Parapharyngeal space tumors: Anatomical and image analysis findings

Cervical approach for prestyloid parapharyngeal pleomorphic adenoma resection

OBJECTIVE

To describe the key points of cervical resection for prestyloid parapharyngeal pleomorphic adenoma and to discuss the role of modern imaging.

OBSERVATION

Retrospective case series of 10 patients (4 women and 6 men, age 29-63 years) with prestyloid parapharyngeal pleomorphic adenoma with 2 to 8cm largest diameter on MRI, consecutively resected via a cervical approach between 2000 and 2020 in a French tertiary university referral care center. Seven patients had a minimum 10 years' follow-up, and one was lost to follow-up before the fifth postoperative year. Peri- and postoperative complications comprised great auricular nerve transection without subsequent symptomatic neuroma (2 patients), associated transoral approach to free the upper pole of the adenoma (2 patients), capsule effraction (3 patients), and hematoma (1 patient). There were no cases of facial paresis or palsy, other cranial nerve impairment, trismus, auriculotemporal or first-bite syndrome. One of the three patients with capsule effraction showed local recurrence at month 17.

CONCLUSION

In agreement with previous reports, the present case series confirmed the role of the cervical approach to resect prestyloid parapharyngeal pleomorphic adenoma, and hence the need to continue teaching it.

Parapharyngeal Space Ganglioneuroma: Clinical Experience and Review of the Literature

Ganglioneuroma is a rare benign tumor originating in the sympathetic ganglia, composed of differentiated ganglion cells, nerve sheath cells, and nerve fibers, which tend to occur in the posterior mediastinum, adrenal gland, retroperitoneal, and other locations, occurring in the head and neck is relatively rare, and parapharyngeal space involvement is extremely rare. In our report, we present 2 adult male patients whose preoperative imaging and fine needle cytology did not confirm the diagnosis of a parapharyngeal space mass and who completely resected the tumor through a combined cervical and oral approach. Finally, pathology confirmed ganglioneuroma; we also reviewed the English articles on parapharyngeal ganglioneuroma over the past 40 years, and summarized the diagnostic and treatment characteristics of parapharyngeal ganglioneuroma in combination with our cases to improve understanding of the disease.

Nasal Endoscopic Incision and Drainage Transnasal Retropterygoid Approach to Upper Parapharyngeal Abscess: A Novel Technique

Parapharyngeal infection is a well-known disease of otorhinolaryngologists. Rapid onset, short duration, severe symptoms, and manifestations such as sore throat and dysphagia are common characteristics treated primarily by surgical incision and drainage. Traditional surgical approaches encompass endoscopic transoral/nasal, transparotid, transcervical, or a combination thereof. We report a novel technique of nasal endoscopic incision and drainage transnasal retropterygoid approach to an upper parapharyngeal abscess. This report presents a case of a 14-year-old man presented with severe right neck and head pain, who was found to have an upper parapharyngeal abscess during a nasal endoscopic parapharyngeal exploration via a retropterygoid approach. The intraoperative frozen section revealed chronic mucosal inflammation and mild to moderate dysplasia of the squamous epithelium, but no carcinoma.

Differentiation of neurogenic tumours and pleomorphic adenomas in the parapharyngeal space based on texture analysis of T2WI

BACKGROUND

The purpose of this study was to identify neurogenic tumours and pleomorphic adenomas of the parapharyngeal space based on the texture characteristics of MRI-T2WI.

METHODS

MR findings and pathological reports of 25 patients with benign tumours in the parapharyngeal space were reviewed retrospectively (13 cases with pleomorphic adenomas and 12 cases with neurogenic tumours). Using PyRadiomics, the texture of the region of interest in T2WI sketched by radiologists was analysed. By using independent sample t-tests and Mann‒Whitney U tests, the selected texture features of 36 Gray Level Co-Occurrence Matrix (GLCM) and Gray Level Dependence Matrix (GLDM) were tested. A set of parameters of texture features showed statistically significant differences between the two groups, which were selected, and the diagnostic efficiency was evaluated via the operating characteristic curve of the subjects.

RESULTS

The differences in the three parameters - small dependence low level emphasis (SDLGLE), low level emphasis (LGLE) and difference variance (DV) of characteristics - between the two groups were statistically significant (P < 0.05). No significant difference was found in the other indices. ROC curves were drawn for the three parameters, with AUCs of 0.833, 0.795, and 0.744, respectively.

CONCLUSIONS

There is a difference in the texture characteristic parameters based on magnetic resonance T2WI images between neurogenic tumours and pleomorphic adenomas in the parapharyngeal space. For the differential diagnosis of these two kinds of tumours, texture analysis of significant importance is an objective and quantitative analytical tool.

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.

A Rare Case of Extracranial Schwannoma of the Hypoglossal Nerve Located in the Parapharyngeal Space Mimicking a Deep Neck Abscess

Schwannomas are neurogenic benign tumors originating from the myelin sheath of peripheral nerves, and hypoglossal Schwannomas account for 5% of nonvestibular ones. Extracranial localizations are substantially rare, especially those affecting exclusively the parapharyngeal space; for this reason, the retrostyloid neoformations could initially masquerade as a carotid tumor or deep organized neck abscess. The purpose of this report is to highlight the importance of a multidisciplinary approach in the correct management of differential diagnosis.

Transoral Approach to Parotid Tumors: A Review of the Literature

Different surgical techniques have been proposed for parapharyngeal space tumors, including transcervical, transparotid, trans-mandibular, infratemporal, and transoral. The choice of the correct approach depends on the size, localization and nature of the tumor. The transoral approach can be used for benign prestyloid masses, such as tumors of the deep lobe of the parotid gland. It guarantees a short hospitalization without skin scars. The narrowed access represents the main limitation of this technique. This review will summarize and analyze the current knowledge about the transoral approach to parotid lesions. Thirty-seven studies were included in a qualitative and quantitative synthesis. The novelty of this review is the quantitative analyses of the clinical data reported in the included studies.

Surgical Management of Parapharyngeal Tumors: Our Experience

Context Tumors of parapharyngeal space (PPS) are rare and histologically diverse. The management of these tumors requires diligent assessment and planning with due consideration of various anatomical and pathological aspects of the lesion.

Aims This retrospective study aims to present our experiences in the clinical and pathological aspects of PPS tumors with a critical evaluation of management.

Settings and Design Retrospective analytical study.

Methods and Material The electronic medical records of 60 cases of PPS tumors, managed surgically from 2007 to 2017, were reviewed and analyzed using SPSS 22 software. The mean follow-up duration was 44 months.

Results The mean age was 45 years with a male-to-female ratio of 1.7 (38:22). The majority of the tumors were benign (71.7%) and the most common presentation being upper neck mass or oropharyngeal mass. Histologically, neurogenic tumors were most common (43.3%) PPS tumors, followed by tumors of salivary gland origin. Magnetic resonance imaging was used as a diagnostic modality in 70% of cases, and computed tomography scan and positron emission tomography/CT were used in 26.7 and 3.3% of cases, respectively. In our study, the diagnostic accuracy of fine-needle aspiration cytology was 71% for benign and 47% for malignant lesions. The most common approach for surgery used was transcervical (72%).

Conclusion The study reveals that cranial nerve palsy is the most common complication associated with PPS tumors. Completely resected, malignant tumors originating within PPS have a good prognosis, as compared with tumors extending or metastasized to PPS.

Endoscopic Transoral Approach for Resection of Basal Cell Adenoma Arising in Parapharyngeal Space

Objectives  The clinical and radiological characteristics of the basal cell adenoma (BCA) and its association with the internal carotid artery (ICA) in the parapharyngeal space (PPS), have not been sufficiently explored. This study aims to analyze the characteristics of patients with BCA arising in the PPS and to evaluate the feasibility of a total resection via an endoscopic transoral corridor. Design and Main Outcome Measures  The clinical, radiological, and histopathological characteristics of four patients with BCA arising in the PPS were retrospectively analyzed. The endoscopic transoral approach was performed for resection of BCA. Its technical nuances, perioperative comorbidities, and outcomes are introduced. Results  The clinical presentation, symptoms, and signs of patients with BCA are variable. The tumor was lateral to the ICA in two patients and anterior to the ICA in the remaining two. All four BCA were successfully removed en bloc ( n  = 3) or by piecemeal ( n  = 1) via an endoscopic transoral approach. The ICA was not injured, and no additional nerve damage, venous bleeding, postoperative infection, or salivary gland fistula were encountered in any of the four patients. Cystic degeneration is the predominant appearance of BCA on MRI; however, they are difficult to differentiate from other lesions arising in the PPS. No recurrence was detected at the time of the study analysis. Conclusion  BCA of the PPS could have variable relationships with the ICA. An endoscopic transoral approach can provide an adequate corridor for total resection of BCA in PPS with seemingly low morbidity.

Giant deep lobe parotid tumor removal via total parotidectomy without mandibulotomy. A simple and safe technique

The transmandibular route is often combined with the transparotid-transcervical approach when extensive surgical field exposure is required, as in the case of deep parotid lobe tumors measuring over 4 cm in size. This procedure implies great morbidity and prolongs surgery time. Furthermore, in cases where additional lip division is performed, the aesthetic outcomes may be poorer. A description is made of the technique used for the removal of giant pleomorphic adenomas of the parapharyngeal space, without mandibulotomy.

Key words:Parapharyngeal space tumor, pleomorphic adenoma, transcervical-transparotid approach, transmandibular approach.

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.

Endoscopic transnasal transmaxillary approach to the upper parapharyngeal space and the skull base

PURPOSE

Treatment of tumors arising in the upper parapharyngeal space (PPS) or the floor of the middle cranial fossa is challenging. This study aims to present anatomical landmarks for a combined endoscopic transnasal and anterior transmaxillary approach to the upper PPS and the floor of the middle cranial fossa and to further evaluate their clinical application.

METHODS

Dissection of the upper PPS using a combined endoscopic endonasal transpterygoid and anterior transmaxillary approach was performed in six cadaveric heads. Surgical landmarks associated with the approach were defined. The defined approach was applied in patients with tumors involving the upper PPS.

RESULTS

The medial pterygoid muscle, tensor veli palatini muscle and levator veli palatini muscle were key landmarks of the approach into the upper PPS. The lateral pterygoid plate, foramen ovale and mandibular nerve were important anatomical landmarks for exposing the parapharyngeal segment of the internal carotid artery through a combined endoscopic transnasal and anterior transmaxillary approach. The combined approach provided a better view of the upper PPS and middle skull base, allowing for effective bimanual techniques and bleeding control. Application of the anterior transmaxillary approach also provided a better view of the inferior limits of the upper PPS and facilitated control of the internal carotid artery.

CONCLUSIONS

Improving the knowledge of the endoscopic anatomy of the upper PPS allowed us to achieve an optimal approach to tumors arising in the upper PPS. The combined endoscopic transnasal and anterior transmaxillary approach is a minimally invasive alternative approach to the upper PPS.

A minimally invasive endoscopic transnasal retropterygoid approach to the upper parapharyngeal space: anatomic studies and surgical implications

BACKGROUND

Surgery remains the mainstay of treatment for lesions in the parapharyngeal space. However, gaining access to the parapharyngeal space is often challenging. In this study we aim to describe a minimally invasive technique of approaching the upper parapharyngeal space through an endoscopic transnasal retropterygoid approach, based on anatomic studies and surgeries.

METHODS

Six fresh human cadaver heads were prepared for anatomic study at the Surgical Neuroanatomy Laboratory of the Center for Cranial Base Surgery within the Department of Neurological Surgery at the University of Pittsburgh School of Medicine. Three clinical cases seen in the Department of Otolaryngology, Eye, Ear, Nose, and Throat Hospital, Shanghai Medical College of Fudan University, were used to illustrate the technique and feasibility of this approach and to assess its indications, advantages, and drawbacks.

RESULTS

The medial pterygoid plate is the primary landmark of the endoscopic transnasal retropterygoid approach to the upper parapharyngeal space. Access to the upper parapharyngeal space could be obtained by removing the mucosa on the medial pterygoid plate and the mucosa below the pharyngeal orifice of the Eustachian tube. The 3 patients in our study tolerated the procedure well and had no serious complications after surgery.

CONCLUSION

The anatomic data and clinical cases in this study confirm that an endoscopic transnasal retropterygoid approach is a feasible and effective surgical treatment for selected tumors in the upper parapharyngeal space.

[Diagnosis and treatment of parapharyngeal space tumors]

The parapharyngeal space extends from the nasopharynx to the oropharynx. It is bordered medially by the pharyngeal wall and the constrictor pharyngis muscles, and laterally by the mandible. One distinguishes between a pre- and a poststyloid space. Tumors of the parapharyngeal space are rare and represent less than 1 % of all head and neck neoplasms. Benign (70-80 %) as well as malignant (20-30 %) tumors arise from different structures of the parapharyngeal space, mainly from salivary glands and nerve structures. Concerning salivary gland tumors, most are pleomorphic adenomas typically appearing in the prestyloid space, whereas the schwannomas that may also arise are located in the poststyloid space. The main symptom is dysphagia, with the tumor generally presenting as a visible bulking of the pharyngeal wall, in rare cases also as an externally visible cervical mass. Treatment is generally surgical resection, particularly in benign tumors, preferably via transcervical access. If R0 resection of malignancies is possible, this should be performed. In malignant lymphomas and nonresectable tumors, primary chemo-, radio-, or combination therapy should be considered after histologic confirmation. For neurogenic tumors, particularly vagal nerve schwannoma and especially in older patients, a wait-and-scan strategy is most favorable, since postoperative vagal palsy is unavoidable with surgical resection. Treatment planning for parapharyngeal space tumors requires good knowledge of topographic anatomy and careful evaluation of imaging findings.

A modified method for locating parapharyngeal space neoplasms on magnetic resonance images: implications for differential diagnosis

The parapharyngeal space (PPS) is an inverted pyramid-shaped deep space in the head and neck region, and a variety of tumors, such as salivary gland tumors, neurogenic tumors, nasopharyngeal carcinomas with parapharyngeal invasion, and lymphomas, can be found in this space. The differential diagnosis of PPS tumors remains challenging for radiologists. This study aimed to develop and test a modified method for locating PPS tumors on magnetic resonance (MR) images to improve preoperative differential diagnosis. The new protocol divided the PPS into three compartments: a prestyloid compartment, the carotid sheath, and the areas outside the carotid sheath. PPS tumors were located in these compartments according to the displacements of the tensor veli palatini muscle and the styloid process, with or without blood vessel separations and medial pterygoid invasion. This protocol, as well as a more conventional protocol that is based on displacements of the internal carotid artery (ICA), was used to assess MR images captured from a series of 58 PPS tumors. The consequent distributions of PPS tumor locations determined by both methods were compared. Of all 58 tumors, our new method determined that 57 could be assigned to precise PPS compartments. Nearly all (13/14; 93%) tumors that were located in the pre-styloid compartment were salivary gland tumors. All 15 tumors within the carotid sheath were neurogenic tumors. The vast majority (18/20; 90%) of trans-spatial lesions were malignancies. However, according to the ICA-based method, 28 tumors were located in the pre-styloid compartment, and 24 were located in the post-styloid compartment, leaving 6 tumors that were difficult to locate. Lesions located in both the pre-styloid and the post-styloid compartments comprised various types of tumors. Compared with the conventional ICA-based method, our new method can help radiologists to narrow the differential diagnosis of PPS tumors to specific compartments.

Head and neck fascia and compartments: no space for spaces

An accurate understanding of the arrangement of cervical fascia and its associated compartments is essential for differential diagnosis, predicting the spread of disease, and surgical management. The purpose of this detailed review is to summarize the anatomic, clinical, and radiological literature to determine what is known about the arrangement of cervical fascia and to highlight controversies and consensus. The current terminology used to describe cervical fascia and compartments is replete with confusing synonyms and inconsistencies, creating important interdisciplinary differences in understanding. The term "spaces" is inappropriate. A modified nomenclature underpinned by evidence-based anatomic and radiologic findings is proposed. This should not only enhance our understanding of cervical anatomy but also facilitate clearer interdisciplinary communication.

Pediatric parapharyngeal lesions: criteria for malignancy

INTRODUCTION

Parapharyngeal space (PPS) pediatric lesions represent a heterogeneous group of uncommon neoplasms of both benign and malignant nature. These tumors tend to be locally advanced by the time they are diagnosed; consequently, an early presumptive diagnosis of malignancy is of utmost importance.

OBJECTIVE

To highlight the occurrence of malignant PPS tumors in pediatric population, to determine their incidence and to describe probable warning clues for diagnosis.

PATIENTS AND METHODS

The charts of 23 pediatric patients with PPS swellings were retrospectively reviewed to analyze clinical and pathologic data. We describe possible criteria to suspect malignancy by clinical and radiological examination.

RESULTS

Twenty-three patients presented with neoplastic lesions in the PPS, benign tumors in 43.5% and malignant in 56.5%. Malignancy was suspected in 13 cases according to combined clinical and radiological criteria: a painless intraoral and neck swelling in children below one year old, presentation with cranial nerve palsy, nasopharyngeal mucosal or sub-mucosal irregular lesion, the presence of multiple lymph nodes with no evidence of infection, and adjacent bony skull base destruction with intracranial extension.

CONCLUSION

Occurrence of malignancy in PPS tumors in the pediatric population is not uncommon. Clinicians should deliberately look for associated secondary signs that predict malignancy. The surgeon must understand the pathological spectrum of tumors of this space and the proper use of imaging studies to make a preoperative diagnosis. This allows for planning of a sound surgical approach and a proper preoperative counseling.

Anesthetic management of schwannoma mimicking carotid body tumor

Schwannomas are rare and slow-growing neurogenic tumors for which surgery is the standard of care. However, the anesthetic management of these tumors can be challenging. This case report describes the anesthetic management of a patient who underwent carotid endarterectomy and excision of a presumed carotid body tumor. Histopathologic examination showed that the excised tissue was a schwannoma, which in this location can mimic a carotid body tumor. The relevant literature is also reviewed.

Pseudo-lyre sign

Carotid body tumours cause characteristic splaying of the internal and external carotid arteries, known as ‘Lyre Sign’. Vagal paragangliomas are rare tumours that arise from glomus cells along the length of the vagus nerve. We present a case in which a vagal paraganglioma has arisen from the vagus nerve at the carotid bifurcation, and has mimicked the ‘Lyre Sign’ of a carotid body tumour.