出典(authority):フリー百科事典『ウィキペディア(Wikipedia)』「2015/06/05 19:59:25」(JST)
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Pleomorphic Xanthoastrocytoma is a neoplasm of the brain that most frequently occurs in children and teenagers. It usually develops within the supratentorial region (the area of the brain located above the tentorium cerebelli), located superficially in the cerebral hemispheres (uppermost sections) of the brain and involving the leptomeninges, rarely arising from the spinal cord. The neoplasms are formed through the mitosis of astrocytes. They are found in the area of the temples, frontal lobe or on top of the parietal lobe. In about 20% of cases more than one lobe is involved.
These tumors are usually slow-growing. The neoplasms are associated with the sudden onset of seizures. Histologically, they can be associated with inflammatory cell infiltration and reticulin deposits. Pleomorphic Xanthoastrocytoma is generally considered a benign tumor, very rarely undergoing transformation to a malignant tumor. It will show up as a contrast-enhancing tumor by current imaging investigations (e.g., CT scan, MRI). It is classified as a WHO Grade II astrocytoma.
Children affected by Pleomorphic Xanthoastrocytoma can present different symptoms that may include headaches or seizures. The complaints may vary and present to the doctor symptoms that have been occurring for many months often linked with more common diseases. Some children however, will present a sudden onset of symptoms, especially those with seizures.
At Boston Children's Hospital the average age at diagnosis is 12 years.[1]
Diagnosis includes interview with the patient and a clinical exam which includes a neurological exam. An EEG might be part of the diagnostic process for children experiencing seizures (through a continuous EEG recording of the brain's electrical activity in order to identify and localize seizure activity). A CT scan of the brain and or MRI scan of the brain and the spine will be performed. A special dye may be injected into a vein before these scans to provide contrast and make tumors easier to identify. A biopsy of the tumor taken through a needle during a simple surgical procedure helps to confirm the diagnosis.
The following quote from an article found on Biomedsearch.com tells us what Pleomorphic Xanthoastrocytoma looks like on CT-scan and MRI images: On CT without contrast enhancement, PXA was an iso- or hypoattenuating mass, and calcification was seen in six tumors and inner table remodeling was seen in three patients younger than 12 years. On MR, the solid component of PXA was isointense relative to gray matter on T1-weighted images, hyperintense on T2-weighted images in more than 90% and enhanced intensely following intravenous contrast material administration. Cystic areas showed hyperintensity relative to CSF. Two imaging patterns were differentiated: first a cystic mass containing a mural nodule (70%) and second a predominantly solid mass that may show cystic changes (30%). CONCLUSION: The most consistent imaging features of PXA were a superficial location, leptomeningeal contact, and enhancement of the solid component. Apart from the classical PXA appearance of a cystic lesion with an enhancing mural nodule, a second pattern consisting of a predominantly solid mass was recognized.[2]
Surgery is often the treatment of choice. Total resection is often possible. The medical team will advise on treatment depending on factors such as:
Treatment of the tumor after complete resection may not be required, other than serial 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 may also be recommended by the medical team, using high-energy radiation to damage or kill cancer cells and shrink tumors.
Children with pleomorphic xanthoastrocytomas may experience side effects related to the tumor itself and related to the treatment.
Children with pleomorphic xanthoastrocytomas may experience seizures as a symptom of their disease, but any person undergoing brain surgery is at risk from epileptic seizures.
Parents of children after surgery should be made aware of this fact and should be prepared to take adequate action in case of seizure.
Radiation therapy may cause swelling related to tissue inflammation.
Pleomorphic xanthoastrocytomas are associated with a high rate of cure.[3]
The recommended course of action according to different literature sources is to monitor and reattempt a complete surgical removal. In cases of progressive/recurrent disease or when maximal surgical removal has been achieved, radiation therapy will be considered by the medical team.
On the Boston Children's Hospital website the following quote has been found. Dana-Farber Cancer Institute is one of nine institutes in the nation belonging to the Pediatric Brain Tumor Consortium. The consortium 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. [5]
After total resection people undergoing the surgery have a long-term survival rate of 90%. After incomplete resection, the long-term survival rate is higher than 50%. Morbidity is determined by type and evolution of the tumor : high graded anaplastic tumors causing more fatalities.
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リンク元 | 「多形黄色星状細胞腫」 |
関連記事 | 「pleomorphic」 |
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