Koeller Kelly K, Rushing Elisabeth J
Department of Radiologic Pathology, Armed Forces Institute of Pathology, Washington, DC, USA.
Radiographics. 2005 Nov-Dec;25(6):1669-88. doi: 10.1148/rg.256055137.
Oligodendroglioma is the third most common glial neoplasm and most commonly arises in the frontal lobe. It occurs in males more frequently, and the peak manifestation is during the 5th and 6th decades. Children are affected much less commonly. The clinical presentation is often of several years duration with most patients presenting with seizures, reflecting the strong predilection of this tumor to involve the cortical gray matter. Current histopathologic classification schemes recognize two main types of tumors: well-differentiated oligodendroglioma and its anaplastic variant. Less commonly, neoplastic mixtures of both oligodendroglial and astrocytic components occur and are termed oligoastrocytomas, with both well-differentiated and anaplastic forms. Surgical resection is the mainstay of initial treatment, and many patients experience a long progression-free period. Recent genotyping has revealed chromosomal loss of 1p and 19q as a genetic signature in most oligodendrogliomas, and these tumors respond favorably to chemotherapy. Hence, radiation therapy is now generally reserved for partially resected tumors and cases that failed to benefit from chemotherapy. At cross-sectional imaging, the tumor characteristically involves the cortical gray matter and frequently contains calcification. Robust enhancement is not a common feature and suggests transformation to a higher histologic grade. Advanced magnetic resonance imaging techniques and metabolic imaging play increasingly important roles in both pre- and postoperative assessment of these complex neoplasms.
少突胶质细胞瘤是第三常见的神经胶质瘤，最常发生于额叶。男性发病率更高，发病高峰在50至60岁之间。儿童受累情况则少见得多。临床表现通常持续数年，大多数患者以癫痫发作为主要表现，这反映了该肿瘤极易侵犯皮质灰质。目前的组织病理学分类方案将肿瘤主要分为两种类型：高分化少突胶质细胞瘤及其间变性变体。较少见的情况是，肿瘤同时含有少突胶质细胞和星形细胞成分，称为少突星形细胞瘤，也有高分化和间变性两种形式。手术切除是初始治疗的主要手段，许多患者有较长的无进展生存期。最近的基因分型显示，大多数少突胶质细胞瘤存在1p和19q染色体缺失这一基因特征，这些肿瘤对化疗反应良好。因此，放射治疗目前一般用于部分切除的肿瘤以及未从化疗中获益的病例。在横断面成像中，肿瘤特征性地侵犯皮质灰质，且常含有钙化。明显强化并非常见特征，提示肿瘤已转变为更高的组织学分级。先进的磁共振成像技术和代谢成像在这些复杂肿瘤的术前和术后评估中发挥着越来越重要的作用。
