Hongo Hiroki, Takai Keisuke, Komori Takashi, Taniguchi Makoto
Departments of1Neurosurgery and.
2Laboratory Medicine and Pathology, Tokyo Metropolitan Neurological Hospital, Fuchu, Tokyo, Japan.
J Neurosurg Spine. 2018 Oct 19;30(1):133-139. doi: 10.3171/2018.7.SPINE18230. Print 2019 Jan 1.
OBJECTIVEThe intraoperative differentiation of ependymomas from astrocytomas is important because neurosurgical strategies differ between these two tumor groups. Previous studies have reported that the diagnostic accuracy of intraoperative frozen sections of intracranial central nervous system (CNS) tumors is higher than 83%-97%, whereas that for spinal intramedullary tumors remains unknown. Herein, authors tested the hypothesis that intraoperative frozen-section diagnosis is the gold standard for a differential diagnosis of intramedullary spinal cord tumors.METHODSThe clinical characteristics, intraoperative histological diagnosis from frozen sections, extent of tumor resection, progression-free survival (PFS), and overall survival (OS) of 49 cases of intramedullary spinal cord ependymomas (n = 32) and astrocytomas (n = 17) were retrospectively evaluated.RESULTSThe frozen-section diagnosis and final diagnosis with permanent sections agreed in 23 (72%) of 32 cases of ependymoma. Of the 9 cases of ependymoma in which the frozen-section diagnosis disagreed with the final diagnosis, 4 were incorrectly diagnosed as astrocytoma and the other 5 cases had a nonspecific diagnosis, such as glioma. Nonetheless, gross-total resection was achieved in 6 of these 9 cases given the presence of a dissection plane. The frozen-section diagnosis and final diagnosis agreed in 12 (71%) of 17 cases of astrocytoma. Of the 5 cases of astrocytoma in which the frozen-section diagnosis disagreed with the final diagnosis, 1 was incorrectly diagnosed as ependymoma and the other 4 had a nonspecific diagnosis. Gross-total resection was achieved in only 1 of these 5 cases.A relationship between the size of tumor specimens and the diagnostic accuracy of frozen sections was not observed. Ependymal rosettes and perivascular pseudorosettes were observed in 30% and 57% of ependymomas, respectively, but were absent in astrocytomas.Progression-free survival and OS were both significantly longer in cases of ependymoma than in cases of astrocytoma (p < 0.001). Gross-total resection was achieved in 69% of ependymomas and was associated with longer PFS (p = 0.041). In the astrocytoma group, gross-total resection was achieved in only 12% and there was no relationship between extent of resection and OS. Tumor grades tended to correlate with OS in astrocytomas (p = 0.079).CONCLUSIONSThe diagnostic accuracy of intraoperative frozen sections was lower for intramedullary spinal cord ependymomas and astrocytomas in the present study than that for intracranial CNS tumors reported on in the literature. Surgical strategies need to be selected based on multiple factors, such as clinical characteristics, preoperative imaging, frozen-section diagnosis, and intraoperative findings of the tumor plane.
目的
在手术中鉴别室管膜瘤和星形细胞瘤很重要，因为这两类肿瘤的神经外科手术策略有所不同。以往研究报告称，颅内中枢神经系统（CNS）肿瘤术中冰冻切片的诊断准确率高于83%-97%，而脊髓髓内肿瘤的诊断准确率尚不清楚。在此，作者检验了术中冰冻切片诊断是脊髓髓内肿瘤鉴别诊断金标准这一假设。
方法
回顾性评估49例脊髓髓内室管膜瘤（n = 32）和星形细胞瘤（n = 17）的临床特征、术中冰冻切片组织学诊断、肿瘤切除范围、无进展生存期（PFS）和总生存期（OS）。
结果
32例室管膜瘤中，23例（72%）的冰冻切片诊断与永久切片最终诊断一致。在9例冰冻切片诊断与最终诊断不一致的室管膜瘤中，4例被误诊为星形细胞瘤，另外5例诊断不明确，如胶质瘤。尽管如此，这9例中有6例因存在分离平面而实现了全切除。17例星形细胞瘤中，12例（71%）的冰冻切片诊断与最终诊断一致。在5例冰冻切片诊断与最终诊断不一致的星形细胞瘤中，1例被误诊为室管膜瘤，另外4例诊断不明确。这5例中只有1例实现了全切除。
未观察到肿瘤标本大小与冰冻切片诊断准确率之间的关系。分别在30%的室管膜瘤和57%的室管膜瘤中观察到室管膜玫瑰花结和血管周围假玫瑰花结，而在星形细胞瘤中未观察到。
室管膜瘤患者的无进展生存期和总生存期均显著长于星形细胞瘤患者（p < 0.001）。69%的室管膜瘤实现了全切除，且与更长的无进展生存期相关（p = 0.041）。在星形细胞瘤组中，仅12%实现了全切除，切除范围与总生存期之间无关联。在星形细胞瘤中，肿瘤分级与总生存期有一定相关性（p = 0.079）。
结论
在本研究中，脊髓髓内室管膜瘤和星形细胞瘤术中冰冻切片的诊断准确率低于文献报道的颅内CNS肿瘤。手术策略需要基于多种因素来选择，如临床特征、术前影像学检查、冰冻切片诊断和肿瘤平面的术中发现。
