Department of Neurosurgery, Emory University School of Medicine, Atlanta, Georgia, USA.
Department of Pathology, Emory University School of Medicine, Atlanta, Georgia, USA.
World Neurosurg. 2020 Dec;144:99-105. doi: 10.1016/j.wneu.2020.08.170. Epub 2020 Sep 2.
Vestibular schwannomas are benign tumors of the cerebellopontine angle that are often treated with radiation therapy. Radiation therapy maintains good tumor control rates but involves a small risk of radiation-induced malignancies. We present a case of high-grade sarcoma arising within a previously irradiated vestibular schwannoma and a literature review of this rare but important clinical entity.
A 66-year-old woman presented with rapid clinical and radiographic deterioration 17 years after receiving stereotactic radiosurgery for vestibular schwannoma. After resection, pathology revealed a high-grade sarcoma arising within a conventional schwannoma. After further decline and tumor growth, the patient died of her disease 7 months postoperatively. Literature review was performed using PubMed and EMBASE databases and key words "vestibular schwannoma," "acoustic," "triton," "malignant," "sarcoma," "malignant peripheral nerve sheath tumor," "radiation," and "radiosurgery." All previous cases and the clinical circumstances related to these radiation-induced malignancies were assessed and quantified.
The systematic review yielded 20 prior cases of radiation-induced malignant transformation of a vestibular schwannoma in patients without neurofibromatosis. Most tumors (60%) transformed into malignant nerve sheath tumors. At the time of presentation, 70% of patients had new cranial neuropathies, and all had evidence of tumor growth with brainstem compression. Prognosis was poor with mean time to death of 7.6 months.
Radiation-induced malignant transformation of vestibular schwannomas is a rare but important clinical entity. Given its scarcity, the risk of malignancy should not sway initial management, but rapid clinical deterioration and radiographic growth during follow-up should prompt consideration of malignant transformation.
前庭神经鞘瘤是桥小脑角的良性肿瘤，常采用放射治疗。放射治疗能很好地控制肿瘤，但存在发生放射性诱导恶性肿瘤的小风险。我们报告一例先前接受过放射治疗的前庭神经鞘瘤内发生高级别肉瘤，以及对此罕见但重要临床实体的文献复习。
一位 66 岁女性，在因前庭神经鞘瘤接受立体定向放射外科治疗 17 年后，出现临床和影像学迅速恶化。切除后，病理显示在常规神经鞘瘤内发生高级别肉瘤。在进一步恶化和肿瘤生长后，患者在术后 7 个月死于该病。通过 PubMed 和 EMBASE 数据库进行文献复习，并使用“vestibular schwannoma（前庭神经鞘瘤）”“acoustic（听神经瘤）”“triton（水神星）”“malignant（恶性的）”“sarcoma（肉瘤）”“malignant peripheral nerve sheath tumor（恶性外周神经鞘瘤）”“radiation（放射）”和“radiosurgery（放射外科）”等关键词检索相关文献。评估和量化所有先前的病例以及与这些放射性诱导恶性肿瘤相关的临床情况。
系统综述得出 20 例先前在无神经纤维瘤病患者中因放射治疗而发生前庭神经鞘瘤恶性转化的病例。大多数肿瘤（60%）转化为恶性神经鞘瘤。在就诊时，70%的患者有新的颅神经病变，所有患者均有肿瘤生长并伴有脑干压迫的证据。预后较差，平均死亡时间为 7.6 个月。
前庭神经鞘瘤的放射性诱导恶性转化是一种罕见但重要的临床实体。鉴于其罕见性，恶性肿瘤的风险不应影响初始治疗，但在随访期间出现快速临床恶化和影像学进展应促使考虑恶性转化。
