Ultrastructural features of tumor-associated mast cells in parasympathetic paragangliomas (chemodectomas) of the neck

The mechanisms of the pathogenesis of neck paraganglioma (PGL) and the possible role of mast cells (MCs) in its development and metastasis are still poorly understood. We analyzed MCs' morphologic characterization, activation, and the properties of their cytoplasmic/released granules in PGLs, using light and transmission electron microscopy. Paragangliomas showed a large tumor-associated MC population both in the connective tissue layers of the tumor and between the tumor cells. Notably, MCs were presented by a high expression of specific proteases, size variation, polymorphism, and variable ultrastructural phenotype of granules. A massive number of granules were released surrounding the degranulated MCs while the integrity of MC membrane was maintained. Granules were electron-dense with or without a membrane, ranging from 0.2 to 0.8 μm in diameter. MC plasmalemma was not found at the site of MC-collagen fibrils contact, whereas the secretome and fibrils were directly contacted. We observed direct and mediator-based interactions between MCs and paraganglioma cells. The latter preserved their membrane integrity when MC granules were not in proximity. The effects of the MC secretome on the paraganglioma microenvironment demonstrated its pathogenetic role in tumor progression and allow its application to new diagnostic criteria and the development of protocols for personalized therapy. RESEARCH HIGHLIGHTS: Ultrastructural analysis reveals novel regulatory effects of mast cells via diverse secretory pathways on the pathogenesis of parasympathetic paraganglioma, including fibrous extracellular matrix remodeling and mediator-based interactions between MCs and cells of the tumor microenvironment.

Management of Abdominal Paraganglioma: A Single Center's Experience

Background and Objectives: Paragangliomas (PGLs) are rare neuroendocrine extra-adrenal tumors that could be secreting mass. The symptoms are the typical triad of paroxysmal headache, hypertension and sweating, but could also be accompanied by symptoms involving multiple organs. Surgery is the gold standard treatment for both PGLs and pheochromocytomas (PHEOs). Material and Methods: We used a computerized endocrine surgery registry to record the demographic and clinical data of 153 patients who underwent surgery for PPGL between 2010 and 2023 at our hospital. Results: Thirteen patients (8.43%) with paragangliomas underwent surgery at our institute. Five patients presented symptomatic syndrome. Preoperative investigations included enhanced abdominal CT (nine patients) and enhanced MRI (seven patients). In cases of suspicious mass, we performed 131I-MIBG scans (two patients) or 68GA-DOTATOC PET-CT scans (11 patients). Laparoscopic approach was used in four cases (30.7%) and abdominal laparotomy in the other nine (69.3%). Biochemical tests were performed on all patients. Conclusions: In this retrospective study, we discuss the multidisciplinary management in our institute of this rare disease, from its challenging diagnosis to the surgical strategy for PGLs. Laparoscopic surgery is the gold standard, but a tailored approach should be adopted for each patient.

Sex-Related Differences in Self-Reported Symptoms at Diagnosis in Pheochromocytomas and Paragangliomas

Context

Biological sex can play a role in the severity of certain diseases.

Objective

Our objective was to evaluate whether sex-related differences affect the signs and symptoms of pheochromocytomas and paragangliomas (PPGLs) at presentation.

Methods

We reviewed the records of patients with PPGLs at our center from 1995 to 2022.

Results

Our study included 385 patients with PPGLs: 118 (30.6%) head and neck paragangliomas (HNPGLs), 58 (15.1%) thoracoabdominal paragangliomas (TAPGLs) and 209 (54.3%) pheochromocytomas (PHEOs). The cohort consisted of 234 (60.8%) women and 151 (39.2%) men. At diagnosis, more women than men presented with headaches (47.5% vs 32.4%; P = .007); however, more men presented with diabetes (21.1% vs 12.5%; P = .039). When subdivided by tumor location, headaches occurred more often in women with HNPGLs and TAPGLs (31.0% vs 11.4%; P = .0499 and 60.0% vs 21.7%; P = .0167). More men presented with diabetes among patients with PHEOs (28.2% vs 11.2%; P = .0038). In regard to nonsecretory PPGLs, women presented with a higher prevalence of headaches (46.9% vs 3.6%; P = .0002), diaphoresis (16.3% vs 0.0%; P = .0454), and palpitations (22.4% vs 0.0%; P = .0057). In patients with secretory tumors, women presented with more headaches (58.9% vs 42.7%; P = .0282) and men with more diabetes (29.3% vs 12.5%; P = .0035).

Conclusion

In our cohort, more women presented with headaches across all tumor types and secretory statuses. More men presented with diabetes among patients with PHEOs and secretory tumors. In nonsecretory PPGLs, women had more adrenergic symptoms. These findings can be explained by differences in adrenergic receptor sensitivity, self-reported symptoms, and possibly other vasoactive peptides and sex-hormone status.

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.

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.

Peptide receptor radionuclide therapy in advanced Pheochromocytomas and Paragangliomas: a systematic review and meta-analysis

Objective

Peptide receptor radionuclide therapy (PRRT) for advanced pheochromocytomas and paragangliomas (PPGLs) has received increasing attention. The purpose of this article is to evaluate the efficacy and safety of PRRT in patients with metastatic or inoperable PPGLs by meta-analysis.

Methods

A literature search was conducted in PubMed, Embase, Scopus, and Cochrane Library databases up to November 2022. All articles on PRRT for PPGLs were searched, and appropriate data were included for analysis. The measures evaluated included objective response rate (ORR), disease control rate (DCR), clinical response rate, biochemical response rate, progression-free survival (PFS), overall survival (OS), and adverse events. Statistical analysis was performed using Stata 16.0 and the R programming language, data were combined using a random-effects model, and the results were presented using forest plots.

Results

A total of 20 studies with 330 patients were included in the analysis. The results showed that ORR and DCR were 20.0% (95% CI: 12.0%-28.0%) and 90.0% (95% CI: 85.0%-95.0%), respectively. Clinical and biochemical responses were 74.9% (95% CI: 56.3%-90.2%) and 69.5% (95%CI: 40.2%-92.9%). Median PFS and median OS were 31.79 (95% CI:21.25-42.33) months and 74.30 (95% CI: 0.75-147.84) months, respectively. Any grade of hematotoxicity and nephrotoxicity occurred in 22.3% (95% CI:12.5%-33.5%) and 4.3% (95% CI:0.2%-11.4%) patients. Grade 3-4 hemotoxicity occurred in 4.3% (95% CI:0.2%-11.4%) and grade 3-4 nephrotoxicity in 4/212 patients. Additionally, Treatment was discontinued in 9.0% (95% CI: 0.5%-23.3%) patients and one patient died as a result of a toxicity.

Conclusion

Patients with metastatic or inoperable PPGLs can be effectively treated with PRRT, and it has a favorable safety profile.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO, identifier CRD42022359232.

Clinical consensus guideline on the management of phaeochromocytoma and paraganglioma in patients harbouring germline SDHD pathogenic variants

Patients with germline SDHD pathogenic variants (encoding succinate dehydrogenase subunit D; ie, paraganglioma 1 syndrome) are predominantly affected by head and neck paragangliomas, which, in almost 20% of patients, might coexist with paragangliomas arising from other locations (eg, adrenal medulla, para-aortic, cardiac or thoracic, and pelvic). Given the higher risk of tumour multifocality and bilaterality for phaeochromocytomas and paragangliomas (PPGLs) because of SDHD pathogenic variants than for their sporadic and other genotypic counterparts, the management of patients with SDHD PPGLs is clinically complex in terms of imaging, treatment, and management options. Furthermore, locally aggressive disease can be discovered at a young age or late in the disease course, which presents challenges in balancing surgical intervention with various medical and radiotherapeutic approaches. The axiom-first, do no harm-should always be considered and an initial period of observation (ie, watchful waiting) is often appropriate to characterise tumour behaviour in patients with these pathogenic variants. These patients should be referred to specialised high-volume medical centres. This consensus guideline aims to help physicians with the clinical decision-making process when caring for patients with SDHD PPGLs.

Treatment of relapses of benign latero-cervical pathology: a narrative literature review

Benign laterocervical pathologies are not without pitfalls. Many may relapse after many years and, sometimes, they cannot be predicted. The purpose of this review is to describe the surgical measures necessary for the treatment of relapses of the most common benign laterocervical masses. We searched PubMed, Embase and Cochrane Central Register of Controlled Trials databases for articles describing the treatment of the most common benign cervical disease recurrences, and summarised available evidence in this narrative review. We overviewed observations about recurrent benign mixed tumour (pleomorphic adenoma), parapharyngeal space tumours and carotid body paragangliomas, thyroglossal duct anomalies and branchial cleft anomalies. Proper surgical technique is crucial for safely and effectively managing the relapses of benign latero-cervical diseases. Radiotherapy is indicated in several cases of recurrence such as pleomorphic adenoma and unresectable paraganglioma. Long-term follow-up is of utmost importance to promptly recognise and treat recurrencies.

Long-Term Outcomes in Head and Neck Paragangliomas Managed with Intensity-Modulated Radiotherapy

OBJECTIVES

Head & Neck Paragangliomas have been historically relying on surgery mostly, with worsened quality of life and major sequelae. Conventional external radiation therapy seems to offer an equivalent control rate with a low toxicity profile. The aim of this study was to assess the safety and efficiency of intensity-modulated radiation therapy in Head & Neck paragangliomas.

METHODS

This is a retrospective monocentric study conducted in a referral center, including all patients treated with IMRT, whether as an exclusive or post-operative treatment for a tympanic and jugular, carotid, or vagal paraganglioma. Data collection was performed through the manuscript and computerized medical files, including consultation, operative, imaging, pathological analyses, delineation, and treatment planning reports. Success was defined as the complete or partial regression or stabilization without progression, or relapse in accordance with the RECIST criteria. Acute toxicities and long-term sequelae were assessed.

RESULTS

Our cohort included 39 patients included between 2011 and 2021: 18 patients treated for a TJ PG (45.9%), 11 patients for a carotid PG (28.4%), and 9 for a vagal PG (23.1%). Twenty-nine patients had IMRT as an exclusive treatment (74.4%), whereas 10 patients had a post-operative complementary treatment (25.6%). Median follow-up in our cohort was 2318 days (average = 2200 days, 237-5690, sd = 1281.9). Among 39 patients, 37 were successfully controlled with IMRT (94.8%), and the toxicity profile was low without any major toxicity.

CONCLUSION

IMRT seems an ideal treatment, whether exclusive or post-operative for Head & Neck paragangliomas.

LEVEL OF EVIDENCE

3 Laryngoscope, 133:607-614, 2023.

Response to Peptide Receptor Radionuclide Therapy in Pheocromocytomas and Paragangliomas: A Systematic Review and Meta-Analysis

INTRODUCTION

Peptide receptor radionuclide therapy (PRRT) with 177Lu-DOTATATE and 90Y-DOTATOC showed efficacy in the metastatic setting of pheocromocytomas (PCCs) and paragangliomas (PGLs) where no standard therapies have been established.

BACKGROUND

A search of peer-reviewed and English articles reporting on 177Lu-DOTATATE and 90Y-DOTATOC efficacy was performed through Medline and Scopus. A subsequent meta-analysis was performed to evaluate the pooled effect size on disease control rate (DCR) with PRRT. Secondary endpoints were description of patients' genetic characteristics, hematologic toxicity, and time-to-outcome. The pooled effect was estimated with both a mixed-effects model and a random-effects model.

RESULTS

Twelve studies met the criteria for this meta-analysis: ten with 177Lu- and two with 90Y-PRRTs (213 patients). The largest one included 46 patients. Median ages ranged from 32.5 to 60.4 years. When reported, mutations of SDHB were the most frequent genetic alterations. The pooled DCRs were 0.83 (95% CI: 0.75-0.88) and 0.76 (95% CI: 0.56-0.89) for 177Lu- and 90Y-PRRT, respectively. The pooled DCR for PRRT was 0.81 (95% CI: 0.74-0.87).

CONCLUSIONS

We report an updated and solid estimate of DCR achieved with 177Lu- and 90Y-PRRT in PCCs and PGLs, showing that these therapies can be considered in the multidisciplinary treatment of PCCs and PGLs as alternatives to I-131 MIBG and chemotherapy.

SDHB exon 1 deletion: A recurrent germline mutation in Colombian patients with pheochromocytomas and paragangliomas

Pheochromocytomas (PCCs) and paragangliomas (PGLs) (known as PPGL in combination) are rare neuroendocrine tumors of the adrenal medulla and extra-adrenal ganglia. About 40% of the patients with PPGL have a hereditary predisposition. Here we present a case-series of 19 unrelated Colombian patients with a clinical diagnosis of PPGL tumors that underwent germline genetic testing as part of the Hereditary Cancer Program developed at the Instituto Nacional de Cancerología, Colombia (INC-C), the largest reference cancer center in the country. Ten of 19 patients (52.63%) were identified as carriers of a pathogenic/likely pathogenic (P/LP) germline variant in a known susceptibility gene. The majority of the P/LP variants were in the SDHB gene (9/10): one corresponded to a nonsense variant c.268C>T (p.Arg90*) and eight cases were found to be carriers of a recurrent CNV consisting of a large deletion of one copy of exon 1, explaining 42% (8/19) of all the affected cases. Only one additional case was found to be a carrier of a missense mutation in the VHL gene: c.355T>C (p.Phe119Leu). Our study highlights the major role of SDHB in Colombian patients with a clinical diagnosis of PGL/PCC tumors and supports the recommendation of including the analysis of large deletions/duplications of the SDHB gene as part of the genetic counselling to improve the detection rate of hereditary cases and their clinical care.

Surgical strategies of complicated pheochromocytomas/paragangliomas and literature review

Pheochromocytomas (PCC)/paragangliomas (PGL) are catecholamine (CA) -secreting neuroendocrine tumors, which are known as PPGL due to their histological and pathophysiological similarities. In addition to the typical triad of paroxysmal headache, palpitation, and sweating, PPGL may also be accompanied by symptoms and signs involving multiple organs and systems such as the cardiovascular system, digestive system, endocrine system, and nervous system. Currently, surgical resection is the first choice for PPGL. Safe and effective surgical management of complicated PPGL is the goal of clinical work. In this paper, we discuss this hot issue based on complicated PPGL cases, aiming to share our experience of the surgical management strategy of PPGL.

Multifocal Paraganglioma Including the Cervical Sympathetic Chain

Multifocal head and neck paragangliomas are exceptionally rare. We present a patient with 4 synchronous tumors including a sympathetic chain lesion. This is a case report and literature review conducted from September 2021 to the present. Our 69-year-old male patient presented to the clinic with multifocal paraganglioma involving the right carotid body, right cervical sympathetic trunk, right glomus jugulare, and left glomus tympanicum. After preoperative embolization, successful surgical resection was performed for the right sympathetic trunk and right carotid body tumor. Postoperatively, the patient had a right Horner's syndrome but a strong voice and intact recurrent laryngeal nerve function. He also had first-bite syndrome and right cranial nerve XII weakness which resolved. Of interest, patient also has a strong family history of paragangliomas: his sister has malignant paragangliomas with lymph node involvement and his mother and nephew have non-malignant paragangliomas. To our knowledge, multifocal tumors including synchronous carotid body, sympathetic chain, glomus jugulare, and glomus tympanicum lesions occurring in 1 person have not been reported until now. As a result of this study, there is new light shed on the treatment and evaluation of patients who present with multifocal paraganglioma involving the sympathetic chain.

The Clinical Characteristics of Pheochromocytomas and Paragangliomas with Negative Catecholamines

Pheochromocytomas and paragangliomas (PPGLs) associated with negative catecholamines are not uncommon. However, few studies have examined clinical features of patients with these tumors. In the absence of available data, it is difficult to identify characteristics of patients with potential PPGLs and normal serum and urine screens. Therefore, an analysis of patients with PPGLs was conducted retrospectively to compare the clinical features of patients with positive and negative catecholamines. This study included 214 patients, including 69 patients with negative catecholamines. Prevalence rates of diabetes (p < 0.001) and hypertension (p < 0.001) were lower and tumor diameter (p < 0.001) was smaller in the negative-catecholamine group compared with the positive-catecholamine group. Multivariable logistic regression analysis showed that extra-adrenal PPGLs were independently positively associated with negative catecholamines (p = 0.004); hypertension (p = 0.001) and tumor diameter (p = 0.016) were independently negatively associated with negative catecholamines. There was no significant difference in tumor recurrence between the two groups (mean follow-up, 20.54 ± 11.83 months) (p = 0.44). The results demonstrated that PPGL patients with negative catecholamines were more likely to have extra-adrenal tumors and less likely to have comorbidities, and these patients should also be closely monitored for tumor recurrence.

Postoperative Recurrences in Patients Operated for Pheochromocytomas and Paragangliomas: New Data Supporting Lifelong Surveillance

Simple Summary

At least 10% of pheochromocytomas (PHEOs) and paragangliomas (PPGLs) may recur after the initial surgery. The optimal follow-up time for these tumors remains unknown. We present a cohort of recurrent PPGLs in a clinical care setting of a quaternary center. In this paper, we describe recurrence patterns based on tumor location (head and neck paragangliomas, thoracoabdominal paragangliomas, and pheochromocytomas). We report that the overall mean delay of recurrence was 9.7 years and that one-third of the cohort had a recurrence more than 10 years after the initial surgery. Additionally, 17.6% of recurrent PHEOs were smaller than the predicted cutoff for recurrence (5 cm). Finally, more than 50% of recurrent PPGLs harbored a germline mutation in a susceptibility gene. In sum, this paper supports that overall, the safest option remains a lifelong follow-up.

Abstract

At least 10% of pheochromocytomas (PHEOs) and paragangliomas (PGLs) (PPGLs) may recur after the initial surgery. Guidelines recommend annual screening for recurrence in non-metastatic tumors for at least 10 years after the initial surgical resection and lifelong screening in high-risk patients. However, recent data suggest that a shorter follow-up might be appropriate. We performed a retrospective analysis on patients with PPGLs who had local and/or metastatic recurrences between 1995 and 2020 in our center. Data were available for 39 cases of recurrence (69.2% female) including 20 PHEOs (51.3%) and 19 PGLs (48.7%) (13 head and neck (HNPGL) and 6 thoracoabdominal (TAPGL)). The overall average delay of recurrence was 116.6 months (14–584 months) or 9.7 years and the median was 71 months or 5.9 years. One-third of the cohort had a recurrence more than 10 years after the initial surgery (10–48.7 years). The average tumor size at initial diagnosis was 8.2 cm for PHEOs, 2.7 cm for HNPGLs, and 9.6 cm for TAPGLs. Interestingly, 17.6% of PHEOs were under 5 cm at the initial diagnosis. Metastatic recurrence was identified in 75% of PHEOs, 15.4% of HNPGLs, and 66.7% of TAPGLs. Finally, 12/23 (52.2%) patients with recurrence who underwent genetic testing carried a germline mutation. Overall, the safest option remains a lifelong follow-up.

Efficacy and safety of preoperative embolization in carotid body tumor treatment: A propensity score matching retrospective cohort study

BACKGROUND

To assess the efficacy and safety of preoperative embolization (PE) in patients with carotid body tumor (CBTs).

METHODS

In a single-center retrospective cohort study, 127 patients underwent surgical resection of CBTs from January 2003 to December 2019. One-to-one propensity score matching was conducted between patients with or without PE.

RESULTS

Thirty-two (25.2%) patients received PE. After propensity score matching, no statistically significant differences were found in the baseline characteristics of 28 patients in each group. Compared with NPE group, operative time and estimated blood loss (EBL) were significantly reduced in the PE group. The incidence of stroke, perioperative complications, intraoperative blood transfusion, vascular reconstruction, hospital stay, tumor recurrence, and all-cause mortality were not different between the PE and NPE group.

CONCLUSIONS

Preoperative embolization was efficient and safe with a reduction of intraoperative blood loss and operative time during CBT resection.

Metastatic pheochromocytomas and paragangliomas: where are we?

Pheochromocytomas and paragangliomas (PPGLs) can metastasize in approximately 15-20% of cases. This review discusses the available evidence on the biology and treatment of metastatic PPGLs. Chemotherapy is the first-line treatment option for this evolving and symptomatic disease. In patients with high MIBG uptake and positive PETGa-68, radiometabolic treatment may be considered. The efficacy of sunitinib has been shown in observational studies, and pembrolizumab has been evaluated in phase II clinical studies, while other agents investigated in this setting are anti-angiogenic drugs cabozantinib, dovitinib, axitinib and lenvatinib. As these agents' efficacy and safety data, alone or in combination, are scant and based on few treated patients, enrollment in clinical trials is mandatory. Future therapeutic options may be represented by DNA repair system inhibitors (such as olaparib), HIF2 inhibitors and immunotherapy.

Perioperative Management of Pheochromocytomas and Sympathetic Paragangliomas

Pheochromocytomas and paragangliomas (PPGLs) are rare neuroendocrine tumors arising from chromaffin cells of the adrenal medulla or extra-adrenal paraganglia, respectively. PPGLs have the highest degree of heritability among endocrine tumors. Currently, ~40% of individuals with PPGLs have a genetic germline and there are at least 12 different genetic syndromes related to these tumors. Metastatic PPGLs are defined by the presence of distant metastases at sites where chromaffin cells are physiologically absent. Approximately 10% of pheochromocytomas and ~40% of sympathetic paragangliomas are linked to metastases, explaining why complete surgical resection is the first-choice treatment for all PPGL patients. The surgical approach is a high-risk procedure requiring perioperative management by a specialized multidisciplinary team in centers with broad expertise. In this review, we summarize and discuss the most relevant aspects of perioperative management in patients with pheochromocytomas and sympathetic paragangliomas.

Silent pheochromocytoma and paraganglioma: Systematic review and proposed definitions for standardized terminology

Pheochromocytomas and paragangliomas (PPGLs) are rare neuroendocrine tumors with heterogeneous clinical presentations and potential lethal outcomes. The diagnosis is based on clinical suspicion, biochemical testing, imaging and histopathological confirmation. Increasingly widespread use of imaging studies and surveillance of patients at risk of PPGL due to a hereditary background or a previous tumor is leading to the diagnosis of these tumors at an early stage. This has resulted in an increasing use of the term "silent" PPGL. This term and other variants are now commonly found in the literature without any clear or unified definition. Among the various terms, "clinically silent" is often used to describe the lack of signs and symptoms associated with catecholamine excess. Confusion arises when these and other terms are used to define the tumors according to their ability to synthesize and/or release catecholamines in relation to biochemical test results. In such cases the term "silent" and other variants are often inappropriately and misleadingly used. In the present analysis we provide an overview of the literature and propose standardized terminology in an attempt at harmonization to facilitate scientific communication.

Insights into Mechanisms of Pheochromocytomas and Paragangliomas Driven by Known or New Genetic Drivers

Simple Summary

Pheochromocytomas and paragangliomas are rare neuroendocrine tumors that are often hereditary. Although research has advanced considerably, significant gaps still persist in understanding risk factors, predicting metastatic potential and treating aggressive tumors. The study of rare mutations can provide new insights into how pheochromocytomas and paragangliomas develop. In this review, we provide examples of such rare events and how they can inform our understanding of the spectrum of mutations that can lead to these tumors and improve our ability to provide a genetic diagnosis.

Abstract

Pheochromocytomas and paragangliomas are rare tumors of neural crest origin. Their remarkable genetic diversity and high heritability have enabled discoveries of bona fide cancer driver genes with an impact on diagnosis and clinical management and have consistently shed light on new paradigms in cancer. In this review, we explore unique mechanisms of pheochromocytoma and paraganglioma initiation and management by drawing from recent examples involving rare mutations of hypoxia-related genes VHL, EPAS1 and SDHB, and of a poorly known susceptibility gene, TMEM127. These models expand our ability to predict variant pathogenicity, inform new functional domains, recognize environmental-gene connections, and highlight persistent therapeutic challenges for tumors with aggressive behavior.

Hereditary Endocrine Tumors and Associated Syndromes: A Narrative Review for Endocrinologists and Endocrine Surgeons

OBJECTIVE

Hereditary endocrine tumors (HET) were among the first group of tumors where predisposition syndromes were recognized. The utility of genetic awareness is having the capacity to treat at an earlier stage, screen for other manifestations and initiate family cascade testing. The aim of this narrative review is to describe the most common hereditary syndromes associated with frequently encountered endocrine tumors, with an emphasis on screening and surveillance.

METHODS

A MEDLINE search of articles for relevance to endocrine tumors and hereditary syndromes was performed.

RESULTS

The most common hereditary syndromes associated with frequently encountered endocrine tumors are described in terms of prevalence, genotype, phenotype, penetrance of malignancy, surgical management, screening and surveillance.

CONCLUSION

Medical practitioners involved in the care of patients with endocrine tumors, should have an index of suspicion for an underlying hereditary syndrome. Interdisciplinary care is integral to successful, long-term management of these patients and affected family members.

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.

Incomplete penetrance of a novel SDHD variation causing familial head and neck paraganglioma

Objective

Identification of variations in tumour suppressor genes encoding the tetrameric succinate dehydrogenase (SDHx) mitochondrial enzyme complex may lead to personalised therapeutic concepts for the orphan disease, familial paraganglioma (PGL) type 1‐5. We undertook to determine the causative variation in a family suffering from idiopathic early‐onset (22 ± 2 years) head and neck PGL by PCR and Sanger sequencing.

Design

Prospective genetic study.

Setting

Tertiary Referral Otolaryngology Centre.

Participants

Twelve family members.

Main outcome measures

Main outcomes were clinical analysis and SDH genotyping

Results and Conclusions

A novel heterozygous c.298delA frameshift variation in exon 3 of SDH subunit D (SDHD) was associated with a paternal transmission pattern of PGL in affected family members available to the study. Family history over five generations in adulthood indicated a variable penetrance for PGL inheritance in older generations. The c.298delA variant would cause translation of a 34‐residue C‐terminus distal to lysine residue 99 in the predicted transmembrane domain II of the full‐length sequence p.(Thr100LeufsTer35) and would affect the translation products of all protein‐coding SDHD isoforms containing transmembrane topologies required for positional integration in the inner mitochondrial membrane and complex formation. These results underly the importance of genetic screening for PGL also in cases of unclear inheritance, and variation carriers should benefit from screening and lifelong follow‐up.

HEREDITARY ENDOCRINE TUMOURS: CURRENT STATE-OF-THE-ART AND RESEARCH OPPORTUNITIES: Metastatic pheochromocytomas and paragangliomas: proceedings of the MEN2019 workshop

Pheochromocytomas and paragangliomas (PPGLs) are adrenal or extra-adrenal autonomous nervous system-derived tumors. Most PPGLs are benign, but approximately 15% progress with metastases (mPPGLs). mPPGLs are more likely to occur in patients with large pheochromocytomas, sympathetic paragangliomas, and norepinephrine-secreting tumors. Older subjects, those with larger tumors and synchronous metastases, advance more rapidly. Germline mutations of SDHB, FH, and possibly SLC25A11, or somatic MAML3 disruptions relate to a higher risk for metastatic disease. However, it is unclear whether these mutations predict outcome. Once diagnosed, there are no well-established predictors of outcome in mPPGLs, and aggressive tumors have few therapeutic options and limited response. High-specific activity (HSA) metaiodine-benzyl-guanidine (MIBG) is the first FDA approved treatment and shows clinical effectiveness for MIBG-avid mPPGLs. Ongoing and future investigations should involve validation of emerging candidate outcome biomarkers, including somatic ATRX, TERT, and microRNA disruptions and identification of novel prognostic indicators. Long-term effect of HSA-MIBG and the role of other radiopharmaceuticals should be investigated. Novel trials targeting molecular events prevalent in SDHB/FH mutant tumors, such as activated hypoxia inducible factor 2 (HIF2), angiogenesis, or other mitochondrial defects that might confer unique vulnerability to these tumors should be developed and initiated. As therapeutic options are anticipated to expand, multi-institutional collaborations and well-defined clinical and molecular endpoints will be critical to achieve higher success rates in improving care for patients with mPPGLs.

Microsurgical Anatomy of the Jugular Foramen Applied to Surgery of Glomus Jugulare via Craniocervical Approach

The jugular foramen remains one of the most complex regions of the human body. Approaching lesions in this area requires extensive anatomical knowledge and experience, due to the many critical neurovascular structures passing through or around the jugular foramen. Here, we present a concise review of the microsurgical anatomy of the jugular foramen in relation to the craniocervical approach.

Head and neck paragangliomas: 30-year experience

BACKGROUND

We aimed to review our experience and the changing trends in the management of head and neck paragangliomas (HNPG) over the last three decades.

METHODS

We retrospectively reviewed 103 patients with HNPG treated at our center (1986-2017). We included patients treated with surgery, radiotherapy, and patients maintained under active surveillance.

RESULTS

Of the surgically treated patients (n = 79), 20% (12/59) of the carotid body tumors (CBT) had a cranial nerve deficit as sequela compared to 95% (19/20) of the non-CBT. Radiotherapy controlled growth in all tumors treated with this modality (n = 10). Of the initially observed patients, 70% (14/20) remained stable and did not require additional treatment. Stratifying by decades, there was a progressive increase in patients initially attempted to be observed and a decrease in upfront surgery. No deaths attributable to the HNPG were encountered.

CONCLUSIONS

Surgery is an effective treatment for CBT. Nonsurgical treatment should be considered for non-CBT.

Pheochromocytoma and Paraganglioma: A Review of Diagnosis, Management and Treatment of Rare Causes of Hypertension

Pheochromocytomas (PHEO) and paragangliomas (PGL) are rare tumors originated in cells derived from the neural crest. The first ones are located in the adrenal medulla, and the second ones in the sympathetic and parasympathetic nervous system. These kind of tumors may secrete excess catecholamines, including epinephrine, norepinephrine, dopamine and/or their metabolite metanephrine, normetanephrine and 3-methoxytyramine, respectively. Its clinical manifestations depend on the location, the secretory profile and the malignant potential of the tumor. These tumors are frequently benign in their presentation. Some arise in the context of familiar syndromes, accounting for up to one-third of the total of diagnosis. The metastatic form is the most common presentation of the tumors with familiar origin and due to their rarity, their diagnosis and management is often difficult. Over the years, our knowledge and perception of PHEO and PGL has greatly expanded and changed. This review article aims to focus on the genetic, clinical, diagnostic, therapeutic and prognostic approaches, to give the clinician knowledge of the most recent updates regarding these themes.

Genetic Determinants of Pheochromocytoma and Paraganglioma Imaging Phenotypes

Parallel to the application of new PET radiopharmaceuticals for pheochromocytoma and paraganglioma (collectively named PPGLs) imaging, several studies have increased our understanding on their biology, genetics, metabolomics, and embryologic origin. In this review, we highlight the current relationship between genotypes and molecular imaging phenotypes. Additionally, we summarize the referral guidelines for imaging of PPGL patients with or without knowledge of their genetic background.

The VHL/HIF Axis in the Development and Treatment of Pheochromocytoma/Paraganglioma

Pheochromocytomas and paragangliomas (PPGLs) are rare neuroendocrine tumors originating from chromaffin cells in the adrenal medulla (PCCs) or extra-adrenal sympathetic or parasympathetic paraganglia (PGLs). About 40% of PPGLs result from germline mutations and therefore they are highly inheritable. Although dysfunction of any one of a panel of more than 20 genes can lead to PPGLs, mutations in genes involved in the VHL/HIF axis including PHD, VHL, HIF-2A (EPAS1), and SDHx are more frequently found in PPGLs. Multiple lines of evidence indicate that pseudohypoxia plays a crucial role in the tumorigenesis of PPGLs, and therefore PPGLs are also known as metabolic diseases. However, the interplay between VHL/HIF-mediated pseudohypoxia and metabolic disorder in PPGLs cells is not well-defined. In this review, we will first discuss the VHL/HIF axis and genetic alterations in this axis. Then, we will dissect the underlying mechanisms in VHL/HIF axis-driven PPGL pathogenesis, with special attention paid to the interplay between the VHL/HIF axis and cancer cell metabolism. Finally, we will summarize the currently available compounds/drugs targeting this axis which could be potentially used as PPGLs treatment, as well as their underlying pharmacological mechanisms. The overall goal of this review is to better understand the role of VHL/HIF axis in PPGLs development, to establish more accurate tools in PPGLs diagnosis, and to pave the road toward efficacious therapeutics against metastatic PPGLs.

Exploring the link between tumour metabolism and succinate dehydrogenase deficiency: A 18 F-FDOPA PET/CT study in head and neck paragangliomas

OBJECTIVES

Nuclear imaging findings by virtue of phenotyping disease heavily depend on genetic background, metabolites, cell membrane specific targets and signalling pathways. PPGL related to succinate dehydrogenase subunits mutations (SDHx mutations) are less differentiated than other subgroups and therefore may lack to concentrate ¹⁸ F-FDOPA, a precursor of catecholamines biosynthesis. However, this ¹⁸ F-FDOPA negative phenotype has been reported mostly in SDHx-PPGL of sympathetic origin, suggesting that both genotype status and location (from sympathetic vs parasympathetic paraganglia; adrenal vs extra-adrenal) could influence ¹⁸ F-FDOPA uptake. The aim of this study was to test if SDHx drives ¹⁸ F-FDOPA uptake in presence of normal epinephrine/norepinephrine concentrations.

DESIGN

Retrospective study PATIENTS: A cohort of 86 head and neck PPGL patients (including three metastatic) with normal metanephrines underwent ¹⁸ F-FDOPA PET/CT. The relationships between ¹⁸ F-FDOPA uptake and tumour genotype were evaluated.

RESULTS

In nonmetastatic HNPGL (50 non-SDHx/33 SDHx), no significant difference was observed between these two groups for SUVmax (P = .256), SUVmean (P = .188), MTV 42% (P = .596) and total lesion uptake (P = .144). Metastatic HNPGL also had high elevated uptake values.

CONCLUSIONS

Our results suggest that SDH deficiency or metastatic behaviour have no influence on ¹⁸ F-FDOPA uptake in HNPGL probably due to their very-well differentiation status, even at metastatic stage. The potential prognosticator value of ¹⁸ F-FDOPA uptake would need to be further explored in the setting of metastatic PPGL of sympathetic origin.

Surgical treatment of abdominal paragangliomas

INTRODUCTION

Extraperitoneal, abdominal paragangliomas most commonly originate from the sympathetic nervous system. Typical features include catecholamine overproduction and the potential for malignancy. Lesions are usually located paravertebrally, but when growing in a more expansive manner they may also appear between the inferior vena cava and aorta. In the authors' opinion this site excludes laparoscopic tumourectomy.

MATERIAL AND METHODS

Twenty-eight patients were selected for surgical management of abdominal paragangliomas in the past eight years at our endocrine surgical centre. This group consisted of 21 (75%) women and seven (25%) men, aged 14 to 84 years (mean 47.9). In 13 (46.4%) cases paroxysmal hypertension was observed. Type 2 diabetes was noted in another 10 (35.7%) patients, and Takotsubo acute coronary syndrome in two (7.1%). Patients were preoperatively qualified for either open surgery or laparoscopic tumourectomy based on visualisation and location of the tumours in imaging studies.

RESULTS

All patients were successfully operated. Eleven (39.3%) patients qualified for laparoscopy, while the remaining 17 (60.7%) were treated with an open surgical approach due to difficult access to the lesion. The mean operative time was 130 minutes for laparoscopy and 120 minutes for laparotomy (p = 0.2). There were no local or general complications after either type of procedure.

CONCLUSIONS

The use of laparoscopic access is practically excluded in the treatment of paragangliomas located between the inferior vena cava and aorta, especially at the level of the renal vessels and extending superiorly to the diaphragm.

Tumor multifocality with vagus nerve involvement as a phenotypic marker of SDHD mutation in patients with head and neck paragangliomas: A 18 F-FDOPA PET/CT study

BACKGROUND

¹⁸ F-FDOPA PET/CT was proved to be a highly sensitive imaging method for detecting head and neck paraganglioma (HNPGL). The primary aim of the study was to evaluate the relationship between tumor characteristics and the SDHx-mutational status in a large series of patients with HNPGL evaluated by ¹⁸ F-FDOPA PET/CT.

METHODS

A total of 104 patients with HNPGL (65 sporadic/39 SDHx-mutated) were included.

RESULTS

In comparison to SDHB/SDC/SDHx-negative cases, patients with SDHD were younger at diagnosis and had a higher rate of multifocal, vagal, and carotid paraganglioma. In patients with SDHD, vagal paraganglia represented the primary site of tumor origin. Multicentric involvement of the vagus nerve alone or in association with other locations was found to be a typical feature of SDHD cases compared to other cases (odds ratio = 59.4).

CONCLUSION

The present study shows that tumor multifocality within the vagus nerve is a phenotypic marker of SDHD mutation. This information is essential in the choice of the therapeutic strategy.

Spinal paragangliomas: Surgical treatment and follow-up outcomes in eight cases

Paragangliomas are neuro-endocrine tumors originating from the adrenal gland. They are usually benign and nonfunctioning, rarely seen in central nervous system. More than 90% of central nervous system paragangliomas are manifested as carotid and glomus jugulare tumors. Spinal paragangliomas are quite rare.The study was conducted through retrospective analysis of the files of the patients who had undergone surgery with pre-diagnosis of spinal intradural tumor between 2011 and 2017 and diagnosed with paraganglioma.A total of 8 patients (4 females and 4 males) were included in the study. Mean age of the patients was 51.1 years (28-64). Time to admission was mean 6.5 months (3 weeks-24 months). Recurrence was not observed in 7 patients, 1 patient is being followed up due to residual tumor.Treatment may be achieved through recognizing malignant transformation in patients who were not diagnosed histopathologically. We consider that quality of life of the patients may be improved through this way.

Challenges in the surgical treatment of undiagnosed functional paragangliomas: A case report

INTRODUCTION

Paragangliomas (PGs) or extra-adrenal pheochromocytomas are rare neuroendocrine neoplasms of ubiquitous distribution. Those that produce excess catecholamine are categorized as functional, and those that do not are categorized as nonfunctional. Although modern medical technology is becoming more widespread, there are still substantial risks of misdiagnosis or missed diagnosis of PGs.

CASE PRESENTATION

A 38-year-old woman who lived in an autonomous region of inner Mongolia presented complaining of having experienced coughing for approximately the past month. Chest computed tomography (CT) and magnetic resonance imaging (MRI) revealed a lesion on the right side of thoracic vertebra 5-8 of approximately 66 mm × 54 mm, and it was deemed to be a mediastinal tumor that required surgical treatment. The patient exhibited severe hemodynamic instability during the operation, resulting in substantial challenges and risks with regard to anesthesia management.

CONCLUSION

When a patient is suspected having PG, whether the surgery should be continued or not depends on their overall condition and whether hemodynamic fluctuation can be controlled to within the normal range. Both are factors that should be considered during intraoperative management. Communication between the surgeon and anesthesiologist is necessary, in order to accurately assess the risks associated with the operation. The combination of central venous pressure and the Flotrac/Vigileo system may provide precise guidance for complementary liquid therapy and reduce cardiopulmonary complications. After the operation, hemodynamic changes should be monitored continuously in the intensive care unit, and vasoactive drugs are required to avoid postoperative hypotension. Dramatic hemodynamic changes are certainly a challenge for patients and anesthesiologists, regardless of their origin, and sufficient attention should be paid to avoid serious consequences.

Mathematical Models for Tumor Growth and the Reduction of Overtreatment

Background  To improve our understanding of the natural course of head and neck paragangliomas (HNPGL) and ultimately differentiate between cases that benefit from early treatment and those that are best left untreated, we studied the growth dynamics of 77 HNPGL managed with primary observation. Methods  Using digitally available magnetic resonance images, tumor volume was estimated at three time points. Subsequently, nonlinear least squares regression was used to fit seven mathematical models to the observed growth data. Goodness of fit was assessed with the coefficient of determination ( R ² ) and root-mean-squared error. The models were compared with Kruskal-Wallis one-way analysis of variance and subsequent post-hoc tests. In addition, the credibility of predictions (age at onset of neoplastic growth and estimated volume at age 90) was evaluated. Results  Equations generating sigmoidal-shaped growth curves (Gompertz, logistic, Spratt and Bertalanffy) provided a good fit (median R ² : 0.996-1.00) and better described the observed data compared with the linear, exponential, and Mendelsohn equations ( p  < 0.001). Although there was no statistically significant difference between the sigmoidal-shaped growth curves regarding the goodness of fit, a realistic age at onset and estimated volume at age 90 were most often predicted by the Bertalanffy model. Conclusions  Growth of HNPGL is best described by decelerating tumor growth laws, with a preference for the Bertalanffy model. To the best of our knowledge, this is the first time that this often-neglected model has been successfully fitted to clinically obtained growth data.

Jugular foramen tumour resulting in hypoglossal denervation pseudohypertrophy: a rare and significant cause for tongue asymmetry

Paragangliomas of the jugular foramen are rare. They may present with symptoms of compression of the glossopharyngeal or vagus nerves, or due to secretion of catecholamines from chromaffin cells within the tumour. This case describes a rare presentation of glomus tumour. A 67-year-old patient presented with a 2-month history of right-sided tongue swelling. She was found to have an obvious swelling on the right side of the tongue but no obvious weakness or fasciculation on initial examination. Ultrasound confirmed diffuse muscle swelling, but no lesion within the tongue. Magnetic resonance imaging of the neck revealed an ipsilateral glomus jugulare tumour that extended to the hypoglossal canal, and had resulted in ipsilateral denervation pseudohypertrophy of the lingual muscles. This paper reviews presentation of glomus jugulare tumours and contributes a novel presentation of a rare entity.

Molecular markers of paragangliomas/pheochromocytomas

Paragangliomas/pheochromocytomas comprise rare tumors that arise from the extra-adrenal paraganglia, with an incidence of about 2 to 8 per million people each year. Approximately 40% of cases are due to genetic mutations in at least one out of more than 30 causative genes. About 2530% of pheochromocytomas/paragangliomas develop under the conditions of a hereditary tumor syndrome a third of which are caused by mutations in the VHL gene. Together, the gene mutations in this disorder have implicated multiple processes including signaling pathways, translation initiation, hypoxia regulation, protein synthesis, differentiation, survival, proliferation, and cell growth. The present review contemplates the mutations associated with the development of pheochromocytomas/paragangliomas and their potential to serve as specific markers of these tumors and their progression. These data will improve our understanding of the pathogenesis of these tumors and likely reveal certain features that may be useful for early diagnostics, malignancy prognostics, and the determination of new targets for disease therapeutics.

Role of VHL, HIF1A and SDH on the expression of miR-210: Implications for tumoral pseudo-hypoxic fate

The hypoxia-inducible factor 1α (HIF-1α) and its microRNA target, miR-210, are candidate tumor-drivers of metabolic reprogramming in cancer. Neuroendocrine neoplasms such as paragangliomas (PGLs) are particularly appealing for understanding the cancer metabolic adjustments because of their associations with deregulations of metabolic enzymes, such as succinate dehydrogenase (SDH), and the von Hippel Lindau (VHL) gene involved in HIF-1α stabilization. However, the role of miR-210 in the pathogenesis of SDH-related tumors remains an unmet challenge. Herein is described an in vivo genetic analysis of the role of VHL, HIF1A and SDH on miR-210 by using knockout murine models, siRNA gene silencing, and analyses of human tumors. HIF-1α knockout abolished hypoxia-induced miR-210 expression in vivo but did not alter its constitutive expression in paraganglia. Normoxic miR-210 levels substantially increased by complete, but not partial, VHL silencing in paraganglia of knockout VHL-mice and by over-expression of p76del-mutated pVHL. Similarly, VHL-mutated PGLs, not those with decreased VHL-gene/mRNA dosage, over-expressed miR-210 and accumulate HIF-1α in most tumor cells. Ablation of SDH activity in SDHD-null cell lines or reduction of the SDHD or SDHB protein levels elicited by siRNA-induced gene silencing did not induce miR-210 whereas the presence of SDH mutations in PGLs and tumor-derived cell lines was associated with mild increase of miR-210 and the presence of a heterogeneous, HIF-1α-positive and HIF-1α-negative, tumor cell population. Thus, activation of HIF-1α is likely an early event in VHL-defective PGLs directly linked to VHL mutations, but it is a late event favored but not directly triggered by SDHx mutations. This combined analysis provides insights into the mechanisms of HIF-1α/miR-210 regulation in normal and tumor tissues potentially useful for understanding the pathogenesis of cancer and other diseases sharing similar underpinnings.

Age and Tumor Volume Predict Growth of Carotid and Vagal Body Paragangliomas

Objective  Treatment for head and neck paragangliomas (HNGPL) can be more harmful than the disease. After diagnosis, an initial period of surveillance is often indicated, and surgery or radiotherapy is reserved for progressive disease. With the aim to optimize this "wait and scan" strategy, we studied growth and possible predictors. Design  A retrospective cohort study was conducted. Setting  This study was conducted at a tertiary referral center for patients with HNGPL. Methods  Tumor volume was estimated for 184 SDHD -related carotid and vagal body paragangliomas using sequential magnetic resonance imaging. Cox regression was used to study predictors of tumor growth. Results  The estimated fraction of growing tumors ranged from 0.42 after 1 year of follow-up to 0.85 after 11 years. A median growth rate of 10.4 and 12.0% per year was observed for carotid and vagal body tumors, respectively. Tumor location, initial volume, and age ( p  < 0.05) were included in our prediction model. The probability of growth decreased with increasing age and volume, indicating a decelerating growth pattern. Conclusions  We created a prediction model (available online), enabling a more individualized "wait and scan" strategy. The favorable natural course of carotid and vagal body paragangliomas was confirmed; although with long follow-up growth will be observed in most cases.

Glomus Tumor of the Larynx: A Rare Synchronous Paraganglioma in a Patient with Bilateral Carotid Body Tumor Detected on 68Ga-DOTANOC PET/CT

Paragangliomas are neoplasms arising from extra-adrenal chromaffin tissue. They frequently cause symptoms by overproduction of catecholamines with known predilection to multicentricity. We describe the case of a patient with bilateral carotid body tumor who underwent a baseline 68 Gallium labeled [1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid]-1-NaI3-Octreotide

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.

Imaging findings of malignant bilateral carotid body tumors: A case report and review of the literature

Carotid body tumors (CBTs) are a rare type of extra-adrenal paraganglioma, which originate from the carotid body. A 29-year-old woman was admitted to the Department of Head and Neck Surgery, Beijing Tongren Hospital (Capital Medical University, Beijing, China) with hoarseness of the throat, which had progressively worsened over seven months. The patient had a family history of CBTs. Computed tomography and ultrasound imaging revealed multiple well-enhanced masses located at the bilateral carotid bifurcation and in the left parapharyngeal space. Surgery and pathological examination confirmed that the patient had developed regional lymph node metastasis. Significantly enhanced multiple pulmonary and hepatic lesions indicated that the patient had also developed distal metastasis. A genetic analysis performed on the family members of the patient revealed that the family carried a mutated succinate dehydrogenase D gene. In the present study, a systemic review of the literature indicated that extra vigilance is required in familial forms of CBT, in order to increase the standard of treatment for CBT patients.

Next-generation sequencing for the diagnosis of hereditary pheochromocytoma and paraganglioma syndromes

PURPOSE OF REVIEW

About 40% of the neuroendocrine tumors pheochromocytomas and paragangliomas (PPGLs) are caused by an inherited mutation. Diagnostic genetic screening is recommended for patients and their families. However, the number of susceptibility genes involved is high and continues to grow, making conventional sequencing costly and burdensome. Next-generation sequencing (NGS) enables accurate, thorough, and cost-effective identification of inherited mutations. Here we review recent successes, limitations, and the future of NGS for diagnosis of pheochromocytoma and paraganglioma syndromes.

RECENT FINDINGS

NGS-based screen of genetic disorders in the clinical setting shows improved diagnostic rates over conventional tests. Both broad, whole-exome sequencing, and targeted NGS approaches have been tested for screening of PPGLs, with accurate mutation detection, higher speed, and reduced costs compared with current assays. Flexibility to expand the targeted gene set is immediate in whole-exome sequencing, and adjustable in targeted NGS, but both methods have limitations.

SUMMARY

The high degree of genetic heterogeneity and heritability of PPGLs make NGS an ideal medium for their diagnostic screening. However, improved detection of large genomic defects and underrepresented gene areas are needed before NGS can fully realize its potential as the premier option for routine genetic testing of these syndromes.

Low penetrance of paraganglioma and pheochromocytoma in an extended kindred with a germline SDHB exon 3 deletion

In the Netherlands, the majority of hereditary paragangliomas (PGL) is caused by SDHD, SDHB and SDHAF2 mutations. Founder mutations in SDHD are particularly prevalent, but several SDHB founder mutations have also been described. Here, we describe an extended PGL family with a Dutch founder mutation in SDHB, c.201-4429_287-933del. The proband presented with apparently sporadic head and neck paraganglioma at advanced age. Subsequently, evaluation of the family identified several unaffected mutation carriers, asymptomatic and symptomatic PGL patients, and patients presenting with early-onset malignant pheochromocytoma. The calculated penetrance of the SDHB mutation in this kindred is lower than the risk suggested for SDHB mutations in the literature. This may represent a characteristic of this particular SDHB mutation, but may also be a reflection of the inclusion of relatively large numbers of asymptomatic mutation carriers in this family and adequate statistical correction for ascertainment bias. The low penetrance of SDHB mutations may obscure the hereditary nature of SDHB-linked disease and is important in the counseling of SDHB-linked patients. Risk estimates should preferably be based on the specific mutation involved.

Counseling patients with succinate dehydrogenase subunit defects: genetics, preventive guidelines, and dealing with uncertainty

The discovery that mutations in the succinate dehydrogenase (SDH) complex subunit (SDHA, B/C/D/AF2) genes predispose patients to the development of tumors has led to the identification of a large population of patients and relatives at risk for developing malignancies. The most frequent conditions associated with these mutations are the familial paraganglioma syndromes. Other tumors that are frequently associated with SDH mutations (SDHx) are gastrointestinal stromal tumors and renal cell carcinomas. A number of other rare associations have also been described. SDHx mutations are often clinically silent and metastatic, but they may also be aggressive in their presentation. The penetrance of these mutations is beginning to be understood, and the characteristics of the phenotype are being elucidated. However, the inability to accurately predict the appearance, nature, and location of tumors as well as their tendency to recur or metastasize pose challenges to those who counsel and manage patients with SDHx mutations. In this work, we present our approach for counseling these families in the context of the current uncertainties, while striving to maintain patient autonomy.

Tyrosine kinase receptors as molecular targets in pheochromocytomas and paragangliomas

Pheochromocytomas and paragangliomas are neuroendocrine tumors shown to be responsive to multitargeted tyrosine kinase inhibitor (TKI) treatment. Despite growing knowledge regarding their genetic basis, the ability to predict behavior in these tumors remains challenging. There is also limited knowledge of their tyrosine kinase receptor expression and whether the clinical response observed to the TKI sunitinib relates only to its anti-angiogenic properties or also due to a direct effect on tumor cells. To answer these questions, an in vitro model of sunitinib treatment of a pheochromocytoma cell line was created. Sunitinib targets (VEGFRs, PDGFRs, and C-KIT), FGFRs, and cell cycle regulatory proteins were investigated in human tissue microarrays. SDHB immunohistochemistry was used as a surrogate marker for the presence of succinate dehydrogenase mutations. The FGFR4 G388R single nucleotide polymorphism was also investigated. Sunitinib treatment in vitro decreases cell proliferation mainly by targeting cell cycle, DNA metabolism, and cell organization genes. FGFR1, -2, and -4, VEGFR2, PDGFRα, and p16 were overexpressed in primary human pheochromocytomas and paragangliomas. Discordant results were observed for VEGFR1, p27, and p21 overexpressed in paragangliomas but underexpressed in pheochromocytomas; PDGFRβ, Rb, and Cyclin D1 overexpressed in paragangliomas only; and FGFR3 overexpressed in pheochromocytomas and underexpressed in paragangliomas. Low expression of C-KIT, p53, and Aurora kinase A and B was observed. Nuclear FGFR2 expression was associated with increased risk of metastasis (odds ratio (OR)=7.61, P=0.008), as was membranous PDGFRα (OR=13.71, P=0.015), membranous VEGFR1 (OR=8.01, P=0.037), nuclear MIB1 (OR=1.26, P=0.008), and cytoplasmic p27 (OR=1.037, P=0.030). FGFR3, VEGFR2, and C-KIT levels were associated with decreased risk of metastasis. We provide new insights into the mechanistic actions of sunitinib in pheochromocytomas and paragangliomas, and support current evidence that multitargeted TKIs might be a suitable treatment alternative for these tumors.

Telomerase reverse transcriptase promoter mutations in tumors originating from the adrenal gland and extra-adrenal paraganglia

Hotspot mutations in the promoter of the telomerase reverse transcriptase (TERT) gene have been recently reported in human cancers and proposed as a novel mechanism of telomerase activation. To explore TERT promoter mutations in tumors originating from the adrenal gland and extra-adrenal paraganglia, a set of 253 tumors (38 adrenocortical carcinomas (ACCs), 127 pheochromocytomas (PCCs), 18 extra-adrenal paragangliomas (ea PGLs), 37 head and neck PGLs (HN PGLs), and 33 peripheral neuroblastic tumors) was selected along with 16 human neuroblastoma (NBL) and two ACC cell lines to assess TERT promoter mutations by the Sanger sequencing method. All mutations detected were confirmed by a SNaPshot assay. Additionally, 36 gastrointestinal stromal tumors (GISTs) were added to explore an association between TERT promoter mutations and SDH deficiency. TERT promoter mutations were found in seven out of 289 tumors and in three out of 18 human cell lines; four C228T mutations in 38 ACCs (10.5%), two C228T mutations in 18 ea PGLs (11.1%), one C250T mutation in 36 GISTs (2.8%), and three C228T mutations in 16 human NBL cell lines (18.75%). No mutation was detected in PCCs, HN PGLs, neuroblastic tumors as well as ACC cell lines. TERT promoter mutations preferentially occurred in a SDH-deficient setting (P=0.01) being present in three out of 47 (6.4%) SDH-deficient tumors vs zero out of 171 (0%) SDH-intact tumors. We conclude that TERT promoter mutations occur in ACCs and ea PGLs. In addition, preliminary evidence indicates a potential association with the acquisition of TERT promoter mutations in SDH-deficient tumors.

Role of irradiation in combined treatment of head and neck paragangliomas at the Centre of Oncology in Krakow between 1970-2005

AIM OF THE STUDY

Aim of the study is to evaluate the results of postoperative radiotherapy of paragangliomas, prognostic factors and causes of treatment failure.

MATERIAL AND METHODS

Forty-four patients (39 females and 5 males) aged 20 to 74 years were treated for paraganglioma between 1970 and 2010 at the Centre of Oncology in Kraków. Patient survival probability was estimated with the Kaplan-Meier method. Log-rank tests and Cox proportional hazard model were used in univariate and multivariate analysis, respectively.

RESULTS

The most common locations of paragangliomas were the following: the ear, carotid body and internal jugular vein bulb. Forty (91%) out of them were benign and 4 - malignant. All patients underwent surgery followed by adjuvant radiotherapy. The delivered dose ranged from 50 to 72 Gy, the mean dose was 60 Gy. Five-year overall survival was 84%. Five-year relapse-free survival was 84%, either. The multivariate analysis has shown that the dose in an independent prognostic factor for the overall survival. The univariate analysis has shown significantly higher 5-year overall survival in patients who received a dose of 60 Gy or higher - 92% vs. 70% in patients who received a dose lower than 60 Gy.

CONCLUSIONS

Postoperative radiotherapy with doses higher than 60 Gy in patients with paragangliomas is associated with longer overall survival.

The management of head-and-neck paragangliomas

Paragangliomas (PGLs) are tumours originating from neural crest-derived cells situated in the region of the autonomic nervous system ganglia. Head-and-neck PGLs (HNPGLs) originate from the sympathetic and parasympathetic paraganglia, most frequently from the carotid bodies and jugular, tympanic and vagal paraganglia, and are usually non-catecholamine secreting. Familial PGLs are considered to be rare, but recently genetic syndromes including multiple PGLs and/or phaeochromocytomas have been more thoroughly characterised. Nowadays, genetic screening for the genes frequently implicated in both familial and sporadic cases is routinely being recommended. HNPGLs are mostly benign, generally slow-growing tumours. Continuous growth leads to the involvement of adjacent neurovascular structures with increased morbidity rates and treatment-related complications. Optimal management mostly depends on tumour location, local involvement of neurovascular structures, estimated malignancy risk, patient age and general health. Surgery is the only treatment option offering the chance of cure but with significant morbidity rates, so a more conservative approach is usually considered, especially in the more difficult cases. Radiotherapy (fractionated or stereotactic radiosurgery) leads to tumour growth arrest and symptomatic improvement in the short term in many cases, but the long-term consequences are unclear. Early detection is essential in order to increase the chance of cure with a lower morbidity rate. The constant improvement in diagnostic imaging, surgical and radiation techniques has led to a safer management of these tumours, but there are still many therapeutic challenges, and no treatment algorithm has been agreed upon until now. The management of HNPGLs requires a multidisciplinary effort addressing the genetic, surgical, radiotherapeutic, oncological, neurological and endocrinological implications. Further progress in the understanding of their pathogenesis will lead to more effective screening and earlier diagnosis, both critical to successful treatment.

Malignant and benign sinonasal paragangliomas

OBJECTIVES/HYPOTHESIS

To report on the clinical course and management of sinonasal paragangliomas (PGLs).

STUDY DESIGN AND METHODS

Retrospective chart review of six patients with PGLs of the nasal cavity and paranasal sinuses.

RESULTS

Three patients had tumors with malignant clinical behavior with cerebral metastases or infiltration of brain and local recurrence, despite surgery and/or radiotherapy, while three patients demonstrated a benign course.

CONCLUSION

Sinonasal paragangliomas are frequently malignant. If malignant, they are very aggressive, with rapid local spread as well as high metastatic potential despite surgical resection; and they have a poor prognosis. Malignancy cannot be diagnosed on histology, but only on the basis of clinical behavior. Intracranial metastasis is commonly expected. Long-term follow-up, with particular emphasis put on the intracranial structures, is mandatory as recurrences or metastasis may occur even after a long time interval.