目的：室管膜下巨细胞星形细胞瘤（SEGA）是一种WHOI级小儿神经胶质瘤，在5-15％的结节性硬化症（TSC）患者中出现。已经描述了没有TSC的孤立SEGA的罕见病例。病因,遗传机制，自然史,对这些病变的治疗反应目前尚不清楚。我们描述了两个这样的孤立的SEGA病例，并进行了随访。
方法：在一个机构进行回顾性回顾，以描述在种系检测TSC突变阴性的患者中病理证实的SEGA的临床过程。
结果：确定了2例孤立的SEGA。肿瘤样本的遗传分析有一个，这揭示了TSC1中的18个碱基对缺失。两例病例均采用手术切除治疗，一个术前栓塞。尽管进行了全面切除，1例患者3年后复发.用mTOR抑制剂治疗导致随访MRI上的质量显著间隔减少。患者对药物耐受良好6年，现在停止治疗2年，病变稳定。
结论：在TSC范围之外的SEGA病例极为罕见，以前只描述了48例。对这些病变的遗传机制和治疗反应知之甚少。迄今为止,这些病变似乎对mTOR抑制剂反应良好,可能表现与TSC相关的SEGA相似.然而,鉴于经验极其有限，这些病例应长期随访，以更好地了解其自然史和治疗反应。
OBJECTIVE: Subependymal giant cell astrocytoma (SEGA) is a WHO grade I pediatric glioma arising in 5-15% of patients with tuberous sclerosis (TSC). Rare cases of isolated SEGA without TSC have been described. The etiology, genetic mechanisms, natural history, and response to treatment of these lesions are currently unknown. We describe two such cases of isolated SEGA with follow-up.
METHODS: Retrospective review was performed at a single institution to describe the clinical course of pathology-confirmed SEGA in patients with germline testing negative for TSC mutations.
RESULTS: Two cases of isolated SEGA were identified. Genetic analysis of the tumor specimen was available for one, which revealed an 18 base pair deletion in TSC1. Both cases were managed with surgical resection, one with preoperative embolization. In spite of a gross total resection, one patient experienced recurrence after three years. Treatment with an mTOR inhibitor led to a significant interval reduction of the mass on follow-up MRI. The patient tolerated the medication well for 6 years and is now off of treatment for 2 years with a stable lesion.
CONCLUSIONS: Cases of SEGA outside of the context of TSC are exceedingly rare, with only 48 cases previously described. The genetic mechanisms and treatment response of these lesions are poorly understood. To date, these lesions appear to respond well to mTOR inhibitors and may behave similarly to SEGAs associated with TSC. However, given that experience is extremely limited, these cases should be followed long term to better understand their natural history and treatment response.
