Facial nerve schwannoma and other benign neoplastic facial nerve lesions.

PURPOSE OF REVIEW: Several neoplastic lesions may originate from facial nerves, including facial nerve schwannomas. These neoplastic lesions can cause various symptoms, such as facial nerve paralysis, and decrease the quality of life of patients. Therefore, knowledge of how to manage these diseases is important for otologists. However, the incidence of these diseases is extremely low, and universal management methods have not yet been established. This review summarizes recent advances in knowledge regarding these neoplastic lesions, especially facial nerve schwannomas. RECENT FINDINGS: Recent advances and the accumulation of knowledge regarding these benign facial nerve lesions have provided several preferable treatments and management methods, especially for facial nerve schwannomas. However, this still depends on the patient's symptoms and tumor localization. SUMMARY: This review presents the optimal treatment protocol and differential diagnosis of benign facial nerve lesions. This may be useful for pretreatment differentiation and treatment decision-making.

Pearls & Oy-sters: Trigeminal Cystic Schwannoma Presenting With Foster Kennedy Syndrome, Sixth Nerve Palsy, and Focal Seizures.

Foster Kennedy syndrome refers to a finding of optic atrophy in one eye from direct compression of the optic nerve by a mass lesion and contralateral papilledema in the nonatrophic optic nerve caused by an increased intracranial pressure. When the fundoscopy finding is not due to a direct compressive mass, the term pseudo-Foster Kennedy syndrome is used; this can be caused by any process or processes that result in optic atrophy in one eye and optic disc edema in the other. Identifying Foster Kennedy syndrome in a patient calls for expedient neuroimaging looking for an intracranial mass lesion. In this article, we present the case of a patient presenting with vision loss and Foster Kennedy syndrome who was found to have a large trigeminal cystic schwannoma. While several other accompanying symptoms were not evident from the patient complaint, a careful history and physical examination revealed additional localizing clues: unilateral sensory changes in the face and pterygoid and masseter atrophy, unilateral cranial nerve VI palsy, and episodes of intense déjà vu sensation, which were presumed to represent temporal lobe-onset focal aware seizures. Trigeminal schwannomas are a rare entity, and they are even more rarely cystic. This case highlights an unusual scenario where a slow expansion of the tumor ultimately resulted in vision loss and presentation of the patient to medical attention.

A Large Intratemporal Facial Nerve Schwannoma Presenting as an Occluding External Auditory Canal Mass.

Facial nerve schwannomas are rare, benign, slow-growing tumors that can occur in any segment of the facial nerve, although 71% of cases are intratemporal. Surgical resection can lead to facial nerve injury. Facial function recovery after reanimation is usually not better than House-Brackmann (HB) grade III. Thus, for cases of intratemporal facial nerve schwannomas (IFNSs) with favorable facial function (HB grade I or II), observation by periodic magnetic resonance imaging is the mainstay of management. Here, we present a case of a large IFNS with normal facial function in which the mass fully occluded the external auditory canal. The occlusion caused squamous debris to accumulate, potentially leading to cholesteatoma. Faced with this therapeutic dilemma, we chose surgical resection with the patient's informed consent. Stripping surgery was achieved with normal postoperative facial function. There was no postoperative facial paralysis or recurrence at 2-year follow-up. We describe the experience of diagnosis and treatment process for this case, and discuss the possibility of total resection of the tumor with preserving the integrity of facial nerve.

Cervical vagal nerve schwannoma induced arrhythmia: a rare case report and literature review.

BACKGROUND: Schwannomas are benign tumors deriving from the sheath of cranial and peripheral nerves. The vagus nerve is comprised of a complex neuro-endocrine-immune network that maintains homeostasis, most tracts of it play a role in parasympathetic activity. We present an example of a rare cervical vagal schwannoma case accompanied by arrhythmia. CASE PRESENTATION: A 35-year-old female patient with a left cervical vagus schwannoma and ventricular arrhythmia underwent schwannoma resection in the operating room. The patient's suppressed heart rate increased after tumor removal, and the cardiac rhythm returned to normal postoperatively. Pathological examination demonstrated the diagnosis of schwannoma. CONCLUSIONS: This case explains the link between the vagus nerve and the cardiovascular system, proving that a damaged cervical vagus nerve can inhibit the heart rate and lead to arrhythmias, and eventually requiring surgical intervention.

Microsurgical Resection of Trigeminal Schwannoma via Anterior Petrosal Approach: 2-Dimensional Operative Video.

Trigeminal schwannomas are complex lesions that may be related to many critical neurovascular structures. We present the case of a 59-year-old male presenting a history of left-sided trigeminal neuralgia. Preoperative imaging demonstrated a mass highly suggestive of a trigeminal schwannoma, and microsurgical resection was indicated considering the progressive symptomatology and important mass effect (Video 1). A middle fossa route including an anterior petrosectomy was chosen. The patient was placed supine with the head rotated to the contralateral side, and an arcuate incision was performed. A V-shaped zygomatic osteotomy was done to mobilize the temporalis muscle more inferiorly and better expose the middle fossa floor. Following craniotomy, peeling of the dura propria from the lateral wall of cavernous sinus was carried out starting by coagulation of middle meningeal artery. Some tumor was already identified and removed, and then the anterior petrosectomy was performed until we exposed the posterior fossa dura. The middle fossa dural incision was connected with the other one at the posterior fossa dura, by coagulation of the superior petrosal sinus. The tentorium was completely cut toward the incisura. After lesion debulking, the tumor was progressively removed by peeling the arachnoid from the lesion to maintain arachnoid planes and preserve the nerves and their blood supply. Postoperative imaging demonstrated complete tumor resection. The patient's symptoms improved, and there were no neurologic deficits on follow-up. Extensive laboratory training is fundamental to be familiarized with the normal anatomic nuances and prepared to face the anatomy distorted by lesion. Informed consent was obtained from the patient for the procedure and publication of this operative video.

Oculomotor nerve schwannoma: case series and literature review.

Oculomotor nerve schwannomas are rare benign cranial nerve tumors. There are only a limited number of reports on this pathology in the literature, and there are currently no established management guidelines that aid providers in deciding on surgical versus nonsurgical management. We assess the published literature on the topic to identify indications for treatment as well as outcome measures (e.g., local control rates, survival rates, and complication rates) that have been reported as associated with the various treatment modalities. We attempt to develop an algorithm for evaluation and treatment of oculomotor nerve schwannomas in order to establish consensus on how these tumors should be treated.

Recurrent Third Nerve Palsy Secondary to Instrinsic Schwannoma of the Third Cranial Nerve.

ABSTRACT: A 78 year-old woman has experienced multiple episodes of transient right third nerve palsy over the course of 15 years and has undergone multiple imaging studies as well as investigations for myasthenia gravis and giant cell arteritis in search for the diagnosis. When seen after the most recent episode, MRI with contrast and Fast-Imaging Employing Steady-State Acquisition protocol revealed a subtle enlargement and enhancement of the cisternal and proximal cavernous portions of the right third cranial nerve. An empiric diagnosis of schwannoma intrinsic to third cranial nerve was made. All patients with cyclical third nerve palsies should have appropriate neuroimaging to rule out subtle structural lesions before other investigations are undertaken.

Oculomotor Nerve Palsy Due to Unusual Causes.

BACKGROUND: An isolated oculomotor nerve (CN III) palsy is a diagnostic concern because of the potential for serious morbidity or life-threatening causes. We present 5 unusual causes of oculomotor nerve palsy that escaped initial diagnosis in order to raise awareness of their associated features that will facilitate correct diagnosis. METHODS: This study consisted of a retrospective analysis of clinical features and imaging of 5 patients who were referred for neuro-ophthalmologic evaluation with presumed diagnosis of oculomotor nerve palsy of unknown reasons. RESULTS: A complete CN III palsy and an inferior division CN III palsy were diagnosed with a schwannoma in the cavernous sinus and orbital apex portion, respectively; a middle-aged woman with aberrant regeneration was found to have a small meningioma; an adult man with ptosis was diagnosed with cyclic oculomotor paresis with spasms; and a patient after radiation was diagnosed with neuromyotonia. CONCLUSIONS: Localizing the lesion of oculomotor nerve palsy and careful examination of the imaging is crucial. Aberrant regeneration, cyclic pupil changes, and past medical history of amblyopia, strabismus, or radiation are also very helpful for diagnosis.

[A Case of Trochlear Nerve Neurinoma Presenting with Pathological Laughter].

Trochlear nerve neurinomas are rare and solitary tumors without neurofibromatosis are extremely rare. We report a case of trochlear nerve neurinoma presenting with pathological laughter and diplopia. A 40-year-old male patient presented with diplopia and pathological laughter 2 months before admission. MRI showed a multicystic enhanced mass in the left tentorial incisura compressing the midbrain and the upper pons. The tumor was excised using the left trans-Sylvian approach with partial uncal resection. After excision of the tumor, the left trochlear nerve was identified on the surface of the lateral midbrain. The nerve was connected to the tumor. Pathological laughter completely resolved after the operation. This is the second reported case of trochlear nerve neurinoma presenting with pathological laughter. The lesion responsible for pathological laughter could be the midbrain, upper pons, diencephalon, or all of these.

Oculomotor Neurofibroma: A Different Histology Implying an Unsatisfying Clinical Outcome.

BACKGROUND: Tumors arising from oculomotor nerve are rare, with few cases reported in the literature. Generally, whereas schwannomas are well encapsulated tumors, neurofibromas tend to invade the entire nerve fibers. These differences influence surgical resection and neurological clinical outcome, with neurofibroma often requiring the sacrifice of the nerve. Accordingly, an incorrect preoperative diagnosis can lead to incomplete patient counseling before surgery. CASE DESCRIPTION: We report 2 cases: a patient with oculomotor schwannoma and a patient with oculomotor neurofibroma. After tumor resection, the patient with a diagnosis of schwannoma recovered with 3rd nerve palsy, while patient with the neurofibroma developed a complete oculomotor nerve deficit. For each patient, surgical strategy and neurological outcome are elucidated in relation with differences in preoperative magnetic resonance imaging and histology. CONCLUSIONS: To the best of our knowledge, this is the first report of an oculomotor neurofibroma. When an oculomotor nerve tumor is suspected, a careful preoperative evaluation of magnetic resonance imaging guides in distinguishing the different histology, in selecting the treatment strategy, and in correctly informing the patient on expected postoperative neurologic outcome.

Trochlear Schwannoma Arising from Transition Zone of Nerve Sheath in the Pineal Region: Case Report and Review of the Literature.

BACKGROUND: This report presents the third case of trochlear schwannoma arising from the pineal region and the first case to be resected using a paramedian infratentorial supracerebellar approach. Schwannomas of cranial nerves have traditionally been thought to arise from the transitional point where the axonal envelopment switches from glial cells to Schwann cells; however, recent temporal bone histopathologic evidence from vestibular schwannomas challenges this view. Of the 38 cases of pathology-confirmed trochlear schwannoma in the literature, there are only 2 cases arising from the pineal region, where the nerve sheath transition zone is located. Here, we discuss an unusual case of trochlear schwannoma arising from this transition zone. CASE DESCRIPTION: A 65-year-old man was admitted to our institute after a traffic accident. He complained of headache and dizziness, and a computed tomography scan revealed an isodense mass in the pineal region with obstructive hydrocephalus. Magnetic resonance imaging with contrast showed an enhancing mass in the pineal region. The tumor was subtotally resected using a paramedian infratentorial supracerebellar approach, and pathology confirmed the diagnosis of trochlear schwannoma. CONCLUSIONS: Trochlear schwannoma should be considered when a mass is identified in the pineal region. This diagnosis should still be entertained for mass lesions along the free tentorial edge because the tumor may arise distant from the glial-Schwann transition zone located by the dorsal midbrain. We propose a treatment algorithm for this rare tumor that seeks to maximize functional outcome.

Hypoglossal Nerve Schwannoma: Case Report and Literature Review.

BACKGROUND: Hypoglossal schwannomas are rare, benign intracranial neoplasms; they represent 5% of all nonvestibular schwannomas. CASE DESCRIPTION: A 22-year-old male patient had presented 4 months before admission with left-sided hearing loss, an increase in the base of support with lateralization to the left, and dysphagia to solids. Physical examination on admission showed hypotrophy of the tongue and deviation to the left. Magnetic resonance imaging showed evidence of an extraaxial lesion compressing the medulla oblongata and pons, which protruded through the hypoglossal canal. The patient was prepared for surgical treatment in 2 stages: in the first surgery, a left retrosigmoidal approach with total resection of the intracranial lesion was performed. The biopsy reported a schwannoma, and correlating the signs, symptoms, and imaging, the diagnosis of a hypoglossal nerve schwannoma was established. In the second surgery, a lateral cervical approach was performed, with subtotal resection of the lesion, leaving a remnant adhered to the nerve in the hypoglossal canal. CONCLUSIONS: Hypoglossal schwannomas are a rare entity, in which surgery is the most viable option with high cure rates. However, its complete resection, without leaving permanent neurologic sequels, is a challenge.

Surgical Outcomes of Intratemporal Facial Nerve Schwannomas According to Facial Nerve Manipulation.

OBJECTIVES: The aim of this study was to evaluate the preoperative and postoperative facial nerve (FN) function in patients with FN schwannoma (FNS) and analyze the duration of preoperative facial palsy according to the preoperative and postoperative facial function. MATERIALS AND METHODS: We retrospectively reviewed the medical records of 29 patients with FNS who underwent surgery. We evaluated the FN function according to the type of FN manipulation and location of the anastomoses in the cable nerve graft, and we also analyzed the duration of facial palsy according to the facial function before and after surgery. RESULTS: All 4 patients who underwent nerve-stripping surgery had the House-Brackmann (H-B) Grade III, 12 of 21 who underwent a cable nerve graft had the H-B Grade III or better postoperatively, and all 4 who underwent a hypoglossal facial crossover had the H-B Grade IV. Patients who underwent cable nerve grafting were more likely to have better FN function when the proximal anastomosis site was located in the internal auditory canal, geniculate ganglion, tympanic segment of FN, and distal end in the mastoid segment of FN. The duration of preoperative facial palsy was statistically shorter in patients with better postoperative facial function. CONCLUSION: Surgery can be considered in patients with FNS who have the H-B Grade III or worse. A shorter duration of facial palsy prior to surgery resulted in better postoperative facial function.

Recurrent Painful Ophthalmoplegic Neuropathy and Oculomotor Nerve Schwannoma: A Pediatric Case Report with Long-Term MRI Follow-Up and Literature Review.

Background: Recurrent painful ophthalmoplegic neuropathy (RPON), previously known as ophthalmoplegic migraine (OM), is an uncommon disorder with repeated episodes of ocular cranial nerve neuropathy associated with ipsilateral headache. The age of presentation is most often during childhood or adolescence. MRI has a central role in the assessment of the RPON, especially to distinguish orbital, parasellar, or posterior fossa lesions that mimic symptoms of RPON. Actually, oculomotor nerve tumors may be masquerade as RPON so that MRI follow-ups are required to detect the possibility of tumor etiology. Case presentation: We report a 16-year-old boy with a 7-year follow-up and multiple brain MRI data, previously diagnosed as OM. The last brain MRI, performed during an acute phase of oculomotor paresis with ipsilateral headache, showed a nodular lesion described as schwannoma of III cranial nerve. Then, we reviewed the literature on OM and RPON in pediatric age with a focus on brain MRI findings. Conclusions: This review highlights the important role of serial brain MRIs in the long-term follow-up of RPON, especially in the cases with childhood onset, in order to not delay the diagnosis of a possible oculomotor nerve schwannoma.