Magnetic resonance imaging characteristics of pilomyxoid astrocytoma.
Neurol Res
; 30(9): 945-51, 2008 Nov.
Article
em En
| MEDLINE
| ID: mdl-18662499
ABSTRACT
OBJECTIVE:
Pilomyxoid astrocytoma (PMA) is a recently identified pediatric low-grade neoplasm that was previously classified as pilocytic astrocytoma (PA), yet demonstrates unique histological features and more aggressive behavior. These tumors have been shown to have significantly shorter progression-free and overall survival probability than classical low-grade astrocytomas, as well as a high rate of cerebrospinal fluid (CSF) dissemination. This paper describes the radiographic features of PMA.METHODS:
Magnetic resonance imaging (MRI) was obtained for ten PMAs. Radiographic characteristics of the tumor were recorded in each case. All tissue samples were independently reviewed for confirmation of pathologic diagnosis.RESULTS:
All tumors appeared well-circumscribed with no evidence of peritumoral edema or parenchymal infiltration on MRI. All tumors except one originated from the midline of the neuroaxis. Specifically, five tumors (50.0%) were located in the hypothalamic region, two (20.0%) were located in the spine, two (20.0%) were located in the dorsal brainstem and one was located in the right thalamus. Five tumors (50.0%) demonstrated solid composition, with the remaining five showing some cystic components. Mass effect, hydrocephalus and central necrosis were observed in 62.5, 50.0 and 0.0% of cases, respectively. Eight tumors (80%) were hyperintense on T1-weighted MRI. Seven tumors (77.8%) were hyperintense on T2-weighted MRI. All tumors were hyperintense on fluid attenuated inversion recovery (FLAIR) sequence and hypointense on diffusion weighted imaging (DWI). Upon contrast administration, six tumors (60.0%) enhanced heterogeneously and four tumors (40.0%) enhanced homogenously.CONCLUSION:
Pilomyxoid astrocytoma is a well-circumscribed pediatric neoplasm that commonly originates from the midline of the neuroaxis and lacks peritumoral edema or central necrosis. It is critical to recognize the predominantly solid and well-circumscribed nature of the neoplasm to avoid confusion with an infiltrating astrocytoma.
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Base de dados:
MEDLINE
Assunto principal:
Astrocitoma
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Neoplasias Encefálicas
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Imageamento por Ressonância Magnética
Idioma:
En
Ano de publicação:
2008
Tipo de documento:
Article