to check hormone levels; the blood tests, or venous sampling, involve taking blood from peripheral veins in the arms to look at hormone levels originating from the pituitary gland in the brain
• Magnetic resonance imaging (MRI) or computerized tomography (CT) scan to get visual images of the pituitary gland, brain and spinal cord

Hypothalamic hamartoma treatment is tailored to the patient’s symptoms and the severity of the condition.

Seizures are managed by neurologists with anti-seizure medications. Surgery may also be indicated if medications are not able to control the seizures adequately. If it appears your child may benefit from surgery, neurosurgeons can disconnect the hamartoma from the hypothalamus using a minimally invasive technique known as laser ablation. Other alternatives include removing or reducing the size of the hamartoma with surgery.

When seizures are associated with problems in cognitive, motor, behavioral or social development, therapy may be needed to help the child address these deficits.

Endocrine treatment for hypothalamic hamartoma

For patients with early puberty or other hormonal problems, treatment with medication is used.

• Different combinations of hormone agonists (to block the effects of too much of a particular hormone) and hormone replacements are used to counter the effects of the condition. Specifically, a hormone agonist medication can be used to shut off puberty if it has occurred too early.
• When the child is the appropriate age for puberty, the medicines to stop early puberty from occurring are discontinued, allowing the progression of normal puberty. 
• Treatment for metabolic abnormalities may also be needed.

For many patients with hypothalamic hamartoma, the related problems, most notably seizures, can be challenging to manage, but surgery can sometimes eradicate seizures. Many of the endocrine problems are treatable with medications. The seizure conditions require ongoing and diligent follow-up with a neurologist.

When medication is prescribed to counter the effects of hormonal problems, periodic follow-up tests are needed to ensure that the treatment continues to work effectively. Dosage levels and the combination of medications may need to be adjusted over time.

If the treatment has removed the hamartoma, follow-up tests and imaging will be needed periodically to make sure the tumor has not returned.

Children with hypothalamic hamartoma often require care from many pediatric specialties.

The Neuroendocrine Center at Children’s Hospital of Philadelphia (CHOP) offers families a coordinated and multidisciplinary approach to treatment for neuroendocrine disorders. Our team combines the expertise of pediatric endocrinologists, neuro-oncologists, neuro-surgeons, neuro-ophthalmologists, neuro-radiologists, geneticists and pathologists.

All our team members have vast experience in the treatment of complex neuroendocrine conditions like hypothalamic hamartoma.