The Changing Paradigm of Head and Neck Paragangliomas: What Every Otolaryngologist Needs to Know

Hypoxic Signaling Pathways in Carotid Body Tumors

Carotid body tumors (CBTs) are rare tumors with a 1-2 incidence per 100,000 individuals. CBTs may initially present without apparent symptoms, and symptoms begin to arise since tumors grow bigger to compress surrounding tissue, such as recurrent laryngeal nerve and esophagus. Also, the etiology of CBTs remains unclear since it is more likely to occur in those who live in high-altitude areas or suffer from chronic hypoxic diseases such as COPD. SDH mutations and familial inheritance have been reported to be related to CBTs. SDH complexes play crucial roles in aerobic respiration, and SDH mutations in CBTs have been reported to be associated with hypoxia. Hypoxic signaling pathways, specifically hypoxic markers, have attracted more research attention in tumor exploration. However, the existing literature on these signaling and markers lacks a systematic review. Also, therapeutic approaches in CBTs based on hypoxic signaling are rarely used in clinics. In this review, we concluded the role of hypoxic signaling and markers and their potential implications in the initiation and progression of CBTs. Our findings underscore the involvement of the SDH family, the HIF family, VEGFs, and inflammatory cytokines (ICs) in tumorigenesis and treatment. Of particular interest is the role played by SDHx, which has recently been linked to oxygen sensing through mutations leading to hereditary CBTs. Among the SDH family, SDHB and SDHD exhibit remarkable characteristics associated with metastasis and multiple tumors. Besides SDH mutations in CBTs, the HIF family also plays crucial roles in CBTs via hypoxic signaling pathways. The HIF family regulates angiogenesis during mammalian development and tumor growth by gene expression in CBTs. HIF1α could induce the transcription of pyruvate dehydrogenase kinase 1 (PDK1) to inhibit pyruvate dehydrogenase kinase (PDH) by inhibiting the TCA cycle. Then, carotid body cells begin to hyperplasia and hypertrophy. At the same time, EPAS1 mutation, an activating mutation, could decrease the degradation of HIF2α and result in Pacak-Zhuang syndrome, which could result in paraganglioma. HIFs can also activate VEGF expression, and VEGFs act on Flk-1 to control the hyperplasia of type I cells and promote neovascularization. ICs also play a pivotal signaling role within the CB, as their expression is induced under hypoxic conditions to stimulate CB hyperplasia, ultimately leading to CBTs detecting hypoxic areas in tumors, and improving the hypoxic condition could enhance photon radiotherapy efficacy. Moreover, this review offers valuable insights for future research directions on understanding the relationship between hypoxic signaling pathways and CBTs.

Succinate dehydrogenase mutations in head and neck paragangliomas: A systematic review and meta-analysis of individual patients' data

BACKGROUND

Head and neck paragangliomas (HNPs) have been associated with gene mutations in the succinate dehydrogenase (SDH) complex, but the clinical significance remains unclear. We sought to explore the demographics, clinical characteristics, treatment methods, and outcomes of SDH-mutated HNPs.

METHODS

Databases were systematically searched. Pooled event ratio and relative 95% confidence intervals were calculated for dichotomous outcomes. Meta-regression was performed. Cochran's Q test and I2 test assessed heterogeneity. Funnel plot and Egger's regression test assessed publication bias.

RESULTS

Forty-two studies with 8849 patients were included. Meta-regression revealed a significant correlation between multifocality and SDHD mutations (0.03 ± 0.006, p < 0.0001) and between distant metastases and SDHB mutations (0.06 ± 0.023, p = 0.008). There was no correlation between sex, age, tumor size, or familial occurrences and SDH-related mutations.

CONCLUSION

Multifocality of HNPs correlates with the SDHD mutational subtype, and metastases correlate with the SDHB subtype. Knowledge of HNP phenotypes associated with SDH-related mutations has the potential to influence the management approach to such HNPs.

Paraganglioma of the Recurrent Laryngeal Nerve

Background/Objective

Paragangliomas are rare neuroendocrine tumors that primarily arise in the adrenal gland. Head and neck paragangliomas comprise approximately 3% of all extra-adrenal paragangliomas, with a majority of those being found in the carotid body. Recurrent laryngeal nerve paragangliomas are exceedingly rare, with only 2 reported cases found in literature review. Here, we will present the third.

Case Report

The patient is a 46-year-old woman with a history of a right thyroid nodule that had been previously biopsied benign with "paucity of diagnostic material." Neck ultrasonography revealed a 7.4 cm nodule that demonstrated interval growth over a 2-year period, so it was recommended to proceed with right thyroid lobectomy and isthmusectomy. During resection, the recurrent laryngeal nerve appeared to "disappear" into the nodule, and it was resected along with the nodule to ensure proper margins. The nerve was reconstructed with an ansa cervicalis interposition graft, and the nodule was sent to pathology. Pathology revealed that the nodule was a 4.8 cm paraganglioma of the recurrent laryngeal nerve.

Discussion

Paragangliomas of the head and neck are exceedingly rare. In patients who present with symptoms of dysphagia or dysphonia, further workup, including laryngoscopy and magnetic resonance imaging, could potentially identify and allow for appropriate planning for surgical resection.

Conclusion

In rare cases, consideration of paraganglioma as part of the differential for thyroid nodules may assist with planning of surgery but will unlikely alter treatment.

Diagnosis and Management of Pheochromocytomas and Paragangliomas: A Guide for the Clinician

OBJECTIVE

The aim of this review was to provide a practical approach for clinicians regarding the diagnosis and management of pheochromocytomas and paragangliomas (PPGLs).

METHODS

A literature search of PubMed was carried out using key words, including pheochromocytoma, paraganglioma, treatment, diagnosis, screening, and management. The discussion of diagnosis and management of PPGL is based on the evidence available from prospective studies when available and mostly from cohort studies, cross-sectional studies, and expert consensus.

RESULTS

PPGL are neuroendocrine tumors arising from the chromaffin cells of adrenal medulla and sympathetic and parasympathetic ganglia, respectively. PPGL can be localized or metastatic, and they may secrete catecholamines, causing a variety of symptoms and potentially catastrophic and lethal complications if left untreated. The rarity of these tumors along with heterogeneous clinical presentation often poses challenges for the diagnosis and management. PPGL can be associated with several familial syndromes which are important to recognize.

CONCLUSION

The last few years have witnessed an exponential growth in the knowledge around PPGL. This review aims at providing a comprehensive discussion of current concepts for clinicians regarding clinical presentation, diagnostic tools, and management strategies for PPGL.

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.

John M. Multidisciplinary care improves outcomes for patients with carotid body paragangliomas-The UCLA experience

Objective

To evaluate the effects and outcomes of multidisciplinary surgical approaches in the management of carotid body tumors (CBT).

Methods

A single-center retrospective study at the University of California-Los Angeles Medical Center was conducted on patients who presented with CBTs and underwent surgical resections from 1998 to 2020. Statistical analysis was performed using IBM SPSS v27 and Excel.

Results

A total of 75 patients with 79 CBT resections were included. Operating surgical subspecialties included: 41.8% vascular surgery, 24.1% otolaryngology head and neck surgeons (OHNS), and 31.6% combined OHNS and vascular. 68.4% of tumors underwent preoperative embolization. EBL was directly correlated with tumor size. CBT size was similar for OHNS (30 mm) and vascular (31 mm) but was significantly larger for combined OHNS and vascular cases (38 mm). EBL was higher in combined cases (301 mL) compared to OHNS (124 mL) or vascular (203 mL) alone. Incidence of postoperative cranial nerve deficits was 7.8%, with combined OHNS and vascular cases having an incidence of 4.0% when compared to OHNS (5.3%) versus vascular surgery alone (12.1%).

Conclusion

CBTs can be managed effectively by single surgical specialties with similar outcomes between vascular surgery and OHNS. In larger, higher grade tumors, however, a combined vascular and OHNS approach had lower incidence of postoperative cranial nerve injuries when compared to single specialty resections, despite a larger EBL. Thus, a multidisciplinary surgical approach suggests favorable outcomes with fewer incidence of cranial nerve deficits for larger, more complex CBT resections.

Level of Evidence

2b-Individual retrospective cohort study.

Reduced Risk of Corporal Tumors in Patients With Head and Neck Paragangliomas With p.Pro81Leu Mutations

OBJECTIVE

Patients with head and neck paragangliomas who are positive for the SDHD p.Pro81Leu (P81L) mutation are thought to have a distinct phenotype from other SDHx mutations, but few studies have focused on this mutation. The objective of this study was to determine the hazard of developing a second primary, metastatic, or recurrent paraganglioma in SDHx patients with or without P81L.

STUDY DESIGN

Retrospective chart review of 60 patients with head and neck paragangliomas and genetic testing, followed for a median of 9 years.

SETTING

Single academic medical center.

METHODS

Univariable Cox proportional hazards regression evaluated second primary and recurrent paragangliomas in patients with SDHD P81L, SDHx non-P81L, and nonhereditary paraganglioma.

RESULTS

This series comprised 31 patients without SDHx, 14 with SDHD P81L, and 15 with other SDHx mutations. At a median 9 years of follow-up, corporal (not head and neck) second primary paragangliomas occurred in 31% of patients with SDHx non-P81L mutations, compared with 0% and 4% of patients with SDHD P81L and without SDHx mutations, respectively. Second corporal paragangliomas were more likely in patients with SDHx non-P81L mutations than in those without a mutation (hazard ratio = 5.461, 95% confidence interval: 0.596-50.030, p = .13).

CONCLUSION

This is the first study to report a lower likelihood of corporal tumors for patients with head and neck paragangliomas with SDH mutations positive for P81L. Larger studies are needed to determine if head and neck paraganglioma patients with P81L qualify for less intensive imaging surveillance to screen for second primary paragangliomas outside the head and neck.

Jugulotympanic Paraganglioma With Preoperative Embolization That Led to Facial Nerve Paralysis and Surgical Rerouting of the Nerve

Paragangliomas are mostly benign, slow-growing, hypervascular tumors originating from neural crest derivatives. Head and neck (H&N) paragangliomas represent <1% of all H&N tumors and <5% are malignant. They are mostly non-secreting tumors that originate from autonomous parasympathetic paraganglia. We present a case of right middle ear jugulotympanic paraganglioma, a subtype of H&N paragangliomas, which had been misdiagnosed as otosclerosis for about 10 years. The patient was suffering from worsening tinnitus along with hearing impairment. High clinical suspicion of jugular paraganglioma prevented us from taking a biopsy. Complete surgical excision after preoperative embolization was decided. Embolization resulted in facial nerve paralysis, however, facial nerve rerouting was performed during the complete surgical excision of the tumor. The patient remains disease-free three years postoperatively, with House-Brackmann III facial nerve paralysis.

Hereditary head and neck paraganglioma: from basics to practical consequences

PURPOSE OF REVIEW

This review summarizes practical recommendations for screening, work-up, and management of hereditary head and neck paragangliomas based on the growing molecular and empirical understanding of this disease.

RECENT FINDINGS

The proportion of hereditary cases among head and neck paragangliomas is significant (∼33 to 50%), and specific genetic alterations may increase the risk of malignancy. Genotyping should be performed for each case, and patients carrying a pathological mutation should be regularly screened for new tumors. Computed tomography (CT), magnetic resonance imaging (MRI), digital subtraction angiography (DSA), and functional positron emission tomography (PET) can provide a reliable preoperative diagnosis in the absence of histology. Comparative data on therapeutic outcome and morbidity now render radiation, stereotactic radiosurgery, and active surveillance preferable over surgery in highly advanced cases of jugulotympanic and vagal paragangliomas, whereas surgery remains the first choice for most carotid body paragangliomas.

SUMMARY

Complete paraganglioma removal continues to be the primary therapeutic goal; however, this is sometimes impossible to accomplish with acceptable morbidity. In these cases, therapy selection should focus on preserving cranial nerve function and minimizing both tumor-associated and therapy-associated complications, particularly in genetically predisposed patients. An interdisciplinary approach to the management of hereditary head and neck paragangliomas is strongly recommended.

Paraganglioma of the Head and Neck: A Review

OBJECTIVE

To review the epidemiology, presentation, diagnosis, and management of head and neck paragangliomas.

METHODS

A literature review of english language papers with focus on most current literature.

RESULTS

Paragangliomas (PGLs) are a group of neuroendocrine tumors that arise in the parasympathetic or sympathetic ganglia. Head and neck PGLs (HNPGLs) comprise 65% to 70% of all PGLs and account for 0.6% of all head and neck cancers. The majority of HNPGLs are benign, and 6% to 19% of all HNPGLs develop metastasis outside the tumor site and significantly compromise survival. PGLs can have a familial etiology with germline sequence variations in different susceptibility genes, with the gene encoding succinate dehydrogenase being the most common sequence variation, or they can arise from somatic sequence variations or fusion genes. Workup includes biochemical testing to rule out secretory components, although it is rare in HNPGLs. In addition, imaging modalities, such as computed tomography and magnetic resonance imaging, help in monitoring in surgical planning. Functional imaging with DOTATATE-positron emission tomography, 18F-fluorodeoxyglucose, or 18F-fluorohydroxyphenylalanine may be necessary to rule out sites of metastases. The management of HNPGLs is complex depending on pathology, location, and aggressiveness of the tumor. Treatment ranges from observation to resection to systemic treatment. Similarly, the prognosis ranges from a normal life expectancy to a 5-year survival of 11.8% in patients with distant metastasis.

CONCLUSION

Our review is a comprehensive summary of the incidence, mortality, pathogenesis, presentation, workup and management of HNPGLs.

Neurological Manifestations of Paragangliomas of the Head and Neck

PURPOSE OF REVIEW

This paper will outline the clinical neurologic presentation and diagnostic evaluation of patients with paragangliomas of the head and neck. Contemporary management options will be outlined for these rare and complex tumors.

RECENT FINDINGS

The majority of recent publications and research on these tumors are dedicated to traditional and robotic image-guided radiosurgery in the treatment of head and neck paragangliomas. Paragangliomas are rare, slow-growing tumors of the head and neck which usually cause silent cranial nerve deficits or compensated mild speech or swallowing symptoms. While radiologic surveillance is often the best treatment option, subtotal resection with case-specific radiosurgery is commonly used in patients with large tumors.

Head/neck paragangliomas: focus on tumor location, mutational status and plasma methoxytyramine

Head and neck paragangliomas (HNPGLs) are tumors of parasympathetic origin that occur at variable locations and are often secondary to germline mutations in succinate dehydrogenase (SDH) subunit genes. Occasionally, these tumors produce catecholamines. Here, we assessed whether different locations of HNPGLs relate to the presence of SDHx mutations, catecholamine production and other presentations. In this multicenter study, we collected clinical and biochemical data from 244 patients with HNPGLs and 71 patients without HNPGLs. We clarified that jugulotympanic HNPGLs have distinct features. In particular, 88% of jugulotympanic HNPGLs arose in women, among whom only 24% occurred due to SDHx mutations compared to 55% in men. Jugulotympanic HNPGLs were also rarely bilateral, were of a smaller size and were less often metastatic compared to carotid body and vagal HNPGLs. Furthermore, we showed that plasma concentrations of methoxytyramine (MTY) were higher (P < 0.0001) in patients with HNPGL than without HNPGL, whereas plasma normetanephrine did not differ. Only 3.7% of patients showed strong increases in plasma normetanephrine. Plasma MTY was positively related to tumor size but did not relate to the presence of SDHx mutations or tumor location. Our findings confirm that increases in plasma MTY represent the main catecholamine-related biochemical feature of patients with HNPGLs. We expect that more sensitive analytical methods will make biochemical testing of HNPGLs more practical in the future and enable more than the current 30% of patients to be identified with dopamine-producing HNPGLs. The sex-dependent differences in the development of HNPGLs may have relevance to the diagnosis, management and outcomes of these tumors.

Preoperative Alpha-Blocker Therapy in Patients with Missed Preoperative Diagnosis of Extra-Adrenal Retroperitoneal Paraganglioma Undergoing Resection: A Retrospective Study of 167 Cases at a Single Center

INTRODUCTION

Preoperative α-adrenergic blockade is thought to decrease perioperative risks and mortality in surgeries for adrenal pheochromocytoma. However, there are limited data on the efficacy of α-blockers in surgeries for retroperitoneal paragangliomas. The aim of this study was to evaluate the effects of the preoperative α-adrenergic blockade on outcomes in patients undergoing surgery for extra-adrenal retroperitoneal paraganglioma.

METHODS

We searched the clinical database for patients diagnosed with extra-adrenal retroperitoneal paraganglioma by postoperative histopathology in the General Hospital of People's Liberation Army in China from 2000 to 2017. We compared the preoperative status of patients, preoperative examination, preoperative preparation, intraoperative and postoperative cardiovascular events, intake and output, length of stay in the intensive care unit, length of hospital stays, and short-term outcomes between patients who received preoperative treatment with α-adrenergic blockade and those who did not.

RESULTS

Of the 167 patients enrolled in the study, 61 received preoperative α-adrenergic blockade therapy. Intraoperative heart rate elevation and highest heart rate were higher in patients undergoing tumor manipulation with preoperative α-adrenergic blockade than those who did not (p < 0.05). However, there were no significant differences between these 2 groups in terms of intraoperative blood pressure elevation and systolic blood pressure decrease following tumorectomy (p > 0.05). Moreover, there were no significant differences in postoperative complications and outcomes (p > 0.05).

CONCLUSION

Under the current medical practice, resection of extra-adrenal retroperitoneal paraganglioma can be successfully carried out with or without preoperative α-adrenergic blockade.

Otology-Neurotology 2020 US Workforce Distribution

Objective

Determine the geographic and per capita distribution of otology-neurotology physician-surgeons within the United States.

Study Design

National database review.

Setting

United States.

Methods

The American Neurotology Society and ENThealth.org membership databases were queried to identify otology-neurotology physician-surgeons within the United States. Physician-surgeons were divided by regional national census areas, state, and by largest population statistical area based on 2019 US Census population estimates. The number of otology-neurotology physician-surgeons per 1 million persons was calculated for each population designation.

Results

Four-hundred eighty-two physician-surgeons were identified, representing 49 states and the District of Columbia. The New England division (Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island) was the most concentrated region (1.89), whereas the West-South-Central (Texas, Oklahoma, Arkansas, Louisiana) was the least concentrated region (1.23) per million persons. The highest concentration of physician-surgeons by state is within the District of Columbia (4.25), Vermont (3.21), North Dakota (2.62), Massachusetts (2.61), and New York (2.21) (per million), whereas Mississippi (0.67), Georgia (0.66), Idaho (0.56), New Mexico (0.48), and Wyoming (0.0) were the least concentrated per million persons. Increasing number of physician-surgeons was significantly correlated by state (r2 = 0.9; P < 0.0001), largest statistical area (r2 = 0.88; P < 0.0001), and census region (r2 = 0.95; P < 0.0005).

Conclusions

Otology-neurotology physician-surgeons are evenly distributed across the United States; however, certain areas are likely underrepresented. Variability in clinical practice may account for under or overrepresentation not captured in this analysis.

Diameter-Based Volumetric Models May Inadequately Calculate Jugular Paraganglioma Volume Following Sub-Total Resection

BACKGROUND

As gross total resection of jugular paragangliomas (JPs) may result in cranial nerve deficits, JPs are increasingly managed with subtotal resection (STR) with postoperative radiological monitoring. However, the validity of commonly used diameter-based models that calculate postoperative volume to determine residual tumor growth is dubious. The purpose of this study was to assess the accuracy of these models compared to manual volumetric slice-by-slice segmentation.

METHODS

A senior neuroradiologist measured volumes via slice-by-slice segmentation of JPs pre- and postoperatively from patients who underwent STR from 2007 to 2019. Volumes from three linear-based models were calculated. Models with absolute percent error (APE) > 20% were considered unsatisfactory based on a common volumetric definition for residual growth. Bland-Altman plots were used to evaluate reproducibility, and Wilcoxon matched-pairs signed rank test evaluated model bias.

RESULTS

Twenty-one patients were included. Median postoperative APE exceeded the established 20% threshold for each of the volumetric models as cuboidal, ellipsoidal, and spherical model APE were 63%, 28%, and 27%, respectively. The postoperative cuboidal model had significant systematic bias overestimating volume (p = 0.002) whereas the postoperative ellipsoidal and spherical models lacked systematic bias (p = 0.11 and p = 0.82).

CONCLUSION

Cuboidal, ellipsoidal, and spherical models do not provide accurate assessments of postoperative JP tumor volume and may result in salvage therapies that are unnecessary or inappropriately withheld due to inaccurate assessment of residual tumor growth. While more time-consuming, slice-by-slice segmentation by an experienced neuroradiologist provides a substantially more accurate and precise measurement of tumor volume that may optimize clinical management.

Re-evaluating the prevalence and factors characteristic of catecholamine secreting head and neck paragangliomas

Introduction

We sought to characterize the prevalence and factors characteristic of head and neck paragangliomas (HNPGLs) that secrete catecholamines to inform best practices for diagnosis and management.

Methods

This was a retrospective cohort study from 2000 to 2020 at a single‐institution tertiary centre. One‐hundred fifty‐two patients (182 tumours) with HNPGLs with at least one measurement of urine or plasma catecholamines and/or catecholamine metabolite levels prior to treatment were included. We differentiated and characterized those patients with increased level(s) of any nature and those with ‘clinically significant’ versus ‘clinically insignificant’ catecholamine production.

Results

Thirty‐one (20.4%) patients had increased catecholamine and/or catecholamine metabolite levels. In most patients, these levels were ≤5‐fold above the upper limit of the reference range. Four of these 31 patients with increased levels were ultimately found to have an additional catecholamine secreting mediastinal paraganglioma or pheochromocytoma. Fourteen of 31 patients with HNPGL were deemed clinically significant secretors of catecholamines based on hyper‐adrenergic symptoms and/or profound levels of normetanephrines. This cohort was enriched for patients with paragangliomas of the carotid body or cervical sympathetic chain and those with SDHB genetic mutations. Ultimately, the prevalence of clinically significant catecholamine secreting Hangs was determined to be 9.2% and 7.7% based on a per‐patient and per‐tumour basis, respectively.

Conclusions

The rate of catecholamine excess in the current cohort of patients with HNPGLs was higher than previously reported. Neuroendocrine tumours of any anatomic subsite may secrete catecholamines, although not all increased laboratory level(s) are indicative of clinically significant catecholamine secretion causing symptoms or warranting adrenergic blockade.

The North American Neuroendocrine Tumor Society Consensus Guidelines for Surveillance and Management of Metastatic and/or Unresectable Pheochromocytoma and Paraganglioma

ABSTRACT

This manuscript is the result of the North American Neuroendocrine Tumor Society consensus conference on the medical management and surveillance of metastatic and unresectable pheochromocytoma and paraganglioma held on October 2 and 3, 2019. The panelists consisted of endocrinologists, medical oncologists, surgeons, radiologists/nuclear medicine physicians, nephrologists, pathologists, and radiation oncologists. The panelists performed a literature review on a series of questions regarding the medical management of metastatic and unresectable pheochromocytoma and paraganglioma as well as questions regarding surveillance after resection. The panelists voted on controversial topics, and final recommendations were sent to all panel members for final approval.