Department of Neurosurgery, Hospital Força Aérea do Galeão, Rio de Janeiro, Brazil.
Department of Otorhinology, Clinica Otorrinos Largo do Machado, Rio de Janeiro, Brazil.
World Neurosurg. 2020 Sep;141:251. doi: 10.1016/j.wneu.2020.05.141. Epub 2020 May 23.
Trigeminal schwannomas are benign slow-growing tumors originating from the peripheral nerve sheath. They account for 0.1%-0.4% of all intracranial tumors and 1%-8% of all intracranial schwannomas. While most of these tumors develop in the trigeminal ganglion within the middle fossa, trigeminal schwannomas can develop anywhere along the course of the trigeminal nerve. As a result, they can be intradural, interdural, and extradural. Trigeminal schwannomas from the pterygopalatine fossa (PPF) are extremely rare and very difficult to remove because of limited access to this region and the rich neurovascular contents. Numerous traditional microsurgical approaches to the PPF have been described; however, they are more invasive with increased morbidity. Therefore, endoscopic endonasal surgery is a feasible solution. This technique allows good visualization of the region with decreased morbidity and a shorter recovery period. A previously healthy, 40-year-old woman presented with right facial pain for 3 weeks. On neurologic examination, the patient had hypoesthesia in the territory of the maxillary (V2) branch of the right trigeminal nerve. She had no other symptoms on physical examination. Cranial computed tomography and magnetic resonance imaging were performed and showed a high signal density mass in the right PPF that exhibited heterogeneous contrast enhancement. She was initially treated with low-dose carbamazepine; however, the dose could not be further increased because of drowsiness and dizziness. Given the size and location of the mass, an endoscopic endonasal approach was performed, and the tumor was successfully resected (Video 1). The postoperative course was uneventful, and the patient had significant improvement of her symptoms and was discharged with no new neurologic deficits. However, she continued to have hypoesthesia of the V2 segment of the trigeminal nerve.
三叉神经鞘瘤是起源于外周神经鞘的良性、生长缓慢的肿瘤。它们占所有颅内肿瘤的 0.1%-0.4%，占所有颅内神经鞘瘤的 1%-8%。虽然这些肿瘤大多在中颅窝的三叉神经节中发育，但三叉神经鞘瘤可以在三叉神经的任何部位发育。因此，它们可以是颅内的、硬膜内的、硬膜外的。来自翼腭窝（PPF）的三叉神经鞘瘤极为罕见，由于该区域的进入受限和丰富的神经血管内容物，非常难以切除。已经描述了许多传统的经翼腭窝入路的显微外科手术方法；然而，这些方法具有更大的侵袭性，发病率更高。因此，经鼻内镜手术是一种可行的解决方案。这种技术可以在减少发病率和缩短恢复期的情况下，实现对该区域的良好可视化。一位以前健康的 40 岁女性因右侧面部疼痛 3 周就诊。神经检查时，患者右侧三叉神经上颌支（V2）支配区感觉减退。她在体格检查中没有其他症状。进行了头颅 CT 和磁共振成像检查，显示右侧 PPF 内有高密度信号密度肿块，呈不均匀对比增强。她最初接受了小剂量卡马西平治疗；然而，由于嗜睡和头晕，无法进一步增加剂量。鉴于肿块的大小和位置，采用了经鼻内镜入路，成功切除了肿瘤（视频 1）。术后过程顺利，患者症状明显改善，无新的神经功能缺损出院。然而，她仍然存在三叉神经 V2 段感觉减退。
