Giacobbo Scavo Carlo, Roperto Raffaelino, Cacciotti Guglielmo, Mastronardi Luciano
Division of Neurosurgery, San Filippo Neri Hospital, ASL Rome, Rome, Italy.
J Craniofac Surg. 2018 Nov;29(8):e728-e730. doi: 10.1097/SCS.0000000000004501.
Cavernous malformations (CM) in the cerebellopontine angle (CPA) are rare, and most of them are solid and extend from the internal auditory canal into the CPA. In contrast, cystic CM arising in the CPA and not involving the internal auditory canal and dura of the skull base are extremely rare. The authors present an uncommon large cystic progression of a cavernous malformation at the level of the trigeminal root entry zone evolving to severe trigeminal neuralgia and brainstem compression.
A 62-year-old female presented a sudden onset of left trigeminal neuralgia, caused by a large cystic lesion at the level of the root entry zone of the left 5th nerve. On neurological examination, she showed slight gait ataxia and hypoesthesia on the left hemiface (on the first and second trigeminal branches). Other cranial nerves were in order. Magnetic resonance imaging showed a large cystic intracranial mass, with a small solid portion, leading to brainstem compression.
Microsurgical removal of the lesion was performed via retrosigmoid approach, with intraoperative monitoring of somato-sensory evoked potentials, facial, and cochlear nerves. The posterior-medial portion of the lesion was solid, whereas the main portion was cystic, containing xanthochromic fluid. The small solid lesion continued with a thin capsule of a large cyst adherent to brainstem, cerebellar hemisphere, and trigeminal nerve entry zone. A big draining vein arising from the solid part of the lesion runned parallel to brainstem. The mass was piecemeal totally removed.After surgery the patient recovered both left trigeminal neuralgia and hypoesthesia; ataxia was significantly relieved too. Postoperative magnetic resonance imaging confirmed the total removal. Histopathological features were consistent with a CM. At 6-month follow-up, patient's symptoms at the presentation had resolved.
The authors present a very rare patient of large cystic cavernous malformation at the level of the trigeminal root entry zone presenting with sudden onset of trigeminal neuralgia. Even if it has not established imaging features, a cystic cavernoma of the cerebello-pontine angle may be suspected when a cystic mass is present, not involving the internal acoustic meatus nor the skull base dura mater. Careful microneurosurgical technique and monitoring of cranial nerves allow good long-term results.
桥小脑角（CPA）海绵状畸形（CM）较为罕见，且大多数为实性，从内耳道延伸至CPA。相比之下，起源于CPA且不累及内耳道和颅底硬脑膜的囊性CM极为罕见。作者报告了一例罕见的位于三叉神经根入区水平的海绵状畸形巨大囊性进展，其演变为严重的三叉神经痛和脑干受压。
一名62岁女性因左侧第5神经根部入区的巨大囊性病变突然出现左侧三叉神经痛。神经系统检查显示，她有轻微步态共济失调，左侧半面部（三叉神经第一和第二分支分布区）感觉减退。其他颅神经正常。磁共振成像显示颅内有一个巨大的囊性肿块，有一小部分实性成分，导致脑干受压。
通过乙状窦后入路对病变进行显微手术切除，术中监测体感诱发电位、面神经和听神经。病变的后内侧部分为实性，而主要部分为囊性，含有淡黄色液体。小的实性病变与一个附着于脑干、小脑半球和三叉神经入区的大囊肿的薄囊壁相连。一条从病变实性部分发出的粗大引流静脉与脑干平行。肿块被分块完全切除。术后患者左侧三叉神经痛和感觉减退均恢复；共济失调也明显缓解。术后磁共振成像证实病变已完全切除。组织病理学特征符合CM。随访6个月时，患者就诊时的症状已消失。
作者报告了一例非常罕见的位于三叉神经根入区水平的巨大囊性海绵状畸形患者，其以突然发作的三叉神经痛为表现。即使没有典型的影像学特征，当出现囊性肿块且不累及内耳道和颅底硬脑膜时，也应怀疑为桥小脑角囊性海绵状血管瘤。精细的显微神经外科技术和颅神经监测可取得良好的长期效果。
