Parapharyngeal space benign tumours: Our experience

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.

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.

Neurological Complications in Benign Parapharyngeal Space Tumors - Systematic Review and Meta-Analysis

Introduction  Parapharyngeal space tumors with complex anatomy and diverse histology have remained a challenging phenomenon for treating physicians. Objectives  We have conducted a comprehensive web search on the PubMed, Web of Science, EMBASE, Cochrane Library, Biomedical Literature Database (CBM), and Clinicaltrials.gov databases to determine the factors that are associated with postoperative complications in parapharyngeal space tumors. Data Synthesis  Two researchers reviewed all identified articles independently with a third reviewer for adjudication. Patient demographics and other clinicopathological characteristics were explored. The systematic review has identified 631 benign parapharyngeal space tumors with neurogenic and salivary tissue histology in 13 studies, with a mean age of 42.9 ± 7.76 years old and a median follow-up of 40.98 ± 19.1 months. Salivary gland (50.8%) and neurogenic (49.1%) tumors were the most common histological entities. Tumor size, location, histology, deep parotid lobe involvement, and proximity to great vessels or to the skull base were the deciding factors in selecting the surgical approach. The factors considered to select the surgical approach do not seem to have a correlation with the outcome in terms of neurological sequalae ( p  = 0.106). Tumors with neurogenic histology have significantly increased chances of developing neurological complication (OR 6.07; p  = 0.001). Conclusion  Neurologic complications are significantly associated with neurogenic benign tumors rather than surgical approach.

Keyhole Endoscopic-Assisted Transcervical Approach to the Upper and Middle Retrostyloid Parapharyngeal Space: An Anatomic Feasibility Study

Objectives The aim of this study was to describe the anatomical nuances, feasibility, limitations, and surgical exposure of the parapharyngeal space (PPS) through a novel minimally invasive keyhole endoscopic-assisted transcervical approach (MIKET).

Design Descriptive cadaveric study.

Setting Microscopic and endoscopic high-quality images were taken comparing the MIKET approach with a conventional combined transmastoid infralabyrinthine transcervical approach.

Participants Five colored latex-injected specimens (10 sides).

Main Outcome Measures Qualitative anatomical descriptions in four surgical stages; quantitative and semiquantitative evaluation of relevant landmarks.

Results A 5 cm long inverted hockey stick incision was designed to access a corridor posterior to the parotid gland after independent mobilization of nuchal and cervical muscles to expose the retrostyloid PPS. The digastric branch of the facial nerve, which runs 16.5 mm over the anteromedial part of the posterior belly of the digastric muscle before piercing the parotid fascia, was used as a landmark to identify the main trunk of the facial nerve. MIKET corridor was superior to the crossing of the accessory nerve over the internal jugular vein within 17.3 mm from the jugular process. Further exposure of the occipital condyle, vertebral artery, and the jugular bulb was achieved.

Conclusion The novel MIKET approach provides in the cadaver straightforward access to the upper and middle retrostyloid PPS through a natural corridor without injuring important neurovascular structures. Our work sets the anatomical nuances and limitations that should guide future clinical studies to prove its efficacy and safety either as a stand-alone procedure or as an adjunct to other approaches, such as the endonasal endoscopic approach.

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.

Trans-Oral Robotic Surgery: 14 Cases of Pleomorphic Adenoma of the Parapharyngeal Space

PURPOSE

The aim of this study has been to describe our experience with pleomorphic adenomas of the parapharyngeal space (PPS) treated with trans-oral robotic surgery (TORS). Tumors arising from the PPS comprise less than 0.5% of all head and neck tumors. Salivary gland tumors account for 40% to 50% of PPS lesions with pleomorphic adenomas representing the most common salivary tumors (80%-90%). Parapharyngeal space tumors cause nonspecific symptoms and may be difficult to diagnose.

METHODS

In our study a preoperative diagnosis was conducted by fine needle aspiration biopsy and magnetic resonance imaging and the results were used to plan the correct surgical approach.

RESULTS

In all cases we were able to employ TORS, a minimally invasive procedure that allows us to operate in narrow and anatomically complex spaces that we can only reach thanks to the use of well-articulated hand pieces.

CONCLUSIONS

This report indicates that TORS is a safe surgical procedure for the excision of benign tumors of the PPS in selected cases.

Anatomy of the sphenoidal spine and its implications in endoscopic endonasal surgery of the infratemporal fossa

BACKGROUND

The sphenoidal spine protrudes from the roof of the infratemporal fossa (ITF). This study aims to assess the anatomic relationships among the sphenoidal spine and other structures within the ITF from the perspective of an endoscopic endonasal access (EEA), and to explore the implications of these relationships.

METHODS

An EEA to the ITF was completed on six cadaveric specimens (12 sides). The anatomical relationships among the sphenoidal spine and adjacent structures were explored and associated distances from each other were measured using a navigation system.

RESULTS

The foramen spinosum is located anterosuperior to the sphenoidal spine, whereas the chorda tympani courses caudal and medial to the sphenoidal spine and the Eustachian tube and parapharyngeal internal carotid artery (pICA) are at its posterior aspect. Two virtual vertical planes, at the anterior and posterior aspects of the sphenoidal spine, respectively, correspond to the posterior trunk of V₃ and middle meningeal artery, and the stylopharyngeal aponeurosis. The average length of sphenoidal spine was 8.5 ± 2.43 mm, and the distance from distal apex of the sphenoidal spine to the foramen ovale, foramen spinosum, and pICA were 10.82 ± 0.83 mm, 6.42 ± 0.52 mm, and 5.02 ± 0.54 mm, respectively.

CONCLUSIONS

The sphenoidal spine is a meaningful landmark for endonasal approaches to the ITF. Measurements and conceptualization of vertical planes prior and posterior to the sphenoidal spine are beneficial to better appreciate the anatomic relationships in the ITF.

Surgical management of deep lobe parotid tumours with and without involvement of the parapharyngeal space

The diagnosis and treatment of deep lobe parotid tumours is challenging because of the complex surgical accessibility. There is a lack of studies describing the differences between deep lobe tumours that do and do not occupy the parapharyngeal space (PPS). Patients treated for deep lobe tumours occupying the PPS (PPS group) and not occupying the PPS (non-PPS group) were analysed retrospectively. A total of 227 patients were treated surgically for deep lobe parotid tumours between 1990 and 2019. Sixty patients (26.4%) presented with tumours that involved the PPS (PPS group), while 167 (73.6%) presented with tumours that did not occupy the PPS (non-PPS group). The majority of the PPS group tumours were removed using a transcervical or transcervical-transparotid approach. PPS group tumours were larger (P < 0.001), and tumour spill occurred more frequently in this group (benign tumours: P = 0.002; malignant tumours: P = 0.033). Complication rates did not differ between the PPS and non-PPS groups. A transcervical or transcervical-transparotid approach is the preferred method for the management of deep lobe parotid tumours that occupy the PPS in our practice. Tumour spill occurred more frequently in the PPS group, which is most probably due to the larger tumour size and more complex accessibility.

Transoral Excision of Parapharyngeal Space Tumors

Transoral excision of parapharyngeal space (PPS) tumors has increased in popularity along with the increased use of robotic and endoscopic surgical technology. Here, the authors highlight the indications, techniques, outcomes, and complications of transoral approaches to PPS tumors, with a special emphasis on salivary tumors of the PPS and the transoral robotic surgery approach.

Computed tomography-guided transfacial buccal space core biopsy of deep head and neck space lesions: our experience

Deep head and neck space lesions can present a number of diagnostic challenges due to their deep anatomical position and difficult access for diagnostic tissue sampling. We describe a series of percutaneous 'transfacial' buccal space computed tomography (CT)-guided core biopsies of these lesions and subsequent histological findings. Six patients underwent CT-guided core biopsy of deep parotid, parapharyngeal, or masticator space lesions over a 30-month period. We describe our biopsy technique and correlate our histological findings with subsequent surgical resection where performed. Five of six of CT-guided biopsies obtained sufficient tissue for histological interpretation with varying findings, including salivary gland tumours and squamous cell carcinoma confirmed on subsequent resection. One patient was treated palliatively following core biopsy. No biopsy-related complications were observed. In our small series, percutaneous CT-guided transfacial biopsy via the buccal space has proved an excellent option for the minimally invasive tissue acquisition of deep head and neck space lesions.

Primary neoplasms of the parapharyngeal space: diagnostic and therapeutic pearls and pitfalls

PURPOSE

Parapharyngeal space neoplasms (PSNs) are rare tumors of the head and neck region. In this study, we report our institutional experience with PSNs over a 27-years period.

METHODS

Patients treated between 1992 and 2018 were identified through our tumor board database. Data concerning demographics, clinical presentation, disease features, treatment, complications and follow-up were obtained retrospectively.

RESULTS

In total, 48 patients were identified. Most patients had benign tumors (67.5%), with pleomorphic adenoma and schwannoma being the most frequent entities. Malignant tumors represented the remaining 32.5% of neoplasms. Concerning tissue of origin, 67.5% of neoplasms originated from salivary glands and 17.5% were neurogenic. The vast majority of PSNs required open surgical approaches (77%). The most frequent reversible and irreversible complications included paralysis of facial, vagal, and hypoglossal nerves (transient 62.5%, permanent 31.3%). Tumor recurrences occurred in 16.7% of our patients.

CONCLUSION

Neoplasms of the parapharyngeal space (PPS) are rare. In our series, consistent with the literature, most patients had benign tumors. Fine-needle aspiration cytology (FNAC) and/or transoral biopsy in selected cases combined with radiographic imaging are helpful to plan the optimal approach (open/transoral) and extent of primary surgery. Close follow-up in malignant neoplasms is crucial to assess recurrence early. We present one of the largest recent studies on PPS tumors treated in a center. Given the low incidence of these tumors, our results contribute to the existing sparse evidence regarding the management and outcome of such tumors.

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.

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.

Surgical Approaches to Benign Parapharyngeal Space Tumors-5-Year Experience

Introduction:

Various surgical approaches to parapharyngeal space (PPS) tumors are introduced to obtain complete removal with the preservation of the surrounding structures in parapharyngealneoplasms. Here, we will discuss the main techniques and their outcome.

Materials and Methods:

This retrospective study was conducted on 78 patients undergone either transoral, transcervical or a combination of these two approaches for the resection of PSS tumors from January 2010 to January 2015.

Results:

A number of 33 male and 45 female patients with the mean age of 40.9 ± 9.1 were evaluated. 42.3% of the patients were asymptomatic at the initial presentation. Pleomorphic adenoma and schwannoma were a permanent diagnosis in 61(78.2%) and 11(14.1%) patients, respectively. PPS tumors were resected using transoral, transcervical and combined approaches in 35(44.8%), 33(42.3%) and 10 (12.9%) cases, respectively. Recurrence occurred in 10 patients all of whom had apre-styloid pleomorphic adenoma, operated transcervical (P< 0.0001).Three cases of tenth nerve palsy occurred in schwannomas which were operatedtranscervically (P=0.04). Mean hospital stays were 2.11,3.69, and 4.9 days after transoral, transcervical and combined approaches, respectively (P= 0.001).

Conclusion:

Transoral, transcervical and combined approaches are all able to provide adequate visualization with comparable outcomes.

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.

Early experience in endoscopic transoral resection for parapharyngeal space tumors

The purpose of this study was to investigate the feasibility, safety, and efficacy of the resection of parapharyngeal space (PPS) tumors via an endoscopic transoral approach. We reviewed 9 patients who were diagnosed with PPS tumors and who were treated with an endoscopic transoral approach. PPS tumors ranging from 2.5 to 6 cm were removed completely with no complications and excellent recovery (mean inpatient hospital stay: 6.89 days). Pathology was pleomorphic adenoma (n = 7), schwannoma (n = 1) and malignant pleomorphic adenoma (n = 1). For the malignant lesion, the patient underwent postoperative radiotherapy (70 Gy). There was no radiographic evidence of recurrences, with mean follow-up of 11.22 months (range: 3 to 20). We conclude that resection of PPS tumors via an endoscopic transoral approach appears to be feasible, safe, and effective. Potential advantages of this approach include an excellent surgical view, rapid surgical access, less tissue injury, avoidance of external scar, fewer postoperative complications, and less morbidity.

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.

Canalicular adenoma: A systematic review

OBJECTIVE

Canalicular adenoma (CA) is an uncommon but unique benign tumor of salivary gland origin. It is the third most common benign tumor of minor salivary glands, representing less than 1% of all salivary neoplasms. A systematic review is presented of reported cases of CA, to determine trends in presentation, diagnostic features, treatment, and patient outcome.

METHODS

Searches of specific databases, as reported, were carried out to identify papers reporting CA. The variables were patient symptoms, tumor location, histopathological findings, demographics, treatment, follow-up, and recurrence.

RESULTS

430 cases were identified; the most common location was in the upper lip (66.3%), followed by hard palate (14.5%). The most common clinical presentation was a nodule (46.5%), followed by asymptomatic (29.5%), and discomfort (28.7%). CA was most frequently seen in females (64%). The average age was 66.3 years. 97% of cases were treated surgically. The average follow-up was 136.3 months, and recurrence was reported in 3% of the cases.

CONCLUSION

CA shows a strong predilection for the upper lip. CAs are frequently asymptomatic, but the principal symptom was pressure.

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.