Management of tumors arising from the parapharyngeal space: A systematic review of 1,293 cases reported over 25 years

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.

Comparison of Surgical Outcomes of Robotic and Conventional Approaches in Patients with Pre- and Poststyloid Parapharyngeal Space Tumors

BACKGROUND

Benefits and drawbacks of robotic surgical approaches for parapharyngeal space (PPS) tumors remain undetermined. The purpose of this study is to compare surgical outcomes of PPS tumor patients who underwent robotic surgery with those of patients who received conventional surgical treatment.

PATIENTS AND METHODS

We retrospectively analyzed clinicopathologic data from 136 patients who underwent surgical removal of PPS tumors via conventional or robotic approaches.

RESULTS

We identified PPS tumors in pre- and poststyloid regions in 87 (64%) and 49 (36%) patients, respectively. There were 48 (35.3%) pleomorphic adenomas, 36 (26.5%) schwannomas, and 24 (17.6%) paragangliomas. Conventional surgical techniques were performed in 83 patients, and robotic surgical approaches were administered to 53 patients. Transcervical-parotid and transcervical approaches were most commonly performed in conventional surgery, while transoral and retroauricular approaches were the preferred surgical methods in robotic surgery for pre- and poststyloid PPS tumors, respectively. Robotic surgery resulted in less estimated blood loss during poststyloid PPS tumor surgery. Postoperative cranial nerve complications were noted in 36 of 83 cases (43.4%) in the conventional surgery group and in 17 of 53 cases (32.1%) in the robotic surgery group. Intraoperative tumor spillage of pleomorphic adenoma showed no significant differences between the two groups (13.6% in conventional vs. 15.4% in robotic surgery). The mean follow-up time was 4.9 ± 3.4 years, and recurrences were observed in two patients during follow-up without a significant difference between the two groups (4.5% in conventional vs. 3.8% in robotic surgery).

CONCLUSIONS

Robotic surgery in PPS tumors is feasible through transoral, retroauricular, or combined approaches and provides treatment outcomes comparable to those of conventional open surgery.

Transoral Excision of Parapharyngeal Tumors

OBJECTIVES

The transoral approach for parapharyngeal space tumors has been criticized due to its restrictive exposure and increased rate of vascular and nerve injuries. However, for certain tumors-namely those that are prestyloid, benign, and well-encapsulated-the transoral approach reduces overall morbidity while providing direct access. Transoral surgeons can rely on this approach for select tumors seen clearly on intraoral examination in the bulging lateral pharynx. In this article and with a supplemental operative technique video, we demonstrate our transoral approach in these select patients.

METHODS

We reviewed our 26 cases using this approach and chose a representative case of a 50-year-old man who presented with a large, prestyloid, encapsulated parapharyngeal mass affecting his voice and swallowing. A transoral approach to the parapharyngeal tumor is illustrated.

RESULTS

A vertical curvilinear incision is completed from the hamulus to below the inferior extent of the tumor. Blunt dissection of the tumor capsule proceeds inferiorly. Controlled violation of the tumor capsule can aid in visualization. After tumor delivery, the wound is irrigated and closed.

CONCLUSIONS

In our experience, the transoral approach is an effective method to access well-encapsulated, prestyloid parapharyngeal space tumors. Patient selection is important when considering a transoral approach.

Endonasal endoscopic transpterygoid approach to the upper parapharyngeal space

BACKGROUND

Lesions of the upper parapharyngeal space (UPPS) present a surgical challenge. The objective of this study was to ascertain the feasibility of a novel technique of modified transpterygoid approach to the UPPS.

METHODS

Six fresh cadaveric specimens (12 sides) were dissected, developing a technique that includes en bloc mobilization of the lateral pterygoid plate and muscle to access the UPPS.

RESULTS

Following an endoscopic Denker's approach and the removal of posterolateral wall of the antrum, the lateral pterygoid plate was detached from the pterygoid process. Subsequently, the lateral pterygoid plate and muscle were displaced laterally as a unit, allowing the identification of the posterior trunk of V₃ and the fat in prestyloid compartment. Dissecting off the styloid aponeurosis affords entering the poststyloid UPPS exposing the internal carotid artery, internal jugular vein, and cranial nerves IX to XII.

CONCLUSION

This novel modification of the endonasal transpterygoid approach offers a viable alternative for access to the UPPS.

Preauricular retromandibular trans tympanic plate and styloid process keyhole approach to parapharyngeal lesions: a laboratory study

BACKGROUND

The surgical removal of the infratemporal parapharyngeal lesions (IPL) is challenging due to its anatomical complexity. Previous surgical approaches have often been too invasive and necessitated sacrifice of normal function and anatomical structures, particularly in the retromandibular nerve region. Therefore, we sought to identify an approach corridor to this area that requires less sacrifice and report an innovative approach through a retromandibular fossa route to the IPL.

METHODS

Five cadaveric specimens were dissected bilaterally with a trans-tympanic plate and styloid process approach. These specimens were investigated microanatomically and morphometrically to examine the extent of the approach in the parapharyngeal space. The clinical application of this approach was compared to previous approaches to the IPL used in our clinical series of 20 cases.

RESULTS

Using this novel approach, the inferior alveolar nerve was identified in all specimens, while the chorda tympani and lingual nerve were identified in 6 (60%) and 4 (40%) dissections, respectively. In all specimens, the petrous portion of the internal carotid artery and the exit of the lower cranial nerve were identified. The average length of the exposed lower cranial nerves was 16.6 ± 3.8 mm (range: 11-25 mm).

CONCLUSIONS

The described approach is feasible for accessing the IPL at the retromandibular nerve and is less invasive than conventionally used approaches.

Trans-oral robotic surgery in the management of parapharyngeal space tumors: A systematic review

PURPOSE

To perform a systematic review of studies evaluating Trans-oral Robotic Surgery (TORS) in the treatment of parapharyngeal space (PPS) tumors.

METHODS

A comprehensive electronic search was performed in PubMed/MEDLINE, Cochrane Library, and Google Scholar databases for appropriate published studies. The last search was conducted on November 9, 2019.

RESULTS

Twenty-two studies were included for the systematic review which analyzed a total of 113 patients (median age 53.5, IQR 41.5-58.1). The most common PPS tumor treated with TORS was the pleomorphic adenoma (n = 66; 58.4%). All tumors were successfully resected. The median tumor size was 4.8 cm (n = 73; IQR 3.8-5.4). Combined transcervical (TORS-TC) and transparotid (TORS-TP) approaches were used in 13 (11.5%) and 5 (4.4%) patients, respectively. Capsule disruption was noted in 11 cases (14.5%), while tumor fragmentation was observed in 7 patients (10.3%). The median time of hospitalization was 3 days (n = 79; IQR 2-4.1). Oral diet was possible from the day after surgery in the majority of patients (n = 34, 68%). The most common complication was dysphagia (n = 5, 4.5%).

CONCLUSIONS

This systematic review confirms the safety and feasibility of TORS in the treatment of PPS lesions. Given the low quality of included studies, further evidence is needed in order to establish clinical guidelines.

Endoscopic transvestibular anatomy of the infratemporal fossa and upper parapharyngeal spaces for clinical surgery: a cadaver study

AIMS

To investigate the anatomy of the infratemporal fossa (ITF) and to discuss the practicality of endoscopic transvestibular surgery for an ITF tumor.

METHODS

Five fresh cadaveric specimens (10 sides) with vascular silicone injection were prepared for endoscopic anatomy. A transvestibular vertical incision was made along the ramus of the mandible, and pivotal nerves, arteries, and muscles were exposed to sculpt the anatomic landmarks of the ITF.

RESULTS

The endoscopic transvestibular approach exposed the detailed structure of the ITF. The buccinator muscle and the adjoining superior pharyngeal constrictor muscle shaped the paramedian border of the ITF, while the medial pterygoid muscle (MPM) and the lateral pterygoid muscle formed the lateral border. The ITF was delimited by the skull base in the upper margin, and it was proximal to the parapharyngeal space in the inferior part. The inferior alveolar nerve was the first reference point, and the maxillary artery and the lateral pterygoid muscle were also the landmarks of the ITF. The lingual nerve, the eustachian tube (ET), and the middle meningeal artery were also located in the posterior part of the ITF.

CONCLUSION

The endoscopic transvestibular approach provides a feasible and facile corridor to the ITF. With accurate hemostasis, this approach may provide another option for accessing the ITF for removal of tumors.

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.

Parapharyngeal Space Venous Malformation: An Imaging Mimic of Pleomorphic Adenoma

Venous malformations in the parapharyngeal space are rare and may be challenging to diagnose with imaging secondary to multiple overlapping features with pleomorphic adenoma, which is much more commonly found in this region. While both lesions are T1 isointense and T2 hyperintense relative to skeletal muscle and demonstrate contrast enhancement, more uniform T2 hyperintensity and progressive contrast pooling on delayed postcontrast T1WI may allow the radiologist to include venous malformation in the differential diagnosis. This is important because it has the potential to alter management from surgical resection to observation. The primary aim of this study was to review the imaging appearance of parapharyngeal venous malformations through a retrospective case series.

Transoral robotic resection of benign tumors of the upper aerodigestive tract: Experience of the French group of GETTEC

BACKGROUND

The purpose of this study was to assess the current use of transoral robotic surgery (TORS) in benign tumors of the upper aerodigestive tract through a case series and a literature review.

METHODS

This multicentric retrospective study was conducted in 6 French centers between November 2009 and July 2017.

RESULTS

Twenty-one patients had a TORS resection of a tumor at varied locations with differing histopathologic characteristics. The mean postoperative hospital stay was 6.1 days. Eight patients had nasogastric tubes, which were removed after a mean of 5.6 days. Two patients had a prophylactic tracheostomy for an average of 5.5 days. A third tracheostomy was performed secondarily for postoperative bleeding. No recurrences were observed during the 2-year follow-up.

CONCLUSION

This technique caused few complications and resulted in short hospitalization, with satisfactory functional and recurrence outcomes. However, the risk of bleeding and edema must be considered, and the need for a tracheostomy must be approached wisely.

Basal cell adenoma in the parapharyngeal space resected via trans-oral approach aided by endoscopy: Case series and a review of the literature

RATIONALE

Basal cell adenoma (BCA) is a rare benign salivary gland tumor. It is difficult to be completely resected when arising in parapharyngeal space. A contemporary trend is to develop minimally invasive approaches on the premises of safety and complete resection.

PATIENT CONCERNS

Three patients were referred to our ENT Outpatient Department with the chief complaint of an uncomfortable throat. CT or MRI revealed a unilateral mass in the parapharyngeal space, round or oval in shape, with well-defined borders.

DIAGNOSES

CT and MRI provided useful information for the preoperative evaluation. The appearance of large-scale cystic components may be an important clue for the diagnosis of BCA. PET/CT images were also available in one case. The final diagnoses were all basal cell adenomas (tubular type) in parapharyngeal space according to the regular histopathological examination after surgery.

INTERVENTIONS

All three cases were completely resected by a trans-oral approach. The average operative time and estimated blood loss were 86 (range, 61-106) min and 116.7 (range, 50-200) mL, respectively. Endoscopy was used in the largest case to further assess the residual cavity after the complete resection and hemostasis.

OUTCOMES

Postoperative recovery courses were quick and uneventful, with no neurovascular complication. Patients were discharged on the 3-5 day after surgery on an oral diet. One patient reported symptoms of velopharyngeal incompetence, manifested as mild slurred speech and nighttime salivation, for up to 3 months, which recovered spontaneously thereafter. There was no evidence of recurrence in the follow-up period.

LESSONS

In our experience, the trans-oral approach appeared to be effective, safe, and less invasive for extirpation of selected basal cell adenomas in the parapharyngeal space. An assistance of endoscopy facilitates the surgery.

Parapharyngeal Space Tumor: Submandibular Approach Without Mandibulotomy

Introduction

Among all head and neck tumors, only 0.5% occur in the parapharyngeal space and 80% are benign tumors. Surgery is the cornerstone of treatment. The deep location of this space and surrounding structures has given rise to a large number of surgical approaches for resection of parapharyngeal neoplasms. Our experience using the submandibular transcervical approach on 14 patients who had surgery upfront for treatment of these lesions is described.

Material and methods

This is a retrospective, descriptive case-series analysis of patients with parapharyngeal space tumors treated from January 2009 to July 2016, in whom carotid body tumors were excluded. Fourteen patients were included, 11 females (76.9%) and 3 males (23.1%), with a mean age of 46.9 years (SD 14.85).

Results

The most common symptom reported at patient's presentation to our clinic was a foreign body sensation in the oropharynx and pain. Navigation-guided surgery was used in two cases. Mean tumor size was 4.7 cm (SD 1.785). Complete resection of lesions was performed in all cases, and the major complication was massive bleeding in one case (7.1%).

Conclusion

According to the present analysis, the submandibular transcervical approach is an effective and safe technique that allows resection of large parapharyngeal tumors, even those close to the skull base. It has minimal complication rate, prevents morbidity associated mandibulotomy and allows extension to a transparotid, transmandibular and even to an infratemporal fossa approach. Navigation is indicated in tumors < 2 cm. The submandibular transcervical approach should be considered upfront for neoplasms ≤ 7 cm, preferentially ≥ 0.5 cm distant from skull base.

Surgical management of primary parapharyngeal space tumors in 103 patients at a single institution

PURPOSE

To evaluate clinical features, diagnosis, surgical management, and treatment of parapharyngeal space tumors in a single-center setting due to limited knowledge of diagnosis and treatment of parapharyngeal space.

METHODS

Clinical records of 103 patients were included for the analysis of such clinical characteristics.

RESULTS

A total of 29 different types of tumors were diagnosed after operation: 20 benign and 9 malignant. With a follow-up of 31-84 months for 90 benign cases, 84 cases had no recurrence and 6 cases were lost to follow-up. In contrast, with an 8- to 51-month follow-up for 13 malignant cases, 11 patients died and 2 were lost to follow-up. Furthermore, for postoperative complications, 3 cases had Horner syndrome, 2 had hoarseness, 2 had facial nerve dysfunction, and each for other types.

CONCLUSIONS

Surgery remains the first choice for the treatment of parapharyngeal space tumors, with the transcervical approach used for most tumors. Moreover, CT or MRI may assist in making decisions about operation schemes.

Intracapsular carcinoma ex-pleomorphic adenoma of the parapharyngeal space: report of two cases and review of the literature

BACKGROUND

Carcinoma ex-pleomorphic adenoma of the parapharyngeal space is an exceedingly rare entity.

METHODS

The clinical records of two patients with primary carcinoma ex-pleomorphic adenoma of the parapharyngeal space surgically treated at two different centers were retrospectively analyzed.

RESULTS

Despite ultrasound-guided fine-needle aspiration cytology and magnetic resonance imaging, the correct diagnosis was preoperatively missed in both cases. Excision was obtained through a transcervical-transparotid approach in 1 case and a minimally-invasive endoscopic-assisted transcervical approach in the other. Definitive histology was consistent with intracapsular carcinoma ex-pleomorphic adenoma. Adjuvant radiotherapy was performed in the case with macroscopic malignant degeneration; both patients are alive and free from disease 36 months after surgery.

CONCLUSIONS

Carcinoma ex-pleomorphic adenoma of the parapharyngeal space is a rare disease, and definitive diagnosis may be challenging. Surgery is the mainstay of treatment, but adjuvant radiotherapy also may be required in the presence of specific risk factors.

A Comparative Analysis of Endoscopic-Assisted Transoral and Transnasal Approaches to Parapharyngeal Space: A Cadaveric Study

Background  Surgical resection of parapharyngeal space (PPS) tumors is very challenging. An endoscopic-assisted surgical approach to this region requires detailed and precise anatomic knowledge. The main purpose of this study is to describe and compare the detailed anatomy of the PPS via transnasal transpterygoid (TP) and endoscopic-assisted transoral (TO) approaches. Materials and Methods  Six fresh injected cadaver heads (12 sides) were prepared for dissection of the PPS via TP and TO approaches. Computed tomography (CT) with image-based navigation (Navigation System II; Stryker, Kalamazoo, Michigan, United States) was used to identify bony structures around the PPS. Results  TP and TO approaches could both expose the detailed anatomical structures in the PPS. The TP approach can provide a direct route to the upper PPS, but it is limited inferiorly by the hard palate and laterally by the medial and lateral pterygoid muscles. However, the TO approach can provide a direct route to the lower PPS, but it is difficult to expose the area around the Eustachian tube. The styloglossus and stylopharyngeus muscles could be considered as the safe anterior boundary of the parapharyngeal internal carotid artery (ICA) with the TO approach. Dissection between the stylopharyngeus muscle and the superior pharyngeal constrictor muscle provides direct access to the parapharyngeal ICA. Conclusion  The TP and TO approaches provide new strategies to manage lesions in the PPS. The important neurovascular structures of the PPS could be identified with these approaches. The endoscopic-assisted TO approach can provide direct access to the parapharyngeal ICA.

Parapharyngeal space tumours: video-assisted minimally invasive transcervical approach

The purpose of the present study was to evaluate the advantages of a video-assisted, minimally invasive transcervical approach to benign and malignant parapharyngeal space (PPS) tumours. Ten patients affected by benign and malignant PPS neoplasms underwent a combined transcervical and video-assisted minimally invasive approach, using Hopkins telescopes. We describe the operative technique and perform a review of the literature. Definitive histology revealed 3 pleomorphic adenomas, 2 schwannomas, 2 metastatic papillary thyroid carcinomas, one carcinoma ex pleomorphic adenoma, one cavernous haemangioma and one basal cell adenoma. Mean tumour size was 37.2 mm (range: 19-60). Operation time ranged from 75 min to 185 min (mean: 146.7). One case was converted to transcervical-transparotid approach. Patients were discharged on postoperative day 2-5. One patients presented hypoglossal nerve paresis. The minimally invasive video-assisted transcervical approach is safe and feasible for selected benign and malignant PPS tumours. Furthermore, it offers harmless dissection in a deep and narrow space, accurate haemostasis and continuous control of critical anatomic structures.

Surgical treatment of parapharyngeal space tumors: A report of 29 cases

The present study aimed to establish a strategy for parapharyngeal space (PPS) tumor surgery based on preoperative symptoms, clinical signs, imaging and histological examination. A retrospective cohort study was conducted with 29 adult patients who underwent surgery for primary PPS tumors from 2008-2015. The following data was obtained: Preoperative symptoms of the patient, histological type of the tumor, surgical approach and complications. Of the 29 patients who underwent surgery to remove a PPS tumor, 16 presented with neurogenic tumors and 13 with salivary gland tumors. The most common symptom was the presence of a neck mass. Preoperative computed tomography and magnetic resonance imaging were performed to evaluate the size and location of the tumors. The majority of the salivary gland tumors were located in the prestyloid space, whereas all neurogenic tumor cases were poststyloid. A total of 21 of the 29 patients (72.4%) underwent a preoperative fine needle aspiration (FNAC) examination. FNAC contributed to preoperative diagnosis in 9 of these cases (42.9%). In parotid tumors of the prestyloid space, facial nerve palsy was a common postoperative complication. In the case of neurogenic tumors, a common complication was the postoperative palsy of the nerve of tumor origin. The strategy for PPS surgery, from the preoperative diagnosis to the operative method, remains controversial. The data on pre- and postoperative symptoms, imaging and histological diagnosis, and the selection of surgical method depending on a neurogenic or salivary tumor origin in the present study indicated that improving the method of examination, carefully selecting the method of approach and accurately managing surgery leads to complete tumor removal, and that the use of nerve-preserving techniques may reduce the likelihood of complications.

A rare case of embryonal rhabdomyosarcoma of the parapharyngeal space

A 24-year-old man was admitted to our Otolaryngology Department following a head and neck CT scan performed for cranial trauma that showed a bulky neoformation in the right parapharyngeal space. Magnetic resonance imaging confirmed the presence of an oval formation with sharp margins and colliquative areas of necrosis involving the right parapharyngeal space. The mass was completely excised by a latero-cervical approach. Based on histological features and immunohistochemical analysis, a diagnosis of embryonal rhabdomyosarcoma of the parapharyngeal space was made. The incidental detection at this site of an embryonal rhabdomyosarcoma has never been reported in adult males.

Surgical management and follow-up of lateral skull base tumors: An 8-year review

The purpose of the present article was to describe the diagnostic evaluation of, and surgical approaches to, lateral skull base tumors (LSBTs). The study is a retrospective review of 21 patients diagnosed with tumors that involve lateral skull base (8 with malignant diseases and 13 with benign lesions) who were surgically treated during a 8-year period. The transparotid-transmandibular (38%) was the most commonly performed surgical procedure, followed by the transmandibular (24%), the transmaxillary (24%), the transcervical approach (10%) and the combined approach (4%). The surgical procedures were uneventful and there were no postoperative mortalities. Complications were encountered in 12 cases, and morbidity was not remarkable during the perioperative stages. After an average follow-up of 46 months, only 1 of 14 patients with benign diseases had a recurrence following the resection of a pleomorphic adenoma. Of 7 patients with malignant tumors, 5 are alive with no evidence of disease. The majority of the benign lateral skull base tumors can be removed surgically with a low rate of complications and recurrence. However, malignant neoplasms carry a poor prognosis and a low rate of disease-free survival.

A safe transoral surgical approach to parapharyngeal tumor arising from deep lobe of parotid gland

The management of parapharyngeal tumor is surgical, but the approach remains a challenge. Attention should be paid to avoidance intra-operative bleeding or cranial nerves damage. We report a case of a 67-year-old male complaining of left-ear fullness. A submucosal mass arising from the lateral wall of oropharynx on the left side was observed. Magnetic resonance imaging detected a mass arising from the parotid gland, in particular from the deep lobe, and a fine needle biopsy was compatible with "Warthin tumor." We performed a mini-invasive transoral approach under magnification, previous isolation of homolateral vessels. The decision on which surgical approach to be used is determined by site, size vascularity, and histology of the tumor. A literature review of the main surgical approaches was performed. We performed a combined transoral dissection under magnification with cervicotomic exposure of the neck vascular bundle allowing to dissect the tumor and manage any intra-operative complications.

Multiport Combined Endoscopic Approach to Nonembolized Juvenile Nasopharyngeal Angiofibroma with Parapharyngeal Extension: An Emerging Concept

Background. Surgical approaches to the parapharyngeal space (PPS) are challenging by virtue of deep location and neurovascular content. Juvenile Nasopharyngeal Angiofibroma (JNA) is a formidable hypervascular tumor that involves multiple compartments with increase in size. In tumors with extension to parapharyngeal space, the endonasal approach was observed to be inadequate. Combined Endoscopic Endonasal Approaches and Endoscopic Transoral Surgery (EEA-ETOS) approach has provided a customized alternative of multicorridor approach to access JNA for its safe and efficient resection. Methods. The study demonstrates a case series of patients of JNA with prestyloid parapharyngeal space extension operated by endoscopic endonasal and endoscopic transoral approach for tumor excision. Results. The multiport EEA-ETOS approach was used to provide wide exposure to access JNA in parapharyngeal space. No major complications were observed. No conversion to external approach was required. Postoperative morbidity was low and postoperative scans showed no residual tumor. A one-year follow-up was maintained and there was no evidence of disease recurrence. Conclusion. Although preliminary, our experience demonstrates safety and efficacy of multiport approach in providing access to multiple compartments, facilitating total excision of JNA in selected cases.

[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.

Endocrine tumors associated with the vagus nerve

The vagus nerve (cranial nerve X) is the main nerve of the parasympathetic division of the autonomic nervous system. Vagal paragangliomas (VPGLs) are a prime example of an endocrine tumor associated with the vagus nerve. This rare, neural crest tumor constitutes the second most common site of hereditary head and neck paragangliomas (HNPGLs), most often in relation to mutations in the succinate dehydrogenase complex subunit D (SDHD) gene. The treatment paradigm for VPGL has progressively shifted from surgery to abstention or therapeutic radiation with curative-like outcomes. Parathyroid tissue and parathyroid adenoma can also be found in close association with the vagus nerve in intra or paravagal situations. Vagal parathyroid adenoma can be identified with preoperative imaging or suspected intraoperatively by experienced surgeons. Vagal parathyroid adenomas located in the neck or superior mediastinum can be removed via initial cervicotomy, while those located in the aortopulmonary window require a thoracic approach. This review particularly emphasizes the embryology, molecular genetics, and modern imaging of these tumors.