Paragangliomas of the head and neck: a contemporary review

SDH-related head and neck paragangliomas: Unraveling PET radiomics beyond 18F-FDG

Radiomics revolutionizes medical imaging by providing quantitative analysis that complements traditional qualitative assessments through advanced computational techniques. In this narrative review we have investigated the impact of succinate dehydrogenase (SDH) pathogenic variants on the radiomic profile of 18F-FDG, 18F-DOPA, and 68Ga-DOTA-peptides PET in paragangliomas, focusing on head and neck localizations (HNPGLs). This influence manifests in uptake intensity and textural heterogeneity, revealing a complex radiomic landscape that may reflect specific tumor behaviors and mutation statuses. By combining radiomic analysis with genetic data, we will gain new insights into the relationship between PET imaging features and underlying molecular changes. In the future, we envision an approach integrating macroscopic indices, such as lesion location, size, and SUV, with advanced computer-based algorithms. This comprehensive analysis could facilitate in vivo predictions of SDH pathogenic variants, thereby encouraging genetic testing, and ultimately improving patient outcomes.

Endovascular Embolization as a Stand-Alone Treatment of Head and Neck Paragangliomas with Long-Term Tumor Control

BACKGROUND AND PURPOSE

The impact of therapeutic embolization as a stand-alone treatment of head and neck paragangliomas considered surgically high-risk remains insufficiently understood. The aim of this study was to investigate the procedural risks and long-term volumetric development in head and neck paragangliomas with high surgical risk following therapeutic endovascular embolization as a stand-alone treatment.

MATERIALS AND METHODS

A retrospective database review of patients who underwent endovascular embolization as primary treatment for head and neck paragangliomas lacking appropriate curative treatment options at our institution (from January 2000 to February 2023) was conducted. Tumor volumetric analyses were performed before embolization and during follow-up. To assess the changes in tumor volume over time, the measurements were performed after embolization, first at 6 months and then on a yearly basis up to 6 years (mean follow-up time was 33.7 ± 24.4 months). Subgroup analyses were conducted for vagal and jugular/jugulotympanic paragangliomas.

RESULTS

A total of 32 head and neck paragangliomas in 28 patients (mean age, 56.1 years ± 16.5 [standard deviation]; 18 female) with therapeutic embolization as stand-alone treatment were evaluated, of which 11 were vagal paragangliomas, 15 jugular/jugulotympanic paragangliomas, and 6 carotid body tumors. After a mean follow-up duration of 33.7 ± 24.4 months, tumor control was achieved in 75%, with significant median tumor volume reduction at 6 months (P = .02, n = 21). Vagal paragangliomas responded the most to embolization with a significantly decreased median volume from 22.32 cm3 to 19.09 cm3 (P = .008, n = 8). Transient complications occurred in 3.4%.

CONCLUSIONS

Therapeutic embolization as a stand-alone treatment offers a low-risk control of tumor growth in surgically high-risk lesions, with a significant reduction in tumor volume after treatment. Among the different subtypes, vagal paragangliomas exhibited the strongest and longest regression of the tumor volume.

[Paragangliomas of the head and neck]

Paragangliomas represent a heterogeneous group of rare neuroendocrine tumors with marked variability in symptoms and disease course. Due to the close proximity to neurovascular structures, paragangliomas of the head and neck region can cause a variety of symptoms. To this day, there are no reliable prognostic factors that can predict a potentially malignant course. All patients with newly diagnosed paragangliomas should undergo an early diagnostic workup and regular follow-up examinations in specialized centers. While radical resection was previously regarded as standard treatment for paragangliomas, radiotherapy and active surveillance (watch-and-scan strategy) have become equally important over the years. Low-threshold techniques for molecular pathology analysis of the mutation-specific behavior of paragangliomas are nowadays available.

The Role of Internal Carotid Artery Stent in the Management of Skull Base Paragangliomas

Background: After two decades from its introduction in the lateral skull base paraganglioma surgery, the indications and results of preoperative internal carotid artery stenting should be critically assessed. Materials and Methods: Monocentric retrospective study on 26 patients affected by head and neck paragangliomas (19 tympanojugular paragangliomas, 4 carotid body paragangliomas, 3 vagal paragangliomas) preoperatively treated with internal carotid artery stents between 2008 and 2023. The preoperative findings, the intraoperative complications and the final surgical results were analyzed. Results: The stent complication rate was less than 3.1%. Self-expanding highly flexible intracranial nitinol stents were applied. In all cases, it was possible to completely mobilize the internal carotid artery and perform a vascular dissection of the tumor. Gross total tumor resection was possible in 85% of cases. The median follow up was 7.83 y (SD +/- 3.93 y). No local recurrence was observed. Conclusions: The preoperative vascular stent facilitates tumor dissection from the internal carotid artery without risk of vascular damage, helping the surgeon to achieve surgical radicality. The vascular stent is indicated in the case of revision surgeries, circumferential involvement of the vessel and in cases with non-insufficient intracerebral crossflow. Procedural complications, temporary antiplatelet therapy and delay of surgery are the limitations of the procedure.

Paragangliomas of the Head and Neck: A Review of the Latest Diagnostic and Treatment Methods

Background and objectives: Paragangliomas of the head and neck are rare, slow-growing neuroendocrine tumors, benign in their vast majority, but with a possibility of developing distant metastases. They show great inheritable character, and their behavior has proven to be unpredictable; therefore, they are considered malignant. Material and methods: This article aims to offer a more comprehensive presentation of the pathogenesis, epidemiology, diagnostic methods, imaging development, and treatment guidelines. We tried to bring together all the necessary data that, in our opinion, a head and neck practitioner should know when managing this type of tumor. Our main focus is on the most recent studies, with the purpose of a homogenous presentation of all current guidelines and approaches to this pathology. Results: Paragangliomas of the head and neck are still a disputed topic. One of the main reasons for that is their low incidence of 0.3 to 1 per 100,000 every year. The most frequent locations are the carotid body, the temporal bone, the jugular and mastoid foramen, and the vagal nerve. Their clinical presentation usually involves a painless lateral mass associated with symptoms such as hoarseness, hearing loss, tinnitus, and cranial nerve deficits. Up to 40% of them are inherited, mostly linked with mutations of succinate dehydrogenase complex. Imaging evaluation consists of CT and MRI, and new functional explorations such as 18F-FDA and 18F-FDG PET/CT, 18F-DOPA PET, 123I-MIBG, and 68Ga-DOTATE PET/CT. Measuring the catecholamine levels in the plasma and urine is mandatory, even though paragangliomas of the head and neck rarely display secretory behavior. Treatment mainly consists of surgery, with different approaches and techniques, but conservative management methods such as wait and scan, radiotherapy, proton therapy, and chemotherapy have proven their efficiency. The therapeutical decision lacks consensus, and current studies tend to recommend an individualized approach. Guidelines regarding long-term follow-up are still a matter of debate.

The Radiosurgery Society Case-Based Discussion of the Management of Head and Neck or Skull Base Paragangliomas with Stereotactic Radiosurgery and Radiotherapy

Stereotactic radiosurgery (SRS) and fractionated stereotactic radiotherapy (FSRT) have been used for the treatment of head and neck or skull base paraganglioma for a considerable time, demonstrating promising local control rates and a favorable safety profile compared with surgical approaches. Nevertheless, the choice of treatment must be carefully tailored to each patient's preferences, tumor location, and size, as well as anticipated treatment-related morbidity. This case-based review serves as a practical and concise guide for the use of SRS and FSRT in the management of head and neck or skull base paragangliomas, providing information on the diagnosis, treatment, follow-up considerations, and potential pitfalls.

Laryngeal Paraganglioma-A Case Report

Background and Objectives: Paragangliomas of the head and neck are rare neuroendocrine tumors originating from the paraganglia, which might be sympathetic or parasympathetic. Laryngeal paragangliomas are the rarest subtype of these tumors, with only 1.41% of all paragangliomas, arising from the supraglottic or subglottic paraganglia of the larynx. The vast majority of them are benign, but there are some cases in which they turn out to be malignant, and the only way to know with certainty the difference between them is when we identify distant metastases. The aim of this article is to share our experience with a rare case of laryngeal paraganglioma and review the clinical characteristics, methods of diagnostic, necessary investigation prior to the operation, and surgical management of this type of tumor. Materials and Methods: We present the case of a 68-year-old female patient, a non-smoker, who accused dysphagia, dysphonia, foreign body sensation, chronic cough, and hoarseness for six months. We performed a tracheostomy prior to biopsy to secure the airways in case of bleeding and then took a few biopsy samples. The histopathological exam revealed the presence of a laryngeal paraganglioma. An enhanced CT scan was performed in order to describe the localization, size, and invasion of the tumor. We also measured the vanillylmandelic acid from the urine to determine if the tumor produced catecholamines alongside a full cardiology and endocrinology examinations. In order to prevent massive bleeding during the operation, chemoembolization was attempted before surgery, but it was unsuccessful due to an anatomical variation of the left superior thyroid artery. She underwent surgery, first through transoral endoscopic microsurgery; however, we decided to undertake an external approach because of poor bleeding control, even though we had ligated both the superior thyroid artery and the external carotid artery, with a thyrotomy and laryngofissure achieving the complete resection of the tumor. Results: The patient was discharged 10 postoperative days later, with the recommendation of introducing food step-by-step from liquids to solids. She was decannulated after 30 days, with no complications regarding breathing, phonation, or deglutition. Twelve months after the surgery, we did not identify any local relapses of distant metastases. Conclusions: Laryngeal paragangliomas are rare neuroendocrine tumors that arise from the laryngeal paraganglia. Surgery is the best treatment option available, and it can be done by either an external approach or by transoral endoscopy. Enhanced CT or MRI, as well as full cardiological and endocrinological evaluation are mandatory prior to the operation. Measuring the catecholamines levels show the if the tumor is secretory. Controlling the bleeding poses the biggest challenge in performing the resection of the tumor, especially when a transoral endoscopic approach is chosen. Further standardized follow-up guidelines are required in the future.

The Advantages of Non-Adhesive Gel-like Embolic Materials in the Endovascular Treatment of Benign Hypervascularized Lesions of the Head and Neck

OBJECTIVES

The use of non-adhesive gel-like embolic materials (NAGLEMs) in the endovascular treatment of hypervascularized formations in the head and neck is gaining in popularity because of a number of important characteristics involved. Their primary benefits are their capacity to penetrate diseased vasculature, effectively distribute, and, most importantly, remain controllable during the process. We reviewed the literature and evaluated the results of using NAGLEMs in comparison to other embolizing substances (namely, coils, glue, and particles) as alternative embolizing agents for patients receiving care at our clinic. The process comprised evaluating the safety, effectiveness, and technological elements of endovascular therapy used to treat two categories of hypervascular pathological abnormalities that were surgically corrected between 2015 and 2023. Arteriovenous malformations (AVMs) located in the head, neck, and paragangliomas with jugular/carotid body localization are combined by intense shunting blood flow and shared requirements for the embolic agent used in endovascular treatment (such as penetration, distribution, delayed polymerization, and controllability). An analysis of the literature was also conducted. Results showed 18 patients diagnosed with neck paragangliomas of the carotid body and jugular type. Five patients with arteriovenous malformation (AVM) of the face and neck were included, consisting of sixteen females and seven males with an average age of 55 ± 13 years. Endovascular procedures were performed using NAGLEMs (ONYX (Medtronic, Irvine, CA, USA), SQUID (Balt, Montmorency, France), and PHIL (Microvention, Tustin, CA, USA)) and dimethyl sulfoxide (DMSO)-compatible balloon catheters. All patients achieved complete or partial embolization of hypervascularized formations using one or more stages of endovascular treatment. Additionally, three AVMs of the face and two paragangliomas of the neck were surgically excised following embolization. In other instances, formations were not deemed necessary to be removed. The patients' condition upon discharge was assessed by the modified Rankin Scale (mRs) and rated between 0 and 2.

CONCLUSION

Currently, NAGLEMs are predominantly used to treat hypervascularized formations in the neck and head due to their fundamental properties. These properties include a lack of adhesion and a delay in predictable polymerization (after 30-40 min). NAGLEMs also exhibit excellent distribution and penetration throughout the vascular bed of the formation. Adequate controllability of the process is largely achieved through the presence of embolism forms of different viscosity, as well as excellent X-ray visualization.

Multi-Disciplinary Approach to Skull Base Paragangliomas

The treatment of skull base paragangliomas has moved towards the use of cranial nerve preservation strategies, using radiation therapy and subtotal resection in instances when aiming for gross total resection would be expected to cause increased morbidity compared to the natural history of the tumor itself. The goal of this study was to analyze the role of surgery in patients with skull base paragangliomas treated with CyberKnife stereotactic radiosurgery (SRS) for definitive tumor control. A retrospective review identified 22 patients (median age 65.5 years, 50% female) treated with SRS from 2010-2022. Fourteen patients (63.6%) underwent microsurgical resection. Gross total resection was performed in four patients for tympanic paraganglioma (n = 2), contralateral paraganglioma (n = 1), and intracranial tumor with multiple cranial neuropathies (n = 1). Partial/subtotal resection was performed for the treatment of pulsatile tinnitus and conductive hearing loss (n = 6), chronic otitis and otorrhea (n = 2), intracranial extension (n = 1), or episodic vertigo due to perilymphatic fistula (n = 1). Eighteen patients had clinical and imaging follow-up for a mean (SD) of 4.5 (3.4) years after SRS, with all patients having clinical and radiological tumor control and no mortalities. Surgery remains an important component in the multidisciplinary treatment of skull base paraganglioma when considering other outcomes besides local tumor control.