Hypothalamic Hamartoma

Hypothalamic hamartoma (HH) is a rare, benign (noncancerous) tumor or lesion found in the hypothalamus area of the brain. This part of the brain controls many of the automatic or normal state functions, including hunger, thirst, body temperature, heart rate, blood pressure and hormone regulation. This area of the brain is also involved in hormonal balance. HH is estimated to occur in one out of 200,000 children worldwide. This number is likely understated because of the extreme difficulty in diagnosis.

There are two types of HH classifications:

• Intrahypothalamic (or sessile) is more often associated with neurological issues and seizures. It also common for children with sessile HH to experience a significant decline in behavior and cognitive abilities.
• Parahypothalamic (or pedunculated) is more commonly associated with precocious or early puberty and less so with neurological problems or epilepsy.

Symptoms

HH presents itself in many different ways. From behavior issues to early puberty, the symptoms vary greatly in severity and form. For some, the effects of HH may be so subtle that they may go years without being detected. While symptoms of HH vary greatly, the most common indicator is the presence of gelastic seizures.  

• Seizures: Gelastic or dacrystic seizures (focal seizures with laughing or crying). Other seizure types such as absence, atonic, tonic or tonic-clonic may also present.
• Cognitive impairments, such as memory or attention
• Episodes of rage or changes in mood
• Precocious puberty (early onset of puberty)
• Pallister-Hall syndrome
• Other deficits or delays

Causes

The exact cause of HH is unknown, although research suggests that mutations in the GL13 gene may have an impact.

Diagnosis

HH has proven difficult to diagnose, and many children go undiagnosed and without proper treatment. An early diagnosis is paramount to identifying and achieving successful treatment options before epileptic activity causes permanent damage to the brain. The diagnosis of HH is based on a child’s neurological symptoms and radiographic tests. 

• Symptoms (neurological and physical)
• MRI
• EEG

Treatment

While those with HH do not typically respond well to medication, surgical options are promising with many patients experiencing a seizure free life following surgery. Treatment focuses on partially or completely removing the tumor or lesion from the brain. In 2010, Texas Children’s Hospital was the first hospital in the world to use real-time MRI-guided thermal imaging and laser technology to destroy lesions in the brain that cause seizures. Since then we have operated on more than 140 patients with epilepsy (as of March 2017) from around the world providing them with a safe, less invasive alternative to craniotomies. MRI-guided laser surgery targets abnormal tissue at the speed of light with extraordinary precision. This technology is changing the face of epilepsy treatment, providing a minimally invasive and often life-altering option for many epilepsy patients. Currently, 93% of patients are seizure free one year after having this surgery at Texas Children’s Hospital. The benefits of this new approach – reducing risk and invasiveness – may allow more epilepsy patients to be considered viable surgery candidates in the future.

Additional resources

• Texas Children’s Hospital Laser Ablation Surgery
• Hope for Hypothalamic Hamartomas
• National Organization of Rare Diseases