Cranial Nerve Sheath Research Articles

Metastasis Associated in Colorectal Cancer 1 (MACC1) mRNA Expression Is Enhanced in Sporadic Vestibular Schwannoma and Correlates to Deafness.

Vestibular schwannoma (VS) are benign cranial nerve sheath tumors of the vestibulocochlear nerve. Their incidence is mostly sporadic, but they can also be associated with NF2-related schwannomatosis (NF2), a hereditary tumor syndrome. Metastasis associated in colon cancer 1 (MACC1) is known to contribute to angiogenesis, cell growth, invasiveness, cell motility and metastasis of solid malignant cancers. In addition, MACC1 may be associated with nonsyndromic hearing impairment. Therefore, we evaluated whether MACC1 may be involved in the pathogenesis of VS. Sporadic VS, recurrent sporadic VS, NF2-associated VS, recurrent NF2-associated VS and healthy vestibular nerves were analyzed for MACC1 mRNA and protein expression by quantitative polymerase chain reaction and immunohistochemistry. MACC1 expression levels were correlated with the patients' clinical course and symptoms. MACC1 mRNA expression was significantly higher in sporadic VS compared to NF2-associated VS (p < 0.001). The latter expressed similar MACC1 concentrations as healthy vestibular nerves. Recurrent tumors resembled the MACC1 expression of the primary tumors. MACC1 mRNA expression was significantly correlated with deafness in sporadic VS patients (p = 0.034). Therefore, MACC1 might be a new molecular marker involved in VS pathogenesis.

Extracranial Facial Nerve Schwannoma-Histological Surprise or Therapeutic Planning?

Schwannomas (neurilemomas) are benign, slow-growing, encapsulated, white, yellow, or pink tumors originating in Schwann cells in the sheaths of cranial nerves or myelinated peripheral nerves. Facial nerve schwannomas (FNS) can form anywhere along the course of the nerve, from the pontocerebellar angle to the terminal branches of the facial nerve. In this article, we propose a review of the specialized literature regarding the diagnostic and therapeutic management of schwannomas of the extracranial segment of the facial nerve, also presenting our experience in this type of rare neurogenic tumor. The clinical exam reveals pretragial swelling or retromandibular swelling, the extrinsic compression of the lateral oropharyngeal wall like a parapharyngeal tumor. The function of the facial nerve is generally preserved due to the eccentric growth of the tumor pushing on the nerve fibers, and the incidence of peripheral facial paralysis in FNSs is described in 20-27% of cases. Magnetic Resonance Imaging (MRI) examination is the gold standard and describes a mass with iso signal to muscle on T1 and hyper signal to muscle on T2 and a characteristic "darts sign." The most practical differential diagnoses are pleomorphic adenoma of the parotid gland and glossopharyngeal schwannoma. The surgical approach to FNSs requires an experienced surgeon, and radical ablation by extracapsular dissection with preservation of the facial nerve is the gold standard for the cure. The patient's informed consent is important regarding the diagnosis of schwannoma and the possibility of facial nerve resection with reconstruction. Frozen section intraoperative examination is necessary to rule out malignancy or when sectioning of the facial nerve fibers is necessary. Alternative therapeutic strategies are imaging monitoring or stereotactic radiosurgery. The main factors which are considered during the management are the extension of the tumor, the presence or not of facial palsy, the experience of the surgeon, and the patient's options.

Surgical treatment of multiple plexiform schwannomas arising from the superficial radial nerve: a case report

Schwannoma, or neurilemmoma, is a benign neoplasm that arises from Schwann cells, which surround peripheral, cranial, and autonomic nerve sheaths. Schwannoma has been reported to occur mainly as a singular lesion of the sacral nerve or sciatic nerve in young adults. Plexiform schwannoma, a subtype of schwannoma, is a rare neoplasm known to account for 2% to 5% of total schwannomas. Schwannoma of the upper extremities is relatively rare and is reported to occur mostly in the ulnar nerve. We report, with a literature review, a case of 4.2-cm and 2.8-cm symptomatic multiple plexiform schwannomas that occurred in the superficial radial nerve and were treated without neurologic sequelae by surgical resection.

Cranial nerve and intramedullary spinal malignant peripheral nerve sheath tumor associated with neurofibromatosis-1

Background: Malignant peripheral nerve sheath tumors (MPNSTs) are uncommon but aggressive neoplasms associated with radiation exposure and neurofibromatosis Type I (NF1). Their incidence is low compared to other nervous system cancers, and intramedullary spinal lesions are exceedingly rare. Only a few case reports have described intramedullary spinal cord MPNST.Case Description: We describe the clinical findings, management, and outcome of a young patient with NF1 who developed aggressive cranial nerve and spinal MPNST tumors. This 35-year-old patient had familial NF1 and a history of optic glioma treated with radiation therapy (RT). She developed a trigeminal MPNST that was resected and treated with RT. Four years later, she developed bilateral lower extremity deficits related to an intramedullary cervical spine tumor, treated surgically, and found to be a second MPNST.Conclusion: To the best of our knowledge, this is the first report of cranial nerve and intramedullary spinal MPNSTs manifesting in a single patient, and only the third report of a confined intramedullary spinal MPNST. This unusual case is discussed in the context of a contemporary literature review.

Cranial and Spinal Malignant Peripheral Nerve Sheath Tumor: A Pathological Enigma.

Objective Malignant peripheral nerve sheath tumor (MPNST) arises from nerve sheaths, mostly seen in peripheral nerves but rare in craniospinal nerves. The information available in the literature to build up treatment strategy and improve clinical outcomes is scarce. We are reviewing cases from our institute, with emphasis on radiological features for early differentiation from its benign variants. Methods We analyzed pathologically diagnosed cases retrospectively from January 2007 to December 2018 at our institute. Clinicoradiological details and treatment parameters were collected from medical records for evaluation. Each case was contacted telephonically for final clinical follow-up at the time of writing the manuscript. Results A total of seven cases of MPNST were diagnosed in the last 10 years. It included four intracranial and three spinal cases. The mean age for the cohort was 34.3 years, with five females. We could achieve gross total resection (GTR) and subtotal resection in four (57.1%) and two (28.6%) cases, respectively. We could achieve an overall survival of 57.1% in the average follow-up of 28.2 months (range: 8–84 months). Conclusion MPNST is a rare tumor with a bad prognosis. Radical surgical resection is the mainstay of the treatment, but it is not always possible to achieve it because of the inaccessible location and large size of lesions. Preoperative diagnosis is challenging; however, few radiological findings may give a clue toward it. As a disease entity overall, it has a poor outcome with a high rate of fatality.

Intraparotid Facial Nerve Schwannoma: A Report of Two Cases

ABSTRACT Schwannoma is a benign, asymptomatic, solitary, and encapsulated tumor that grows slowly from peripheral, autonomic, or cranial nerve sheaths. The origin of the schwannomas in the facial nerve is rare and they tend to occur in the intratemporal part of the nerve. An intraparotid facial nerve schwannoma is usually a painless, slow-growing mass like the other benign parotid tumors. In this case report, we will discuss the clinical presentation, management, and outcome of two patients with intraparotid facial nerve schwannoma. How to cite this article: Topuz MF, Genç O, Kadioglu N, et al. Intraparotid Facial Nerve Schwannoma: A Report of Two Cases. Int J Otorhinolaryngol Clin 2020;12(1):4–7.

English

Schwannomas are rare benign tumours arising from neuroectodermal Schwann cells. They can arise from cranial, intraspinal, peripheral and autonomic nerve sheaths. Schwannomas represent 1 - 8 % of head and neck tumours. They constitute 25 – 40 % of extracranial tumours in head and neck region.1 Among the schwannomas arising in head and neck region those arising intraorbitally are very rare. The most common benign intra orbital tumours are haemangiomas. They can arise as localised forms or in association with Neurofibromatosis-1 (NF1). In patients with neurofibromatosis-type 1 or in patients with family history of NF, the risk of developing orbital schwannoma is 1.5 %. Schwannomas constitute 1 - 6.5 % of intra orbital tumours.2-6 Of these tumours those undergoing cystic changes are still rare. The most common cystic lesions in the orbit are dermoid cysts or mucoceles.

Malignant tumor of the peripheral nerve sheath in a left Whippet canine kidney

Background: Malignant tumors of the peripheral nerve sheath (MTPNS`s) are considered rare tumors that can affect soft tissues. In dogs, the occurrence is more common in the nerves of the brachial plexus, but they can affect the lumbosacral plexus and cranial nerves. Rarely, they can affect spinal nerves and nerve roots and the urinary tract, especially in kidneys. The present report aims to describe a clinical case of a 10-year-old sterilized female whippet, who had a history of persistent hematuria for months, with subsequent diagnosis of MTPNS as the cause of hematuria.Case: The patient came for evaluation with a history of persistent hematuria. Evaluation of abnormal elements and sedimentation, showed the description of numerous red blood cells and the presence of proteinuria. The abdominal ultrasound revealed a left kidney with enlarged dimensions, irregular contour, loss of corticomedullary definition. The urinary vesicle showed an increase in cellularity. On physical examination, the patient had vital parameters within the normal range. A Snap 4DX® Plus exam was requested, which showed a reaction for Dirofilaria immitis. With this result, it was initially suspected that renal vasculitis. After starting the treatment, the patient started to present normal colored urine. However, after the end of this period, the patient returned to hematuria. After six months of treatment and without justification for the permanence of hematuria, urethrocystoscopy was indicated, which revealed a urinary vesicle with a hemorrhagic focus. A urinary bladder wall biopsy was performed, which showed no changes. Four months after the urethrocystoscopic exam, the patient had her first azotemic crisis. This time that the left renal neoformation observed on ultrasound examination. With the discovery of the origin of the problem, a therapeutic approach could be instituted, consisting of the left nephrectomy. The histopathological analysis showed malignant spindle cell neoplasia. Immunohistochemical analysis in peroxidase revealed positivity for the markers, concluding the diagnosis as a tumor of the peripheral nerve sheath. Seven months after surgery, a new ultrasound examination of the abdominal region, as well as tests for the assessment of renal function, all of which were within normal parameters.Discussion: Most of the MTPNS originate in the peripheral nerves and in the cranial nerve sheath, but it can rarely originate in the abdominal cavity, as in the case reported here, in which the origin was renal. Such neoplasms are not common in dogs, with an incidence of 0.5%. The age of the affected dogs is, on average, nine years for the appearance of the neoplasia, with females with the highest frequency of occurrence. Both data corroborate the patient's age at the time of diagnosis. This is a tumor that is considered to be highly malignant and progressive, which did not occur in the patient in question, since she had a history of persistent hematuria for a long period, with no manifestation of the presence of the tumor on imaging. Still regarding the clinical manifestation of the patient's persistent hematuria, the same occurrence can be observed in a human patient who also reported a history of persistent hematuria and, like the patient in the report, not associated with any other clinical signs. It is important to differentiate this type of neoplasia from the others, because in many cases, the histological patterns are similar, making the performance of immunohistochemistry essential for the diagnosis. Renal MTPNS is rare in humans, and in dogs it is no different. This fact makes it difficult to describe the prognosis. Thus, efforts should be considered for the early diagnosis of peripheral nerve neoplasms, in view of their low response to available halopathic treatments and taking into account the rare aspect and evolution of this disease.

The Schwannoma of the facial nerve in the extra-skull segment – a case report

The aim of the report is to present a rare case of facial schwannoma in the parotid gland. Schwannomas are benign, well-defined tumors arising from Schwann cells that form myelin sheaths of peripheral, cranial or spinal nerves. 25-45% of them are located within the head and neck, mainly in the parapharyngeal space. The intraparotid location is rare. The etiology of cancer is unknown. Preoperative diagnosis, both radiological and cytological, is difficult and often does not give the correct diagnosis. Radiologically, a multiform adenoma is usually suspected, and the fine needle biopsy is non-diagnostic. Due to the rarity and benign nature of the tumor, there is a debate about the need for surgical treatment.

Glymphatic Pathway of Gadolinium-Based Contrast Agents Through the Brain: Overlooked and Misinterpreted.

The "glymphatic system" (GS), a brain-wide network of cerebrospinal fluid microcirculation, supplies a pathway through and out of the central nervous system (CNS); malfunction of the system is implicated in a variety of neurological disorders. In this exploratory study, we analyzed the potential of a new imaging approach that we coined delayed T2-weighted gadolinium-enhanced imaging to visualize the GS in vivo. Heavily T2-weighted fluid-attenuated inversion recovery (hT2w-FLAIR) magnetic resonance imaging was obtained before, and 3 hours and 24 hours after intravenous gadolinium-based contrast agent (GBCA) application in 33 neurologically healthy patients and 7 patients with an impaired blood-brain barrier (BBB) due to cerebral metastases. Signal intensity (SI) was determined in various cerebral fluid spaces, and white matter hyperintensities were quantified by applying the Fazekas scoring system. Delayed hT2w-FLAIR showed GBCA entry into the CNS via the choroid plexus and the ciliary body, with GBCA drainage along perineural sheaths of cranial nerves and along perivascular spaces of penetrating cortical arteries. In all patients and all sites, a significant SI increase was found for the 3 hours and 24 hours time points compared with baseline. Although no significant difference in SI was found between neurologically healthy patients and patients with an impaired BBB, a significant positive correlation between Fazekas scoring system and SI increase in the perivascular spaces 3 hours post injection was shown. Delayed T2-weighted gadolinium-enhanced imaging can visualize the GBCA pathway into and through the GS. Presence of GBCAs within the GS might be regarded as part of the natural excretion process and should not be mixed up with gadolinium deposition. Rather, the correlation found between deep white matter hyperintensities, an imaging sign of vascular dementia, and GS functioning demonstrated feasibility to exploit the pathway of GBCAs through the GS for diagnostic purposes.

Intracranial schwannomas arising from cranial nerves: Case series and review of literature

Tumors arising from the cranial nerve sheath are common intracranial neoplasms, with only few articles describing their imaging characteristics. In this present study of four cases of schwannomas originating from the cranial nerves in the head region, we are discussing the radiological features on imaging with the clinical presentation and contrasting them with other differentials in their respective locations. Magnetic resonance imaging and computed tomography were done in these cases and correlated with clinical and biopsy findings.

MR assessment of pediatric hydrocephalus: a road map.

This study was conducted to design a rational approach to the MR diagnosis of hydrocephalus based on a pathophysiologic reevaluation of its possible mechanisms and to apply it to the different etiological contexts. A review of the literature reports describing new physiologic models of production and absorption and of the hydrodynamics of the CSF was made. Besides the secretion of CSF by the choroid plexuses, and its passive, pressure-dependent transdural absorption (arachnoid villi, dural clefts, cranial, and spinal nerve sheaths), water transporters, aquaporins, allow water (if not ions and organic molecules) to exchange freely between the brain parenchyma and the CSF spaces across the ependymal and the pial interfaces (including the Virchow-Robin spaces). Consequently, the CSF bulk flow is not necessarily global, and situations of balanced absorption-secretion may occur separately in different CSF compartments such as the ventricular, intracranial, or intraspinal CSF spaces. This means that rather than from a hypothetical pressure gradient from the plexuses to the dural sinuses, the dynamics of the CSF depend on the force provided in those different compartments by the arterial systolic pulsation of the pericerebral (mostly), intracerebral, and intraventricular (choroid plexuses) vascular beds. Using MR imaging, diverse varieties of hydrocephalus may tentatively be explained by applying those concepts to the correspondingly diverse causal diseases. Hopefully, this may have an impact on the choice of the treatment strategies also.

Pathways of cerebrospinal fluid outflow: a deeper understanding of resorption.

Cerebrospinal fluid (CSF) absorption has long been held to predominantly entail drainage into the venous outflow system via the intracranial arachnoid granulations. Newer data suggest pathways involving spinal arachnoid granulations and lymphatic channels may also make substantial contributions to CSF outflow. The putative major CSF outflow pathways and their proportionate contribution to CSF absorption were reviewed in this article. CSF is absorbed and drained in bulk not just through cerebral arachnoid granulations (CAG) but also through spinal arachnoid granulations (SAG) and a lymphatic pathway involving egress through cranial and spinal nerve sheaths. The proportions of CSF that efflux through each of these major pathways have yet to be determined with any certainty in humans, though existing evidence (the majority of which is derived from animal studies) suggests that lymphatic pathways may account for up to 50% of CSF outflow-presumably leaving the CAG and SAG to process the balance. Knowledge of the CSF pathways holds implications for our ability to understand, prognose, and even treat diseases related to CSF circulation and so is a matter of considerable relevance to neuroradiology and neurology.

Cranial arachnoid protrusions and contiguous diploic veins in CSF drainage.

Studies have suggested that arachnoid villi or granulations found in the walls of the cranial dural sinuses, olfactory mucosa, and cranial nerve sheaths function as outlets for intracranial CSF. However, their role as CSF outlets has not yet been verified. Here we show that arachnoid protrusions and contiguous diploic veins provide an alternative drainage route for intracranial CSF. Four hundred patients with intact skull, dura mater, and dural sinuses underwent MR imaging to explore arachnoids protruding into the skull and diploic veins. Patients with symptoms of increased intracranial pressure or intracranial hypotension were excluded. For 15 patients undergoing craniotomy, both peripheral and diploic venous blood was collected. Albumin and the CSF-specific biomarkers were measured by enzyme-linked immunosorbent assay. With MR imaging, arachnoid protrusions into the skull and contiguous diploic veins were consistently identified throughout the cranium with their characteristic appearance depending on the cranial region. In addition, elevated amounts of prostaglandin D synthase and cystatin C were confirmed in diploic veins compared with peripheral venous blood. Diploic veins are distributed ubiquitously throughout the cranium. A portion of the intracranial CSF may be drained through arachnoid protrusions and contiguous diploic veins.

AN UNUSUAL BUMP ON THE HEAD: INTRAEXTRACRANIAL MENINGIOMA PRESENTING INCIDENTALLY

An 82–year–old gentleman presented to hospital following a fall. The patient had no recollection of the fall, and was found conscious sometime later on the floor by the neighbours. At...

Primary intraocular ancient schwannoma: A case report and review of the literature

Schwannomas comprise 8% to 10% of all primary intracranial tumors. Primary intraorbital schwannomas are rare, accounting for 1% to 2% of all intracranial tumors. Schwannomas arise from Schwann cells in the myelin sheaths of sensory and cranial nerves. We present the case of a 56-year-old white man blind since 1970 who presented to an outside hospital for a painful right eye. Physicians identified no clinical or radiologic features of neurofibromatosis. The patient underwent enucleation; the final pathologic diagnosis was ancient schwannoma. We describe herein a case of intrascleral schwannoma with ancient changes arising within the globe of the right eye occupying the subretinal space and completely replacing the vitreous body.

Extent of resection and early postoperative outcomes following removal of cystic vestibular schwannomas: surgical experience over a decade and review of the literature

Vestibular schwannomas (VSs) are benign tumors of the eighth cranial nerve sheath, representing approximately 6%-8% of all newly diagnosed brain tumors, with an annual incidence of 2000-2500 cases in the US. Although most of these lesions are solid, cystic vestibular schwannomas (CVSs) compose 4%-20% of all VSs and are commonly larger at the time of presentation. The authors present their experience with the operative management of CVSs, including surgical approach, extent of resection, and postoperative facial nerve outcomes. The literature pertaining to clinical and histopathological differences between CVSs and their solid counterparts is reviewed. The University of Southern California Department of Neurosurgery database was retrospectively reviewed to identify patients who had undergone resection of a VS between 2000 and 2010. One hundred seventy-nine patients with VS were identified. Patients with CVSs were the subject of the present analysis. Diagnosis of a CVS was made based on MRI findings. Clinical and neuroimaging data, including pre- and postoperative assessments and operative notes, were collected and reviewed. Twenty-three patients, 14 men (61%) and 9 women (39%), underwent 24 operations for CVSs. These patients composed 12.8% of all cases of VS. Patient ages ranged from 28 to 78 years (mean 55 years), and the mean maximal tumor diameter was 3.6 cm (range 2.0-4.0 cm). Patients most frequently presented with headache, hearing loss, vertigo, and dizziness. Preoperative facial numbness was reported in 44% of patients. Among the 24 cases, 13 were treated with retrosigmoid craniotomy and 11 via a translabyrinthine approach. Complete resection was achieved in 11 patients (48%), subtotal resection (STR) in 8 patients (35%), and near-total resection (NTR) in 4 patients (17%). Facial nerve outcomes were available in all except one case. Good facial nerve outcomes (House-Brackmann [HB] Grades I-III) were achieved in 82% of the patients who had undergone either NTR or STR, as compared with 73% of patients who had undergone gross-total resection (GTR; p > 0.05, Fisher exact test). In comparison, 83% of patients with solid VSs had a good HB grade (p = 0.38, Fisher exact test), although this finding did not reach statistical significance. Complications included wound infection (2 patients), delayed CSF leakage (1 patient), and a delayed temporal encephalocele following a translabyrinthine approach and requiring surgical repair (1 patient). Cystic vestibular schwannoma represents a clinical and surgical entity separate from its solid counterpart, as demonstrated by its more rapid clinical course and early surgical outcomes. Facial nerve grades may correlate with the degree of tumor resection, trending toward poorer grades with more significant resections. Although GTR is recommended whenever possible, performing an STR when facial nerve preservation is in jeopardy to improve facial nerve outcomes is the preferred strategy at the authors' institution.

Clinical study of 7 cases of missed diagnosis of micro-tumor of cranial nerve sheath and literature review

Objective To analyze the clinical characteristics of the rare micro-lower cranial nerve sheath tumor,and investigate the clinical symptoms,early treatment options,as well as surgical elements/effectiveness.Methods Seven missed diagnoses of micro-lower cranial nerve sheath tumor admitted to our department from October 1999 to August 2009 were analyzed retrospectively.Diagnosis,clinical characteristics,early treatment options,surgical elements and effectiveness were summarized and analyzed in combined with literature review.Results In this group of patients,there were 5 glossopharyngeal nerve sheath tumors,1 vagus nerve sheath tumor and 1 hypoglossal nerve sheath tumor.Total resections were achieved in all of the patients.Postoperative complications included 1 case of transient mild paralysis,2 cases of hoarseness and 1 case of dysphagia.Conclusions For patient with lower cranial nerve symptoms,nerve sheath tumors should be taken into consideration.Early diagnosis and effective surgery will contribute to patient's treatment and rehabilitation. Key words: Micro; Lower cranial nerve; Sheath tumor

Anterior Cranial Fossa and Ethmoid Sinus Schwannoma: Case Report

Objective: Schwannomas arise from the nerve sheaths of cranial nerves, most commonly from vestibular. They are rare in the region of anterior cranial fossa and ethmoid sinus, where they are very similar to meningeoma or neuroblastoma. A hypothesis on the possible origin of subfrontal schwannoma is that it is associated with meningeal branches of ethmoidal nerves.

Peripheral and Cranial Nerve Sheath Tumors—A Clinical Spectrum

To analyze the incidence of nerve sheath tumors in a tertiary care hospital over a period of 5years and review the literature. Medical case records from last 5years were retrieved and histopathology and operative details were studied in a retrospective analysis. There is a slight male preponderance when it comes to nerve sheath tumors and acoustic schwannomas accounted for the largest fraction among schwannomas. Nerve sheath tumors include a wide spectrum of schwannomas, neurofibromas and malignant peripheral nerve sheath tumors. Hence combination of clinical, pathological and surgical expertise is needed to diagnose accurately.