Komotar Ricardo J, Zacharia Brad E, Sughrue Michael E, Mocco J, Carson Benjamin S, Tihan Tarik, Otten Marc L, Burger Peter C, Garvin James H, Khandji Alexander G, Anderson Richard C E
Department of Neurosurgery, Columbia University Medical Center, 710 West 168th Street, New York, NY 10032, USA.
Neurol Res. 2008 Nov;30(9):945-51. doi: 10.1179/174313208X322806. Epub 2008 Jul 25.
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.
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.
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.
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.
毛黏液样星形细胞瘤（PMA）是一种最近才被确认的儿童低级别肿瘤，以前被归类为毛细胞型星形细胞瘤（PA），但其具有独特的组织学特征且行为更具侵袭性。这些肿瘤的无进展生存期和总生存概率明显短于经典的低级别星形细胞瘤，并且脑脊液（CSF）播散率很高。本文描述了PMA的影像学特征。
对10例PMA进行了磁共振成像（MRI）检查。记录每个病例中肿瘤的影像学特征。所有组织样本均经过独立复查以确认病理诊断。
所有肿瘤在MRI上均表现为边界清晰，无瘤周水肿或实质浸润的迹象。除1例肿瘤外，所有肿瘤均起源于神经轴中线。具体而言，5例肿瘤（50.0%）位于下丘脑区域，2例（20.0%）位于脊柱，2例（20.0%）位于脑桥背侧，1例位于右侧丘脑。5例肿瘤（50.0%）表现为实性成分，其余5例有一些囊性成分。分别在62.5%、50.0%和0.0%的病例中观察到占位效应、脑积水和中央坏死。8例肿瘤（80%）在T1加权MRI上呈高信号。7例肿瘤（77.8%）在T2加权MRI上呈高信号。所有肿瘤在液体衰减反转恢复（FLAIR）序列上呈高信号，在扩散加权成像（DWI）上呈低信号。注射对比剂后，6例肿瘤（60.0%）呈不均匀强化，4例肿瘤（40.0%）呈均匀强化。
毛黏液样星形细胞瘤是一种边界清晰的儿童肿瘤，通常起源于神经轴中线，无瘤周水肿或中央坏死。认识到该肿瘤主要为实性且边界清晰的性质对于避免与浸润性星形细胞瘤混淆至关重要。
