Juvenile Pilocytic Astrocytomas
Juvenile pilocytic astrocytomas are tumors that form from astrocytes, star-shaped cells that maintain brain and spinal cord health. At Columbia University Irving Medical Center/NewYork-Presbyterian Hospital, we specialize in diagnosing and treating juvenile pilocytic astrocytomas using the most advanced tools and techniques.
This page covers juvenile pilocytic astrocytomas of the brain.
Juvenile pilocytic astrocytomas tend to occur in children and adolescents, but can sometimes occur in adults. (For this reason, they are sometimes called just pilocytic astrocytomas). They belong to a group of tumors known as astrocytomas, which all arise from astrocytes. On a scale of one to four, the World Health Organization grades tumors according to their speed of growth and ability to invade nearby tissues. The lower the grade, the less aggressive the tumor. Juvenile pilocytic astrocytomas tend to grow slowly. Thus they are labeled as Grade I, the least aggressive, and are considered benign.
Juvenile pilocytic astrocytomas can grow anywhere in the brain and spinal cord. Most often they develop in one of the following locations:
- Cerebellum: the rear, lower area of the brain, near the base of the skull. The cerebellum coordinates muscle movement, posture and balance.
- Brainstem: the lower area of the brain, close to the neck, that connects to the top part of the spinal cord. The role of the brainstem is to regulate functions essential for survival, such as heart rate and breathing.
- Hypothalamus: a small region of the brain located above the brainstem. Its role is to produce hormones that regulate temperature, thirst, hunger, and sleep, among other functions.
- Optic nerve pathways: the series of structures that transmit information between the retina of the eye and the brain.
- Cerebrum: the largest, frontmost area of the brain. The cerebrum is responsible for thought and voluntary movement.
Symptoms may differ among patients and often depend on the location and size of the tumor. The most common symptom is increased intracranial pressure. This increased pressure is caused by the growth of the tumor, blockage in the flow of cerebrospinal fluid (CSF) due to tumor growth or sometimes a combination of the two. CSF cycles through the four ventricles in the brain, and its role is to bathe and cushion the brain. When the flow of CSF is blocked, fluid builds up—a condition called hydrocephalus. Individuals who have increased pressure inside the skull may experience headaches that worsen in the morning or when waking up, as well as vomiting, lethargy and changes in behavior.
Individuals with juvenile pilocytic astrocytomas may also experience the following:
- Visual problems, such as diplopia, nystagmus and proptosis
- Weight loss or gain
- Premature puberty
A physician first evaluates a patient in the clinic for symptoms of a juvenile pilocytic astrocytoma. To further characterize symptoms, a physician often performs a neurological examination to assess brain function. If a brain tumor is suspected, a physician may recommend imaging tests, which are necessary to provide a diagnosis.
Magnetic resonance imaging (MRI) is the preferred imaging test. It uses magnets, radio waves, and a computer to produce highly detailed images of the brain. For some patients, MRI cannot be used, so computed tomography (CT) scan is used instead. CT scan uses X-ray technology and a computer to produce images. For both MRI and CT, a contrast agent is often used to make the tumor more visible.
A biopsy is performed, most often during the brain tumor surgery performed to remove the tumor, to acquire a sample of the tumor tissue. Alternatively, a stereotactic biopsy can be performed, which does not require a neurosurgeon to perform open surgery. Instead, a neurosurgeon inserts a thin needle through a small hole in the skull. Then the neurosurgeon guides the needle to the tumor and withdraws a tissue sample. The sample is then examined under a microscope to confirm a diagnosis.
The cause of juvenile pilocytic astrocytoma is unclear.
Juvenile pilocytic astrocytomas tend to occur before 20 years of age and occur equally in boys and girls.
Individuals who have the inherited disorders neurofibromatosis type 1, Li-Fraumeni syndrome, and tuberous sclerosis are at a greater risk of developing juvenile pilocytic astrocytomas. These risk-conferring disorders are inherited, but otherwise, juvenile pilocytic astrocytomas are not inherited.
Treatment of juvenile pilocytic astrocytomas depends on several factors, including an individual’s age and the location of the tumor. Our neurosurgeons will create a customized treatment approach for each patient in order to achieve the best prognosis.
The first step of treatment is often for a neurosurgeon to perform brain tumor surgery to remove as much of the tumor as possible. To access the brain, a neurosurgeon performs a craniotomy. Juvenile pilocytic astrocytomas that develop in the cerebellum can often be removed completely during surgery and are then considered cured. However, some tumors are located in a region where they cannot be safely removed.
If the tumor cannot be removed completely or at all, a combination of radiotherapy and chemotherapy is recommended. However, radiotherapy is usually avoided in infants and young children, particularly those younger than five years of age. During this stage of life, the brain is developing; radiotherapy can hinder this development, producing severe long-term effects.