Extracranial schwannoma in the carotid space: A retrospective review of 91 cases

A Retrospective Analysis of High Resolution Ultrasound Evaluation of the "Split Fat Sign" in Peripheral Nerve Sheath Tumors

Peripheral nerve sheath tumors (PNST) comprise schwannomas and neurofibromas. The finding of increased adipose tissue around benign PNSTs has been described as the "split fat sign" on magnetic resonance imaging exams, which is suggestive of an intramuscular or intermuscular location of the tumor. However, few studies have described this sign as a salient ultrasound feature of PNSTs. The main purpose of this study was to retrospectively evaluate the presence of increased fatty tissue deposition around benign PNSTs diagnosed by high-resolution ultrasound. In addition, we aimed to corroborate the presence of vascularization around the affected area. A retrospective analysis of ten cases of PNSTs and two cases of post-traumatic neuromas diagnosed by high-resolution ultrasound was performed with a Logiq® P8 ultrasound with a 2-11 MHz multifrequency linear probe L3-12-D (central frequency: 10 MHz). Localized types of neurofibromas and schwannomas in any location were seen as predominantly hypoechoic tumors with an oval or fusiform shape. Exiting and entering nerves (tail sign) were observed in six cases, showing localized lesions both in intermuscular and subcutaneous locations. The presence of increased hyperechoic tissue (the split fat sign) was noted in cases of solitary intermuscular and intramuscular peripheral nerve sheath tumors, mainly the schwannomas. Though small tumors did not demonstrate the tail sign, the increase in adipose tissue and vascularity on US was well demonstrated. In conclusion, the nerve in continuity forms the basis of the ultrasonographic diagnosis of PNSTs. However, high-resolution US can convincingly demonstrate the increased presence of fat in the upper and lower poles as well as circumferentially in intermuscular or intramuscular benign PNSTs.

Topohistology of the cranial nerves IX-XII at the cranial base and upper parapharyngeal space: A histological study using human fetuses

The topographical relationships among the lower cranial nerves, internal carotid artery (ICA), and internal jugular vein (IJV) in the upper parapharyngeal neurovascular bundle remain obscure. Thus, details of the anatomy were examined in human fetus histology. We observed the horizontal histological sections from 20 midterm (9-18 weeks) and 12 near-term (28-40 weeks) fetuses. At the external skull base, the glossopharyngeal nerve crosses the anterior aspect of the IJV to reach the medially located Hyrtl's fissure in the petrous temporal bone. The nerve crossed the anterior aspect of the ICA medially near or below the first cervical nerve root. Below the hypoglossal nerve canal, the accessory nerve crosses the anterior or posterior aspects of the IJV and moves laterally. During the half-spiral course, the hypoglossal nerve was tightly attached to the posterolateral-anterior aspects of the vagus nerve and surrounded by a common nerve sheath. The glossopharyngeal ganglia sometimes extended inferiorly to the level of the hypoglossal nerve canal but were absent along the inferior course. The inferior vagal ganglion rarely extends above the occipital condyle. The superior cervical sympathetic ganglion occasionally extends above the first cervical nerve root. The IJV (or ICA) descends to the lateral (or medial) margins of the parapharyngeal neurovascular bundle. The glossopharyngeal (or accessory) nerve crosses the ICA (or IJV) to exit the bundle at the base of the skull (or below the hypoglossal nerve canal). The glossopharyngeal and vagus inferior ganglia differ at each site.

Utility of sodium fluorescein in recurrent cervical vagus schwannoma surgery

Background

Cervical schwannoma is a rare neoplasm that usually occurs like a nondolent lateral neck mass but when growing and symptomatic requires radical excision. Sodium fluorescein (SF) is a dye that is uptake by schwannomas, which makes it amenable for its use in the resection of difficult or recurrent cases.

Methods

We describe the case of a patient presenting with a recurrence of a vagus nerve schwannoma in the cervical region and the step-by-step technique for its complete microsurgical exeresis helped by the use of SF dye.

Results

We achieved a complete microsurgical exeresis, despite the presence of exuberant perilesional fibrosis, by exploiting the ability of SF to stain the schwannoma and nearby tissues. That happens due to altered vascular permeability, allowing us to better differentiate the lesion boundaries and reactive scar tissue under microscope visualization (YELLOW 560 nm filter).

Conclusion

Recurrent cervical schwannoma might represent a surgical challenge due to its relation to the nerve, main cervical vessels, and the scar tissue encompassing the lesion. Although SF can cross both blood-brain and blood-tumor barriers, the impregnation of neoplastic tissue is still greater than that of nonneoplastic peripheric tissues. Such behavior may facilitate a safer removal of this kind of lesion while respecting contiguous anatomical structures.

Quantification of vessel separation using the carotid-jugular angle to predict the nerve origin of neck peripheral nerve sheath tumours: a pooled analysis of cases from the literature and a single-center cohort

BACKGROUND

Postoperative nerve palsy is a major complication following resection of neck peripheral nerve sheath tumours (PNSTs). Accurate preoperative identification of the nerve origin (NO) can improve surgical outcomes and patient counselling.

MATERIAL AND METHODS

This study was a retrospective cohort and quantitative analysis of the literature. The authors introduced a parameter, the carotid-jugular angle (CJA), to differentiate the NO. A literature review of neck PNST cases from 2010 to 2022 was conducted. The CJA was measured from eligible imaging data, and quantitative analysis was performed to evaluate the ability of the CJA to predict the NO. External validation was performed using a single-centre cohort from 2008 to 2021.

RESULTS

In total, 17 patients from our single-centre cohort and 88 patients from the literature were analyzed. Among them, 53, 45, and 7 patients had sympathetic, vagus, and cervical nerve PNSTs, respectively. Vagus nerve tumours had the largest CJA, followed by sympathetic tumours, whereas cervical nerve tumours had the smallest CJA ( P <0.001). Multivariate logistic regression identified a larger CJA as a predictor of vagus NO ( P <0.001), and receiver operating characteristic (ROC) analysis showed an area under the curve (AUC) of 0.907 (0.831-0.951) for the CJA to predict vagus NO ( P <0.001). External validation showed an AUC of 0.928 (0.727-0.988) ( P <0.001). Compared with the AUC of the previously proposed qualitative method (AUC=0.764, 0.673-0.839), that of the CJA was greater ( P =0.011). The cut-off value identified to predict vagus NO was greater than or equal to 100°. Receiver operating characteristic analysis showed an AUC of 0.909 (0.837-0.956) for the CJA to predict cervical NO ( P <0.001), with a cut-off value less than 38.5°.

CONCLUSIONS

A CJA greater than or equal to 100° predicted a vagus NO and a CJA less than 100° predicted a non-vagus NO. Moreover, a CJA less than 38.5 was associated with an increased likelihood of cervical NO.

Schwanoma of the cervical sympathetic chain: A case report

INTRODUCTION AND IMPORTANCE

Any cranial, peripheral, or autonomic nerve in the body can give rise to a benign, slowly growing encapsulated nerve sheath tumor known as a schwannoma. The majority of parapharyngeal extracranial schwannomas, which typically have vagal origins, are located there. When they first appear, most swannomas are asymptomatic. Vague symptoms may be present in some people.

CASE PRESENTATION

She is a 35-year-old Ethiopian female patient presented with left lateral neck swelling of 11 years duration which was initially small but gradually increases to attain the current size. Associated with the swelling she had had dull aching pain in the same area. On examination, there was a 5*4 cm non-tender hard mass over the left cervical area which had an irregular border, fixed to the underlying structure but not to the overlying skin. Investigations were suggestive of cervical schwannoma. Finally, the patient was operated on and discharged improved.

CLINICAL DISCUSSION

The majority of schwannomas are solitary, however they can also be multifocal and plexiform when they are associated with neurofibromatosis. Schwannomas are typically asymptomatic until late in the course of the disease, when neurologic symptoms brought on by compression of the adjacent nerve may develop. The most popular diagnostic techniques for schwannomas include computed tomography (CT), MRI, ultrasonography, and fine-needle aspiration cytology (FNAC).

CONCLUSION

Cervical sympathetic chain schwannomas are uncommon tumors that typically manifest as asymptomatic unilateral neck masses without Horner's syndrome. For the diagnosis of cervical sympathetic chain schwannoma, imaging tests are crucial.

Transoral Approach to Parapharyngeal Space Tumours: Preliminary Reports from a Single-Centre Retrospective Analysis

Purpose: The aim of this study is to identify certain parapharyngeal space tumours with specific characteristics that can be treated successfully through an endoscopically assisted transoral approach (EATA). Methods: Nine patients with PPS tumours underwent surgery through an EATA between 2003 and 2021. All patients underwent clinical examination and fibrolaryngoscopy. Preoperative CT and/or MRI was performed on all patients. Results: All the patients were successfully treated through an endoscopically assisted transoral approach. Histological examination revealed five pleomorphic adenomas, two schwannomas, one ectopic thyroid gland and one lipoma. The only long-term sequelae observed was Horner syndrome in the two schwannomas arising from the carotid space. The mean hospitalisation time was 2.6 days, while the mean follow-up time was of 9.7 years. Conclusions: An endoscopically assisted transoral approach (EATA) is a valid technique for treating benign capsulated tumours of the true PPS and some benign capsulated tumours of the superomedial aspect of the carotid space.

Evaluation of Carotid Space Schwannoma Using Ultrasonography: Characteristics and Role in Defining the Nerve of Origin

OBJECTIVES

We aimed to evaluate the ultrasonography (US) characteristics of carotid space schwannoma and their role in identifying the nerve of origin.

METHODS

This prospective study enrolled patients with cervical carotid space schwannoma accessible by US. The US characteristics of vagus nerve schwannomas (VNSs) and sympathetic nerve schwannomas (SNSs) were assessed; a carotid space schwannoma was defined as a VNS if the tumor originated in the mid-vagal region and an SNS if it arose posterior to the intact vagus nerve, displacing the vagus nerve anteriorly.

RESULTS

Twenty patients with carotid space schwannoma were enrolled. The vagus and sympathetic nerves were identified as the nerve of origin in 12 and 8 patients, respectively. VNSs were centered at levels II, III, and IV in 5, 3, and 4 patients, respectively, while SNSs were centered at levels II (7 patients) and IV (1 patient) (P = .105). The maximal diameters were 3.2 and 4.8 cm for VNSs and SNSs, respectively (P = .011). Internal vascularity was absent and low in 9 and 3 VNSs, respectively, and low and intermediate in 4 SNSs each (P = .002). Twelve patients with VNSs underwent active surveillance without immediate surgery; no adverse events occurred during the 55.2-month follow-up period. Eight patients with potential SNSs underwent surgery, confirming the sympathetic nerve as the nerve of origin.

CONCLUSIONS

US facilitates identification of the nerve of origin in cervical carotid space schwannoma. VNSs are more frequent in infrahyoid locations and tend to be smaller in size with lower vascularity compared with SNSs on US.

Thyroid-Bed Schwannoma Mimicking a Thyroid Neoplasm: A Challenging Diagnosis: Report of a Case and Literature Review

Background: Schwannomas, also called neurinomas, are rare benign tumors of the neural cells that can develop from the sheaths of nervous structures of several districts, although the most frequent sites are the cranial nerves (25%–45%). Rarely, cases show neck schwannomas in the thyroid parenchyma, while the cases of thyroid-bed schwannomas mimicking a thyroid-gland lesions are anecdotal. Methods: We report the case of a 70-year-old man with a preoperative-imaging diagnosis of a thyroid neoplasm, confirmed as Thyr 4 by fine-needle cytology. Results: During surgery, an extra-thyroidal lesion was discovered, determined to be a neck schwannoma through definitive pathology. A literature review of cases of thyroid-bed-lesion schwannomas misinterpreted as thyroid neoplasms was carried out. Conclusions: In the case of suspicious extra-thyroidal lesions, we advocate for a close routine cooperation between the cytologist, the radiologist, and the surgeon in the attempt to reach an accurate preoperative diagnosis.

Benign Peripheral Non-cranial Nerve Sheath Tumors of the Neck

Benign peripheral non-cranial nerve sheath tumors are rare lesions, including both schwannomas and neurofibromas. These tumors arise from Schwann cells, and may originate from any peripheral, cranial, or autonomic nerve. Most of them are localized and sporadic but multifocal systemic forms can occur. Cervical sympathetic chain, brachial plexus, cervical plexus and spinal roots and nerves are the major nerve systems commonly affected. Dumbbell-shaped intra- and extradural tumors occur most commonly in the cervical spine, as well as purely extradural and paravertebral tumors. The management of these tumors has improved greatly owing to the developments in imaging techniques and surgical innovations such as endoscopically assisted approaches and robotic surgery. Microsurgical intracapsular excision of the tumor helped by the use of intraoperative fluorescent dyes and intraoperative neurophysiological monitoring minimize postoperative neural deficit, since most schwannomas are encapsulated. Most tumors can be removed with a low rate of complications and recurrence. Radiotherapy should be considered for growing lesions that are not amenable to surgery. In asymptomatic patients, observation and serial scans is an option for elderly infirm patients.

The first experience of ultrasound-guided percutaneous microwave ablation for extracranial schwannoma of the cervical vagus nerve in carotid space and treatment response evaluation with contrast-enhanced imaging

Schwannoma is a benign tumor that originates from Schwann cells in the nerve sheathing of cranial, other peripheral, or autonomic nerves. Patients often present with painless mass as the chief complaint. The main symptoms of this tumor are related to its size and specific nerve origin. At present, the pretreatment diagnosis is mainly made by ultrasound, CT, MR, or biopsy, and the main treatment is surgical resection. We reported a new treatment method for cervical schwannoma in a 65-year-old woman with a history of non-small cell lung cancer (NSCLC). When the patient's neck mass was initially found with hoarseness and severe cough, it was considered as cervical lymph node metastasis of lung cancer due to her medical history. And she was diagnosed with schwannoma by core-needle biopsy after chemotherapy failed and the tumor shrank after the radiotherapy with no improvement of the clinical symptoms. After considering the physical condition, the patients were treated in our department for minimal invasiveness treatment. The patient was definitively diagnosed with cervical vagus schwannoma and was treated with ultrasound-guided microwave ablation of schwannoma under general anesthesia with systematic evaluation and improved preoperative examination. Her condition was stable, and the symptoms of severe cough disappeared after anesthesia resuscitation and the ablation. The tumor continued to shrink after the operation with no recurrence of cough symptoms. Ultrasound-guided percutaneous microwave ablation (MWA) for cervical vagus schwannomas might be a minimally invasive, effective, and relatively safe alternative to conventional treatment for those patients with severe symptoms.

A Huge Carotid Space Schwannoma Arising from The Cervical Sympathetic Chain - A Case Report

The Rationale:

Although 25%–45% of schwannomas are originating from the neck, carotid space schwannomas are extremely rare.

Patient Concerns:

We report a rare case of huge-sized schwannoma in a 20-year-old student who presented with a symptomless large carotid space mass.

Diagnosis:

Cervical magnetic resonance imaging (MRI) with contrast revealed a huge, well-defined mass measuring 13.7 cm × 6.4 cm × 4.1 cm. Cervical MRI along with brain MRI were consistent with neurofibromatosis type II.

Treatment and Outcomes:

Preoperative tracheostomy and wide local excision of schwannoma via a transcervical approach were performed with nerve preservation.

Takeaway Lessons:

The scarceness of cervical sympathetic chain schwannoma made this case of our patient very interesting to report. Moreover, our patient's huge tumour size is extremely rare, and we could not find any similar cases in the literature.

Multimodal ultrasound imaging of primary thyroid schwannoma: A case report

RATIONALE

Primary schwannoma of the thyroid gland is very rare, and its preoperative diagnosis is difficult.

PATIENT CONCERNS

We report the case of a thyroid nodule in an 18-year-old woman, who presented with a mass in her left neck with stiffness and normal thyroid function. However, the patient complained of numbness in her left upper extremity, and ultrasound (US) features were suspicious of malignancy.

DIAGNOSES

Multimodal US imaging was performed using B-mode, color doppler, ultrasonic elastography (UE), and contrast-enhanced ultrasound (CEUS). CEUS revealed heterogeneous enhancement and "target sign" within the tumor. The nodule was suspicious for malignancy and classified as TI-RADS 4b, while the elasticity values measured by UE indicated a benign lesion. Fine needle aspiration (FNA) was subsequently performed in the markedly contrast-enhanced area for biopsy. Cytological results revealed a benign schwannoma.

INTERVENTION

The patient underwent left lobe resection. Postoperative pathology confirmed it to be a primary benign schwannoma of the thyroid.

OUTCOMES

After thyroidectomy, the patient was followed-up with US. At present, all laboratory tests and thyroid imaging are normal, and the numbness of the left upper limb has disappeared.

LESSONS

The combination of different US modalities is useful for the diagnosis of thyroid lesions. FNA performed under CEUS guidance improves the accuracy of biopsy sampling.

Cytologic and histological features of rare nonepithelial and nonlymphoid tumors of the thyroid

Thyroid tumors can be classified into epithelial, nonepithelial, and nonprimary lesions. Nonepithelial thyroid tumors are rare. They can be of primary origin within the thyroid gland, arise secondary to contiguous growth from adjacent tissues, or represent metastatic disease. The incidence of nonepithelial tumors of the thyroid is only 1% to 2%, most of which are lymphomas; the remainder includes mesenchymal and histiocytic tumors. This review examines the cytohistological features of various nonepithelial and nonlymphoid tumors of the thyroid, including vascular lesions, neural tumors (including granular cell tumor and paraganglioma), smooth muscle tumors, solitary fibrous tumor, histiocytic neoplasms (eg, Langerhans cell histiocytosis and Rosai-Dorfman disease), and follicular dendritic cell sarcoma. Their differential diagnosis is discussed, including recommendations to prevent the pitfall of mistaking these rare tumors for more common epithelial thyroid neoplasms.

Selection of the surgical approach for lesions with parapharyngeal space involvement: A single-center experience on 153 cases

BACKGROUND

The parapharyngeal space (PPS) can harbor a variety of tumors that can be approached through a wide spectrum of surgical routes. A decisional algorithm on the surgical approach to resect PPS lesions was tested in terms of reliability by retrospectively applying it to a large series of patients.

METHODS

Patients treated at the Unit of Otorhinolaryngology - Head and Neck Surgery of the University of Brescia, Italy, for tumor or tumor-like lesions involving the PPS between October 1986 and July 2019 were included in the retrospective analysis. Tumor characteristics, clinical presentation, diagnostic work-up, type of resection, surgical approach, and oncologic and morbidity outcomes were reviewed. Reliability of the algorithm was calculated as the number of cases in which the expected approach was confirmed/total number of cases × 100.

RESULTS

The analysis included 153 patients. Most lesions (64.1%) were benign. The most frequent complaint at presentation was unilateral oropharyngeal medialization (47.1%), followed by neck/parotid swelling (41.2%). Ninety-two (61.3%) lesions were excised through an enucleation/extracapsular dissection. Wide-margin resection and compartmental resection were performed in 17 (11.3%) and 41 (27.3%) patients, respectively. A single-corridor approach was employed in 132 (87.4%) cases. Combinations of multiple corridors were adopted in 19 (12.6%) patients. Reliability of the decision-making algorithm was 91.2%. Capsular integrity and margin status affected prognosis of pleomorphic adenomas and PPS malignancies, respectively.

CONCLUSION

The proposed decision-making algorithm can reliably guide approach selection, which should primarily aim at ensuring intact-capsule excision of benign lesions suspicious for pleomorphic adenomas and clear-margins resection of PPS malignancies.

Schwannoma of the thyroid bed: A case report and review of the literature

RATIONALE

Schwannomas involving the thyroid gland are very rare and only a few cases have been reported in the literature. However, previous reports did not distinguish between thyroid bed schwannomas and intrathyroidal schwannomas. Here, we report a thyroid bed schwannoma mimicking a malignant thyroid nodule and review the literature on thyroid bed schwannomas.

PATIENT CONCERNS

A 33-year-old woman presented at our hospital with mild neck swelling.

DIAGNOSIS

Thyroid ultrasound revealed a well-defined, oval-shaped, markedly hypoechoic solid nodule with echogenic foci suggesting macro- and microcalcifications in the left thyroid gland. The lesion was considered a "highly suspicious" intrathyroidal nodule, based on the guidelines for the assessment of thyroid nodules. Fine needle aspiration was performed twice, but the cytological results were nondiagnostic.

INTERVENTIONS

Left thyroidectomy was performed, and schwannoma of the thyroid bed was confirmed on histopathologic analysis.

OUTCOMES

The patient was in a stable condition after surgery, and the thyroid function test results were within the normal range.

LESSONS

Diagnosis of a schwannoma of the thyroid bed is challenging because its incidence is extremely low, and it is often misdiagnosed as an intrathyroidal nodule on ultrasonography. Therefore, it is advisable to adopt a diagnostic strategy to perform additional core needle biopsy in cases of thyroid nodules with nondiagnostic fine needle aspiration results and to consider the location of the lesion more carefully to determine the suitable therapy.

Anterolateral Approach for Retrostyloid Superior Parapharyngeal Space Schwannomas Involving the Jugular Foramen Area: A 20-Year Experience

BACKGROUND

Schwannomas encompassing the superior parapharyngeal space are challenging lesions because of the anatomical complexity of this region and the frequent involvement of the neurovascular structures of the jugular foramen. The purpose of this study is to report the technical aspects and the advantages of the anterolateral approach, here proposed for schwannomas of this complex area.

METHODS

The main steps of the anterolateral approach are described in detail, along with the results of a consecutive series of 38 patients with a retrostyloid superior parapharyngeal schwannoma involving the jugular foramen operated on by means of this route between 1999 and 2019.

RESULTS

The supine position is generally preferred. The medial border of the sternocleidomastoid muscle, mastoid tip, and superior nuchal line are the landmarks for the hockey-stick skin incision. The accessory nerve is retrieved and mobilized cranially. Detachment of the sternocleidomastoid, digastric, and nuchal muscles allows for a 180° exposure of the extracranial side of the jugular foramen. Three working corridors, namely the pre-carotid, pre-jugular, and retro-jugular, allow access to the deeper part of the jugular foramen area and the superior parapharyngeal space. In the present series, a gross total resection was achieved in 89.4% of the patients. Three recurrences occurred after an average follow-up of 80.5 ± 51 months.

CONCLUSIONS

The anterolateral approach is highly effective in the treatment of retrostyloid superior parapharyngeal space schwannomas involving the jugular foramen. Its simplicity of execution, versatility, and very low morbidity are among its main strengths.