Alomari Ahmed, Rauch Philipp J, Orsaria Maria, Minja Frank J, Chiang Veronica L, Vortmeyer Alexander O
Neuropathology Program, Department of Pathology, Yale University School of Medicine, 416A Lauder Hall, 310 Cedar Street, New Haven, CT, 06520, USA.
J Neurooncol. 2014 Mar;117(1):33-42. doi: 10.1007/s11060-014-1359-8. Epub 2014 Jan 18.
Progressively enlarging encephalopathic changes are now well-documented effects of gamma knife radiosurgery (GKRS) occurring ~3-30 months after treatment of both benign and malignant brain lesions. These changes can be variably associated with inflammatory demyelination and necrosis and/or recurrent tumor. While radiographic differentiation between encephalopathic changes and recurrent tumor is of high clinical relevance, confident interpretation of post-radiosurgery imaging changes can be challenging or even impossible in some cases. Gadolinium-enhanced MRI of these lesions reveals variable amounts of enhancing and non-enhancing components within these lesions that have not been clearly correlated with structural-pathologic change. The goal of this study is to characterize the histopathological changes associated with enhancing versus non-enhancing regions of GKRS-treated lesions. MRI images of patients with progressive, etiologically ambiguous brain lesions following GKRS were reviewed prior to explorative neurosurgery. Chosen for this study were lesions in which distinct areas of enhancement and non-enhancement of at least 5 mm in size could be identified (n = 16). Distinctly enhancing and non-enhancing areas were separately biopsied and histologically evaluated. Only cases with uniform histological results are presented in this study. Enhancing and non-enhancing areas in post GKRS lesions represent separate pathological changes. Radiographically enhancing areas correlate either with recurrent tumor growth or inflammatory demyelinating changes. Lack of radiographic enhancement correlates with coagulative necrosis if the sample is taken from the center of the lesion, or with reactive astrocytosis if the sample is taken from the periphery. Separate biopsy of enhancing and non-enhancing regions of post-GKRS encephalopathy was able to confirm that the pathologies in these areas are distinct. These findings allow for better-informed correlation of histological and radiological changes and a better understanding of post-treatment tissue pathology.
进行性扩大的脑病性改变是伽玛刀放射外科手术（GKRS）的一种已被充分记录的效应，在治疗良性和恶性脑病变后约3 - 30个月出现。这些改变可能与炎症性脱髓鞘、坏死和/或肿瘤复发存在不同程度的关联。虽然脑病性改变与肿瘤复发之间的影像学鉴别具有高度临床相关性，但在某些情况下，对放射外科手术后影像学改变进行可靠解读可能具有挑战性，甚至是不可能的。这些病变的钆增强磁共振成像（MRI）显示，病变内有不同程度的强化和非强化成分，这些成分与结构病理变化之间尚未明确关联。本研究的目的是描述与GKRS治疗病变的强化区和非强化区相关的组织病理学变化。在进行探索性神经外科手术之前，对GKRS后出现进行性、病因不明的脑病变患者的MRI图像进行了回顾。本研究选择的病变是那些可以识别出至少5毫米大小的明显强化区和非强化区（n = 16）。分别对明显强化区和非强化区进行活检并进行组织学评估。本研究仅呈现组织学结果一致的病例。GKRS后病变中的强化区和非强化区代表不同的病理变化。影像学上的强化区与肿瘤复发或炎症性脱髓鞘改变相关。如果样本取自病变中心，无影像学强化与凝固性坏死相关；如果样本取自周边，则与反应性星形细胞增生相关。对GKRS后脑病的强化区和非强化区进行单独活检能够证实这些区域的病理情况是不同的。这些发现有助于更深入地关联组织学和放射学变化，并更好地理解治疗后组织病理学。
