Hypothalamic Hamartoma Center of the Neuroscience Institute


Hypothalamic hamartomas are rare tumors present at birth that reside in a critical part of the brain directly over the optic nerves. Made up of various brain cells, these benign (non-cancerous) masses form in the third ventricle (fluid-filled cavity) at the base of the skull during the first months of embryonic development. Hypothalamic hamartomas interfere with the function of the hypothalamus. The hypothalamus is located at the base of the brain and controls many of the basic functions of life such as hunger, aggression, sexual drive, growth, hormonal development, body temperature and salt and water metabolism.

These rare birth defects are found in only one in every million births. They lead to seizures and seldom respond to medication. Although benign, the tumors cause severe hormonal difficulties, early puberty, progressive deterioration of behavior and intelligence and short-term memory loss that may deteriorate over time. On diagnostic scans, hypothalamic hamartomas appear to be small, benign tumors.

Hypothalamic hamartoma symptoms are expertly diagnosed and treated by a multidisciplinary team of specialists at the Hypothalamic Hamartoma Center at Northwell Health Neuroscience Institute. Although benign (non-cancerous), hypothalamic hamartomas cause serious symptoms such as severe hormonal difficulties, early puberty, progressive deterioration of behavior and intelligence and short-term memory loss which may worsen over time. Rare birth defects, hypothalamic hamartomas (also referred to as benign tumors or lesions) develop prenatally in or around the hypothalamus gland in the brain. The hypothalamus is part of the body's endocrine system, a system of glands that influences almost every cell, organ and function of our bodies.


Children born with hypothalamic hamartoma sometimes show significant symptoms during the first year of life, or they may not show any symptoms at all until later on. Symptoms may include: seizures, precocious puberty or both. Individuals may also exhibit aggressive and violent behavior.

Symptoms include:

  • Laughing (gelastic) seizures. These seizures typically show up in infancy and continue into childhood and can be so debilitating that they often interfere with school attendance and social activities. Characteristically, laughing or gelastic seizures in infants are brief and involve sudden laughter followed by fright or anxiety. A seizure may also be triggered by loud noises, excitement or fear. The seizures become progressively worse with age. Characteristics of these seizures include:
    • Inappropriate or forced laughter. At times, gelastic seizures may also resemble crying and, in some cases, the child may seem to be in pain and exhibit facial contortions.
    • Squirming or wriggling.
    • Arousal from sleep or being startled while falling asleep. Once the seizure is complete, the child returns to sleep.
  • Behavioral disorders. In many individuals, emotional and behavioral disorders may be part of the hypothalamic hamartoma symptoms set. Some of the symptoms include anger, rage and aggressive behavior, including kicking and biting. Also known as hypothalamic rages, they are often mistaken for temper tantrums. This behavior may include the child not making eye contact and appearing to be in a trance. Once the behavior has ceased, the child is often unaware of or does not remember his action.
  • Endocrine disturbances. Endocrine disorders are sometimes a manifestation of hypothalamic hamartoma. Symptoms may include:
    • Bed wetting
    • Lack of thirst
    • Lack of appetite
    • Unexplained weight gain
  • Movement disorders. Motor disorders, including problems with balance, coordination and walking, as well as speech and language deficits, are sometimes associated with hypothalamic hamartoma. 
  • Cognitive dysfunction. Symptoms of memory and learning difficulties may appear, including:
    • Attention deficit disorder
    • Autism
    • Asperger’s syndrome
    • Depression
    • Paranoid disorder
    • Obsessive-compulsive disorder
  • Pallister Hall Syndrome. A disorder which causes the growth of extra fingers and/or toes (polydactyly) or the fusion of fingers or toes (cutaneous syndactyly)


Hypothalamic hamartoma can be challenging to diagnose. Standard methods of diagnostic imaging such as CT Scans or low-resolution MRIs are often unreliable, since the hamartomas are sometimes not clearly seen on a scan, or they may be initially misdiagnosed as other types of masses.

In the initial stages of diagnosis, gelastic seizures are often associated with epilepsy. Since EEG studies often “miss” the hamartoma due to its location deep in the brain, the reports come back negative or inconclusive.

The diagnosis of hypothalamic hamartoma is often made as a child grows. As a child with an undiagnosed hypothalamic hamartoma develops, symptoms such as generalized seizures appear, along with or before and after the gelastic seizure. In addition, behavioral and cognitive difficulties appear at this time.

The diagnosis of hypothalamic hamartoma is best conducted through a two-pronged approach:

  • Thorough review of the neurological symptoms
  • Diagnostic imaging analysis

It is important that the physicians conducting the diagnostic testing be well-versed in hypothalamic hamartoma and have experience in the treatment of hypothalamic hamartoma patients. Other common misdiagnoses include:

  • Colic
  • Acid reflux
  • Irritable bowel syndrome (IBS)

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