Clinical diagnosis and treatment outcomes for parapharyngeal space schwannomas: A single-institution review of 21 cases

A comparative study of transcervical, endoscope-assisted transcervical, and endoscope-assisted transoral resection of retrostyloid space schwannomas

BACKGROUND

The aim of this retrospective study was to compare the efficacy of transcervical (TC), endoscope-assisted transoral (TO), and endoscope-assisted TC for resection of retrostyloid space schwannomas.

METHODS

The study included patients who underwent complete resection of schwannomas by only one surgical approach. The data we collected included tumor size, estimated blood loss, postoperative complications, and so on. Statistical analysis was performed using one-way analysis of variance and Fisher's exact test.

RESULTS

The study collected 85 patients with tumors mostly located at the oropharyngeal level who were followed up 6 months at least. The results showed that endoscope-assisted TO had certain advantages over others. Additionally, the endoscope-assisted TO set the lowest incidence of neurological complications.

CONCLUSION

Our findings demonstrate that for team with rich experience in the skull base surgery, endoscope-assisted TO is a superior option compared to the other two groups for resection of retrostyloid space schwannomas, with the better preservation of neurological function.

Differentiation between pleomorphic adenoma and schwannoma in the parapharyngeal space: histogram analysis of apparent diffusion coefficient

OBJECTIVES

To elucidate the differences between pleomorphic adenomas and schwannomas occurring in the parapharyngeal space by histogram analyses of apparent diffusion coefficient (ADC) values measured with diffusion-weighted MRI.

METHODS

This retrospective study included 29 patients with pleomorphic adenoma and 22 patients with schwannoma arising in the parapharyngeal space or extending into the parapharyngeal space from the parotid region. Using pre-operative MR images, ADC values of tumor lesions showing the maximum diameter were measured. The regions of interest for ADC measurement were placed by contouring the tumor margin, and the histogram metrics of ADC values were compared between pleomorphic adenomas and schwannomas regarding the mean, skewness, and kurtosis by Wilcoxon's rank sum test. Subsequent to the primary analysis which included all lesions, we performed two subgroup analyses regarding b-values and magnetic field strength used for MRI.

RESULTS

The mean ADC values did not show significant differences between pleomorphic adenomas and schwannomas for the primary and subgroup analyses. Schwannomas showed higher skewness (p = 0.0001) and lower kurtosis (p = 0.003) of ADC histograms compared with pleomorphic adenomas in the primary analysis. Skewness was significantly higher in schwannomas in all the subgroup analyses. Kurtosis was consistently lower in schwannomas but did not reach statistical significance in one subgroup analysis.

CONCLUSIONS

Skewness and kurtosis showed significant differences between pleomorphic adenomas and schwannomas occupying the parapharyngeal space, but the mean ADC values did not. Our results suggest that the skewness and kurtosis of ADC histograms may be useful in differentiating these two parapharyngeal tumors.

Triggered episodic vestibular syndrome and transient loss of consciousness due to a retrostyloidal vagal schwannoma: a case report

Background

Various conditions may trigger episodic vertigo or dizziness, with positional changes being the most frequently identified condition. In this study, we describe a rare case of triggered episodic vestibular syndrome (EVS) accompanied by transient loss of consciousness (TLOC) linked to retrostyloidal vagal schwannoma.

Case description

A 27-year woman with known vestibular migraine presented with a 19-month history of nausea, dysphagia, and odynophagia triggered by swallowing food and followed by recurrent TLOC. These symptoms occurred independently of her body position, resulting in a weight loss of 10 kg within 1 year and in an inability to work. An extensive cardiologic diagnostic work-up undertaken before she presented to the neurologic department was normal. On the fiberoptic endoscopic evaluation of swallowing, she showed a decreased sensitivity, a slight bulging of the right lateral pharyngeal wall, and a pathological pharyngeal squeeze maneuver without any further functional deficits. Quantitative vestibular testing revealed an intact peripheral-vestibular function, and electroencephalography was read as normal. On the brain MRI, a 16 x 15 x 12 mm lesion in the right retrostyloidal space suspicious of a vagal schwannoma was detected. Radiosurgery was preferred over surgical resection, as resection of tumors in the retrostyloid space bears the risk of intraoperative complications and may result in significant morbidity. A single radiosurgical procedure (stereotactic CyberKnife radiosurgery, 1 x 13Gy) accompanied by oral steroids was performed. On follow-up, a cessation of (pre)syncopes was noted 6 months after treatment. Only residual infrequent episodes of mild nausea were triggered by swallowing solid food remained. Brain MRI after 6 months demonstrated no progression of the lesion. In contrast, migraine headaches associated with dizziness remained frequent.

Discussion

Distinguishing triggered and spontaneous EVS is important, and identifying specific triggers by structured history-taking is essential. Episodes being elicited by swallowing solid foods and accompanied by (near) TLOC should initiate a thorough search for vagal schwannoma, as symptoms are often disabling, and targeted treatment is available. In the case presented here, cessation of (pre)syncopes and significant reduction of nausea triggered by swallowing was noted with a 6-month delay, illustrating the advantages (no surgical complications) and disadvantages (delayed treatment response) of first-line radiotherapy in vagal schwannoma treatment.

Resection of Primary and Recurrent Parapharyngeal Space Pleomorphic Adenomas via a Combined Transcervical-Transparotid Approach: A Case Series

Primary parapharyngeal space tumors are rare, and due to the complex anatomy of the parapharyngeal space, their diagnosis and treatment are challenging. Pleomorphic adenoma is the most common histologic type followed by paragangliomas and neurogenic tumors. They can present as a neck lump or an intraoral submucosal mass with the displacement of the ipsilateral tonsil or might be asymptomatic and discovered incidentally on imaging obtained for other reasons. Magnetic resonance imaging (MRI) with gadolinium is the imaging of choice. Surgery remains the treatment of choice and many approaches have been described. In this study, we present three patients with PPS pleomorphic adenoma (two primary and one recurrent), which were resected successfully with a transcervical-transparotid approach without mandibulotomy. Division of the following anatomical structures: the posterior belly of the digastric muscle, stylomandibular ligament, stylohyoid muscle and ligament, and styloglossus muscle is a very important tip for the surgeons because enables displacement of the mandible providing excellent exposure for complete tumor excision. The only postoperative complication was temporary facial nerve palsy in two patients who fully recovered within two months. The aim of this mini case series is to present our experience, together with some tips and benefits of the transcervical-transparotid approach for the resection of pleomorphic adenomas of the PPS.

Endoscopy-assisted transoral approach for parapharyngeal space tumors: Our experience and a systematic review of the literature

Background

Several approaches have been described for the excision of parapharyngeal space tumors (PPSTs). Advances in endoscopy gave a further stimulus to the use of the transoral route.

Aims

We present our experience with the endoscopy-assisted transoral approach (EATA) in this regard and a review of the most recent literature about EATA for PPSTs excision.

Materials and Methods

We retrospectively analyzed our experience and systematically reviewed the literature about the outcomes of this technique.

Results

Seven PPSTs were completely excised, with three of them requiring a combined transcervical approach. Only one case of postoperative wound dehiscence was registered, and the mean length of stay was 3.9 days. Final histopathological examination confirmed the results obtained with preoperative fine-needle aspiration biopsy in all cases and no recurrences were apparent after a mean follow-up of 28.1 months.

Discussion

Magnetic resonance imaging, the modified Mallampati score and the 8 Ts criteria are useful instruments for the choice of the most appropriate surgical approach.

Conclusion

In light of our experience and following other published series in the literature, we believe that EATA may represent a safe and effective approach for the treatment of the majority of PPSTs.

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.

A rare cause of cervical swelling: Solitary plexiform neurofibroma

INTRODUCTION

Plexiform cervical neurofibromas are benign neoplasm, extremely rare, difficult to diagnose and to manage. Only some cases have been reported in the literature.

CASE PRESENTATION

We report the case of a 60-year-old man admitted for a lateral neck mass, for which the surgical indication was the increase in volume of this mass, as well as the aesthetical impairment, the surgical exploration found the tumor attached to the cervical plexus. The excision of the mass was performed without damaging nerve. The pathological study was in favor of a plexiform neurofibroma.

DISCUSSION

Even though Plexiform cervical neurofibroma are extremely rare, and their diagnosis are not often primary evoked in front of any growing mass of this region, the surgeon must keep in mind the existence of these neoplasms as a differential diagnosis of a neck tumor.

CONCLUSION

Surgery remains the gold standard in the treatment of these locally invasive tumors. It is essential that the surgeon keep in mind the possibility of these tumors as a differential diagnosis of a neck tumor.

The development of a clinical algorithm for the diagnosis of tumours in the parapharyngeal space. A systematic review

INTRODUCTION

Parapharyngeal space (PPS) is defined as a deep space, located around the upper pharynx, in the shape of an inverted pyramid. Primary tumours in this region are rare, accounting for 0.5% of head and neck neoplasms, and most are benign. The objective of this study is to propose a new study algorithm based on a systematic review and our experience.

MATERIALS AND METHODS

A cross-sectional and analytical study was carried out through review of the clinical records of our hospital. Patients with tumours of the parapharyngeal space operated from January 2010 to December 2019 and a systematic review of Pubmed studies from the last 5years were included. We considered clinical signs, diagnostic methods, presumptive diagnosis and histopathological findings. Statistical analysis was performed with STATA v.14 software.

RESULTS

53 of our cases and 1392 from the review were included. The clinical algorithm showed a sensitivity of 76.4% and a specificity of 96.3%, with an AUC of 0.57 for diagnosis.

DISCUSSION

Complementary radiological examinations are essential in the topographic diagnosis of the tumour. Angio-MRI links the tissue of origin of the tumours and provides the highest diagnostic certainty. FNA has some disadvantages in PPS, but it is useful in some patients.

CONCLUSION

The proposed algorithm contributes to obtaining excellent results in the management of these tumours because it turned out to be effective in diagnosis, and this enables improved surgical planning.

First Bite Syndrome: What Neurologists Need to Know

PURPOSE OF REVIEW

Though first bite syndrome is well known in surgical settings, it is not commonly included in the differential for sharp paroxysmal facial pain in the neurology literature. This paper will highlight the clinical features and relevant anatomy of first bite syndrome, with the goal of helping clinicians differentiate this from other similar facial pain disorders.

RECENT FINDINGS

First bite syndrome is severe sharp or cramping pain in the parotid region occurring with the first bite of each meal and improving with subsequent bites. Pathophysiology has been attributed to imbalanced sympathetic/parasympathetic innervation of the parotid gland. This is seen most typically in the post-surgical setting following surgery in the parotid or parapharyngeal region, but neoplastic etiologies have also been reported. It is common for patients to present with concurrent great auricular neuropathy and/or Horner's syndrome. Evidence regarding treatment is limited to case reports/series, however, botulinum toxin injections and neuropathic medicines have been helpful in select cases. It is critical for clinicians to be able to differentiate first bite syndrome from other paroxysmal facial pain. To help with this, we have proposed diagnostic criteria for clinical assessment. Patients often improve gradually over time, but symptomatic treatment with botulinum toxin or neuropathic medicine may be required.

Endoscope-Assisted Resection of a Vagal Neurofibroma Using a Posterior Styloid Approach

It is very challenging to expose and remove tumors above the hard palate in the retrostyloid space using the typical cervical approach. Other approaches, such as the cervical-parotid approach, may result in prominent scars, facial paralysis, or masticatory dysfunction. Here, we report a case of a vagal neurofibroma between the internal carotid artery and internal jugular vein in the retrostyloid space. We used a 3D model to design a surgical approach that reduced the risk to the surrounding vessels and nerves. We performed an endoscope-assisted resection of the tumor using a posterior styloid approach. Following surgery, there were no obvious scars on the face or neck, facial paralysis, or dysphagia, but mild hoarseness.

Resection of Parapharyngeal Space Tumors Located in the Prestyloid Compartment: Efficacy of the Cervical Approach

BACKGROUND

Parapharyngeal space tumors are rare. Among them, tumors in the prestyloid compartment are particularly suitable for surgery; however, there are no detailed reports of such surgery and their features remain unknown.

METHODS

We conducted a retrospective cohort study. For 67 surgical cases of benign tumors in this compartment, we examined the patient and tumor characteristics, fine-needle aspiration cytology (FNAC), and intraoperative details such as surgical approach, use of complete excision, and postoperative complications.

RESULTS

Pleomorphic adenomas (PAs) comprised 73.1% of the lesions. The diagnostic accuracy of FNAC to differentiate benign and malignant tumors was 97.7%. Of the treated lesions, 94.0% were removed via the cervical approach alone, including all PAs. The remaining 6.0% were resected via the cervical-parotid approach. The median operative time and bleeding volume were 89 min and 50 mL, respectively. Operative time using the cervical approach was significantly shorter (p = 0.021). All cases could be treated via complete surgical excision. Postoperative complications occurred in 32.8% of patients, with transient slight facial palsy being the most common. No fatal complications occurred and 92.5% of patients had no sequelae. There was no significant association between complications and surgical approach.

CONCLUSION

Based on diagnosis by FNAC, with a high accuracy rate, most benign prestyloid tumors, especially PAs, were resected using the cervical approach alone, with a shorter operative time and without severe complications.

A rare case of giant retroperitoneal neurilemmoma

Neurilemmoma, also known as schwannoma or neurinoma, is a tumor that originates from neural sheath Schwann cells. Giant neurilemmomas derived from the retroperitoneum have rarely been reported. We herein describe a woman with a giant retroperitoneal neurilemmoma that was initially incorrectly diagnosed as an inflammatory abdominal mass. The tumor extended from the patient's hypogastrium to her pelvic cavity and measured 20 × 15 × 10 cm. The tumor was excised via laparotomy and diagnosed as a retroperitoneal neurilemmoma through histological and immunohistochemical examination. Although rare, particularly in the giant form, neurilemmoma should be considered as an important differential diagnosis in patients with a retroperitoneal tumor or inflammatory abdominal mass. Complete excision should be considered for the potential cure of giant retroperitoneal neurilemmomas.

Endoscopy-assisted transoral resection of a parapharyngeal space schwannoma without mandibular dissection

Of the schwannomas that arise from the parapharyngeal space, those in the high cervical region are particularly invasive, requiring mandibular dissection. Because these tumors are benign, however, excessive surgical invasion and postoperative neurological complications should be avoided. Postoperative dropout symptoms may be avoided by intracapsular extraction, including nerve integrity monitoring (NIM) and narrow-band imaging (NBI). Video laryngoscopy surgery is reported to be useful for transoral resection of pharyngeal and laryngeal tumors. This report describes the transoral removal of a giant schwannoma located in the high cervical region from a 74-years-old man using a surgical support device without mandibular dissection. The tumor was located on the right lateral pharyngeal wall and extended from the upper oropharynx to the hypopharynx while compressing the epiglottis to the skull base. No separation was observed between the internal jugular vein and the internal carotid artery. The tumor was diagnosed as a schwannoma with no malignancy on the basis of the histology of a core needle biopsy (CNB), and was completely and safely removed endoscopically using NIM and NBI, with no need for an external incision or mandibular dissection. This case illustrates that even a huge sympathetic schwannoma located in the parapharyngeal space at a high cervical position can be excised transorally using video-laryngoscopic surgery (TOVS) without mandibular dissection.

Peripheral neck nerve tumor: A 73-case study and literature review

OBJECTIVES

Peripheral neck nerve tumors are rare and mostly benign neoplasms. The exceptional malignant forms are very aggressive, and diagnosis is difficult. The objective of this study was to evaluate diagnostic and therapeutic management and identify possible predictive factors.

MATERIAL AND METHODS

A retrospective study was conducted of 73 patients treated for peripheral neck nerve tumor between 1995 and 2015.

RESULTS

Mean age was 44years. The main presenting symptom was a cervical mass, isolated or associated with signs related to the affected nerve structure. Diagnosis was suspected by slow progression of a firm mass, featuring T1 hyposignal and T2 hypersignal on magnetic resonance imaging. Surgery was performed in 99% of cases, completed by adjuvant chemotherapy in case of malignant neuroblastic tumor. Type 1 neurofibromatosis and sudden increase in mass with or without associated pain suggested malignant transformation. Age below 10years suggested neuroblastic tumor.

CONCLUSION

Neck nerve tumors are very often benign with low degenerative potential. Surgery is the treatment of choice after risk/benefit analysis. However, there is no clearly defined consensus regarding the timing of surgery for these lesions.

Comprehensive Analyses of Intraoral Benign and Malignant Nerve Sheath Tumors: The Rare Disease Entities Revisited

INTRODUCTION

Intraoral benign and malignant nerve sheath tumors (BNST and MNST) are rare tumors with non-specific clinical presentations and represent diagnostic and therapeutic challenges. Current knowledge regarding their demographic, clinicopathological features and treatments remains fragmented.

MATERIALS AND METHODS

The original data about patients diagnosed as intraoral BNST and MNST were retrieved from our disease registry (2005-2017). Comprehensive reviews of English and Chinese literature were performed to collect and analyze the epidemiological, clinicopathological data and treatment outcomes about those published cases.

RESULTS

Thirty-four intraoral BNSTs were found at our institution in the past 13 years. Literature reviews identified 354 intraoral BNSTs in 223 articles and 60 intraoral MNSTs in 50 articles. Most intraoral BNSTs and MNSTs were presented in the second to fifth decade of life. Males outnumbered females in MNSTs, while BNSTs displayed a slight female preponderance. The common sites for intraoral BNSTs were parapharyngeal space followed by tongue, whereas mandible was the most common site for MNSTs. Most intraoral BNSTs were presented as slow-growing, painless mass or swelling, while MNSTs usually appeared as painful and invasive mass with discomfort. Surgical excision was preferred for intraoral BNSTs with excellent prognosis. Complete resection was indicated for intraoral MNST with dismal prognosis as evidenced by much recurrence, metastasis, and death.

CONCLUSION

Intraoral BNST and MNST are rare diseases which should not be ignored when intraoral painless or painful mass/swelling is found. Surgical excision is indicated for intraoral BNST with favorable outcomes. However, further investigations are warranted to optimize the treatment for intraoral MNST to improve its prognosis.

Contemporary management of primary parapharyngeal space tumors

The parapharyngeal space is a complex anatomical area. Primary parapharyngeal tumors are rare tumors and 80% of them are benign. A variety of tumor types can develop in this location; most common are salivary gland neoplasm and neurogenic tumors. The management of these tumors has improved greatly owing to the developments in imaging techniques, surgery, and radiotherapy. Most tumors can be removed with a low rate of complications and recurrence. The transcervical approach is the most frequently used. In some cases, minimally invasive approaches may be used alone or in combination with a limited transcervical route, allowing large tumors to be removed by reducing morbidity of expanded approaches. An adequate knowledge of the anatomy and a careful surgical plan is essential to tailor management according to the patient and the tumor. The purpose of the present review was to update current aspects of knowledge related to this more challenging area of tumor occurrence.

Endoscopic Transvestibular Transmandibular Approach for Trigeminal Schwannoma in Infratemporal Fossa and Parapharyngeal Space

BACKGROUND

Schwannomas that involve the mandibular division of the trigeminal nerve and localize exclusively in the parapharyngeal space (PPS) and infratemporal fossa (ITF) are extremely rare, and a surgical approach to treat such tumors has not been well established.

CASE DESCRIPTION

We present our experience in the treatment of a giant trigeminal schwannoma with wide extension in the ITF and PPS using an endoscopic transvestibular transmandibular approach. The clinical and radiologic findings, preoperative planning, advantages of the surgical approach, and clinical outcome are discussed.

CONCLUSIONS

Schwannomas located in the ITF and PPS are rare benign neoplasms. They are usually detected late after considerable signs and symptoms appear. Preoperative planning is beneficial to individual surgical approach selection. Total surgical excision following careful evaluation of preoperative computed tomography and magnetic resonance images is the treatment of choice. Recurrence is rare after complete excision.