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Pleomorphic xanthoastrocytoma (PXA) is a
brain tumor A brain tumor (sometimes referred to as brain cancer) occurs when a group of cells within the Human brain, brain turn cancerous and grow out of control, creating a mass. There are two main types of tumors: malignant (cancerous) tumors and benign ...
that occurs most frequently in children and teenagers. At
Boston Children's Hospital Boston Children's Hospital (formerly known as Children's Hospital Boston until 2013) is the main pediatric training and research hospital of Harvard Medical School, Harvard University. It is a nationally ranked, freestanding acute care children ...
, the average age at diagnosis is 12 years. Pleomorphic xanthoastrocytoma usually develops within the
supratentorial region In anatomy, the supratentorial region of the brain is the area located above the tentorium cerebelli. The area of the brain below the tentorium cerebelli is the infratentorial region. The supratentorial region contains the cerebrum, while the in ...
(the area of the brain located above the
tentorium cerebelli The cerebellar tentorium or tentorium cerebelli (Latin for "tent of the cerebellum") is one of four dural folds that separate the cranial cavity into four (incomplete) compartments. The cerebellar tentorium separates the cerebellum from the cere ...
). It is generally located superficially (in the uppermost sections) in the
cerebral hemisphere The vertebrate cerebrum (brain) is formed by two cerebral hemispheres that are separated by a groove, the longitudinal fissure. The brain can thus be described as being divided into left and right cerebral hemispheres. Each of these hemispheres ...
s and involves the
leptomeninges In anatomy, the meninges (; meninx ; ) are the three membranes that envelop the brain and spinal cord. In mammals, the meninges are the dura mater, the arachnoid mater, and the pia mater. Cerebrospinal fluid is located in the subarachnoid spa ...
. It rarely arises from the
spinal cord The spinal cord is a long, thin, tubular structure made up of nervous tissue that extends from the medulla oblongata in the lower brainstem to the lumbar region of the vertebral column (backbone) of vertebrate animals. The center of the spinal c ...
. These tumors are formed through the
mitosis Mitosis () is a part of the cell cycle in eukaryote, eukaryotic cells in which replicated chromosomes are separated into two new Cell nucleus, nuclei. Cell division by mitosis is an equational division which gives rise to genetically identic ...
of
astrocytes Astrocytes (from Ancient Greek , , "star" and , , "cavity", "cell"), also known collectively as astroglia, are characteristic star-shaped glial cells in the brain and spinal cord. They perform many functions, including biochemical control of end ...
. They are found in the area of the temples, in the brain's
frontal lobe The frontal lobe is the largest of the four major lobes of the brain in mammals, and is located at the front of each cerebral hemisphere (in front of the parietal lobe and the temporal lobe). It is parted from the parietal lobe by a Sulcus (neur ...
or on top of the
parietal lobe The parietal lobe is one of the four Lobes of the brain, major lobes of the cerebral cortex in the brain of mammals. The parietal lobe is positioned above the temporal lobe and behind the frontal lobe and central sulcus. The parietal lobe integra ...
. In about 20% of cases, tumors exist in more than one lobe.


Symptoms and signs

Children with PXA can present with a variety of symptoms. Complaints may vary, and patients may report symptoms that have been occurring for many months and are often linked with more common diseases. (For example, headaches are a common complaint.) Some children, however, will present with symptoms that start very suddenly, like
seizure A seizure is a sudden, brief disruption of brain activity caused by abnormal, excessive, or synchronous neuronal firing. Depending on the regions of the brain involved, seizures can lead to changes in movement, sensation, behavior, awareness, o ...
s.


Diagnosis

PXA is diagnosed through a combination of diagnostic processes: * Initially, a doctor will interview the patient and do a clinical exam, which will include a
neurological examination A neurological examination is the assessment of sensory neuron and motor responses, especially reflexes, to determine whether the nervous system is impaired. This typically includes a physical examination and a review of the patient's medical his ...
. * A
CT scan A computed tomography scan (CT scan), formerly called computed axial tomography scan (CAT scan), is a medical imaging technique used to obtain detailed internal images of the body. The personnel that perform CT scans are called radiographers or ...
of the brain, and/or an
MRI scan Magnetic resonance imaging (MRI) is a medical imaging technique used in radiology to generate pictures of the anatomy and the physiological processes inside the body. MRI scanners use strong magnetic fields, magnetic field gradients, and ra ...
of the brain and spine, will be performed. A special dye may be injected into a vein before these scans to provide contrast and make tumors easier to see. * For children experiencing seizures, an
EEG Electroencephalography (EEG) is a method to record an electrogram of the spontaneous electrical activity of the brain. The bio signals detected by EEG have been shown to represent the postsynaptic potentials of pyramidal neurons in the neoc ...
might be part of the diagnostic process (the goal being to record the brain's electrical activity in order to identify and localize seizure activity). * Finally, a
biopsy A biopsy is a medical test commonly performed by a surgeon, interventional radiologist, an interventional radiologist, or an interventional cardiology, interventional cardiologist. The process involves the extraction of sampling (medicine), sample ...
of the tumor, taken through a needle during a simple surgical procedure, helps to confirm the diagnosis.


Treatment

Surgery is often the treatment of choice. Total resection (removal of the tumor) is often possible. However, the best choice of treatment will depend on many individual factors, including: * The patient's medical history and overall health condition * The type, location, and size of the tumor * The patient's age * How well the patient tolerates specific medications, procedures, or therapy * How slowly or quickly the tumor is expected to progress If surgery is performed and the tumor is completely resected, further treatment may not be required. The patient will, however, need repeated MRIs to monitor for tumor re-growth. For tumors that recur, another surgical resection might be attempted. For tumors that could not be completely removed,
radiation therapy Radiation therapy or radiotherapy (RT, RTx, or XRT) is a therapy, treatment using ionizing radiation, generally provided as part of treatment of cancer, cancer therapy to either kill or control the growth of malignancy, malignant cell (biology), ...
may also be recommended. Also called radiotherapy, this treatment uses high-energy radiation to damage or kill cancer cells and shrink tumors.


Effects of treatment on symptoms

Symptoms of PXA may disappear, or improve progressively, after treatment. For example: * Symptoms related to increased pressure in the brain often disappear after surgical removal of the tumor. * Effects like seizures might progressively improve as recovery progresses. *
Steroid A steroid is an organic compound with four fused compound, fused rings (designated A, B, C, and D) arranged in a specific molecular configuration. Steroids have two principal biological functions: as important components of cell membranes t ...
treatment is often used to control tissue swelling that may occur before and after surgery.


Side effects of treatment


Brain surgery

Children with PXA may experience seizures as a symptom of their disease. However, any person undergoing
brain surgery Neurosurgery or neurological surgery, known in common parlance as brain surgery, is the medical specialty that focuses on the surgical treatment or rehabilitation of disorders which affect any portion of the nervous system including the brain, s ...
is at risk of developing
epileptic seizure A seizure is a sudden, brief disruption of brain activity caused by abnormal, excessive, or synchronous neuronal firing. Depending on the regions of the brain involved, seizures can lead to changes in movement, sensation, behavior, awareness, o ...
s. Medication is administered to minimize or prevent seizure activity. Additionally, after surgery, parents should be informed of the risk of seizures, and educated on what to do in the event of a seizure. With any brain surgery, there is also a risk of
brain damage Brain injury (BI) is the destruction or degeneration of brain cells. Brain injuries occur due to a wide range of internal and external factors. In general, brain damage refers to significant, undiscriminating trauma-induced damage. A common ...
.


Radiation therapy

Radiation therapy may cause swelling in the brain, related to tissue inflammation. This inflammation may lead to symptoms like headaches. It may be treated with oral medication.


Prognosis following treatment

With treatment, pleomorphic xanthoastrocytomas are associated with a high rate of cure. * Grade II pleomorphic xanthoastrocytomas are known to progress towards grade II tumors, which are more likely to recur after surgical removal. * Grade III anaplastic pleomorphic xanthoastrocytomas may evolve and show signs of
anaplasia Anaplasia () is a condition of cell (biology), cells with poor cellular differentiation, losing the morphology (biology), morphological characteristics of mature cells and their orientation with respect to each other and to endothelium, endotheli ...
, according to evidence in the medical literature.


Response to progressive or recurrent disease

If PXA recurs or gets worse, the recommended course of action is to monitor the disease and reattempt a complete surgical removal, according to the medical literature. In cases of progressive or recurrent disease, or when maximal surgical removal has been achieved, the medical team will consider radiation therapy. Nine medical institutions in the United States have formed a Pediatric Brain Tumor Consortium, which "is dedicated to the development of new and innovative treatments for children with progressive/recurrent brain tumors not responsive to standard therapies. Children with pleomorphic xanthoastrocytomas would be eligible for a number of experimental therapies available through the consortium.''


Prognosis

Among people with PXA who were able to have their tumors completely resected during surgery, there is a long-term survival rate of 90%. After incomplete resection, the long-term survival rate is higher than 50%.
Morbidity A disease is a particular abnormal condition that adversely affects the structure or function of all or part of an organism and is not immediately due to any external injury. Diseases are often known to be medical conditions that are asso ...
is determined by the type and evolution of the tumor, with high-graded anaplastic tumors causing more fatalities.


References


Further reading

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External links

{{DEFAULTSORT:Pleomorphic Xanthoastrocytoma Pediatric cancers Disorders causing seizures Brain tumor Brain disorders Neurological disorders in children