Genetics of hereditary head and neck paragangliomas

Algorithm of genetic diagnosis for patients with head and neck paraganglioma-update

Paragangliomas are rare tumors originating from the paraventricular bodies of the autonomic nervous system located in the adrenal glands, chest, abdomen, pelvis and head and neck. Tumors of this type account for 0.5% of head and neck cancers, 0.03% of all cancers and their incidence is estimated at 1-30/100,000 per year. Head and Neck Paragangliomas (HNPGL) are localized in carotid body, tympanic cavity or jugular foramen. It is established that HNPGL may be associated with mutations of the SDH complex, with SDHD being the most prevalent. However, SDHB, SDHC and SDHAF are also potential causes. The aforementioned mutations are influenced by various risk factors, including young age, a positive family history of paraganglioma, the presence of metastases and gender The purpose of this study is to summarize the results of genetic testing performed on patients with head and neck paraganglioma and to create an up-to-date genetic diagnosis algorithm for patients with HNPGL based on previous studies published in the literature that can be used in daily practice. Several papers observed that among SDHD mutation carriers, most or all of those studied had HNPGL, and SDHB mutations were more frequently found in the presence of metastasis. Based on the results, it was concluded that there is no basis for genetic testing for VHL in patients without a positive family history. In each algorithm proposed by different authors, proposals for rational genetic diagnosis were analyzed based on the studies cited by the author and the analyses included in our paper. For the analysis of the treatment algorithms, the following were included: Martin, Mannelli, Neumann, Gupta. Subsequently, publications related to the genetic diagnosis of HNPGL were analyzed to verify the proposed algorithms in light of the latest genetic studies and to establish an updated diagnostic management scheme.

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.

Newly Recognized Genetic Tumor Syndromes of the CNS in the 5th WHO Classification: Imaging Overview with Genetic Updates

The nervous system is commonly involved in a wide range of genetic tumor-predisposition syndromes. The classification of genetic tumor syndromes has evolved during the past years; however, it has now become clear that these syndromes can be categorized into a relatively small number of major mechanisms, which form the basis of the new 5th edition of the World Health Organization book (beta online version) on genetic tumor syndromes. For the first time, the World Health Organization has also included a separate chapter on genetic tumor syndromes in the latest edition of all the multisystem tumor series, including the 5th edition of CNS tumors. Our understanding of these syndromes has evolved rapidly since the previous edition (4th edition, 2016) with recognition of 8 new syndromes, including the following: Elongator protein complex-medulloblastoma syndrome, BRCA1-associated protein 1 tumor-predisposition syndrome, DICER1 syndrome, familial paraganglioma syndrome, melanoma-astrocytoma syndrome, Carney complex, Fanconi anemia, and familial retinoblastoma. This review provides a description of these new CNS tumor syndromes with a focus on imaging and genetic characteristics.

Molecular pathology of endocrine gland tumors: genetic alterations and clinicopathologic relevance

Tumors of the endocrine glands are common. Knowledge of their molecular pathology has greatly advanced in the recent past. This review covers the main molecular alterations of tumors of the anterior pituitary, thyroid and parathyroid glands, adrenal cortex, and adrenal medulla and paraganglia. All endocrine gland tumors enjoy a robust correlation between genotype and phenotype. High-throughput molecular analysis demonstrates that endocrine gland tumors can be grouped into molecular groups that are relevant from both pathologic and clinical point of views. In this review, genetic alterations have been discussed and tabulated with respect to their molecular pathogenetic role and clinicopathologic implications, addressing the use of molecular biomarkers for the purpose of diagnosis and prognosis and predicting response to molecular therapy. Hereditary conditions that play a key role in determining predisposition to many types of endocrine tumors are also discussed.

Research progress on the pathogenesis of the SDHB mutation and related diseases

With the improvement of genetic testing technology in diseases in recent years, researchers have a more detailed and clear understanding of the source of cancers. Succinate dehydrogenase B (SDHB), a mitochondrial gene, is related to the metabolic activities of cells and tissues throughout the body. The mutations of SDHB have been found in pheochromocytoma, paraganglioma and other cancers, and is proved to affect the occurrence and progress of those cancers due to the important structural functions. The importance of SDHB is attracting more and more attention of researchers, however, reviews on the structure and function of SDHB, as well as on the mechanism of its carcinogenesis is inadequate. This paper reviews the relationship between SDHB mutations and related cancers, discusses the molecular mechanism of SDHB mutations that may lead to tumor formation, analyzes the mutation spectrum, structural domains, and penetrance of SDHB and sorts out some of the previously discovered diseases. For the patients with SDHB mutation, it is recommended that people in SDHB mutation families undergo regular genetic testing or SDHB immunohistochemistry (IHC). The purpose of this paper is hopefully to provide some reference and help for follow-up researches on SDHB.

Report of a vagal paraganglioma at the cervicothoracic junction

BACKGROUND

Vagus nerve paragangliomas are rare tumors, comprising 0.03% of head and neck neoplasms. These tumors are usually located cephalad to the hyoid bone, and there is only one previously reported case that arose from the lower third of the neck.

METHODS

We describe the second reported case of a lower neck vagus nerve paraganglioma that was managed with a limited sternotomy for access and surgical removal.

RESULTS

A 66-year-old male presented with a long-standing lesion of the cervicothoracic junction. CT, MRI, and Ga-68 DOTATATE PET/CT showed an avidly enhancing 5.2 × 4.2 × 11.5 cm mass extending from C6 to approximately T4 level. FNA confirmed the diagnosis. The patient underwent catheter angiography and embolization via direct puncture technique followed by excision of the mass via a combined transcervical and limited sternotomy approach.

CONCLUSION

We describe an unusual case of vagal paraganglioma at the cervicothoracic junction with retrosternal extension requiring a sternotomy for surgical excision.

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

OBJECTIVE

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

STUDY DESIGN

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

SETTING

Single academic medical center.

METHODS

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

RESULTS

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

CONCLUSION

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

Vagal paragangliomas

PURPOSE OF REVIEW

A vagal paraganglioma is a rare head and neck tumor arising from the paraganglionic tissue within the perineurium of the vagus nerve, anywhere along the course of the nerve. Due to its proximity to the internal carotid artery, the internal jugular vein and the lower cranial nerves, this disorder poses significant diagnostic and therapeutic challenges. The diagnostic workup and management keep on evolving.

RECENT FINDINGS

This article gives a concise update of the clinical spectrum and the current state-of-the-art diagnostic workup and management of vagal paraganglioma.

SUMMARY

Every patient with suspected vagal paraganglioma needs to be evaluated by a multidisciplinary team. The management strategy is selected depending on the growth rate of the tumor, the age and fitness of the patient, the number of affected cranial nerves, the metabolic activity of the paraganglioma, and the eventual multicentricity. An algorithm guiding the clinician through the different treatment options is presented.

Hereditary head and neck paraganglioma: from basics to practical consequences

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

SUMMARY

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

Resection of Carotid Body Tumors in Patients of Advanced Age: Experience From a Single Center

INTRODUCTION

Resection of carotid body tumor (CBT) in patients of advanced ages has not been appreciated.

OBJECTIVES

This study aims to assess the clinical characteristics and perioperative comorbidities for CBT resection in patients of advanced age and to validate the application of an "isolated island" technique for extirpation of CBT.

METHODS

Eight patients of advanced age (≥60 years) who underwent CBT resection were enrolled as the study group (SG). Another 29 patients of younger age (<45 years old) underwent CBT extirpation were assigned as the control group (CG). The perioperative issues were compared between these 2 groups.

RESULTS

The "isolated island" technique was successfully applied for resection of CBT in all 37 patients. The prevalence of Shamblin classification I, II, and III tumors in the SG was 12.5%, 62.5%, and 25%; whereas in the CG was 10.3%, 55.2%, and 34.5%, respectively. Bilateral CBT was observed in 7 patients of the CG and none in the SG. Vascular reconstruction was required for 1 (12.5%) patient in the SG, while it was required for 8 (27.6%) patients in the CG. Postoperative vocal cord palsy occurred in 37.5% of patients in SG, whereas the vocal cord palsy (34.5%) and dysphagia (6.9%) were commonly encountered in CG. In addition to postoperative length of stay (P = .004), no significant difference for operative time, intraoperative blood loss, or mortality were observed between these 2 groups (P > .05).

CONCLUSION

Extirpation of CBT in patients of advanced age is rationale in appropriately selected patients. The "isolated island" technique is safe for CBT resection with seemingly low complication rates.

A Case for Genetic Testing in Isolated Tympanic Paragangliomas

OBJECTIVE

The aim of this study is to describe two clinical cases, which we believe highlight the need to consider routine genetic testing of all patients with new diagnosis of a tympanic paraganglioma (PGL).

PATIENTS

Two patients seen in the ENT clinic at a tertiary center with a diagnosis of isolated tympanic PGL, without family history.

INTERVENTION

Since 2016, all patients with newly diagnosed isolated tympanic PGL (glomus tympanicum) are offered review by the clinical genetic team and genetic testing of a panel of paraganglioma/phaeochromocytoma predisposition genes. Previously only those with multiple PGL or a family history were tested.

MAIN OUTCOME MEASURES

We describe the results of genetic testing, the clinical course and discuss the ongoing implications for management.

RESULTS

Both cases were identified to have a pathogenic variant in the SDHB gene after initial surgery. The clinical course for both cases was complicated by disease recurrence, as well as metastatic and secretory disease in one case. Knowledge of genetic status has influenced ongoing management, with annual MRI surveillance for other SDH-related tumors.

CONCLUSION

These two cases reinforce the importance of offering genetic testing for all cases of isolated tympanic PGL. The discovery of a significant underlying genetic variant may affect management decisions and subsequent follow-up.

Treatment decision and estimation of growth of head and neck paragangliomas

PURPOSE

Head and neck paragangliomas are slow growing tumors where observation has become more widely accepted. Tumor growth rate as well as predictors of increased tumor growth were analyzed with the goal to identify factors to better predict disease progression and counsel patients.

MATERIALS AND METHODS

Multi-institutional retrospective cohort study from 2011 to 2020.

RESULTS

130 head and neck paragangliomas in 125 patients were analyzed. 38 were observed (30.4%), 16 radiated (12.8%), and 71 underwent surgery (56.8%). Surgical patients were significantly younger (p = 0.038) and with more genetically mediated paragangliomas (p = 0.026). Significantly more patients were asymptomatic in the observation group (p = 0.005). Of the 39 observed tumors, 43.6% (n = 17) grew with a tumor doubling time of 5.67 years. More than half of the observed paragangliomas had no growth. When examining symptoms postoperatively and at follow-up, the surgical cohort had significantly more worsening symptoms (p = 0.007) and new cranial neuropathies (p = 0.031).

CONCLUSIONS

Head and neck paragangliomas have slow growth rates if they grow at all. Patients in the surgical cohort had more clinical symptoms at presentation and worsening postoperative symptoms.

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.

Clinical and histopathological principles for the diagnosis of a recurrent paraganglioma of the jugular foramen initially diagnosed as a middle ear adenoma: illustrative case

BACKGROUND

Paragangliomas (PGLs) are rare neoplasms that may be associated with hereditary PGL syndromes and variable risk of metastasis. Middle ear adenomas are extremely rare tumors with no known hereditary predisposition and extremely low risk of metastasis. Although often easily differentiated, they may share clinical and pathological features that misdirect and confuse the diagnosis.

OBSERVATIONS

The authors discussed a 35-year-old woman with left-sided hearing loss and bleeding from the external ear canal who presented to an outside hospital. She underwent resection of a middle ear and mastoid mass, initially diagnosed as a middle ear adenoma with neuroendocrine features, with later mastoidectomy and ligation of the sigmoid sinus with microsurgical excision of persistent tumor in the jugular foramen and temporal bone. Histopathologically, her tumor was vascular, composed of benign-appearing epithelioid cells with “salt and pepper” neuroendocrine chromatin arranged in vague nests. Lesional cells were GATA3-immunopositive, glucagon-negative, and succinate dehydrogenase-immunonegative, consistent with PGL rather than middle ear adenoma, and required further workup for hereditary PGL syndromes.

LESSONS

This case demonstrates potential challenges in differentiating a PGL from a middle ear adenoma. The authors offer clinical, histopathological, and imaging principles to aid in diagnosis and workup.

A patient with paraganglioma undergoing laparoscopic resection: A case report

Paraganglioma is a very rare extraadrenal nonepithelial tumor. The number of cases of laparoscopic surgery in Paraganglioma is small and controversial. This study encountered a case of successful transperitoneal laparoscopic surgery for a 56-mm paraganglioma in a 53-year-old female. Moreover, previous reports on laparoscopic surgery for paraganglioma are reviewed.

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.

Rare Diseases of the Middle Ear and Lateral Skull Base

Otalgia, otorrhea and hearing loss are the most common ear-related symptoms that lead to the consultation of an otolaryngologist. Furthermore, balance disorders and affections of the cranial nerve function may play a role in the consultation. In large academic centres, but also in primary care, the identification of rare diseases of the middle ear and the lateral skull base is essential, as these diseases often require interdisciplinary approaches to establish the correct diagnosis and to initiate safe and adequate treatments. This review provides an overview of rare bone, neoplastic, haematological, autoimmunological and infectious disorders as well as malformations that may manifest in the middle ear and the lateral skull base. Knowledge of rare disorders is an essential factor ensuring the quality of patient care, in particular surgical procedures. Notably, in untypical, complicated, and prolonged disease courses, rare differential diagnoses need to be considered.

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.

Head and neck paragangliomas in Norway, importance of genetics, updated diagnostic workup and treatment

BACKGROUND

Head and neck paragangliomas (HNPG) are rare and predominantly benign tumours, originating from the neuroendocrine paraganglionic system. A considerable proportion of HNPGs are hereditary, depending on the population.

AIMS/OBJECTIVES

The purpose of this study was to estimate the rate of hereditary HNPGs in a Scandinavian (Norwegian) population, report long-term experience with HNPGs and offer all patients diagnosed an updated follow-up, with emphasis on identifying hereditary HNPGs through genetic screening and multifocality by 18 F-2-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT).

MATERIAL AND METHODS

Our study was a partly retrospective and partly prospective cohort study. It included patients with HNPG diagnosed at Oslo University Hospital (OUH), Rikshospitalet between 1990 and 2017. The patients underwent genetic testing, ¹⁸F-FDG PET/CT and measurement of catecholamines and meta-nephrines in the plasma. All resection specimens and biopsies were subjected to histopathological review. The genetic testing protocol consisted of testing for mutations in the following genes; SDHD, SDHB, SDHC, VHL and RET.

RESULTS

Sixty-three patients were included in the study with a median age of 49 years (range 12 - 80). Cranial nerve dysfunction was present upon diagnosis in 13%, and 14% had multifocal paraganglioma (PG) disease. Fifty-six patients (89% of all the patients) underwent genetic testing, and 29% of these had a PG related mutation. Seven of the eight patients (88%) with multifocal PGs who underwent genetic testing had a mutation. In two of the patients, the ¹⁸F-FDG PET/CT revealed unknown and subclinical multifocality.

CONCLUSIONS AND SIGNIFICANCE

This is the first study with systematic genetic workup and PET/CT imaging in Scandinavia of HNPG patients. The mutation rate was within the lower range reported in the literature with respect to HNPGs. Combining genetic testing and PET/CT imaging in the diagnostic workup of HNPGs is valuable.

Mutation Frequency in Main Susceptibility Genes Among Patients With Head and Neck Paragangliomas

Head and neck paragangliomas (HNPGLs) are rare neuroendocrine tumors that have a high degree of heritability and are predominantly associated with mutations in ten genes, such as SDHx, SDHAF2, VHL, RET, NF1, TMEM127, MAX, FH, MEN2, and SLC25A11. Elucidating the mutation prevalence is crucial for the development of genetic testing. In this study, we identified pathogenic/likely pathogenic variants in the main susceptibility genes in 102 Russian patients with HNPGLs (82 carotid and 23 vagal paragangliomas) using whole exome sequencing. Pathogenic/likely pathogenic variants were detected in 43% (44/102) of patients. We identified the following variant distribution of the tested genes: SDHA (1%), SDHB (10%), SDHC (5%), SDHD (24.5%), and RET (5%). SDHD variants were observed in the majority of the patients with bilateral/multiple paragangliomas. Thus, among Russian patients with HNPGLs the most frequently mutated gene was SDHD followed by SDHB, SDHC, RET, and SDHA.

Haemorrhagic retroperitoneal paraganglioma initially manifesting as acute abdomen: a rare case report and literature review

BACKGROUND

Paragangliomas (PGLs) are extremely rare neuroendocrine tumours arising from extra-adrenal chromaffin cells. PGLs are clinically rare, difficult to diagnose and usually require surgical intervention. PGLs mostly present catecholamine-related symptoms. We report a case of Acute abdomen as the initial manifestation of haemorrhagic retroperitoneal PGL. There has been only one similar case reported in literature.

CASE PRESENTATION

We present a unique case of a 52-year-old female with acute abdomen induced by haemorrhagic retroperitoneal PGL. The patient had a 5-h history of sudden onset of serve right lower quadrant abdominal pain radiating to the right flank and right lumbar region. Patient had classic symptoms of acute abdomen. Abdominal ultrasound revealed a large abdominal mass with a clear boundary. A Computed Tomography Angiography (CTA) of superior mesenteric artery was also performed to in the emergency department. The CTA demonstrated a large retroperitoneal mass measured 9.0 × 7.3 cm with higher density inside. A provisional diagnosis of retroperitoneal tumour with haemorrhage was made. The patient received intravenous fluids, broad-spectrum antibiotics and somatostatin. On the 3rd day of admission, her abdominal pain was slightly relieved, but haemoglobin decreased from 10.9 to 9.4 g/dL in 12 h suggesting that there might be active bleeding in the abdominal cavity. Thus, we performed a midline laparotomy for the patient. Haemorrhage was successfully stopped during operation. The retroperitoneal tumour with haemorrhage was completely removed. The abdominal pain was significantly relieved after surgery. The patient initially presented with acute abdomen instead of catecholamine-related symptoms. The diagnosis of retroperitoneal PGL with haemorrhage was finally confirmed by postoperative pathological and immunohistochemical results. The postoperative course was uneventful. At the 1-year follow-up visit, no tumour recurrence was observed by Single Photon Emission Computed Tomography. A literature review was performed to further understand and analyse the aforementioned disease.

CONCLUSION

Acute abdomen as the initial manifestation of haemorrhagic retroperitoneal paraganglioma is extremely rare. Abdominal Computed Tomography is essential to locate the lesion and differentiate between other causes of acute abdomen. PGLs are hypervascular tumours. We should be aware that ruptured retroperitoneal PGL with massive bleeding could be life threatening and require emergency laparotomy.

Head and Neck Paragangliomas-A Genetic Overview

Pheochromocytomas (PCC) and paragangliomas (PGL) are rare neuroendocrine tumors. Head and neck paragangliomas (HNPGL) can be categorized into carotid body tumors, which are the most common, as well as jugular, tympanic, and vagal paraganglioma. A review of the current literature was conducted to consolidate knowledge concerning PGL mutations, familial occurrence, and the practical application of this information. Available scientific databases were searched using the keywords head and neck paraganglioma and genetics, and 274 articles in PubMed and 1183 in ScienceDirect were found. From these articles, those concerning genetic changes in HNPGLs were selected. The aim of this review is to describe the known genetic changes and their practical applications. We found that the etiology of the tumors in question is based on genetic changes in the form of either germinal or somatic mutations. 40% of PCC and PGL have a predisposing germline mutation (including VHL, SDHB, SDHD, RET, NF1, THEM127, MAX, SDHC, SDHA, SDHAF2, HIF2A, HRAS, KIF1B, PHD2, and FH). Approximately 25–30% of cases are due to somatic mutations, such as RET, VHL, NF1, MAX, and HIF2A. The tumors were divided into three main clusters by the Cancer Genome Atlas (TCGA); namely, the pseudohypoxia group, the Wnt signaling group, and the kinase signaling group. The review also discusses genetic syndromes, epigenetic changes, and new testing technologies such as next-generation sequencing (NGS).

Mutation profiling in eight cases of vagal paragangliomas

Background

Vagal paragangliomas (VPGLs) belong to a group of rare head and neck neuroendocrine tumors. VPGLs arise from the vagus nerve and are less common than carotid paragangliomas. Both diagnostics and therapy of the tumors raise significant challenges. Besides, the genetic and molecular mechanisms behind VPGL pathogenesis are poorly understood.

Methods

The collection of VPGLs obtained from 8 patients of Russian population was used in the study. Exome library preparation and high-throughput sequencing of VPGLs were performed using an Illumina technology.

Results

Based on exome analysis, we identified pathogenic/likely pathogenic variants of the SDHx genes, frequently mutated in paragangliomas/pheochromocytomas. SDHB variants were found in three patients, whereas SDHD was mutated in two cases. Moreover, likely pathogenic missense variants were also detected in SDHAF3 and SDHAF4 genes encoding for assembly factors for the succinate dehydrogenase (SDH) complex. In a patient, we found a novel variant of the IDH2 gene that was predicted as pathogenic by a series of algorithms used (such as SIFT, PolyPhen2, FATHMM, MutationTaster, and LRT). Additionally, pathogenic/likely pathogenic variants were determined for several genes, including novel genes and some genes previously reported as associated with different types of tumors.

Conclusions

Results indicate a high heterogeneity among VPGLs, however, it seems that driver events in most cases are associated with mutations in the SDHx genes and SDH assembly factor-coding genes that lead to disruptions in the SDH complex.

Single-center study: dynamic contrast-enhanced ultrasound in the diagnostic assessment of carotid body tumors

Background

Carotid body tumors (CBTs) depict the most common paraganglioma of the head and neck that can metastasize in up to 15% of cases. They develop either sporadically or hereditarily and may produce catecholamines ("functioning CBTs") resulting in associated symptoms like headache, palpitations or flush. Non-functioning CBTs usually present as slowly and often tender growing mass which may affect adjacent cranial nerves. CBTs can be visualized by ultrasound, CT, MRI or angiography. Pre-surgical interventional embolization, surgical resection and radiation therapy are therapeutical options. The aim of this retrospective single-center study is to assess the safe and real-time evaluation of CBTs by contrast-enhanced ultrasound (CEUS).

Methods

Ten patients with CBT were included in this study on whom CEUS was performed between 2007-2018 (mean age: 62 years). In 6/10 patients, results were confirmed by MRI, 4/12 patients underwent subsequent angiography. CEUS was performed and interpreted by a single consultant radiologist with experience since 2000 (EFSUMB level 3). VueBox^® software was used for standardized perfusion quantification.

Results

CEUS allowed to detect all CBTs and visualize intratumoral microcirculation. Perfusion quantification was performed in 6/10 cases. CBTs showed significantly reduced peak-enhancement (PE), reduced wash-in perfusion index (WiPI) and significantly elevated time to peak (TTP) compared to common carotid arteries (CCA).

Conclusions

CEUS is a useful and safe tool for identifying CBTs and evaluating intratumoral microperfusion at high spatial and temporal resolutions in real-time. In addition to conventional ultrasound, CT, MRI and digital substraction angiography (DSA), CEUS may be implemented in the future diagnostic work-up and follow-up of CBT patients.

Tinnitus With Unexpected Spanish Roots: Head and Neck Paragangliomas Caused by SDHAF2 Mutation

It is estimated that up to 40% of all head and neck paragangliomas (HNPGL) have a hereditary background with the most common mutations being found in the succinate dehydrogenase (SDH) genes. SDHAF2 mutation leads to the rare paraganglioma syndrome 2. The authors present the case of a 15-year-old male patient with 2, non-secretory HNPGLs, presenting with left-sided, pulsatile tinnitus, and hearing loss. Imaging led to the suspicion of a jugulotympanic paraganglioma on the left, as well as a carotid body tumor on the right. After resection of the jugulotympanic tumor, histology confirmed the presence of a paraganglioma; immunohistochemistry furthermore suggested a loss of SDHB expression. Genetic testing revealed a rare germline, loss-of-function mutation in the SDHAF2 gene, previously described to cause hereditary paraganglioma syndrome 2. Twenty months after the first operation, the patient underwent a resection of the right carotid body paraganglioma. Plasma-free metanephrines/catecholamines always remained within the reference range; the patient is under regular follow-up, and his relatives will be screened. Our findings emphasize the relevance of genetic testing in patients with HNPGL, also with negative family history, especially when the patients present at a young age and with multiple lesions.

Proton therapy for head and neck paragangliomas: A single institutional experience

BACKGROUND

Although slow growing, head and neck paragangliomas (HNPG) can cause significant morbidity. We evaluated the efficacy of proton therapy in the management of HNPG.

METHODS

Retrospective review of an institutional proton therapy experience of treating patients between 1997 and 2016; 37 patients and 40 tumors were included.

RESULTS

Proton therapy was delivered to a median of 50.4 Gy(RBE) (range: 45-68). Having a genetic/family predisposition for HNPG was associated with multifocal tumors (P = .02) and younger diagnosis age (P = .02). Twenty-six (70%) patients had symptom improvement posttreatment, and 65% of treated tumors showed ≥20% volumetric shrinkage. The 5-year recurrence-free and overall survival rates were both 97%. Grade 2 to grade 3 toxicities (54%) included subjective hearing impairment (19%), middle ear inflammation (14%), and dry mouth (8%). There were no grade 4-5 toxicities.

CONCLUSIONS

Patients with HNPGs can be effectively and safely treated with proton therapy with excellent tumor control, successful volumetric tumor reduction, and symptomatic improvement.

A systematic review on the genetic analysis of paragangliomas: primarily focused on head and neck paragangliomas

Head and neck paragangliomas Paragangliomas and pheochromocytomas are rare, mostly benign neuroendocrine tumors, which are embryologically derived from neural crest cells of the autonomic nervous system. Paragangliomas are essentially the extra-adrenal counterparts of pheochromocytomas. As such this family of tumors can be subdivided into head and neck paragangliomas, pheochromocytomas and thoracic and abdominal extra-adrenal paragangliomas. Ten out of fifteen genes that contribute to the development of paragangliomas are more susceptible to the development of head and neck paragangliomas when mutated. Gene expression profiling revealed that pheochromocytomas and paragangliomas can be classified into two main clusters (C1 and C2) based on transcriptomes. These groups were defined according to their mutational status and as such strongly associated with specific tumorigenic pathways. The influence of the main genetic drivers on the somatic molecular phenotype was shown by DNA methylation and miRNA profiling. Certain subunits of succinate dehydrogenase (SDHx), von Hippel-Lindau (VHL) and transmembrane protein 127 (TMEM127) still have the highest impact on development of head and neck paragangliomas. The link between RAS proteins and the formation of pheochromocytoma and paragangliomas is clear due to the effect of receptor tyrosine-protein kinase (RET) and neurofibromatosis type 1 (NF1) in RAS signaling and recent discovery of the role of HRAS. The functions of MYC-associated factor X (MAX) and prolyl hydroxylase 2 (PHD2) mutations in the contribution to the pathogenesis of paragangliomas still remain unclear. Ongoing studies give us insight into the incidence of germline and somatic mutations, thus offering guidelines to early detection. Furthermore, these also show the risk of mistakenly assuming sporadic cases in the absence of definitive family history in head and neck paragangliomas.

[Surgical treatment options for cervical paragangliomas]

The therapies available for the rare tumor entity of cervical paraganglioma (PG) are currently undergoing a paradigm shift. The treatment of choice for small carotid body tumors, malignant and active endocrine tumors is surgical resection; however, for locally advanced carotid body tumors and vagal PG, surgical therapy should be critically evaluated. Due to the immediate proximity of these hypervascularized tumors to the caudal cranial nerves, there is a risk of severe nerve damage with a significant impairment of quality of life after resection, particularly for locally advanced cervical PG, emphasizing further the importance of a restrictive surgical strategy. External radiotherapy can provide an equivalent primary therapeutic option with respect to the rate of recurrence and is accompanied by a lower morbidity. The slow rate of tumor progression and the multifocality of the familial variant of cervical PG or significant comorbidities in older, asymptomatic patients warrant a less aggressive treatment strategy for these tumors. When a wait and scan approach is implemented, a closely monitored radiological and clinical re-evaluation is of upmost importance. In a multidisciplinary approach the following critical points require consideration before a therapy is implemented,: size and location of the tumor, progression rate, genetic background, patient age and general condition, relevant comorbidities, the presence of synchronous PG and/or vasoactive catecholamine-producing tumors. Although best practice algorithms for the treatment of cervical PG have already been devised, recent innovative developments have led to more patient-tailored, individualized treatment approaches.

Data Set for the Reporting of Ear and Temporal Bone Tumors: Explanations and Recommendations of the Guidelines From the International Collaboration on Cancer Reporting

The International Collaboration on Cancer Reporting (ICCR) was established to internationally unify and standardize the pathologic reporting of cancers based on collected evidence, as well as to allow systematic multi-institutional intercountry data collection to guide cancer care in the future. Such collaborative efforts are particularly essential for developing an evidence base for rare neoplasms or those with marked geographic variation in incidence, such as the tumors of the ear and the temporal bone. The ear and the temporal bone, including the external auditory canal and the middle and inner ear, with the closely associated facial nerve, internal carotid artery, and internal jugular vein, is one of the most complex anatomic structures in the head and neck. A wide range of benign and malignant neoplasms arise in this region. The management of these neoplasms involves complex surgery because of the anatomic confines, and as such, both benign and malignant tumors are included in this data set, as the oncologically equivalent management requires a multidisciplinary approach and standardized nomenclature and terminology. Surgical procedures at this site result in multifaceted 3-dimensional specimens that can be difficult to handle at macroscopic exam. A comprehensive macroscopic examination is important for identifying critical prognostic factors and often requires clinical and radiologic correlation. Histologic examination is straightforward for basal cell or squamous cell carcinoma but can be quite challenging for other neoplasms. A summary of the ICCR guidelines for ear tumors is presented, along with discussion of the salient evidence and practical issues.

Pathology and genetics of phaeochromocytoma and paraganglioma

Phaeochromocytoma and paraganglioma (PHEO/PGL) are rare tumours with an estimated annual incidence of 3 per million. Advances in molecular understanding have led to the recognition that at least 30-40% arise in the setting of hereditary disease. Germline mutations in the succinate dehydrogenase genes SDHA, SDHB, SDHC, SDHD and SDHAF2 are the most prevalent of the more than 19 hereditary genetic abnormalities which have been reported. It is therefore recommended that, depending on local resources and availability, at least some degree of genetic testing should be offered to all PHEO/PGL patients, including those with clinically sporadic disease. It is now accepted that that all PHEO/PGL have some metastatic potential; therefore, concepts of benign and malignant PHEO/PGL have no meaning and have been replaced by a risk stratification approach. Although there is broad acceptance that certain features, including high proliferative activity, invasive growth, increased cellularity, large tumour nests and comedonecrosis, are associated with an increased risk of metastasis, it remains difficult to predict the clinical behaviour of individual tumours and no single risk stratification scheme is endorsed or in widespread use. In this review, we provide an update on advances in the pathology and genetics of PHEO/PGL with an emphasis on the changes introduced in the WHO 2017 classification of endocrine neoplasia relevant to practising surgical pathologists.

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.

A meta-analysis on the surgical management of paraganglioma of the carotid body per Shamblin class

OBJECTIVE

The aim of this study was to evaluate the risk associated with different types of surgery for carotid body paraganglioma of different Shamblin class. A meta-analysis was conducted to evaluate per tumour class, the local control, cranial nerve damage and complication rates of different techniques using internal carotid artery (ICA) and external carotid artery (ECA) ligation, clamping or bypassing, as well as the craniocaudal vs caudocranial techniques.

DESIGN

A meta-analysis is conducted after a systematic search in PubMed and the Cochrane library, in accordance with the PRISMA guidelines.

MAIN OUTCOME MEASURES

Local control, cranial nerve damage, complications, function recovery.

RESULTS

Out of 3565 articles, 27 were selected. The overall quality of evidence of studies was low. Cranial nerve damage (3%, 17% and 39%) and complication rates (0%, 1% and 10%) were significantly related to Shamblin class (class 1, 2 and 3, respectively, P < .01). For class 3 tumours, an increased risk of complications was found associated with routine ICA manipulation/reconstruction (RR 3.12 with a 95% CI of 1.29-7.59), as well as a trend towards enhanced risk of routine ECA ligation (RR 3.48 with a 95% CI of 0.88-13.81).

CONCLUSIONS

For class 1 and 2 tumours, surgery seems a viable treatment option. For class 3 tumours, morbidity in terms of cranial nerve deficit and complications is considerable; particularly, the use of ICA manipulation/reconstruction and potentially ECA ligation seem to be accompanied by high stroke incidence.

Results of a systematic literature review of treatment modalities for jugulotympanic paraganglioma, stratified per Fisch class

OBJECTIVE

Key for successful jugulotympanic paraganglioma management is a personalised approach aiming for the best practice for each individual patient. To this end, a systematic review is performed, evaluating the local control and complication rates for the different treatment modalities stratified by the broadly accepted Fisch classification.

DESIGN

A systematic literature review according to the PRISMA statement was performed. A detailed overview of individual treatment outcomes per Fisch class is provided.

MAIN OUTCOME MEASURES

Local control, cranial nerve damage, complications, function recovery.

RESULTS

Eighteen studies were selected, resembling 83 patients treated with radiotherapy and 299 with surgery. Excellent local control was found post-surgery for class A and B tumours, and risk of cranial nerve damage was <1%. For class C1-4 tumours, local control was 80%-95% post-surgery (84% post-radiotherapy), and cranial nerve damage was found in 71%-76% (none post-radiotherapy; P < .05). There was no difference in treatment outcomes between tumours of different C class. For class C1-4De/Di tumours, local control was 38%-86% (98% post-radiotherapy; P < .05) and cranial nerve damage/complication rates were 67%-100% (3% post-radiotherapy; P < .05). C1-4DeDi tumours showed lesser local control and cranial nerve damage rates when compared to C1-4De tumours.

CONCLUSIONS

An individual risk is constituted for surgery and radiotherapy, stratified per Fisch class. For class A and B tumours, surgery is a suitable treatment option. For class C and D tumours, radiotherapy results in lower complication rates and similar or better local control rates when compared to the surgical group.

When should genetic testing be performed in patients with neuroendocrine tumours?

Neuroendocrine tumours (NETs) are a heterogenous group of tumours arising from neuroendocrine cells in several sites around the body. They include tumours of the gastroenteropancreatic system, phaeochromocytoma and paraganglioma and medullary thyroid cancer. In recent years, it has become increasingly apparent that a number of these tumours arise as a result of germline genetic mutations and are inherited in an autosomal dominant pattern. The number of genes implicated is increasing rapidly. Identifying which patients are likely to have a germline mutation enables clinicians to counsel patients adequately about their future disease risk, and allows for earlier detection of at-risk patients through family screening. The institution of screening and surveillance programmes may in turn lead to a major shift in presentation patterns for some of these tumours. In this review, we examine the features which may lead a clinician to suspect that a patient may have an inherited cause of a NET and we outline which underlying conditions should be suspected. We also discuss what type of screening may be appropriate in a variety of situations.

Head and neck paragangliomas: A two-decade institutional experience and algorithm for management

Objectives

Paragangliomas of the head and neck and cranial base are typically benign, slow‐growing tumors arising within the jugular foramen, middle ear, carotid bifurcation, or vagus nerve proper. The objective of this study was to provide a comprehensive characterization of our institutional experience with clinical management of these tumors and posit an algorithm for diagnostic evaluation and treatment.

Methods

This was a retrospective cohort study of patients undergoing treatment for paragangliomas of the head and neck and cranial base at our institution from 2000–2017. Data on tumor location, catecholamine levels, and specific imaging modalities employed in diagnostic work‐up, pre‐treatment cranial nerve palsy, treatment modality, utilization of preoperative angiographic embolization, complications of treatment, tumor control and recurrence, and hereditary status (ie, succinate dehydrogenase mutations) were collected and summarized.

Results

The mean (SD) age of our cohort was 51.8 (±16.1) years with 123 (63.4%) female patients and 71 (36.6%) male patients. Catecholamine‐secreting lesions were found in nine (4.6%) patients. Fifty‐one patients underwent genetic testing, with mutations identified in 43 (20 SDHD, 13 SDHB, 7 SDHD, 1 SDHA, SDHAF2, and NF1). Observation with serial imaging, surgical extirpation, radiation, and stereotactic radiosurgery were variably employed as treatment approaches across anatomic subsites.

Conclusion

An algorithmic approach to clinical management of these tumors, derived from our longitudinal institutional experience and current empiric evidence, may assist otolaryngologists, radiation oncologists, and geneticists in the care of these complex neoplasms.

Level of Evidence

4

Updates on Immunohistochemical and Molecular Markers in Selected Head and Neck Diagnostic Problems

CONTEXT

- The head and neck regions have complex anatomic structures. They are not exempted from the rare occurrences of highly unusual, diagnostically challenging malignant neoplasms and mimickers.

OBJECTIVE

- To review and update the utility of immunohistochemistry and molecular biomarkers and to pursue diagnostic accuracy on selected rare neoplasms, especially some poorly differentiated malignancies.

DATA SOURCES

- Personal experience and information from the literature.

CONCLUSIONS

- Head and neck tumors include neoplasms originating from heterogeneous tissue. Using the selected clinical cases, this review illustrates a continuous development of emerging molecular-genetic techniques to assist in the interpretation of uncommon, often poorly differentiated, highly malignant neoplasms. The diagnostic results are appropriately transmitted to the oncologists, radiation oncologists, and surgeons to create a coordinated plan of care for patients with these unusual disorders affecting the head and neck.

Radiological Surveillance Screening in Asymptomatic Succinate Dehydrogenase Mutation Carriers

There has been a significant increase in the availability of testing for pheochromocytoma and paraganglioma (PPGL) germline susceptibility genes. As more patients with genetic mutations are identified, cascade genetic testing of family members is also increasing. This results in identifying genetic predispositions at a much earlier age. With our current understanding of familial PPGL syndromes, lifelong surveillance is required. This review focuses on carriers of succinate dehydrogenase (SDH) mutations. For genetic testing to be proven worthwhile, the results must be used for patient benefit. For SDHx mutations, this should equate to a surveillance program that is safe and removes as much uncertainty around diagnosis as possible. Early identification of these tumors is the goal of any surveillance program, as surgical resection is the mainstay of treatment with curative intent to prevent the morbidity and mortality consequences associated with catecholamine excess, in addition to the risk of malignancy. Modality and frequency of surveillance imaging and how to engage individuals in the process of surveillance remain controversial questions. The data reviewed here and the cumulative advice supports the avoidance of using radiation-exposing imaging in this group of individuals that require lifelong screening.

Paragangliomas of the Head and Neck: An Overview from Diagnosis to Genetics

Paragangliomas (PGL) develop from the parasympathetic system in the head and neck (HN) and arise primarily in four distinct areas: Carotid body, vagal, middle ear, and larynx. Globally, the diagnosis and morphologic features are the same regardless of anatomic site, however the incidence, frequency of genetic alterations/syndromes and differential diagnosis vary. It is now recognized that nearly 40% of all HN PGLs are hereditary, including a significant subset without a known family history. Now pathologists are central to the evaluation for diagnosis and further management of patients with HNPGLs. Specifically, SDHB immunohistochemical evaluation is an excellent screening tool to detect tumors with alterations in the SDH family of genes that represent the majority of hereditary cases in HNPGL. Similarly, SDHB immunohistochemical analysis allows for screening of PGL syndrome associated tumors (gastrointestinal stromal tumor (GIST), renal cell carcinoma (RCC), and pituitary adenomas) that have now been linked by their overlapping gene alterations. Awareness of the spectrum of these syndromes, and their associated tumors, positions the pathologist to augment patient care and surveillance.

Update from the 4th Edition of the World Health Organization Classification of Head and Neck Tumours: Paragangliomas

Updated editions of The World Health Organization Classification of Tumours Pathology & Genetics for both Head and Neck Tumours and Tumours of Endocrine Organs took place in 2016 based on consensus conferences. These editions present unification of concepts in paragangliomas and highlight expanding knowledge of their etiology. There is a major emphasis in the new bluebooks on familial/syndromic paragangliomas, representing ~40% of all head and neck paragangliomas. Ancillary use of immunohistochemical evaluation, specifically of SDHB, allows the pathologist to screen for a large subset of these potentially hereditary cases. In addition, similarly to other neuroendocrine tumors, paragangliomas are now considered to represent a continuum of risk, and are assessed in terms of risk stratification. Tumors with SDHB mutations pose the highest risk for metastasis. There is currently no validated or endorsed histologic grading system. Paragangliomas remain tumors of undetermined biologic potential and should not be termed benign.

Evaluation of Head and Neck Paragangliomas by Computed Tomography in Patients with Pheochromocytoma-Paraganglioma Syndromes

Background

Hereditary head and neck paragangliomas (HNP) are very often associated with pheochromocytoma-paraganglioma syndromes, which are caused by mutations in genes encoding subunits of succinate dehydrogenase (SDHx) complex.

The aim of this study was to determine the frequency and location of HNP among SDHx carriers.

Material/Methods

A total of 72 patients with SDHx mutations underwent computed tomography examinations of the head and neck. HNP were present in 44 (61.1%) out of 72 patients (31 SDHD, 11 SDHB, 2 SDHC); 113 HNP were found; the most common were carotid paragangliomas (59) and vagal paragangliomas (27).

Results

The HNP were statistically more frequent in carriers of SDHD mutations compared to carriers of SDHB mutations (72.1% vs. 43.5%, p=0.033). Multiple tumors more often occurred in patients with SDHD mutations 26/31 (83.9%) than in patients with SDHB mutations 6/11 (54.5%) p=0.05.

There was a significant difference in the prevalence of carotid paragangliomas between patients with SDHB and SDHD mutations (7/11 [63.6%] vs. 30/31 [96.8%], respectively, p=0.004). Patients with SDHD mutations more often had carotid paragangliomas located on the left side than on the right side, as compared to SDHB mutations 25/31 (80.6%) vs. 4/11 (36.4%), p=0.006.

Conclusions

SDHx mutations predispose to multifocal and bilateral HNP. Carotid and vagal paragangliomas occurred most often.

Patients with SDHD mutations are characterized by higher frequency of HNP than patients with SDHB mutations, which is mainly driven by higher frequency of carotid body tumors in patients with SDHD mutations. No difference in the frequency of head and neck paragangliomas in other locations was found.

External-beam radiation therapy for malignant paraganglioma of the head and neck

BACKGROUND

Malignant paragangliomas of the head and neck are very rare tumors of the neuroendocrine cells associated with the peripheral nervous system. There are limited data available to help guide treatment of these tumors and the role of radiation therapy (RT) is not well-defined. This article briefly reviews the pathology, clinical presentation, and treatment modalities of these tumors and reviews our institutional experience in treating this malignancy.

PATIENTS AND METHODS

From November 1993 through May 2005, 5 patients with 5 malignant paragangliomas of the jugular bulb and carotid body were treated with RT at the University of Florida to a median dose of 70 Gy at 1.8 Gy per fraction. Mean and median follow-up times are 12.8 years and 14.4 years, respectively.

RESULTS

We were able to achieve significant disease-free intervals of >10 years for 3 of 5 patients and >5 years for 4 of 5 patients. Of the 2 patients who failed treatment, 1 recurred 7.3 years after the RT salvage treatment following combination surgery and RT at another institution, and 1 experienced distant metastasis 2.8 years after treatment without obvious recurrence of local disease.

CONCLUSION

Malignant paragangliomas are a very rare entity whose main treatment modality has yet to be well established. Overall, data concerning outcomes are sparse, but particularly data on the role of RT in the treatment of these difficult tumors. We recommend doses to 70 Gy at 2 Gy per once-daily fraction as an adjuvant treatment with surgery to both remove the source of disease and provide microscopic control. Patients with incompletely resectable tumors are treated with RT alone.

Paragangliomas: À Propos of Two Cases. Diagnostics and Treatment

Background

Paraganglioma develops from cells of the parasympathetic and sympathetic system. It usually manifests as a slow-growing and painless mass. Peragangliomas may be hereditary, benign or malignant, unilateral or bilateral tumors. They are well vascularized. In most cases, paraganglioma is located around the common carotid artery, but may also be located within the middle ear or in the abdomen.

Case Report

A 49-year-old patient with bilateral paragangliomas around branches of carotid arteries. Diagnostic imaging was performed, including MRI and CT angiography. To reduce the size of the tumors, the patient was subjected to radiotherapy, with no result. Finally, the tumor on the right side was removed.

A 67-year-old patient with the third recurrence of retroperitoneal paraganglioma. Diagnostic imaging was performed. Vascular embolisation was not performed as the vessels were too narrow for microcatheter introduction.

Conclusions

Paragangliomas are rare tumors. Total resection is sometmies impossible because of the rich vascularity and difficult location. Radiotherapy is a good alternative, though not always effective. Proper diagnostic imaging is necessary.

15 YEARS OF PARAGANGLIOMA: Genetics and mechanism of pheochromocytoma-paraganglioma syndromes characterized by germline SDHB and SDHD mutations

Pheochromocytomas and paragangliomas (PPGL) are rare neuroendocrine neoplasms that derive from small paraganglionic tissues which are located from skull base to the pelvic floor. Genetic predisposition plays an important role in development of PPGLs. Since the discovery of first mutations in the succinate dehydrogenase D (SDHD) gene, which encodes the smallest subunit of mitochondrial complex II (SDH), genetic studies have revealed a major role for mutations in SDH subunit genes, primarily in SDHB and SDHD, in predisposition to both familial and non-familial PPGLs. SDH-mutated PPGLs show robust expression of hypoxia induced genes, and genomic and histone hypermethylation. These effects occur in part through succinate-mediated inhibition of α-ketoglutarate-dependent dioxygenases. However, details of mechanisms by which SDH mutations activate hypoxic pathways and trigger subsequent neoplastic transformation remain poorly understood. Here, we present a brief review of the genetic and mechanistic aspects of SDH-mutated PPGLs.