Current approaches and recent developments in the management of head and neck paragangliomas

Current Management of Head and Neck Paragangliomas: A Multicenter Series With Long-Term Follow-Up

OBJECTIVE, STUDY DESIGN, SETTING, METHODS

To improve our knowledge about head and neck paragangliomas (HN-PGL), the clinical characteristics of all the patients with HN-PGL included in the Spanish Registry were analyzed, as well as the treatment modalities and their outcomes.

RESULTS

A total of 202 patients, 67.8% women, aged 53.1 ± 17.4, with 264 HN-PGL, from 16 Spanish hospitals, were included. Tumors were located in the carotid body in 61%, jugular bulb in 20.5%, tympanic area in 10.2%, and along the vagal nerve in 6.4%. Multiple tumors developed in 20.8% and metastatic disease in 4%. A genetic study was done in 64.4% and showed a pathogenic variant in SDHx in 50%. These patients were younger, with no sex predominance, and had more multiple and metastatic tumors. Tumors were treated by surgery in 134 patients, radiotherapy in 33, and other treatments in 20, and were observed without active treatment in 41 patients, who were older, more often asymptomatic, and had smaller tumors. Tumors treated with radiotherapy were larger and more often in locations other than the carotid body. After a median follow-up of 80 months (interquartile range: 41-136), 6.9% had died; among the survivors, 48.4% were disease-free, 42.1% stable, and 9.4% had progressed. The rate of sequelae was similar among patients submitted to surgery, radiotherapy, or observation. We could not identify any prognostic factor for progression.

CONCLUSION

Most HN-PGL are localized slow-growing tumors. Long-term survival is high, even in case of metastasis. Although surgery is the most common treatment, radiotherapy and active surveillance are safe approaches.

Overview of recent guidelines and consensus statements on initial screening and management of phaeochromocytoma and paraganglioma in SDHx pathogenic variant carriers and patients

Phaeochromocytomas and paragangliomas (PPGLs) are rare neuroendocrine tumours with a strong genetic predisposition, involving over 20 genes and with germline pathogenic variants identified in 40 % of cases. The succinate dehydrogenase (SDHx) genes are the most commonly implicated in hereditary PPGLs, accounting for 20 % of cases, and present unique diagnostic and treatment challenges due to their potential for multiple, recurrent, and aggressive manifestations, often necessitating lifelong follow-up. Over the past two decades, advances in biochemical and imaging assessments, management, and follow-up protocols have significantly improved care for both adult and paediatric patients. These advances include next-generation sequencing, new biochemical tests, cluster-specific functional imaging, and improved surgical and radiotherapy techniques, such as stereotactic surgery and peptide receptor radionuclide therapy (PRRT). International consensus guidelines have been developed to standardise the management of patients with SDHx pathogenic variants, emphasising multidisciplinary approaches and frequent tumour board discussions. These guidelines, summarised below, cover recommendations for initial genetic testing, tumour screening, follow-up care, and management of patients and asymptomatic carriers.

Thyroid Paraganglioma: A Rare Manifestation of Paraganglioma Syndrome Associated With Pathogenic Variant in SDHD

Evaluation of an incidentally discovered indeterminate thyroid nodule (TN) in a previously healthy 59-year female led to diagnosis of thyroid paraganglioma (TPGL) and subsequently hereditary succinate dehydrogenase complex subunit D (SDHD)-related multifocal head and neck paragangliomas (PGLs). An ultrasound-guided fine needle aspiration (FNA) biopsy of the 1.7-cm TN was nondiagnostic and core biopsy was suspicious for papillary thyroid carcinoma. Pathology slides reviewed at tertiary center showed neuroendocrine neoplasm consistent with PGL. Her 24-hour urinary catecholamines and metanephrines were normal. Given the diagnosis of TPGL, genetic testing was recommended, which identified a pathogenic variant in SDHD (c.242C > T(p.P81L). Gallium-68-DOTATATE PET/CT revealed multifocal areas of increased somatostatin receptor expression from the skull base to thoracic inlet. Magnetic resonance imaging of the brain/neck showed multiple PGLs (right jugular, carotid, thyroid, left vagal, left level II, and superior mediastinal), all measured up to 1.7 cm. The right jugular PGL was treated with external beam radiation therapy of 3000 cGy. All PGLs remained stable and asymptomatic at 22-month follow-up imaging. TPGL should be considered in the differential diagnosis of a hypervascular TN in patients with SDHx-related pheochromocytoma-PGL syndromes and when such lesions with indeterminate cytology are encountered in patients with no known history of SDHx-mutation or syndrome.

Neck paragangliomas: a case report and literature review

OBJECTIVE

Thyroid-originated paragangliomas are very uncommon, and there is a lack of established guidelines regarding their management.

METHODS

A case study was presented, and a review of the literature was conducted.

RESULTS

Diagnosing a paraganglioma requires multiple diagnostic methods, including a 24-h measurement of metanephrines or catecholamines, anatomical imaging using magnetic resonance or computed tomography (CT) scans, and functional imaging using metaiodobenzylguanidine or 18F-DOPA PET/CT scans. Additionally, with the presence of somatostatin receptors on paragangliomas, the use of octreotide scans such as a 68Ga DOTATATE PET/CT scan is expected to increase soon. The primary treatment for laryngeal paragangliomas is surgical intervention aimed at achieving optimal tumor removal while retaining the highest possible level of laryngeal function. One should not do elective neck dissection given the low risk of metastasis and recurrence. Although the rate of recurrence and metastasis for paragangliomas is low, continued monitoring through clinic visits, biochemical testing, and imaging is still necessary. Furthermore, follow-up efforts should also consider genetic testing of the critical genes associated with paragangliomas.

CONCLUSION

Although there is still debate regarding the existence of thyroid paraganglioma, it can nonetheless be classified as a subtype of laryngeal paragangliomas. All hypervascular thyroid nodules require the consideration of thyroid-associated paragangliomas.

Approach to the Patient: Concept and Application of Targeted Radiotherapy in the Paraganglioma Patient

Paragangliomas can metastasize, posing potential challenges both in symptomatic management and disease control. Systemic targeted radiotherapies using 131I-MIBG and 177Lu-DOTATATE are a mainstay in the treatment of metastatic paragangliomas. This clinical scenario and discussion aim to enhance physicians' knowledge of the stepwise approach to treat these patients with paraganglioma-targeted radiotherapies. It comprehensively discusses current approaches to selecting paraganglioma patients for targeted radiotherapies and how to choose between the two radiotherapies based on specific patient and tumor characteristics, when either therapy is feasible, or one is superior to another. The safety, efficacy, toxicity profiles, and optimization of these radiotherapies are also discussed, along with other therapeutic options including radiotherapies, available for patients besides these two therapies. Perspectives in radiotherapies of paraganglioma patients are outlined since they hold promising approaches in the near future that can improve patient outcomes.

[Paragangliomas of the head and neck]

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

Head and Neck Paraganglioma (HNPGL) Registry: A study protocol for prospective data collection in patients with Head and Neck Paragangliomas

INTRODUCTION

There is a lack of comprehensive and uniform data on head and neck paragangliomas (HNPGLs), and research is challenging due to its rarity and the involvement of multiple medical specialties. To improve current research data collection, we initiated the Head and Neck Paraganglioma Registry (HNPGL Registry). The aim of the HNPGL Registry is to a) collect extensive data on all HNPGL patients through a predefined protocol, b) give insight in the long term outcomes using patient reported outcome measures (PROMs), c) create uniformity in the diagnostic and clinical management of these conditions, and thereby d) help provide content for future (randomized) research.

METHODS AND ANALYSIS

The HNPGL Registry is designed as a prospective longitudinal observational registry for data collection on HNPGL patients and carriers of (likely) pathogenic variants causative of HNPGLs. All patients, regardless of the received treatment modality, can be included in the registry after informed consent is obtained. All relevant data regarding the initial presentation, diagnostics, treatment, and follow-up will be collected prospectively in an electronic case report form. In addition a survey containing the EuroQol 5D-5L (EQ-5D-5L), European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ-C30), Modified Fatigue Impact Scale (MFIS), Short QUestionnaire to Assess Health-enhancing physical activity (SQUASH), Cancer Worry Scale (CWS) and Hospital Anxiety and Depression Scale (HADS) will be sent periodically. The registry protocol was approved by the Medical Ethical Review Board of the University Medical Center Utrecht.

CONCLUSION

The HNPGL Registry data will be used to further establish the optimal management for HNPGL patients and lay the foundation for guideline recommendations and the outline of future research.

Phaeochromocytoma and paraganglioma

Phaeochromocytomas and paragangliomas are rare catecholamine-producing neuroendocrine tumours which can potentially cause catastrophic crises with high morbidity and mortality. This best practice article considers the causes and presentation of such tumours, screening and diagnostic tests, management of these patients and consideration of family members at risk.

Treatment for paraganglioma with stereotactic radiotherapy

BACKGROUND

Paragangliomas (PG) are rare neoplasms of neuroendocrine origin that tend to be highly vascularized, slow-growing, and usually sporadic. To date, common treatment options are surgical resection (SR), with or without radiation therapy (RT), and a watch-and-wait approach.

AIM

To evaluate the local control and effectiveness of exclusive fractionated stereotactic RT (FSRT) treatment in unresectable PG (uPG).

METHODS

We retrospectively evaluated patients with uPG (medically inoperable or refused SR) treated with FSRT with a Cyberknife System (Accuray Incorporated, Sunnyvale, California). Toxicity and initial efficacy were evaluated.

RESULTS

From May 2009 to January 2023, 6 patients with a median age of 68 (range 20-84) were treated with FSRT. The median delivered dose was 21 Gy (range 20-30 Gy) at a median isodose line of 75.5% (range 70%-76%) in 4 fractions (range 3-5 fractions). The median volume was 13.6 mL (range 12.4-65.24 mL). The median cumulative biological effective dose and equivalent dose in 2-Gy fractions were 70 Gy and 37.10 Gy respectively. Site of origin involved were the timpa-nojugular glomus (4/6), temporal bone, and cervical spine. In 1 of the 6 patients, the follow-up was insufficient; 5 of 6 patients showed a 5-year overall survival and 5-year progression-free survival of 100%. We observed negligible toxicities during and after RT. The majority of patients showed stable symptoms during follow-up. Only 1 patient developed spine metastases.

CONCLUSION

Our preliminary results on this small cohort of patients suggest that FSRT could be an effective and safe alternative to SR.

Treatment for paraganglioma with stereotactic radiotherapy

BACKGROUND

Paragangliomas (PG) are rare neoplasms of neuroendocrine origin that tend to be highly vascularized, slow-growing, and usually sporadic. To date, common treatment options are surgical resection (SR), with or without radiation therapy (RT), and a watch-and-wait approach.

AIM

To evaluate the local control and effectiveness of exclusive fractionated stereotactic RT (FSRT) treatment in unresectable PG (uPG).

METHODS

We retrospectively evaluated patients with uPG (medically inoperable or refused SR) treated with FSRT with a Cyberknife System (Accuray Incorporated, Sunnyvale, California). Toxicity and initial efficacy were evaluated.

RESULTS

From May 2009 to January 2023, 6 patients with a median age of 68 (range 20-84) were treated with FSRT. The median delivered dose was 21 Gy (range 20-30 Gy) at a median isodose line of 75.5% (range 70%-76%) in 4 fractions (range 3-5 fractions). The median volume was 13.6 mL (range 12.4-65.24 mL). The median cumulative biological effective dose and equivalent dose in 2-Gy fractions were 70 Gy and 37.10 Gy respectively. Site of origin involved were the timpa-nojugular glomus (4/6), temporal bone, and cervical spine. In 1 of the 6 patients, the follow-up was insufficient; 5 of 6 patients showed a 5-year overall survival and 5-year progression-free survival of 100%. We observed negligible toxicities during and after RT. The majority of patients showed stable symptoms during follow-up. Only 1 patient developed spine metastases.

CONCLUSION

Our preliminary results on this small cohort of patients suggest that FSRT could be an effective and safe alternative to SR.

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

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

Head and Neck Malignant Paragangliomas: Experience from a Single Institution

Objectives: To summarize the clinicopathological and genetic features of malignant paragangliomas in head and neck cancer and to explore the appropriate treatment options for this rare lesion. Methods: Six patients harboring head and neck malignant paraganglioma from Beijing Tongren Hospital were retrospectively reviewed. The clinicopathological characteristics, gene mutations, and prognosis of these patients were analyzed. Results: Of these 6 patients, 3 were male and 3 were female; 4 patients harbored malignant carotid body tumors, and two had malignant vagal paragangliomas. Three patients had cervical lymph node metastasis, two presented with lung and bone metastasis, and 1 had lung and liver metastasis. Of the 6 patients, four underwent surgical resection, and the other two patients denied surgery and instead received chemotherapy with paclitaxel, ifosfamide, and dacarbazine. These 2 patients with vagal paraganglioma received postoperative radiotherapy. All 6 patients are still alive at the present time, with a median follow-up time of 66 months. Positive Ki-67 expression in tumor tissue ranged from 1% to 40%. Genetic mutations in SDHD, SDHB, ATR, and MAP3K13 were identified in 4 patients. Conclusions: After comprehensive treatment, head and neck malignant paraganglioma can attain a favorable prognosis. Genetic mutations are commonly detected in patients with malignant paragangliomas. This study also identified mutations in ATR and MAP3K13 in these patients.

Tumor metabolism in pheochromocytomas: clinical and therapeutic implications

Pheochromocytomas and paragangliomas (PPGLs) have emerged as one of the most common endocrine tumors. It epitomizes fascinating crossroads of genetic, metabolic, and endocrine oncology, providing a canvas to explore the molecular intricacies of tumor biology. Predominantly rooted in the aberration of metabolic pathways, particularly the Krebs cycle and related enzymatic functionalities, PPGLs manifest an intriguing metabolic profile, highlighting elevated levels of oncometabolites like succinate and fumarate, and furthering cellular malignancy and genomic instability. This comprehensive review aims to delineate the multifaceted aspects of tumor metabolism in PPGLs, encapsulating genetic factors, oncometabolites, and potential therapeutic avenues, thereby providing a cohesive understanding of metabolic disturbances and their ramifications in tumorigenesis and disease progression. Initial investigations into PPGLs metabolomics unveiled a stark correlation between specific genetic mutations, notably in the succinate dehydrogenase complex (SDHx) genes, and the accumulation of oncometabolites, establishing a pivotal role in epigenetic alterations and hypoxia-inducible pathways. By scrutinizing voluminous metabolic studies and exploiting technologies, novel insights into the metabolic and genetic aspects of PPGLs are perpetually being gathered elucidating complex interactions and molecular machinations. Additionally, the exploration of therapeutic strategies targeting metabolic abnormalities has burgeoned harboring potential for innovative and efficacious treatment modalities. This review encapsulates the profound metabolic complexities of PPGLs, aiming to foster an enriched understanding and pave the way for future investigations and therapeutic innovations in managing these metabolically unique tumors.

Head and Neck Paragangliomas: Overview of Institutional Experience

Head and neck paragangliomas (HNPGLs) are rare and have high rates of genetic mutations. We conducted a retrospective review of 187 patients with 296 PGLs diagnosed between 1974 and 2023. The mean age of diagnosis was 48.8 years (range 10 to 82) with 69.0% female and 26.5% patients with multiple PGLs. Among 119 patients undergoing genetic testing, 70 (58.8%) patients had mutations, with SDHB (30) and SDHD (26) being the most common. The rates of metastasis and recurrence were higher among patients with SDHB mutations or SDHD mutations associated with multiple PGLs. Metabolic evaluation showed elevated plasma dopamine levels were the most common derangements in HNPGL. MRI and CT were the most common anatomic imaging modalities and DOTATATE was the most common functional scan used in this cohort. Most patients (81.5%) received surgery as the primary definitive treatment, while 22.5% patients received radiation treatment, mostly as an adjuvant therapy or for surgically challenging or inoperable cases. Systemic treatment was rarely used in our cohort. Our single-center experience highlights the need for referral for genetic testing and metabolic evaluation and for a team-based approach to improve the clinical outcomes of patients with HNPGLs.

Long-Term Surgical Outcome of Class A and B Tympanomastoid Paragangliomas

OBJECTIVE

To analyze the long-term facial function as well as overall postoperative condition in surgically treated tympanomastoid PGL patients.

STUDY DESIGN

Retrospective study.

METHOD

The medical records of patients with surgically managed class A and B tympanomastoid PGLs between 1983 and 2023 were thoroughly evaluated.

RESULT

Our center has treated a total of 213 cases of tympanomastoid PGL surgically. The mean age of patients was 54, and the male-to-female ratio was 1:6. The most common symptoms at presentation were hearing loss (80%), pulsatile tinnitus (77%), and vertigo (15%). According to the modified Fisch classification, 45% of the cases were classified as class A (A1 and A2), while 55% were classified as class B (B1, B2, and B3). All class A and most class B1 and B2 tumors were removed either with transcanal or retroauricular-transcanal approaches. However, more advanced class B3 lesions were removed with subtotal petrosectomy (SP) along with middle ear obliteration. Facial nerve outcome was excellent in all class A and B cases, while chances of postoperative paresis slightly increased with the size and extent of the tumor (p < 0.05). The hearing outcome is excellent for class A1, A2, B1, and B2 tumors, whereas more advanced class B3 cases have a loss of air conduction (AC) and increased bone conduction (BC) threshold (p < 0.05). Complete surgical removal was achieved in 97% of our cases. The most common late complication was permanent TM perforation (7%), and the recurrence rate was 3%.

CONCLUSIONS

Tympanomastoid PGL represents the most common neoplasm of the middle ear space. The most frequent presenting symptoms include pulsatile tinnitus and hearing loss, whereas the presence of retrotympanic mass was evident in all cases at the time of initial otoscopic evaluation. Proper documentation of facial function and audiometric evaluation are crucial elements of preoperative workup. The most preferred preoperative radiologic examination is high-resolution computer tomography (HRCT), whereas magnetic resonance imaging (MRI) with or without gadolinium enhancement is reserved for cases with a dilemma of carotid artery or jugular bulb involvement. The main goal of tympanomastoid PGL treatment is complete disease removal with preservation of hearing and facial functions. Surgical treatment remains the preferred treatment modality with the benefits of complete disease removal, lower rate of recurrence and complication, and acceptable postoperative hearing level. Here, we present our 40 years of experience, which, to the very best of our knowledge, is the largest series of tympanomastoid PGL in the English literature.

Pitfalls in the Diagnostic Evaluation of Pheochromocytomas

Pheochromocytomas and paragangliomas (PPGLs), rare neuroendocrine tumors arising from chromaffin cells, present a significant diagnostic challenge due to their clinical rarity and polymorphic symptomatology. The clinical cases demonstrate the importance of an integrated approach that combines clinical assessment, biochemical testing, and imaging to distinguish PPGLs from mimicking conditions, such as obstructive sleep apnea and interfering medication effects, which can lead to false-positive biochemical results. Although a rare condition, false-negative metanephrine levels can occur in pheochromocytomas, but imaging findings can give some clues and increase suspicion for a pheochromocytoma diagnosis. This expert endocrine consult underscores the critical role of evaluating preanalytical conditions and pretest probability in the biochemical diagnosis of PPGLs. Moreover, a careful differentiation of PPGLs from similar conditions and careful selection and interpretation of diagnostic tests, with focus on understanding and reducing false positives to enhance diagnostic accuracy and patient outcomes, is crucial.

Management of phaeochromocytoma and paraganglioma in patients with germline SDHB pathogenic variants: an international expert Consensus statement

Adult and paediatric patients with pathogenic variants in the gene encoding succinate dehydrogenase (SDH) subunit B (SDHB) often have locally aggressive, recurrent or metastatic phaeochromocytomas and paragangliomas (PPGLs). Furthermore, SDHB PPGLs have the highest rates of disease-specific morbidity and mortality compared with other hereditary PPGLs. PPGLs with SDHB pathogenic variants are often less differentiated and do not produce substantial amounts of catecholamines (in some patients, they produce only dopamine) compared with other hereditary subtypes, which enables these tumours to grow subclinically for a long time. In addition, SDHB pathogenic variants support tumour growth through high levels of the oncometabolite succinate and other mechanisms related to cancer initiation and progression. As a result, pseudohypoxia and upregulation of genes related to the hypoxia signalling pathway occur, promoting the growth, migration, invasiveness and metastasis of cancer cells. These factors, along with a high rate of metastasis, support early surgical intervention and total resection of PPGLs, regardless of the tumour size. The treatment of metastases is challenging and relies on either local or systemic therapies, or sometimes both. This Consensus statement should help guide clinicians in the diagnosis and management of patients with SDHB PPGLs.

Fluorescence-guided minimally-invasive resection of abdominal paragangliomas using indocyanine green

This retrospective study explores the utility of near-infrared (NIR) fluorescence imaging with indocyanine green (ICG) in enhancing the intraoperative identification and guidance for the resection of abdominal paragangliomas. They can be challenging to detect during minimally invasive surgery, due to their anatomical location, varying size and similar appearance in regard to their surrounding tissue. Patients with suspected abdominal paragangliomas planned for a minimally-invasive resection were included. As part of standard of care they received single intravenous dose of 5 mg ICG after abdominal exploration. NIR fluorescence imaging of the anatomical region of the suspected lesion was performed immediately following intravenous administration, to assess fluorescence signals, intraoperative identification, and histopathological correlation. Out of five resected suspicious lesions, four were imaged with NIR fluorescence, pathology confirming four as paragangliomas, the latter turned out to be an adrenal adenoma. NIR fluorescence identified all four lesions, surpassing the limitations of white-light visualization. Homogeneous fluorescence signals appeared 30-60 s post-ICG administration, which lasted up to 30 min. The study demonstrates the feasibility and potential clinical value of fluorescence-guided minimally-invasive resections of abdominal paragangliomas using a single intravenous ICG dose. These findings support the scientific basis for routine use of ICG-fluorescence-guided surgery in challenging anatomical cases, providing valuable assistance in lesion detection and resection.

Jugular Foramen Paragangliomas

Paragangliomas are the most common tumors at jugular foramen and pose a great surgical challenge. Careful clinical history and physical examination must be performed to adequately evaluate neurological deficits and its chronologic evolution, also to delineate an overview of the patient performance status. Complete imaging evaluation including MRI and CT scans should be performed, and angiography is a must to depict tumor blood supply and sigmoid sinus/internal jugular vein patency. Screening for multifocal paragangliomas is advisable, with a whole-body imaging. Laboratory investigation of endocrine function of the tumor is necessary, and adrenergic tumors may be associated with synchronous lesions. Preoperative prepare with alpha-blockage is advisable in norepinephrine/epinephrine-secreting tumors; however, it is not advisable in exclusively dopamine-secreting neoplasms. Best surgical candidates are young otherwise healthy patients with smaller lesions; however, treatment should be individualized each case. Variations of infratemporal fossa approach are employed depending on extensions of the mass. Regarding facial nerve management, we avoid to expose or reroute it if there is preoperative function preservation and prefer to work around facial canal in way of a fallopian bridge technique. If there is preoperative facial nerve compromise, the mastoid segment of the nerve is exposed, and it may be grafted if invaded or just decompressed. A key point is to preserve the anteromedial wall of internal jugular vein if there is preoperative preservation of lower cranial nerves. Careful multilayer closure is essential to avoid at most cerebrospinal fluid leakage. Residual tumors may be reoperated if growing and presenting mass effect or be candidate for adjuvant stereotactic radiosurgery.

High incidence of occult familial SDHD cases amongst Czech patients with head and neck paragangliomas

Introduction

Head and neck paragangliomas (HNPGLs) are rare neuroendocrine tumors, which are mostly benign in nature. Amongst all genes, Succinate Dehydrogenase Subunit D (SDHD) is the most commonly mutated in familial HNPGLs. In about 30% of HNPGLs, germline mutations in SDHD can also occur in the absence of positive family history, thus giving rise to "occult familial" cases. Our aim was to evaluate the pattern of SDHD germline mutations in Czech patients with HNPGLs.

Materials and methods

We analyzed a total of 105 patients with HNPGLs from the Otorhinolaryngology departments of 2 tertiary centers between 2006 - 2021. All underwent complex diagnostic work-up and were also consented for genetic analysis.

Results

Eighty patients aged 13-76 years were included; around 60% with multiple PGLs were males. Carotid body tumor was the most frequently diagnosed tumor. Germline SDHD mutation was found in only 12% of the Czech patients; approximately 78% of those harboring the mutation had negative family history. The mutation traits had higher affiliation for multiple tumors with nearly 70% patients of ≤ 40 years of age.

Conclusion

An SDHD mutation variant was shared amongst unrelated patients but no founder-effect was established. Our findings confirmed that the pattern of SDHD mutation distribution amongst HNPGLs in Czech Republic differs from most studies worldwide.

A case of neck paraganglioma in a 49-year-old male: Case report and review of the literature

INTRODUCTION AND SIGNIFICANCE

Paragangliomas are rare tumors that most commonly occur in the head and neck. They are typically slow-growing tumors that are often associated with genetic syndromes and mutations in the enzyme succinate dehydrogenase.

CASE PRESENTATION

We describe a case of a male patient who presented with ear pain and dysphagia. On physical examination, there was a left neck mass and swalling in the left oropharynx. The mass was excised through a cervical approach and it was found to be a vagal paraganglioma.

CLINICAL DISCUSSION

A few cases of head and neck paragangliomas (HNPGLs) have been reported in the medical literature. These tumors often present as asymptomatic masses, but this case, the patient presented with ear pain and dysphagia the location of the mass in the parapharyngeal space presents a surgical challenge. HNPGLs should be considered in the differential diagnosis of any neck mass.

CONCLUSION

Paragangliomas are generally considered to have a good prognosis when they are completely excised. They rarely metastasize to adjacent or distant tissues. Cervical approach is a valid option for complete excision of cervical paraganglioma.

Metastatic Malignant Glomus Jugulare Tumor: A Rare Case Report with Clinical Manifestations and Treatment Approach

BACKGROUND Paragangliomas are neuroendocrine neoplasms derived from paraganglia of the sympathetic and parasympathetic nervous systems. Parasympathetic ganglia-derived tumors, also called non-chromaffin, are located almost exclusively in the neck and skull base and are usually non-secretory and inactive. A case of malignant glomus jugulare with a metastatic cervical lymph node is described here. CASE REPORT A 24-year-old woman was referred to an otolaryngology clinic for concern of voice change for 1 month, which was associated with right progressive hearing loss, pulsating tinnitus, and right facial weakness. A clinical examination revealed a reddish mass in the right ear behind an intact tympanic membrane with right facial weakness of House-Brackmann grade VI. A bedside flexible nasopharyngoscopy revealed an immobile right vocal fold. A computed tomography scan of the brain revealed a destructive lesion within the right jugular foramen. The patient underwent embolization followed by glomus tumor resection via infra-temporal fossa with Fisch type A approach. Pathology revealed that the tumor was an infiltrative epithelioid tumor with a spindle and nesting pattern separated by fibrovascular stroma. The submitted lateral neck lymph node revealed a metastatic tumor. CONCLUSIONS Glomus jugulare tumors are uncommon paragangliomas, and malignant behavior with metastasis is extremely rare. Metastatic tumors are often associated with facial and vagal nerves palsy. There are no histological features that distinguish malignant glomus jugulare tumors. Malignant neoplasms are characterized by the presence of metastases. Tumors of the glomus jugulare that are malignant are treated with surgery, radiotherapy, or both. However, our search of the literature revealed no clear guidelines, given the scarcity of cases. Moreover, the presence of metastasis increases the risk of death.

The connection between tricarboxylic acid cycle enzyme mutations and pseudohypoxic signaling in pheochromocytoma and paraganglioma

Pheochromocytomas and paragangliomas (PPGLs) are rare neuroendocrine tumors originating from chromaffin cells, holding significant clinical importance due to their capacity for excessive catecholamine secretion and associated cardiovascular complications. Roughly 80% of cases are associated with genetic mutations. Based on the functionality of these mutated genes, PPGLs can be categorized into distinct molecular clusters: the pseudohypoxia signaling cluster (Cluster-1), the kinase signaling cluster (Cluster-2), and the WNT signaling cluster (Cluster-3). A pivotal factor in the pathogenesis of PPGLs is hypoxia-inducible factor-2α (HIF2α), which becomes upregulated even under normoxic conditions, activating downstream transcriptional processes associated with pseudohypoxia. This adaptation provides tumor cells with a growth advantage and enhances their ability to thrive in adverse microenvironments. Moreover, pseudohypoxia disrupts immune cell communication, leading to the development of an immunosuppressive tumor microenvironment. Within Cluster-1a, metabolic perturbations are particularly pronounced. Mutations in enzymes associated with the tricarboxylic acid (TCA) cycle, such as succinate dehydrogenase (SDHx), fumarate hydratase (FH), isocitrate dehydrogenase (IDH), and malate dehydrogenase type 2 (MDH2), result in the accumulation of critical oncogenic metabolic intermediates. Notable among these intermediates are succinate, fumarate, and 2-hydroxyglutarate (2-HG), which promote activation of the HIFs signaling pathway through various mechanisms, thus inducing pseudohypoxia and facilitating tumorigenesis. SDHx mutations are prevalent in PPGLs, disrupting mitochondrial function and causing succinate accumulation, which competitively inhibits α-ketoglutarate-dependent dioxygenases. Consequently, this leads to global hypermethylation, epigenetic changes, and activation of HIFs. In FH-deficient cells, fumarate accumulation leads to protein succination, impacting cell function. FH mutations also trigger metabolic reprogramming towards glycolysis and lactate synthesis. IDH1/2 mutations generate D-2HG, inhibiting α-ketoglutarate-dependent dioxygenases and stabilizing HIFs. Similarly, MDH2 mutations are associated with HIF stability and pseudohypoxic response. Understanding the intricate relationship between metabolic enzyme mutations in the TCA cycle and pseudohypoxic signaling is crucial for unraveling the pathogenesis of PPGLs and developing targeted therapies. This knowledge enhances our comprehension of the pivotal role of cellular metabolism in PPGLs and holds implications for potential therapeutic advancements.

An Update on Temporal Bone Paragangliomas

OPINION STATEMENT

Temporal bone paragangliomas (TBPs) are indolent, classically benign and highly vascular neoplasms of the temporal bone. There are two types of TBPs, tympanomastoid paragangliomas (TMPs) and tympanojugular paragangliomas (TJPs). The most common symptoms are hearing loss and pulsatile tinnitus. Diagnostic workup, besides conventional physical and laboratory examinations, includes biochemical testing of catecholamine and genetic testing of SDHx gene mutations as well as radiological examination. Although surgery is traditionally the mainstay of treatment, it is challenging due to the close proximity of tumor to critical neurovascular structures and thus the high risk of complications, especially in patients with advanced lesions. Radiotherapy and active surveillance have been increasingly recommended for selected patients. Decision on treatment should be made comprehensively. Curative effect depends on various factors. Long-term follow-up with clinical, laboratory, and radiological examinations is essential for all patients.

A Laboratory Medicine Perspective on the Investigation of Phaeochromocytoma and Paraganglioma

Phaeochromocytomas (PC) and sympathetic paragangliomas (PGL) are potentially malignant tumours arising from the adrenal medulla (PC) or elsewhere in the sympathetic nervous system (PGL). These tumours usually secrete catecholamines and are associated with significant morbidity and mortality, so accurate and timely diagnosis is essential. The initial diagnosis of phaeochromocytoma/paraganglioma (PPGL) is often dependent on biochemical testing. There is a range of pre-analytical, analytical and post-analytical factors influencing the analytical and diagnostic performance of biochemical tests for PPGL. Pre-analytical factors include patient preparation, sample handling and choice of test. Analytical factors include choice of methodology and the potential for analytical interference from medications and other compounds. Important factors in the post-analytical phase include provision of appropriate reference ranges, an understanding of the potential effects of various medications on metanephrine concentrations in urine and plasma and a consideration of PPGL prevalence in the patient population being tested. This article reviews these pre-analytical, analytical and post-analytical factors that must be understood in order to provide effective laboratory services for biochemical testing in the diagnosis of PPGL.

Can Superoxide Anions Predict the Malignant Potential of Carotid body Tumor? - A Pilot Study

Currently, there is no consensus on estimating the malignant potential of Carotid Body Tumor (CBT) and the only way to predict a metastatic CBT is through DOTANOC Positron Emission Tomography (PET) scan. There is a well-established correlation between CBT and superoxide anions inside tumor cells. The purpose of this pilot study was to measure superoxide anions inside CBT cells and find if these can be used as marker to predict malignant potential of CBT. The results were also co-related with findings of DOTANOC PET scan retrospectively. The CBT tissue from 10 patients was stained using a fluorogenic dye and superoxide anions were measured by analysis of fluorescent image. The patients were divided into two groups - First group with four patients having potentially malignant CBT based upon clinico-surgical characteristics and second group with the rest of the six patients. It was seen that the superoxide anions were highest in the first group which included patients with metastatic carotid body tumor, patients with multiple paragangliomas and patient with positive family history (p = 0.011). The same patients also had metastasis and multiple tumors detected on DOTANOC PET scan. It was concluded that measuring superoxide anions in excised tumor tissue can be used to estimate malignant potential of CBT and can identify patients who truly require DOTANOC PET scan; without affecting the treatment, as it is an expensive investigation involving ionizing radiation and may not be available in all centres.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12070-023-03623-6.

Rare presentation of vagal paraganglioma in an early age: A case report and literature review

INTRODUCTION AND IMPORTANCE

Vagal paragangliomas of neck are rare tumours of neural crest origin usually arising in elderly age with female predominance. They have a vague clinical presentation therefore difficult to diagnose preoperatively. We hope that this case report and literature review would add to the existing literature and help devise a comprehensive diagnostic and therapeutic plan for vagal paragangliomas.

CASE PRESENTATION

We report a case of vagal paraganglioma occurring in a 13-year-old male which is an extremely rare presentation in this age group. The patient presented with a large solitary painless progressively growing mass in posterior triangle of neck. External jugular vein was stretched and trachea was deviated medially. The mass was arising via a twig from vagus nerve and was surgically excised. Diagnosis was established post-operatively through histopathological analysis.

CLINICAL DISCUSSION

Vagal paraganglioma is a rare occurrence in male teenagers and may mimic schwannoma, neuroma, jugular meningioma, or other gangliomas. Surgical excision is mainstay of treatment but resultant vagal complications and neurological consequences are usually unavoidable. Nonetheless, the prognosis may be easily improved with sound surgical judgement, skill, and routine follow-up.

CONCLUSIONS

Vagal paraganglioma usually presents as a swelling in neck and cannot be diagnosed on simple clinical examination. CT scan and MRI are imaging modalities of choice and can be coupled with angiography to increase diagnostic accuracy. Although both radiation therapy and surgical excision have both been found to be successful treatment options, it is still unclear which is more beneficial.

Case Report: Paraganglioma in the sellar region: longitudinal observation and surgical outcome

Background

Paraganglioma in the sellar region is an extremely rare entity, with a limited number of cases reported in the literature. Due to the paucity of clinical evidence, the diagnosis and treatment of paragangliomas in the sellar region remain challenging. Herein, we reported a case of sellar paraganglioma with parasellar and suprasellar extension. Particularly, the dynamic evolution of this benign tumor within a 7-year longitudinal observation was presented. Additionally, the relevant literature regarding sellar paraganglioma was comprehensively reviewed.

Case description

A 70-year-old woman presented with progressive visual deterioration and headache. Brain magnetic resonance imaging demonstrated a mass in the sellar region with parasellar and suprasellar extension. The patient refused surgical treatment. Seven years later, brain magnetic resonance imaging showed the lesion significantly progressed. Neurological examination revealed bilateral tubular contraction of visual fields. Laboratory examinations showed endocrine hormone levels were normal. Surgical decompression was performed via a subfrontal approach, and subtotal resection was achieved. Histopathological examination confirmed a diagnosis of paraganglioma. Postoperatively, she developed hydrocephalus, and ventriculoperitoneal shunting was performed. Eight months later, cranial CT showed no recurrence of the residual tumor, and the hydrocephalus had been relieved.

Conclusion

Paraganglioma occurring in the sellar region is rare, and the preoperative differential diagnosis is difficult. Owing to the infiltration to the cavernous sinus and internal carotid, complete surgical resection is usually impracticable. There has been no consensus regarding postoperative adjuvant radiochemotherapy for the tumor residue. In-situ recurrence and metastasis have been reported in the literature, and close follow-up is warranted.

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.

Molecular basis of carotid body tumor and associated clinical features in Japan identified by genomic, immunohistochemical, and clinical analyses

Carotid body tumor (CBT) is classified as a paraganglioma (PGL). Here, we report the genetic background, protein expression pattern, and clinical findings of 30 Japanese CBT cases. Germline pathogenic or likely pathogenic (P/LP) variants of genes encoding succinate dehydrogenase subunits (SDHs) were detected in 15 of 30 cases (50%). The SDHB variants were the most frequently detected, followed by SDHA and SDHD variants. One case with SDHAF2 variant was bilateral CBT, and other two multiple PGL cases were not detected P/LP variants. The three cases with germline variants that could be tested did not have somatic P/LP variants of the same genes. Immunohistochemical analysis showed negative SDHB signals in CBT tissues in five cases with germline P/LP variants of SDHB, SDHD, or SDHA. In addition, SDHB signals in CBT tissues were negative in four of nine cases without germline P/LP variants of SDHs. These findings suggest the involvement of unidentified molecular mechanisms affecting SDHs.

Targeted metabolomics detects a putatively diagnostic signature in plasma and dried blood spots from head and neck paraganglioma patients

Head and neck paragangliomas (HNPGLs), rare chemoresistant tumors curable only with surgery, are strongly influenced by genetic predisposition, hence patients and relatives require lifetime follow-up with MRI and/or PET-CT because of de novo disease risk. This entails exposure to electromagnetic/ionizing radiation, costs, and organizational challenges, because patients and relatives are scattered far from reference centers. Simplified first-line screening strategies are needed. We employed flow injection analysis tandem mass spectrometry, as used in newborn metabolic screening, to compare the plasma metabolic profile of HNPGL patients (59 samples, 56 cases) and healthy controls (24 samples, 24 cases). Principal Component Analysis (PCA) and Partial Least Discriminant Analysis (PLS-DA) highlighted a distinctive HNPGL signature, likely reflecting the anaplerotic conversion of the TCA cycle to glutaminolysis and catabolism of branched amino acids, DNA damage and deoxyadenosine (dAdo) accumulation, impairment of fatty acid oxidation, switch towards the Warburg effect and proinflammatory lysophosphatidylcholines (LPCs) signaling. Statistical analysis of the metabolites that most impacted on PLS-DA was extended to 10 acoustic neuroma and 2 cholesteatoma patients, confirming significant differences relative to the HNPGL plasma metabolomic profile. The best confusion matrix from the ROC curve built on 2 metabolites, dAdo and C26:0-LPC, provided specificity of 94.29% and sensitivity of 89.29%, with positive and negative predictive values of 96.2% and 84.6%, respectively. Analysis of dAdo and C26:0-LPC levels in dried venous and capillary blood confirmed that dAdo, likely deriving from 2'-deoxy-ATP accumulated in HNPGL cells following endogenous genotoxic damage, efficiently discriminated HNPGL patients from healthy controls and acoustic neuroma/cholesteatoma patients on easily manageable dried blood spots.

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.

Tumour microenvironment in pheochromocytoma and paraganglioma

Pheochromocytomas and Paragangliomas (Pheo/PGL) are rare catecholamine-producing tumours derived from adrenal medulla or from the extra-adrenal paraganglia respectively. Around 10-15% of Pheo/PGL develop metastatic forms and have a poor prognosis with a 37% of mortality rate at 5 years. These tumours have a strong genetic determinism, and the presence of succinate dehydrogenase B (SDHB) mutations are highly associated with metastatic forms. To date, no effective treatment is present for metastatic forms. In addition to cancer cells, the tumour microenvironment (TME) is also composed of non-neoplastic cells and non-cellular components, which are essential for tumour initiation and progression in multiple cancers, including Pheo/PGL. This review, for the first time, provides an overview of the roles of TME cells such as cancer-associated fibroblasts (CAFs) and tumour-associated macrophages (TAMs) on Pheo/PGL growth and progression. Moreover, the functions of the non-cellular components of the TME, among which the most representatives are growth factors, extracellular vesicles and extracellular matrix (ECM) are explored. The importance of succinate as an oncometabolite is emerging and since Pheo/PGL SDH mutated accumulate high levels of succinate, the role of succinate and of its receptor (SUCNR1) in the modulation of the carcinogenesis process is also analysed. Further understanding of the mechanism behind the complicated effects of TME on Pheo/PGL growth and spread could suggest novel therapeutic targets for further clinical treatments.

Vagal Paraganglioma of Neck Mimicking Carotid Body Tumor: Clues to Differentiate on Imaging

Paragangliomas of the head and neck can arise in many locations along the carotid sheath and middle ear. A hypervascular tumor in relation to the major cervical vessels can be either a carotid body tumor or vagal paraganglioma. Carotid bifurcation separation is a characteristic feature of carotid body tumours. We present a case of vagal paraganglioma of the neck, causing carotid bifurcation separation similar to that of a carotid body tumor. In this case report, we highlight the imaging features that can differentiate these two paragangliomas in such a confusing situation.

Comparison of the Sensitivity of 68Ga-DOTATATE PET/CT with Other Imaging Modalities in Detecting Head and Neck Paraganglioma: Experience from Western India

Background  This study aimed to compare the sensitivity of ⁶⁸ Ga-DOTATATE positron emission tomography/computed tomography (PET/CT) with other imaging modalities in the detection of head and neck paraganglioma (HNPGL).

Methods  The data of consecutive HNPGL patients ( n  = 34) who had undergone at least ⁶⁸ Ga-DOTATATE PET/CT and anatomical imaging (contrast-enhanced computed tomography/magnetic resonance imaging [CECT/MRI]) were retrospectively reviewed. The diagnosis of HNPGL (the primary tumor) was confirmed either by histopathology ( n  = 10) or was based on clinical follow-up and correlation of anatomical with functional imaging in whom histopathology was not available ( n  = 24). The sensitivities of ⁶⁸ Ga DOTATATE PET/CT, 18F-fluorodeoxyglucose positron emission tomography/computed tomography ( ¹⁸ F-FDG-PET/CT), ¹³¹ I-metaiodobenzylguanidine ( ¹³¹ I-MIBG) scintigraphy, and CECT/MRI for primary HNPGL, associated primary pheochromocytoma + sympathetic paraganglioma (PCC + sPGL), and metastatic lesions were analyzed.

Results  Thirty-four patients (males: 15) [isolated HNPGL: 26, HNPGL + PCC: 04, HNPGL+ sPGL: 03, HNPGL + PCC + sPGL: 01] harboring 50 primary lesions were included. For total lesions, ⁶⁸ Ga-DOTATATE PET/CT (99.3%) had significantly higher lesion-wise sensitivity than ¹⁸ F-FDG PET/CT (81.6%, p  = 0.0164), ¹³¹ I-MIBG (15.2%, p ≤0.0001), CECT (46.3%, p ≤ 0.0001) but similar sensitivity as MRI neck (97%, p  = 0.79). On head-to-head comparison (21 primary HNPGL and 39 metastatic lesions), ⁶⁸ Ga DOTATATE PET/CT had significantly higher lesion-wise sensitivities for the detection of metastatic (100 vs. 71.9%, p  = 0.04) and total lesions (100 vs. 77.2%, p ≤ 0.0001).

Conclusion   ⁶⁸ Ga-DOTATATE PET/CT was the most sensitive imaging modality for the detection of HNPGL and related lesions with significantly higher lesion-wise sensitivities than those of ¹⁸ F-FDG PET/CT, ¹³¹ I-MIBG, and CECT.

Metformin Treatment Induces Different Response in Pheochromocytoma/Paraganglioma Tumour Cells and in Primary Fibroblasts

Simple Summary

Pheochromocytoma/paragangliomas (PPGLs) are neuroendocrine tumours and are often non-metastatic. However, no effective treatment is available for their metastatic form. Recent studies have shown that metformin exhibits antiproliferative activity in many human cancers, including PPGLs. Nevertheless, no data are available concerning whether metformin is also able to inhibit PPGL metastatic spread. A tumour is a very complex system, comprising not only cancer cells, but also other cells that all together form the so-called tumour microenvironment. Cancer-associated fibroblasts are residential or recruited fibroblasts, transformed by cancer cells, to promote tumour growth and spread. Therefore, the interplay between tumour cells and cancer-associated fibroblasts has become an interesting target for cancer therapy. Here, we demonstrate that metformin has different effects on cancer cells and fibroblasts, providing evidence that metformin may hold promise for altering tumour microenvironment homeostasis. Improving our knowledge on malignant tumour microenvironment properties could lead to develop complementary strategies to target tumour spread and progression.

Abstract

Pheochromocytoma/paragangliomas (PPGLs) are neuroendocrine tumours, often non-metastatic, but without available effective treatment for their metastatic form. Recent studies have shown that metformin exhibits antiproliferative activity in many human cancers, including PPGLs. Nevertheless, no data are available on the role of metformin on PPGL cells (two-dimension, 2D) and spheroids (three-dimension, 3D) migration/invasion. In this study, we observed that metformin exerts an antiproliferative effect on 2D and 3D cultures of pheochromocytoma mouse tumour tissue (MTT), either silenced or not for the SDHB subunit. However, metformin did not affect MTT migration. On the other hand, metformin did not have a short-term effect on the proliferation of mouse primary fibroblasts, but significantly decreased their ability to migrate. Although the metabolic changes induced by metformin were similar between MTT and fibroblasts (i.e., an overall decrease of ATP production and an increase in intracellular lactate concentration) the activated signalling pathways were different. Indeed, after metformin administration, MTT showed a reduced phosphorylation of Akt and Erk1/2, while fibroblasts exhibited a downregulation of N-Cadherin and an upregulation of E-Cadherin. Herein, we demonstrated that metformin has different effects on cell growth and spread depending on the cell type nature, underlining the importance of the tumour microenvironment in dictating the drug response.

Efficacy and safety of 225Ac-DOTATATE targeted alpha therapy in metastatic paragangliomas: a pilot study

PURPOSE

In this study, we aim to evaluate the efficacy and safety of 225AC-DOTATATE targeted alpha therapy in advanced-stage paragangliomas (PGLs).

METHODS

Nine (6 males and 3 females) consecutive patients with histologically proven PGLs were treated with 225Ac-DOTATATE targeted alpha therapy (TAT) and concomitant radiosensitizer, capecitabine, at 8-weekly intervals up to a cumulative activity of ~ 74 MBq. The primary endpoint included evaluating therapy response and disease control rate (DCR) using the RECIST 1.1 criteria. Additional secondary endpoints comprised clinical response assessment using EORTC QLQ-H&N35 questionnaire, Karnofsky Performance Scale (KPS), Eastern Cooperative Oncology Group performance status (ECOG), analgesic score (AS), dose alterations of anti-hypertensive drugs (anti-HTN), and the safety and side-effect profile evaluation as per CTCAE criteria version 5.0.

RESULTS

Following 225Ac-DOTATATE treatment, morphological response revealed partial response in 50%, stable disease in 37.5%, and disease progression in 12.5%, with a DCR of 87.5%. Similarly, the symptomatic response was remarkable, and anti-HTN drugs were stopped in 25% and reduced in 37.5%. Another significant finding in our study revealed a morphologic DCR of 66.6% (2/3) in patients who failed previous lutetium-177 peptide receptor radionuclide therapy (177Lu-PRRT). Regarding the KPS, ECOG, and AS performance scores, a notable improvement was observed post-225Ac-DOTATATE treatment. The QLQ-H&N35 symptom scores evaluated in seven H&N PGL patients showed significant improvement in all aspects. No improvement in sexual function was noted (P = 0.3559). Despite the significant reduction in the analgesic score post-treatment (P = 0.0031), the QLQ-H&N35 revealed only marginal significance concerning the intake of pain killers (P = 0.1723). No grade III/IV hematological, renal, and hepatological toxicities were noted.

CONCLUSION

The evidence from this study suggests 225Ac-DOTATATE therapy is effective and safe in the treatment of advanced-stage PGLs and also reports a clear benefit even in patient's refractory to the previous 177Lu-PRRT.

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.

Personalized Management of Pheochromocytoma and Paraganglioma

Pheochromocytomas/paragangliomas are characterized by a unique molecular landscape that allows their assignment to clusters based on underlying genetic alterations. With around 30% to 35% of Caucasian patients (a lower percentage in the Chinese population) showing germline mutations in susceptibility genes, pheochromocytomas/paragangliomas have the highest rate of heritability among all tumors. A further 35% to 40% of Caucasian patients (a higher percentage in the Chinese population) are affected by somatic driver mutations. Thus, around 70% of all patients with pheochromocytoma/paraganglioma can be assigned to 1 of 3 main molecular clusters with different phenotypes and clinical behavior. Krebs cycle/VHL/EPAS1-related cluster 1 tumors tend to a noradrenergic biochemical phenotype and require very close follow-up due to the risk of metastasis and recurrence. In contrast, kinase signaling-related cluster 2 tumors are characterized by an adrenergic phenotype and episodic symptoms, with generally a less aggressive course. The clinical correlates of patients with Wnt signaling-related cluster 3 tumors are currently poorly described, but aggressive behavior seems likely. In this review, we explore and explain why cluster-specific (personalized) management of pheochromocytoma/paraganglioma is essential to ascertain clinical behavior and prognosis, guide individual diagnostic procedures (biochemical interpretation, choice of the most sensitive imaging modalities), and provide personalized management and follow-up. Although cluster-specific therapy of inoperable/metastatic disease has not yet entered routine clinical practice, we suggest that informed personalized genetic-driven treatment should be implemented as a logical next step. This review amalgamates published guidelines and expert views within each cluster for a coherent individualized patient management plan.

Contemporary management of paragangliomas of the head and neck

Head and neck paragangliomas (HNPGLs) are rare neuroendocrine tumors typically arising from nonsecretory head and neck parasympathetic ganglia. Historically thought of as aggressive tumors that warranted equally aggressive surgical intervention, evidence has emerged demonstrating that the vast majority of HNPGLs are slow growing and indolent. It is also now recognized that a large proportion of HNPGLs are hereditary with succinate dehydrogenase gene mutations typically implicated. These recent advances have led to significant changes in the way in which clinicians investigate and treat HNPGLs with most now opting for more conservative treatment strategies. However, a proportion of patients present with more aggressive disease and still require nonconservative treatment strategies. Recent studies have sought to determine in which groups of patients the morbidity associated with treatment is justified. We summarize the recent advances in the understanding and management of these tumors and we provide our recommendations regarding the management of HNPGLs.

[Jugulotympane paraganglioma associated with polysegmentary congenital hemangioma]

The describes a clinical observation of a combination of jugulotympanic paraganglioma of the left temporal bone with multifocal congenital hemangioma. The interest of the case is that such a combination of pathologies is extremely rare. A comprehensive study and surgical treatment of a patient with this clinical diagnosis was carried out. In the diagnosis, objective otorhinolaryngological studies, otomicroscopy and MSCT of the temporal bones and MRI of the middle ear with contrast were used. Surgical intervention was performed under multicomponent anesthesia with tracheal intubation, transmastoid access. The postoperative management of the patient after surgical treatment is described.

Papillary Thyroid Carcinoma in Ectopic Thyroid Tissue Within a Suspected Cervical Paraganglioma

ABSTRACT

Ectopic differentiated thyroid carcinoma represents less than 1% of all thyroid carcinoma cases, which usually arises along the cervical midline, and (delving into literature) there are scarce reports of such entity in nuclear medicine imaging studies. We present a rare case of a confirmed synchronous, orthotopic, and heterotopic (in lateral ectopic thyroid tissue) differentiated thyroid carcinoma in a patient who was previously misdiagnosed as having a cervical paraganglioma, based on compatible clinical, analytical, and imagenological (both structural and functional) findings.

Head and Neck Paragangliomas in the Czech Republic: Management at the Otorhinolaryngology Department

Head and neck paragangliomas (HNPGLs) are rare neuroendocrine tumors, comprising only 3% of all head and neck tumors. Early diagnosis forms an integral part of the management of these tumors. The two main aims of any treatment approach are long-term tumor control and minimal cranial nerve morbidity. The scope of this article is to present our case series of HNPGLs to stress most important clinical aspects of their presentation as well as critical issues of their complex management. Thirty patients with suspected HNPGLs were referred to our otorhinolaryngology clinic for surgical consultation between 2016–2020. We assessed the demographical pattern, clinicoradiological correlation, as well as type and outcome of treatment. A total of 42 non-secretory tumors were diagnosed—16.7% were incidental findings and 97% patients had benign tumors. Six patients had multiple tumors. Jugular paragangliomas were the most commonly treated tumors. Tumor control was achieved in nearly 96% of operated patients with minimal cranial nerve morbidity. Surgery is curative in most cases and should be considered as frontline treatment modality in experienced hands for younger patients, hereditary and secretory tumors. Cranial nerve dysfunction associated with tumor encasement is a negative prognostic factor for both surgery and radiotherapy. Multifocal tumors and metastasis are difficult to treat, even with early detection using genetic analysis. Detecting malignancy in HNPGLs is challenging due to the lack of histomorphological criteria; therefore, limited lymph node dissection should be considered, even in the absence of clinical and radiological signs of metastasis in carotid body, vagal, and jugular paragangliomas.

Quantitative biomarkers allow the diagnosis of head and neck paraganglioma on multiparametric MRI

PURPOSE

The aim of this study is to identify quantitative MR biomarkers in head and neck paragangliomas.

METHODS

The study was approved by an institutional review board. A retrospective review of patients with head and neck paragangliomas (HNPGL) evaluated by time-resolved MRA sequences between 2009 and 2019 was performed. A control group investigated during the same period was analyzed, including nerve sheath tumors and metastatic lymph nodes from squamous cell carcinomas or undifferentiated nasopharyngeal cancer (UCNT). A gold standard was obtained for all cases. Semi-quantitative parameters of enhancement were extracted from time-intensity curves on time-resolved MRA sequences and diffusion weighted imaging/DWI was assessed for each lesion.

RESULTS

Sixty head and neck paragangliomas (HNPGLs) were included from 50 patients. The control group consisted of 30 parapharyngeal space lesions (27 patients), which included nerve sheath tumors (n = 12) and metastatic lymph nodes (n = 18) from squamous cell carcinomas or UCNT. PGLs showed a shorter time-to-peak value compared to other groups, measured at 25.0 +/- 29 sec. The wash-in and wash-out ratios were also significantly higher for PGLs, respectively measured at 5.34 ± 2.99 (p < 0,001) and 1.24 ± 0.80 (p < 0.001). On DWI sequences, the mean ADC value for PGLs (1.17 ± 0.19 10^-3 mm2/s) was significantly different than the other tumor groups (p < 0.001). HNPGLs were clearly distinguishable from other tumors on classification with regression tree based on TTP and ADC values. These distinct group features were also consistent on principal component analysis.

CONCLUSION

Our study identifies a multiparametric signature for disease subtyping, providing a strong impetus for switching from qualitative to quantitative analysis of deep soft-tissue tumors of the neck.

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.

Genetic Variants in Patients with Multiple Head and Neck Paragangliomas: Dilemma in Management

Multiple head and neck paragangliomas (HNPGLs) are neuroendocrine tumors of a mostly benign nature that can be associated with a syndrome, precipitated by the presence of a germline mutation. Familial forms of the disease are usually seen with mutations of SDHx genes, especially the SDHD gene. SDHB mutations are predisposed to malignant tumors. We found 6 patients with multiple tumors amongst 30 patients with HNPGLs during the period of 2016 to 2021. We discuss the phenotypic and genetic patterns in our patients with multiple HNPGLs and explore the management possibilities related to the disease. Fifty percent of our patients had incidental findings of HNPGLs. Twenty-one biochemically silent tumors were found. Four patients had germline mutations, and only one had a positive family history. Three out of five underwent surgery without permanent complications. Preventative measures (genetic counselling and tumor surveillance) represent the gold standard in effectively controlling the disease in index patients and their relatives. In terms of treatment, apart from surgical and radiotherapeutic interventions, new therapeutic measures such as gene targeted therapy have contributed very sparsely. With the lack of standardized protocols, management of patients with multiple HNPGLs still remains very challenging, especially in those with sporadic or malignant forms of the disease.

Resorbable Purified Porcine Skin Gelatin Cross-Linked with Glutaraldehyde Spheres for Preoperative Embolization of Carotid Body Paraganglioma

Chemodectomas are rare neuroendocrine tumors that typically arise at the carotid bifurcation and progressively englobe the internal and external carotid artery. Surgical asportation of the capsulated mass is the elective treatment. Pre-procedural embolization of this high vascular tumors is highly recommended because it has shown to improve surgical outcome by reducing both, mean blood loss and total operation time. Many different embolization techniques have been described in literature. In the here presented case we opted for an endovascular approach using resorbable purified porcine skin gelatin cross-linked with glutaraldehyde microspheres (Optisphere - MEDTRONIC) as an embolic agent. These turned out to be very safe and effective in improving surgical outcome by reducing operative blood loss and thus reducing treatment-related morbidity.

Head and Neck Paragangliomas: Patterns of Otolaryngology Referrals for Genetic Testing Over 2 Decades

Objective

A large proportion of head and neck paragangliomas (HNPGLs) arise in patients with a genetic predisposition due to pathogenic variants in succinate dehydrogenase (SDHx) genes. Contemporary practice guidelines recommend consideration of referral for genetic testing for all patients with HNPGLs. We sought to assess adherence to these recommendations, factors associated with referral, and temporal trends in referral patterns by otolaryngologists over the past 2 decades.

Study Design

Retrospective cohort study.

Setting

Single tertiary care center.

Methods

All patients with newly diagnosed HNPGLs treated at a single academic center between 2000 and 2019 were included. Bivariable association of specific features of referral for genetic testing by treating surgeons were tested with χ² and Wilcoxon rank-sum tests. Logistic regression was used to assess temporal trends in referral patterns overall and for specific clinical subgroups over time.

Results

Of 221 patients included, only 77 (34.8%) were referred for genetic testing. Factors associated with referral included young age, family history of paraganglioma, more recent year of diagnosis (ie, closer to study end date), tumor subsite (all P < .0001), and treatment by an otolaryngologist (vs vascular surgeon or neurosurgeon, P = .009). Overall, referral rates increased over time (P = .0002), but even in the most recent 5 years, only 51% of newly diagnosed patients were referred.

Conclusion

Our analysis suggests that referral rates for genetic testing in patients with HNPGLs are growing yet are still largely based on young age, family history, and tumor subsite.

PPAR-α Modulators as Current and Potential Cancer Treatments

Cancer is one of the leading causes of mortality worldwide. PPAR modulators may hold great potential for the management of cancer patients. Indeed, PPARs are critical sensors and regulators of lipid, and they are able to promote eNOS activation, regulate immunity and inflammation response, and affect proliferation and differentiation of cancer cells. Cancer, a name given to a group of diseases, is characterized by multiple distinctive biological behaviors, including angiogenesis, abnormal cell proliferation, aerobic glycolysis, inflammation, etc. In the last decade, emerging evidence has shown that PPAR-α, a nuclear hormone receptor, can modulate carcinogenesis via exerting effects on one or several characteristic pathological behaviors of cancer. Therefore, the multi-functional PPAR modulators have substantial promise in various types of cancer therapies. This review aims to consolidate the functions of PPAR-α, as well as discuss the current and potential applications of PPAR-α agonists and antagonists in tackling cancer.