A case report on lingual schwannoma.

SUMMARY: Schwannomas are benign tumours of peripheral nerves originating in the nerve sheaths. Only 1% are reported in the oral cavity. We report a 24-year-old female who presented with a 10-year history of a mass at the base of the tongue with associated odynodysphagia, referred otalgia and loss of weight. Oral examination revealed a large left sided base of tongue mass extending into the vallecula. An open transcervical suprahyoid resection was performed with a good outcome.

Long-term analysis of ABI auditory performance in patients with neurofibromatosis type 2-related schwannomatosis.

PURPOSE: This retrospective monocentric study aimed to evaluate long-term auditory brainstem implant (ABI) function in patients with neurofibromatosis type 2, and to investigate the prognostic factors for ABI use. METHODS: Between 1997 and 2022, 27 patients with at least five years of follow-up underwent implantation with 32 ABIs. At 1- and 5-years post-implantation and at last follow-up, ABIs were classified as used or non-used and the size of the ipsilateral tumor was recorded. For patients who used their ABIs, we assessed speech perception (disyllabic words, MBAA sentences) in quiet conditions with the ABI only, by lip-reading (LR), and with a combination of the two (ABI + LR). Hearing improvement was calculated as Δ ABI = (ABI + LR)-LR scores. Predictive factors for ABI use were analyzed. RESULTS: One year post-implantation, 74% patients were ABI-users and 66% of the ABIs were used. Two of these patients were non-users at five years, and another two at last follow-up (14 ± 5.2 years); 54% of the patients were ABI-users at last follow-up. Δ ABI revealed a hearing improvement of 32-41% (disyllabic words) and 28-37% (MBAA sentences). Among 16 ABIs with at least LR improvement at 1-year post-implantation, 4 decreased their performance, coinciding with a large growing ipsilateral tumor in 3/4 ABIs. We identified no significant prognostic factors for ABI use. CONCLUSIONS: ABIs are indicated in case of bilateral deafness with a non-functional cochlear nerve. Half the patients with ABIs used their implants and auditory performance remained stable over time, except in cases of ipsilateral tumor growth.

Supraclavicular-median sternotomy approach for a large neurilemmoma invading the thoracic outlet: a case report and review of the literature.

BACKGROUND: Large mediastinum tumors invading the thoracic outlet have consistently been a challenge in thoracic surgery. Due to the large size of the tumor and its proximity to many important tissues, appropriate surgical approaches are crucial for a successful surgery. CASE PRESENTATIONS: Here, we present a case of a large neurilemmoma that invaded the thoracic outlet that was resected by a supraclavicular-median sternotomy approach. The case was a 58-year-old woman with a large mass in the right chest cavity that had invaded the thoracic outlet. The preoperative biopsy showed a blood clot with a few fibrous connective tissues covered by a single layer of flat epithelium. There was insufficient evidence to diagnose the mass as a tumor, and imaging examinations suggested a diagnosis of solitary pleural fibroma. For good exposure of the cranial and caudal aspects of the large mass, we devised a median sternotomy combined with a supraclavicular approach and safely achieved complete resection. The patient recovered well and experienced no severe complications or functional restrictions of the upper extremity. The postoperative pathology diagnosis was a neurilemmoma. CONCLUSIONS: The supraclavicular-median sternotomy approach could be an optional approach for the complete resection of large mediastinal tumors invading the thoracic outlet.

A Rare Intracortical Schwannoma of the Distal Tibia: A Case Report.

CASE: A 28-year-old man presented for a painful lower extremity mass. Imaging revealed a nonspecific, poorly defined lucent lesion in the left distal tibial cortex with scalloping. The diagnosis of intracortical schwannoma was made after open biopsy revealed positive S-100 immunohistochemical staining and characteristic spindled cells. Definitive management was achieved through curettage and bone grafting. Six months postoperatively, the patient's pain had improved with complete radiographic healing. CONCLUSION: An intracortical schwannoma is a rare, benign lesion which may have atypical radiological findings and nonspecific presentations. Definitive diagnosis is made with permanent histology and S-100 immunohistochemical staining.

Comprehensive neurosurgical and visceral surgical therapy of retroperitoneal nerve tumors: a descriptive and retrospective analysis.

Nerve tumors in the retroperitoneal space are a rarity. Radical surgery according to soft tissue tumors can lead to persistent pain and neurological deficits. This study aims to evaluate clinical outcomes of patients treated by a visceral- / neurosurgical approach. 33 patients with a retroperitoneal nerve tumor underwent surgery between 01/2002 and 12/2022 at our department. A visceral surgeon provided access to the retroperitoneal space, followed by micro-neurosurgical tumor preparation under neuromonitoring. Clinical examination and MRI were performed 12 weeks after surgery and further 3 months (WHO grade > 1) or 12 months (WHO grade 1). Further examinations were based on MRI findings and residual symptoms with median follow-up time of 24 months. One patient was treated for two distinct masses resulting in a total of 34 histological findings. Schwannomas (n = 15; 44.1%) and neurofibromas (n = 10; 29.4%) were the most common tumors. Long-term improvements were noted in radicular pain (15/18 patients; 83.3%), motor deficits (7/16 patients; 43.8%), abdominal discomfort and pain (5/7 patients; 71.4%). Recurrences were observed in 3/33 (9,1%) patients. This study represents the largest series of retroperitoneal BPNSTs treated with microsurgical techniques. Prospective multicenter studies are warranted to establish standardized treatment guidelines.

Excision of large median and ulnar nerve schwannomas: a case series.

OBJECTIVE: Schwannomas are benign, slow-growing tumors originating from Schwann cells in peripheral nerves, commonly affecting the median and ulnar nerves in the forearm and wrist. Surgical excision is the gold standard treatment. This study presents our treatment strategies and outcomes for large-sized ulnar and median nerve schwannomas at the forearm and wrist level. METHODS: From 2012 to 2023, we enrolled 15 patients with schwannomas over 2 cm in size in the median or ulnar nerve at the forearm and wrist. The study included 12 patients with median nerve schwannomas (mean age: 61 years) and 3 with ulnar nerve schwannomas (mean age: 68 years), with a mean follow-up of 26.9 months. RESULTS: After surgery, all patients with median nerve schwannomas experienced mild, transient numbness affecting fewer than two digits, resolving within six months without motor deficits. Ulnar nerve schwannoma excision caused mild numbness in two patients, also resolving within six months, but all three developed ulnar claw hand deformity, which persisted but improved at the last follow-up. Despite this, patients were satisfied with the surgery due to relief from severe tingling pain. CONCLUSIONS: Schwannomas of the median, ulnar, and other peripheral nerves should be removed by carefully dissecting the connecting nerve fascicles to avoid injury to healthy ones. Sensory deficits may occur but are unlikely to significantly impact quality of life. However, in motor-dominant nerves like the ulnar nerve, there is a risk of significant motor deficits that could affect hand function, though not completely. Therefore, thorough preoperative discussion and consideration of interfascicular nerve grafting are essential.

AB007. Intramedullary schwannoma: a rare case report.

BACKGROUND: Intramedullary schwannomas are a rare case, accounting for only 0.3% of all intraspinal neoplasms and 1.1% of spinal schwannomas. These tumors have most often been reported to involve a single lesion affecting the cervical spinal cord (63%), the thoracic spinal cord (26%), and the lumbar spinal cord (11%). Here we report a very rare case thoracic intramedullary schwannoma. CASE DESCRIPTION: A 24-year-old female patient was admitted with gradual onset weakness of both lower limbs for last 2 years with retention of urine. Neurological examination revealed the motor strengths on both legs were 2. There was a sensibility dissociation below Th8 dermatomal level. Magnetic resonance imaging shows an ill-demarcated intramedullary lesion extending from Th8 to Th9 accompanied by spinal cord edema along Th4 to Th11. The surgery was performed with standard posterior middle approach. Laminectomy decompression was performed and dura opened in the midline. Infiltrative nature of the mass made the total resection impossible. Histopathological result followed by immunohistochemistry confirmed the diagnosis of schwannoma. In the postoperative follow-up, the motor strengths of both legs are absent and no clinical improvement at all until now. Prior to surgery, intramedullary schwannoma is often misdiagnosed as other types of tumour, including ependymoma, astrocytoma and hemangioblastoma, due to its atypical imaging appearance and low incidence. Surgery for spinal intramedullary tumors remains one of the major challenges for surgeons, due to their relative infrequency, and surgical difficulty technique. Worse preoperative McCormick Scale, thoracic tumor location, partial resection, and lack of availability of intraoperative neurophysiology monitoring (IONM) were significant factors for poor prognosis. CONCLUSIONS: Intramedullary schwannomas are slow-growing rare tumors and should be considered as one of the differential diagnoses for the intramedullary spinal lesions. Magnetic resonance imaging may be helpful for diagnosis however clear distinction cannot be made between the intramedullary spinal lesions. Total surgical resection is the treatment choice for this patient but infiltrative lesions cannot be resected completely for which radiotherapy has been suggested.

Risk factors of postoperative trigeminal neuropathy in surgical treatment of trigeminal schwannomas.

OBJECTIVE: Trigeminal schwannomas are rare benign tumors originating from the Schwann cells of the trigeminal nerve. Despite the common occurrence of trigeminal neuropathy in trigeminal schwannomas, a detailed analysis has not yet been performed because of the rarity of this disease. This study aimed to analyze trigeminal neuropathy in trigeminal schwannoma resection and identify the risk factors for postoperative worsening of trigeminal neuropathy. METHODS: A retrospective analysis of 86 surgical cases was performed at our institution between 1975 and 2018. Obtained parameters included age, sex, diagnosis, reoperation, tumor size, tumor location, presence or absence of cysts, surgical approach, degree of tumor removal, and pre/postoperative trigeminal neuropathy. Uni- and multivariate analyses were performed to identify the risk factors for worsening postoperative sensory disturbances. RESULTS: Of 83 patients, 58.1% had preoperative trigeminal neuropathy. Postoperative sensory disturbance occurred in 27.9%, with worsening in two cases and de novo symptoms in 22 cases. Regarding risk factors for worsening postoperative sensory disturbances, older age, smaller tumor size, middle and posterior (MP) type, gross total removal (GTR), and anterior transpetrosal approach were identified in the univariate analysis, while MP type and GTR were identified in the multivariate analysis. CONCLUSIONS: This study analyzed trigeminal neuropathy in trigeminal schwannomas in detail and identified tumor location and removal rate as risk factors for worsening postoperative sensory disturbances. Treatment strategies to reduce the risk of trigeminal neuropathy should be considered.

Rapidly Growing Leiomyoma Mimicking Schwannoma of the Saphenous Nerve in the Lower Extremity: An Unusual Case Report.

Leiomyomas and schwannomas are both types of rare benign soft tissue tumours. Leiomyomas are more commonly found in the lower limbs than in the upper extremities, while schwannomas are rare peripheral nerve sheath tumours that can occur in different anatomical regions. However, they rarely occur in the saphenous nerve. This case study presents a 41-year-old female patient with a solitary mass lesion located deep in the soft tissue of the anteromedial lower extremity. The physical examination revealed a palpable, elastic-hard, mobile and non-tender mass. Magnetic resonance imaging (MRI) showed an oval-shaped subcutaneous mass on contrast-enhanced T1-weighted sections. The initial MRI images suggested a schwannoma, but the tumour was later confirmed to be a leiomyoma after total enucleation. An immunohistochemical study was performed for differential diagnosis. Solitary mass lesions in the lower extremities can be mistaken for various types of tumours and misdiagnosed and require histopathological examination and good radiological imaging for differential diagnosis. Complete surgical excision is usually a safe and effective treatment for leiomyomas.

Letter to editor: Minimally invasive tubular removal of spinal schwannoma and neurofibroma - a case series of 49 patients and review of literature.

The article on "Minimally invasive tubular removal of spinal schwannoma and neurofibroma - a case series of 49 patients and review of the literature" by Dr Argiti et al. in Neurosurgical Review journal. It is based on brief study of this article and also additional points from other references which elaborate it for further research.

Resection of a giant intraspinal and extraspinal schwannoma with cystic change using a two-step surgery: a case report.

BACKGROUND: Schwannomas originating from the intravertebral canal rarely extend into the paravertebral region or form large masses. There are few reports on such medical cases, and their clinical diagnosis and management are poorly understood. Here, we report a case of an intraspinal schwannoma with a giant extraspinal mass in a middle-aged Chinese woman and the clinical implications of the symptoms, diagnosis, and treatment of thoracic vertebral schwannoma. CASE PRESENTATION: A 59-year-old female patient who presented with sudden lower limb numbness and difficulty in walking was referred to our department. Magnetic resonance imaging (MRI) revealed a tumor compressing the T11-T12 spinal canal and extensively invading the left thoracic cavity to form a giant paravertebral mass. Schwannoma was diagnosed after intraoperative pathological examination, in which tumor cells were immunoreactive to S100 and Sox10 but negative for smooth muscle actin (SMH). Intraspinal mass resection through the posterior approach and extraspinal chest mass resection under video-assisted thoracoscopy through the left lateral approach were performed simultaneously, and instrumentation was used to maintain thoracic spinal stability. CONCLUSION: In patients with large schwannomas, customized treatment plans are crucial. Tailoring the approach to an individual's specific condition by considering factors such as tumor size and location is essential for optimal outcomes.

Transcranial Corticospinal Motor-Evoked Potentials in Cases of Ventral and Ventrolateral Intradural Extramedullary Cervical Spinal Cord Tumors.

Background and Objectives: We studied the clinical significance of an amplitude decrement and disappearance alarm criteria in transcranial motor-evoked potential (MEP) monitoring during surgeries on extramedullary tumors at the cervical spine with reference to postoperative morbidity. Material and Methods: We diagnosed and surgically treated fourteen patients with intradural extramedullary ventral or ventrolateral lesions to the cervical spinal cord in the Clinic of Neurosurgery at the University Hospital St Ivan Rilski from January 2018 to July 2022. Eight cases were diagnosed with schwannoma, and the remaining six had meningiomas. The follow-up period for neurological assessment was six months. Results: A decrease in the intraoperative transcranial MEPs of 50% or more compared to baseline in two cases (14.3%) resulted in an immediate postoperative motor deficit. One patient demonstrated full neurological recovery within six months, while the other exhibited only partial improvement. In six cases (42.9%) with preoperative motor deficits, tumor resection and decompression of the cervical spinal cord led directly to an increment of the transcranial MEPs by more than 20%. Postoperatively and at the 6-month follow-up, these patients showed recovery from the preoperative deficits. In the remaining cases, MEPs were stable during surgery with no clinical deterioration of the motor function. Conclusions: The decremented MEP criteria corresponded to postoperative motor deficit, whereas the improvement of the same parameters after decompression implied future recovery of preoperative motor deficits. The combination of different MEP criteria is likely to be helpful when tailored to a specific case of ventral or ventrolateral extramedullary lesions in the cervical spine.

Primary schwannoma of the thyroid gland: analysis of case characteristics and review of the literature.

BACKGROUND: To improve the characteristics of primary thyroid schwannomas (PTS) and to provide reference basis for clinical diagnosis and treatment. METHODS: PubMed was searched for case reports of PTS up to December 2022 using the search terms "Thyroid nerve sheath tumor" or "Thyroid schwannoma" or "Thyroid Neurilemmoma", respectively. 34 cases were screened. RESULTS: PTS can occur at any age, nodules averaged 3.9 cm. The most common symptoms were voice change and dysphagia. Fine needle aspiration cytology showing spindle-shaped cells should be considered for schwannoma. Most cases underwent thyroid lobectomy or nodule removal with a good prognosis. Tissue types with both Antoni A and Antoni B features are common. Positive immunohistochemical staining for S-100 protein, CD34 and waveform proteins helped confirm the diagnosis. CONCLUSIONS: Positive immunohistochemistry for S-100 and wave proteins helps confirm the diagnosis. Preoperative diagnosis is challenging, but pathology and immunohistochemical staining are the gold standard for diagnosis. The first choice of treatment is surgical resection of the nodules, the prognosis is good.

Transoral diode laser-assisted resection of a tongue base schwannoma.

Schwannomas are benign peripheral nerve sheath tumours with a low risk of malignant transformation. About 25%-40% are in the head and neck region with the posterior third of the tongue being a rather rare site of its growth, and a lesion at this site is understandably difficult to approach and treat. Being benign and encapsulated, surgical excision is in the mainstay of treatment. Symptoms can range from a globus pharyngeus and dysphagia to airway compromise depending on the size and site. Traditionally, a paramedian lip split approach with paramedian mandibulotomy and mandible swing may be used. However, some recent reports of the use of carbon dioxide laser and robotic surgery for tongue base lesions are seen in the literature. Our case report is a unique addition to the management strategies for such tongue base lesions as we employed diode 980 nm laser using a minimally invasive transoral approach with a successful outcome.

A Rare Case of a Gigantic Retroperitoneal Schwannoma.

Introduction: Schwannomas (Schs) are benign tumor masses that rarely occur intra-abdominally and rarely reach larger diameters. When present, they occur as rare solitary nerve sheath tumors of peri-neural Schwann cells. Schwannoma mostly affects the nerves of the extremities, trunk, or the head and neck region. They are more common in female patients, mostly among patients between the third and fifth decade. They occur spontaneously but could also be found in association with a group of genetic autosomal dominant disorders called type 2. When present intra-abdominally, schwannomas grow slowly without significant clinical signs and symptoms. Clinical importance is presented in cases of occupying intra-abdominal space and impingement of surrounding structures, which causes intermittent pain. Only 0.5-5% of all retroperitoneal tumors are schwannomas and their malignant transformation is very rare. Case report: The authors present a case of a large intra-abdominal schwannoma in a 70-year-old female patient. She underwent CT scanning due to refractory left-sided subcostal pain, which revealed a large tumor mass in the left-sided hemiabdomen. Preoperative cytologic biopsy confirmed Sch. The patient underwent an MRI scan upon admission to our department, which revealed the origin of the tumor at the left-sided L3 level and intra-abdominal tumor spreading with the largest diameter of 25 cm. The patient underwent multidisciplinary surgical excision, confirmed by MRI scan in a period of five months postoperatively. Conclusions: Its rare presentation leads to the necessity to adequately evaluate such patients, especially to avoid any hidden diagnosis which might lead to further complications. The goal of a multidisciplinary approach should be emphasized as maintaining a good postsurgical condition without neurological deficits.

Thoracoscopic resection of a giant esophageal schwannoma: A case report and review of literature.

INTRODUCTION: Benign esophageal tumors are uncommon, accounting for approximately 2% of esophageal tumors. Esophageal schwannoma is a much rarer solid tumor with few cases reported in the literature. Open surgery is the surgical approach of choice for the treatment of esophageal tumors. With the advent of thoracoscopy, more and more countries are adopting a thoracoscopic approach to treat esophageal tumors, but there is still no clear surgical standard or modality for the treatment of esophageal tumors. PATIENT CONCERNS: A 50-year-old woman was admitted to our hospital. Over the past 2 months, her clinical presentation has included progressively worse swallowing disorder and weight loss. Gastroscopy showed an elevated lesion with a smooth surface visible 18 cm out from the incisors. An electron circumferential ultrasound endoscopy showed a hemispherical bulge with a smooth surface 18 to 23 cm from the incisor; the bulge originated from the intrinsic muscular layer and showed a heterogeneous mixed moderate ultrasound with a little blood flow signal and blue-green elastography in 1 of the sections measuring approximately 4 cm × 3 cm. Chest computed tomography (CT) showed a mass-like soft tissue shadow in the upper esophagus measuring approximately 39 mm × 34 mm, with a CT The lumen was compressed and narrowed, and the lumen of the upper part of the lesion was dilated, and the adjacent trachea was compressed and displaced to the right. INTERVENTIONS: After completion of the examination, assisted by artificial pneumothorax and thoracoscopic resection of esophageal masses were performed. DIAGNOSIS AND OUTCOMES: Postoperative pathology report: Mesenchymal-derived tumor (esophagus), combined with immunohistochemical staining results and morphologic features supported schwannoma. The patient's postoperative course was calm. The patient's postoperative dysphagia subsided. CONCLUSION: We describe a case of successful treatment of a schwannoma of the upper esophagus using artificial pneumothorax-assisted VATS. The combined use of Sox10 and S100 helps to improve the sensitivity and specificity of schwannoma diagnosis. Damage to the esophageal lining was avoided by mixed thoracoscopic and endoscopic exploration. This approach can also be applied to benign esophageal tumors in the thoracic and subthoracic segments, leading to better minimally invasive results.

Cochlear Implantation Outcomes in Patients With Sporadic Inner Ear Schwannomas With and Without Simultaneous Tumor Resection.

OBJECTIVES: Describe a single institution's cochlear implant outcomes for patients with inner ear schwannomas (IES) in the setting of various tumor management strategies (observation, surgical resection, or stereotactic radiosurgery [SRS]). STUDY DESIGN: Single-institution retrospective review. PATIENTS: Patients diagnosed with isolated, sporadic IES who underwent cochlear implantation (CI). INTERVENTIONS: CI with or without IES treatment. MAIN OUTCOME MEASURES: Speech perception outcomes, tumor status. RESULTS: Twelve patients with IES underwent CI with a median audiologic and radiologic follow-up of 12 months. Six patients underwent complete resection of the tumor at the time of CI, four underwent tumor observation, and two underwent SRS before CI. At 1 year after CI for all patients, the median consonant-nucleus-consonant (CNC) word score was 55% (interquartile range, 44-73%), and the median AzBio sentence in quiet score was 77% (interquartile range, 68-93%). Overall, those with surgical resection performed similarly to those with tumor observation (CNC 58 versus 61%; AzBio in quiet 74 versus 91%, respectively). Patients who underwent tumor resection before implantation had a wider range of speech performance outcomes compared with patients who underwent tumor observation. Two patients had SRS treatment before CI (10 months previous and same-day as CI) with CNC word scores of 6 and 40%, respectively. CONCLUSIONS: Patients with IES who underwent CI demonstrated similar speech performance outcomes (CNC 56% and AzBio 82%), when compared with the general cochlear implant population. Patients who underwent either tumor observation or surgical resection performed well after CI.

Narrow-band imaging to enhance intraneural dissection in head and neck schwannoma surgery: a quantitative evaluation.

OBJECTIVE: The objective of this study was to assess the utility of narrow-band imaging (NBI) for improving intraneural dissection during gross total resection of head and neck schwannoma. Specifically, we aimed to quantitatively evaluate whether NBI can enhance the identification of pseudocapsule and true capsule within the tumor. METHODS: Nine schwannoma surgery cases conducted between February 2018 and October 2022 were retrospectively analyzed. The surgical procedures followed established principles with a specific focus on utilizing NBI to distinguish between the pseudocapsule and true capsule. Intraneural dissection was performed by searching for a tumor surface with a fascicle-free window, followed by longitudinal incision of the pseudocapsule. NBI was used to distinguish between the pseudocapsule and true capsule. Surgical views were captured under both white light (WL) illumination and NBI for further analysis. The brightness and contrast of the pseudocapsule and true capsule were quantitatively measured using ImageJ and were compared. RESULTS: Under NBI, the pseudocapsule consistently appeared greenish-gray, whereas the true capsule exhibited a white appearance. Quantitative analysis revealed a statistically significant difference (p < 0.0001) in brightness between the pseudocapsule (mean grayscale value 52.1, 95%CI; 46.4-75.3) and true tumor capsule (mean grayscale value 120.8, 95%CI; 155.7-109.0) under NBI. Conversely, there was no statistically significant difference in the brightness of these structures under WL (p = 0.2067). NBI also showed significantly higher contrast between the two structures than did WL (contrast 73.6, 95%CI; 53.1-89.5 vs. 30.9, 95%CI; 1.0-47.5, p = 0.0034). Further spectral analysis revealed that the most substantial difference in brightness between the pseudocapsule and the true tumor capsule was observed in the red spectrum, with a difference in brightness of -0.6 (95%CI; -16.8-14.8) under WL and 83.5 (95%CI; 50.3-100.0) under NBI (p < 0.0001). CONCLUSION: NBI proved to be a valuable tool for enhancing the identification of pseudocapsule and true capsule during intraneural dissection in head and neck schwannoma surgery. The improved contrast and membrane visibility offered by NBI might have the potential to reduce postoperative neurological deficits and improve surgical outcomes. Further research is warranted to validate our findings and explore the broader applications of NBI in schwannoma surgery.

Is It Time for a Paradigm Shift in the Surgical Management of Trigeminal Schwannomas? Evaluating the Role of the Transorbital Approach: An Anatomo-Clinical Study and Systematic Literature Review.

BACKGROUND: Endoscopic transorbital approach emerged in recent years as an effective, minimally invasive route to access Meckel's cave area. Several case series proved its effectiveness in the surgical treatment of trigeminal schwannomas. This route provides the advantages of a minimally invasive approach associated with low morbidity rates. In this anatomo-clinical study we illustrate the usefulness of the superior eyelid transorbital approach for the surgical treatment of trigeminal schwannoma guiding the clinical applicability of the anatomical findings into real surgical practice. METHODS: Superior eyelid transorbital endoscopic approach was performed on 8 cadaveric specimens, and the surgical results were confirmed in a retrospective review of all the surgical cases of transorbital surgery performed by the senior authors providing an illustrative case. Finally, we performed a literature review of all the case series of trigeminal schwannomas operated through an endoscopic transorbital approach. RESULTS: Stepwise dissection was divided in 3 phases: skin, endo-orbital, and endocranial. The illustrative case provided demonstrate gross total resection of a cavernous sinus type trigeminal schwannomas treated through this route. Literature review revealed 68 cases of trigeminal schwannomas that were successfully treated using the transorbital approach. CONCLUSIONS: The endoscopic transorbital approach may offer a valuable alternative for the surgical treatment of trigeminal schwannomas. This technique provides a minimally invasive, direct and natural "interdural" route to the lateral wall of the cavernous sinus and Meckel's cave.