Intracanalicular schwannoma of the facial nerve: a manifestation of neurofibromatosis type 2

Primary facial nerve tumors, which are relatively uncommon, can present a diagnostic dilemma based on their location and variable pattern of symptoms. Of primary cranial nerve tumors, schwannomas of the facial nerve rank third in frequency after those of the eighth and fifth cranial nerves. We report an illustrative case of an intracanalicular schwannoma associated with several central nervous system tumors, consistent with neurofibromatosis type 2. Initially assumed to be an eighth cranial nerve tumor, the schwannoma was found intraoperatively to arise from the facial nerve. Early diagnosis and treatment enabled excision of the tumor without sacrifice of the facial nerve. Facial nerve schwannomas can resemble acoustic schwannomas in their clinical presentation. Only a heightened level of clinical vigilance will point to the correct diagnosis and result in an optimal therapeutic outcome for patients with these rare tumors.     

Transtemporal facial nerve schwannoma without facial nerve paralysis

Facial schwannoma is a relatively rare but well documented lesion, presenting either as a mass or with facial nerve symptoms. In this report, an extensive facial schwannoma, extending from the brain stem to the periphery with minimal facial nerve symptoms and normal facial function is presented.     

Vestibular-like facial nerve schwannoma

OBJECTIVE: To evaluate the prevalence as well as the management of primary facial nerve schwannoma (PFNS) presenting as vestibular schwannoma. METHODS: A retrospective review was carried out on 146 patients referred to and operated upon in our institution over a 5-year period for tumors of the internal auditory canal extending or not into the cerebello-pontine angle (TICA). A review of the literature included an extensive MEDLINE search of the literature since 1966 and careful inspection of the bibliography of each article. Articles pertaining to facial nerve schwannomas were reviewed to identify cases of vestibular-like facial (V-LF) nerve schwannoma. RESULTS: Two cases of tumors were finally diagnosed as PFNS. Clinical and radiological evaluations were typical of a vestibular schwannoma. Facial function was normal in each case. Unsuspected facial nerve schwannomas were found during surgery. Tumor removal was not performed. Postoperatively House and Brackmann (HB) facial function was normal in one case and grade II in the other case. These two cases represented a 1.4% prevalence, which is within the limits reported in the literature. Among V-LF nerve schwannomas reported in the literature, the postoperative functional facial outcome usually worsened when the tumor was resected. CONCLUSION: The prevalence of V-LF nerve schwannoma has been reported in the two last decades owing to the development of modern imaging. The conservative management of early staged tumors presenting as vestibular schwannoma is recommended in order to counsel the patient regarding the possibility of V-LF nerve schwannoma and to prolong normal facial function.     

A facial nerve schwannoma masquerading as a vestibular schwannoma

Schwannoma of the facial nerve is an extremely rare condition with an incidence far lower than that of vestibular schwannoma. We discuss the case of a woman who had been diagnosed as having vestibular schwannoma and referred to our hospital. Initially, we concurred with the diagnosis, but on reassessment of magnetic resonance imaging scans before surgery, we revised the diagnosis to facial nerve schwannoma. This allowed us to counsel the patient appropriately preoperatively regarding the expected outcome. We discuss the importance of this case and the lessons to be learned from it.     

Intraparotid facial nerve schwannoma. What to do?

• An intraparotid facial nerve schwannoma is often not recognised in pre‐treatment work‐up and frequently results in subsequent significant postoperative morbidity. • We have evaluated the literature regarding pre‐treatment work‐up and facial nerve function outcome. Two of our own cases are presented. • A minority of the intraparotid schwannomas can be removed by resection while preserving facial nerve integrity and function. • In the event of preoperative facial nerve dysfunction, tumour resection and subsequent nerve repair should be considered. • If resection of an intraparotid facial nerve schwannoma cannot be performed with preservation of facial nerve integrity and function, a wait‐and‐see policy seems justified due to the indolent behaviour of the tumour and moderate results of facial nerve reconstruction.     

Intratemporal facial nerve schwannoma: a management dilemma.

OBJECTIVE: To report the findings in patients with facial nerve schwannoma in whom surgery was elected at onset versus patients treated expectantly. STUDY DESIGN: Retrospective case review. SETTING: Tertiary referral center. PATIENTS: Twenty-four patients with a mean age of 44 years (range, 18-65 yr) were followed for an average of 6 years (range, 1-19 yr). INTERVENTION: Eleven patients underwent complete tumor excision and 13 patients were enrolled in ongoing monitoring only. MAIN OUTCOME MEASURES: Facial nerve function and hearing acuity were noted at the time of initial and last visits. Magnetic resonance imaging was used to determine tumor growth in those individuals treated expectantly and as a means of excluding tumor recurrence/persistence in those treated surgically. RESULTS: Of the 11 patients who underwent tumor removal, the facial nerve was spared in 7. Eight had varying degrees of facial nerve dysfunction initially. In this group (mean follow-up, 8 yr), six patients had unchanged nerve function, four had improved nerve function, and one had worsened. No long-term recurrence was noted. Of the 13 patients followed expectantly, three had facial weakness initially. During the follow-up interval (mean, 5 yr), facial function remained unchanged for eight and worsened in five. During this interval, 4 of the 13 patients demonstrated tumor growth and 3 have recently undergone tumor removal. CONCLUSION: Facial nerve schwannomas are extremely slow growing and frequently present without facial dysfunction. It is possible to surgically remove these tumors while sparing the nerve; as a result, postoperative function is correspondingly better. Finally, the decision on how to treat these patients should be individualized and based on initial facial function, growth rate, surgical experience, and informed patient consent.     

Two cases of intraparotid facial nerve schwannoma

Intraparotid facial nerve schwannomas are rare, their preoperative diagnosis is difficult, and there are controversies about how to proceed when they are suspected intraoperatively. We present two cases of intraparotid facial nerve schwannoma that were diagnosed during parotid surgery, and describe the procedure and follow-up performed.     

Intraparotid facial nerve schwannoma: management options

Intraparotid facial nerve schwannoma (FNS) is a very rare, benign tumour mimicking pleomorphic adenoma. Resection of this slow growing tumour may result in unnecessary facial nerve paralysis. The aim of this study is to present results of facial nerve schwannoma treatment at our institution and proposes a management plan. This is a retrospective case series of four patients, three male and one female with a mean age of 47.7 years who presented with a long-standing, asymptomatic parotid swelling. Two patients had facial weakness and underwent superficial parotidectomy, resection of tumour and facial nerve repair with a free graft from the greater auricular nerve. Two patients underwent biopsy without tumour resection. All tumours were confirmed histologically as facial nerve schwannomas. The mean follow up period was 3.5 years. Patients with resection of facial nerve schwannoma had a postoperative House Brackmann grade III and IV. Patients with biopsy had normal postoperative facial nerve function and the tumour did not grow significantly. No adverse effects or recurrence were reported. There is no preoperative diagnostic modality that can identify facial nerve schwannoma with certainty. Difficulty in locating the facial nerve intraoperatively raises suspicion of a neurogenous tumour of the facial nerve and this may prevent unnecessary damage to the nerve. Not every facial nerve schwannoma should be resected. This decision is based on (a) the extent of tumour (b) preoperative facial nerve function (c) best results achieved with nerve repair and (d) patient’s preferences. Large tumours with extension into the mastoid cavity or encroachment of sensitive structures and preoperative facial weakness are indications for surgical intervention. In most other cases, biopsy and observation suffices.     

Chondromyxoid fibroma of the mastoid facial nerve canal mimicking a facial nerve schwannoma

Chondromyxoid fibroma of the skull base is a rare entity. Involvement of the temporal bone is particularly rare. We present an unusual case of progressive facial nerve paralysis with imaging and clinical findings most suggestive of a facial nerve schwannoma. The lesion was tubular in appearance, expanded the mastoid facial nerve canal, protruded out of the stylomastoid foramen, and enhanced homogeneously. The only unusual imaging feature was minor calcification within the tumor. Surgery revealed an irregular, cystic lesion. Pathology diagnosed a chondromyxoid fibroma involving the mastoid portion of the facial nerve canal, destroying the facial nerve. Laryngoscope, 2009     

Intraoperative diagnosis of facial nerve schwannoma at parotidectomy

OBJECTIVE: Our objective was to provide a diagnostic algorithm for facial nerve schwannomas presenting as a parotid mass. STUDY DESIGN: The study is a case report and literature review. METHODS: A clinical case of a patient with an asymptomatic parotid mass diagnosed as a facial nerve schwannoma intraoperatively is presented. The patient's presentation and the diagnostic algorithm and surgical rationale are discussed. A review of the literature on facial nerve schwannomas is presented. CONCLUSIONS: Intraparotid facial nerve schwannomas are an extremely rare entity and are rarely diagnosed preoperatively. Most of these benign lesions can be managed conservatively with the goal of preserving facial nerve function. Intraoperatively, fine-needle aspiration and/or conservative biopsy in a nonstimulating portion of the lesion can be used to make the diagnosis.     

面神经鞘膜瘤诊断和治疗分析(附2例报告)

目的：探讨面神经鞘膜瘤的诊断和治疗。方法：分析我科2002～2004年收治并于术中诊断为面神经鞘膜瘤患者的临床资料,复习面神经鞘膜瘤诊断和治疗的有关文献。结果：2例患者于术中诊断为面神经鞘膜瘤,其中1例行肿瘤切除,并取耳大神经行面神经移植吻合;另1例行腮腺深叶肿瘤切除。结论：原发于面神经的良性肿瘤,由于病变部位的不同所引起的临床表现不同为诊断带来了困难。在临床症状和全面体检的基础上,影像学检查可确定病变范围及其与周围组织的关系,并为手术进路的选择提供必要的信息。治疗原则是全部切除肿瘤组织,保留或恢复面神经功能,保存听力。影响术后面神经功能恢复的主要因素是术前面神经损伤时间的长短,损伤时间达1年以上,术后面神经功能恢复较差,而病变部位和术前面神经功能的分级并不影响面神经功能的恢复。     

Management of facial nerve schwannoma in patients with favorable facial function

OBJECTIVE: We report six cases of facial nerve schwannomas in which surgical management allowed the preservation of facial nerve function. Specifically, this paper reports that a stripping surgery may provide favorable functional outcomes. STUDY DESIGN: A retrospective review of preoperative and postoperative data for six patients with facial nerve schwannoma that had normal facial nerve function or a House-Brackmann grade II facial palsy before the surgery. METHODS: Stripping surgery, which removed the schwannoma from the remaining nerve fascicle, was attempted on the six patients. Postoperative facial nerve function and imaging (magnetic resonance imaging) were evaluated. RESULTS: Stripping surgery with gross total tumor removal of the mass was performed in four cases. In the two remaining cases, the stripping surgery was not possible, and decompression alone was performed. Favorable preservation of facial function was achieved in all six cases. CONCLUSION: It was possible to preserve facial function after surgery to remove facial nerve schwannoma. We suggest that stripping surgery, focused on the preservation of continuity of the facial nerve, may be attempted for facial nerve schwannoma in which favorable facial function has been preserved.     

伴或不伴轻微面神经麻痹的面神经鞘瘤的诊治分析

目的 探讨伴或不伴轻微面神经麻痹的面神经鞘瘤的临床表现、诊断及治疗.方法 回顾性分析8例资料完整、面神经功能House-Brackmann分级(HB)≤Ⅱ级的面神经鞘瘤患者诊断及治疗过程.结果 8例患者均不以面神经麻痹为首发症状且均有误诊史,其中6例存在误治史.术前均行CT和(或)MRI检查,证实肿瘤位于面神经的不同位置.4例术中保留面神经行肿瘤切除术,术后随访17～180个月,面神经功能(HB)Ⅱ～Ⅲ级;2例术中发现肿瘤侵犯广泛,破坏耳蜗及前庭,与面神经无法分离,予以牺牲神经切除肿瘤,行耳大神经移植术,术后分别随访56和79个月,面神经功能(HB)Ⅳ级;1例拒绝牺牲面神经,术中行面神经减压术,术后11个月面神经功能Ⅱ级,肿瘤无增大;1例术中发现肿瘤来源于鼓索神经,予以牺牲面神经分支,并行面神经减压术,术后11个月面神经功能Ⅱ级.结论 面神经功能分级(HB)≤Ⅱ级的面神经鞘瘤多不以面神经麻痹为首发症状,诊断困难.手术方法取决于肿瘤的特点、范围和患者的意愿.对明确面神经来源的肿瘤,如果肿瘤与面神经之间容易分离,可以保留面神经行肿瘤切除;如果不易分离,当肿瘤侵犯桥小脑角、内听道、耳蜗、前庭时,可以考虑牺牲面神经;对拒绝牺牲面神经者,可行面神经减压术,并定期影像学随访.     

Carcinoma ex pleomorphic adenoma mimicking multiple facial nerve schwannoma

Carcinoma ex pleomorphic adenoma (CXPA) is a rare, aggressive, poorly understood malignancy that usually occurs in the salivary glands. CXPA has been reported to account for 3.6% of all salivary neoplasms and 11.7% of salivary malignancies. CXPA not only has a low incidence rate but there are few papers or case reports reporting perineural invasion rates. We report a case of CXPA which occurred in the parotid gland, showing retrograde perineural invasion along the facial nerve back to the internal auditory canal (IAC).     

面神经与前庭神经鞘膜瘤的空间位置对术后面神经功能恢复的影响

目的：探讨面神经（FN）与前庭神经鞘膜瘤（VS）空间位置对于术后FN功能恢复的影响。方法：101例单侧VS患者,采用扩大迷路径路显微全切除肿瘤,观察术中FN-VS空间位置,分为4型：第1位置为FN位于VS前方,第2位置为FN位于VS前上方,第3位置为FN位于VS上方,第4位置为FN位于VS后方。根据House-Brackmann面神经分级法评价患者术后7、30、90、180d的FN功能。结果：术中FN解剖保留率达98％,术中发现FN—VS空间位置有43％为第1位置,33％为第2位置,24％为第3位置,未发现第4位置。术后180d 73％FN功能良好,且随VS直径增大,术后FN功能良好率递减。FN—VS空间位置与术后FN功能呈显著相关,第1位置至第3位置术后FN功能良好率呈递减关系。结论：术中FN解剖保留率并不平行于术后FN功能良好率,VS直径与术后FN功能良好率相关,而FN—VS空间位置能够预测术后FN功能良好率。