Tuberous sclerosis is a congenital condition in which abnormal growths arise throughout the body. Surgical treatments may include brain tumor surgery, laser ablation, shunt placement and/or epilepsy surgery. Nonsurgical approaches—chemotherapy and/or anticonvulsant medication—may also be effective, either as alternatives to surgery or in combination with surgery.
At this time, no cures exist for tuberous sclerosis. However, available treatments may relieve many symptoms of the disorder and restore a sense of normalcy to a patient’s life.
Tuberous sclerosis is one of several congenital neurological disorders known as neurocutaneous syndromes. The group also includes neurofibromatosis type 1 and type 2.
The abnormal growths that characterize tuberous sclerosis are benign, tumor-like growths called hamartomas. Hamartoma is a general term that describes any benign growth that is a disorganized mixture of cell types normally found in an area. These abnormal growths can arise in any organ, favoring the brain, spinal cord, skin, eyes, lungs, kidneys, and heart. Over time, they calcify and harden. When hamartomas arise in the brain, they are called cortical hamartomas.
Individuals with tuberous sclerosis are at increased risk to develop certain types of brain tumors. Those that arise most frequently include:
- Subependymal giant cell astrocytomas: These tumors occur almost exclusively among people with tuberous sclerosis and arise in about 15 percent of individuals with the disease. They are found in the ventricles, particularly the lateral ventricles and the foramen of Monro. Despite the name, a subependymal giant cell astrocytoma arises from a mixture of glial and other cells, not purely astrocytes, and therefore is not a type of astrocytoma.
- Subependymal nodules: These are benign tumors that arise from the ventricles and occur among most individuals with tuberous sclerosis. Subependymal nodules can become subependymal giant cell astrocytomas.
Symptoms vary widely, often depending on a person’s age and which organ systems are affected.
If the brain is affected by tumors or cortical hamartomas, individuals may experience epilepsy, developmental delays during infancy or childhood, and/or autism. Intelligence is affected in about half of individuals with tuberous sclerosis.
Because subependymal giant cell astrocytomas and subependymal nodules grow in the ventricles, these tumors can impede the flow of cerebrospinal fluid, causing hydrocephalus. Symptoms of hydrocephalus include headache, nausea, vomiting, and lethargy.
Skin lesions are common, occurring among about two-thirds of individuals with tuberous sclerosis. Possible lesions include:
- Adenoma sebaceum—Red rash on the face that appears during late childhood or early adolescence
- Shagreen patches—Thick, leathery areas of tissue on the lower back
- Ash leaf macules—Marks on the skin, shaped like the leaves of an ash tree, that are lighter than surrounding areas
Other possible symptoms of tuberous sclerosis include enamel pitting, gingival fibromas, arrhythmias, and dyspnea.
A physical examination is performed and can often yield enough information for a physician to be reasonably certain about a diagnosis. To confirm the diagnosis, genetic testing to identify mutations can be done.
Imaging studies can establish extent of the disease and identify brain tumors. Computed tomography (CT) and magnetic resonance imaging (MRI) scans can reveal images of cortical hamartomas and brain tumors, if present. MRI is typically the imaging test of choice, but CT scans are also important because they can detect calcifications, which occur in most cortical hamartomas and subependymal nodules. CT and MRI scans can be performed with or without contrast enhancement.
CT scans are also useful for identifying hamartomas and tumors in the kidneys, lungs and other organs outside of the central nervous system. Ultrasonography can also be used to detect these growths outside of the central nervous system.
Additional testing may include an electrocardiogram and/or echocardiogram to detect cardiac rhabdomyomas and an eye examination to detect retinal astrocytomas.
If an individual is considering epilepsy surgery, imaging tests may be conducted to help determine where in the brain seizures originate. Electroencephalograms (EEGs), for example, measure electrical activity in the brain, and single-photon emission computed tomography (SPECT) imaging can help visualize blood flow.
Tuberous sclerosis is associated with a mutation in either TSC1 or TSC2.
Tuberous sclerosis can be inherited, but about two-thirds of instances arise from spontaneous mutations among individuals with no family history of the condition.
When inherited, tuberous sclerosis follows an autosomal dominant pattern; an individual has a 50 percent chance of passing the disease to his or her offspring.
This condition is usually diagnosed during early childhood, but it can become evident at any age.
Although there is no cure for tuberous sclerosis, at Columbia, our neurosurgeons can successfully alleviate brain-related symptoms and treat associated brain tumors. Our neurosurgeons use the latest tools and techniques to provide patients with the best possible results.
Because tuberous sclerosis can affect multiple organs, our neurosurgeons provide care as part of a multidisciplinary team to ensure the whole body is treated. Our neurosurgeons specialize in treating tuberous sclerosis as it affects the brain while the other specialists focus on the rest of the body.
Cortical hamartomas, and most brain tumors that affect individuals with tuberous sclerosis, are treated with surgery if they are causing problems or are expected to cause problems, as is often the case for subependymal giant cell astrocytomas.
Surgical resection of a brain tumor can relieve hydrocephalus and sometimes epilepsy, too. If complete resection is achieved, the brain tumor rarely recurs.
If hydrocephalus does not resolve after tumor resection, shunt placement is performed to relieve pressure and alleviate symptoms. Shunt placement involves surgically inserting a shunt that reroutes the fluid, allowing it to safely drain into either the abdomen or a receptacle outside of the brain.
For individuals who cannot undergo traditional surgery, more options are available. Laser ablation is a minimally invasive procedure that may be used to reach a structure that would otherwise be impossible to reach safely. Or, chemotherapy may be used instead to treat a brain tumor.
To treat epilepsy, our neurosurgeons take the most conservative approach first, which in this case means that they begin nonsurgically, with anticonvulsant medication; if this does not provide adequate symptom relief, epilepsy surgery may be considered.