Paraganglioma of the Carotid Body: Treatment Strategy and SDH-gene Mutations

Prevalence, characteristics, evaluation, and management of carotid body tumors: Systematic analysis based on available evidence

OBJECTIVE

Although carotid body tumors (CBTs) are rare, they attract particular attention because of their propensity for malignant transformation and the high surgical risk. Because data are scarce and as it is difficult to achieve a large sample size, no study has yet comprehensively analyzed the characteristics, management, or operative complications of CBTs. Therefore, we collected and analyzed all currently available information on CBTs and used the pooled data to derive quantitative information on disease characteristics and management.

METHODS

We systematically searched PubMed, Embase, the Cochrane Library, and the Web of Science up to December 1, 2022, for studies that investigated the characteristics and management of CBTs. The primary objective was to identify the prevalence of the various characteristics and the incidence of complications. The secondary objective was to compare patients who underwent preoperative embolization (PE) and those who did not (non-PE), as well as to compare patients with different Shamblin grades and those with and without succinate dehydrogenase (SDH) mutations in terms of CBT characteristics and complications. Two reviewers selected studies for inclusion and independently extracted data. All statistical analyses were performed using the standard statistical procedures of Review Manager 5.2 and Stata 12.0.

RESULTS

A total of 155 studies with 9291 patients and 9862 tumors were identified. The pooled results indicated that the median age of patients with CBT was 45.72 years, and 65% were female. The proportion of patients with bilateral lesions was 13%. In addition, 16% of patients had relevant family histories, and the proportion of those with SDH gene mutations was 36%. Sixteen percent of patients experienced multiple paragangliomas, and 12% of CBTs had catecholamine function. The incidence of cranial nerve injury (CNI) was 27%, and 14% of patients suffered from permanent CNI. The incidence rates of operative mortality and stroke were both 1%, and 4% of patients developed transient ischemic attacks. Of all CBTs, 6% were malignant or associated with metastases or recurrences. The most common metastatic locations were the lymph nodes (3%) and bone (3%), followed by the lungs (2%). Compared with non-PE, PE reduced the estimated blood loss (standardized mean difference, -0.95; 95% confidence interval [CI], -1.70 to -0.20) and the operation time (standardized mean difference, -0.56; 95% CI, -1.03 to -0.09), but it increased the incidence of stroke (odds ratio, 2.44; 95% CI, 1.04-5.73). Higher Shamblin grade tumors were associated with more operative complications. Patients who were SDH gene mutation-positive were more likely to have a relevant family history and had more symptoms.

CONCLUSIONS

CBT was most common in middle-aged females, and early surgical resection was feasible; there was a low incidence of serious operative complications. Routine PE is not recommended because this may increase the incidence of stroke, although PE somewhat reduced the estimated blood loss and operation time. Higher Shamblin grade tumors increased the incidence of operative complications. Patients who were SDH gene mutation-positive had the most relevant family histories and symptoms.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Surgical and Histopathological Results in Carotid Body Tumors

OBJECTIVE

 The possible relationships between the histopathological findings of carotid body tumors and age, gender, tumor diameter, and Shamblin classification were investigated. In addition, preoperative embolization status, development of neurological complications, need for vascular reconstruction, hemoglobin change, and discharge time were examined and the effects of these variables on each other were analyzed.

METHODS

 Between 2008 and 2022, 46 cases who underwent carotid body tumor excision were examined retrospectively. The cases were followed for an average of 81 months postoperatively. Histopathological materials were reexamined and the effect of categorical variables was analyzed.

RESULTS

 Mean tumor diameter was 3.55 ± 1.26 cm, mean discharge time was 3.91 ± 2.37 days, and mean hemoglobin change was 1.86 ± 1.25. Neurological complications developed in 13% of cases. The amount of hemoglobin change was significantly (p = 0.003) higher in those who developed neurological complications, whereas the tumor diameter and discharge time were found to be insignificantly higher. Surgical complications requiring vascular repair occurred in 10.8% of cases. Tumor diameter (p = 0.017) and hemoglobin change (p = 0.046) were significantly higher in these patients. There were significant correlations between higher Shamblin classification and tumor diameter, discharge time, postoperative hemoglobin value, and number of surgical and neurological complications. No significant difference was found between Ki-67, capsular invasion, mitosis, pleomorphism, prominent nucleoli, mean island diameter, and tendency of islands to merge with categorical variables.

CONCLUSION

 As the tumor diameter increases, the operation becomes more difficult and the postoperative complication rate increases. We think that subadventitial and capsular removal of the tumor is effective in preventing recurrence. To reach a histopathological conclusion, a larger series of studies including tumors with high Ki-67 and mitosis rates, large size, and one or more of the criteria for necrosis are needed.

Current management of carotid body tumors

Carotid body tumors (CBTs) are neoplasms that occur at the bifurcation of the carotid artery and are pathologically classified as paragangliomas. In the 4th edition of the WHO classification, paragangliomas are categorized as neoplasms with malignant potential. Clinically, about 5% of CBTs present with malignant features such as metastasis. Currently, it is challenging to distinguish between tumors with benign courses and those that present malignantly. Recent advances in genetic testing have elucidated the genetic characteristics of paragangliomas, including carotid body tumors. Over 20 genes have been identified as being involved in tumor development. Particularly in head and neck paragangliomas, abnormalities in genes related to succinate dehydrogenase are frequently observed. Research is ongoing to understand the mechanisms by which these genes contribute to tumor development. The definitive treatment for CBTs is surgical resection. These tumors are prone to bleeding and often adhere firmly to the carotid artery, making intraoperative bleeding control challenging. The risk of lower cranial nerve paralysis is relatively high, and there is a risk of stroke because of manipulation of the carotid artery. Preoperative evaluation with angiography is essential, and a multi-disciplinary surgical team approach is necessary. In cases where the tumor is difficult to resect or has metastasized, radiation therapy or chemotherapy are employed. Clinical trials involving targeted molecular therapies and radiopharmaceuticals have recently been conducted, with some applied clinically. The development of various new treatments is anticipated, providing hope for therapeutic options in refractory cases.

Malignant carotid body tumors: What we know, what we do, and what we need to achieve. A systematic review of the literature

Malignant carotid body tumors (MCBT) are rare and diagnosed after detection of nodal or distant metastases. This systematic review (SR) focuses on MCBT initially approached by surgery. Preferred Reporting Items for SR and Meta-Analysis (MA) guided the articles search from 2000 to 2023 on PubMed, Scopus, and Web of Science. Among 3548 papers, 132 (337 patients) were considered for SR; of these, 20 (158 patients) for MA. Malignancy rate was 7.3%, succinate dehydrogenase (SDH) mutation 17%, age at diagnosis between 4th and 6th decades, with a higher prevalence of females. MCBTs were mostly Shamblin III, with nodal and distant metastasis in 79.7% and 44.7%, respectively. Malignancy should be suspected if CBT >4 cm, Shamblin III, painful or otherwise symptomatic, at the extremes of age, bilateral, with multifocal disease, and SDHx mutations. Levels II-III clearance should be performed to exclude nodal metastases and adjuvant treatments considered on a case-by-case basis.

A Global Bibliometric Analysis of the Top 100 Most Cited Articles on Carotid Body Tumors

The carotid body, situated at the common carotid artery bifurcation, comprises specialized glomus cells responsible for sensing blood oxygen, carbon dioxide, pH, and temperature changes, crucial for regulating breathing and maintaining oxygen homeostasis. Carotid body tumors (CBTs), arising from these cells, are rare, representing only 0.5% of head and neck tumors, often presenting as benign, slow-growing, vascularized masses. In February 2023, this bibliometric analysis was conducted, which involved screening 1733 articles from the Web of Science database. The screening process was based on citation count, and articles were selected for inclusion based on specific criteria that focused on CBTs located within the carotid bifurcation. Rigorous selection involved independent screening and data extraction by four authors. The top 100 articles, published between 1948 and 2019, totaled 6623 citations and were authored by 98 unique first authors from 22 countries and 77 institutions, spanning 42 journals. Treatment articles were the predominant category, comprising 49% of the literature. This analysis offers insights into publication trends, identifies literature gaps, and outlines areas of research focus, providing a valuable resource to guide future studies on CBTs.

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.

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.

Perioperative blood pressure and heart rate alterations after carotid body tumor excision: a retrospective study of 108 cases

BACKGROUND

Arising from chemoreceptor cells, carotid body tumors (CBTs) are rare neoplasms associated with hemodynamics. Perioperative changes in blood pressure (BP) and heart rate (HR) are not completely understood.

METHODS

This retrospective, observational, controlled study included all CBT patients from 2013 to 2018 in Peking Union Medical College Hospital. Perioperative changes in BP/HR within or between unilateral/bilateral/control groups were investigated. Perioperative details across Shamblin types were also assessed.

RESULTS

This study included 108 patients (116 excised CBTs). The postoperative systolic BP and HR increased in both unilateral (mean difference of systolic BP = 5.9mmHg, 95% CI 3.1 ~ 8.6; mean difference of HR = 3.7 bpm, 95% CI 2.6 ~ 4.9) and bilateral (mean difference of systolic BP = 10.3mmHg, 95% CI 0.6 ~ 19.9; mean difference of HR = 8.4 bpm, 95% CI 0.5 ~ 16.2) CBT patients compared with the preoperative measures. Compared with control group, the postoperative systolic BP increased (difference in the alteration = 6.3mmHg, 95% CI 3.5 ~ 9.0) in unilateral CBT patients; both systolic BP (difference in the alteration = 9.2mmHg, 95% CI 1.1 ~ 17.3) and HR (difference in the alteration = 5.3 bpm, 95% CI 1.0 ~ 9.6) increased in bilateral CBT patients. More CBT patients required extra antihypertensive therapy after surgery than controls (OR = 2.5, 95% CI 1.14 ~ 5.5). Maximum tumor diameter, intraoperative vascular injury, continuous vasoactive agent requirement, total fluid volume, transfusion, estimated blood loss, operation duration, postoperative pathology, overall complications, and intensive care unit/hospital lengths of stay significantly varied among Shamblin types.

CONCLUSION

CBT excision may be associated with subtle perioperative hemodynamic changes. Perioperative management of CBT patients necessitates careful assessment, full preparation and close postoperative monitoring.

Carotid body tumor encounters over a two-decade period in an academic hospital

Carotid body tumors (CBTs) are rare and mostly benign. Research outcomes usually arise from single-center data. We conducted this study to present the characteristics and outcomes of patients who underwent surgical resection of CBT at our hospital over the past 20 years. In this retrospective review, the records of CBTs in our hospital were reviewed between 1998 and 2021. All patients who underwent CBT resection were included. The follow-up period was 12 months. A total of 44 CBTs were treated in our hospital. The male-to-female ratio was 1:2.4. Only 4.5% of patients had Shamblin I tumors. Patients with Shamblin II and III tumors were 56.8% and 38.6%, respectively. Duplex scan was used to diagnose CBT in all of the patients. The majority of our patients (97.7%) did not receive any preoperative embolization despite an average tumor size of 4.9 cm. Cranial nerve injuries were observed in 29.5% of cases. Meanwhile, stroke was reported in only two cases (4.5%). No deaths were encountered. Surgery is the definitive treatment for CBT. Size and local extension appear to be the main reasons for adverse events rather than surgical techniques. Our results are consistent with those of previously published studies. Good outcomes are expected in high-volume centers with appropriate preoperative imaging.

Current trends in carotid body tumors: Comprehensive review

BACKGROUND

Carotid body tumor (CBT) is a rare neoplasm that has been increasingly studied during the last decades; nevertheless, it continues to be a topic of controversy. This review aims to provide an update on the general features of CBT and particularly review different treatment strategies and primary outcomes.

METHODS

Data for this literature review were identified by PubMed, Scopus, and Medline. 93 articles from the initial search were included, as well as 28 relevant studies utilizing the snowballing method; totaling 121 articles about CBT.

RESULTS

Main features such as anatomy, embryology, genetics, clinical presentation, and diagnosis of CBT are presented, followed by evidence of different treatment strategies such as radiotherapy, preoperative embolization, vascular resection, and vascular reconstruction. Main complications are also discussed.

CONCLUSION

This review summarizes the most critical aspects regarding CBT. Future studies should compare different treatments to attain the best surgical results with lower morbidity rates.

Bilateral Giant Familial Carotid Body Tumors With Concomitant Skull-Base Paraganglioma and Facial Nerve Palsy

Carotid body tumors, rare neck paragangliomas arising from the common carotid artery bifurcation, can be classified as sporadic, hyperplastic, or familial. The familial type is often bilateral and associated with germline mutation of the mitochondrial enzyme succinate dehydrogenase. We report the rare case of a 42-year-old man who presented with bilateral giant familial carotid body tumors associated with a concomitant skull-base paraganglioma, left-sided facial nerve palsy, and an incomplete circle of Willis. We describe the excision of the tumors in 2 stages (the left mass and associated paraganglioma first and the right mass second), 6 months apart, with use of general anesthesia, and we discuss other operative considerations.

The Influence of Young Age on Difficulties in the Surgical Resection of Carotid Body Tumors

Simple Summary

The aim of this study was to reveal the factors affecting the complexity and difficulties in performing surgery to resect carotid body tumors (CBTs). We analyzed 20 patients with 21 CBTs. We used the “same day surgery” procedure, including preoperative embolization of the feeding arteries in the morning and resection surgery in the afternoon of the same day. Four patients underwent resection of the carotid artery, followed by reconstruction. These four patients were between 18 to 23 years of age at the time of surgery. The mean blood loss and operative time in these patients differed significantly from those in older patients. These results indicated that young age may influence the difficulties faced in CBT surgery, resulting in an increased risk of carotid artery resection. The results obtained from our study could help surgeons safely and effectively perform resection surgery for CBTs.

Abstract

This study evaluated patient characteristics that affect the complexity and difficulties of performing surgery to resect carotid body tumors (CBTs). We retrospectively reviewed the medical records of 20 patients with 21 CBTs who were enrolled in the study. The median patient age was 46 years and the mean tumor diameter was 37.6 mm. The mean blood loss and operative time were 40.3 mL and 183 min, respectively. Four patients underwent resection of the carotid artery followed by reconstruction. These four patients were between 18 to 23 years of age at the time of surgery. The mean blood loss and operative time in these patients were 166 mL and 394 min, respectively, which differed significantly from those of older patients. Therefore, young age influenced the difficulties faced in surgical resection of CBT, with an increased risk of blood loss and carotid artery resection.

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

Objective

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

Design

Prospective genetic study.

Setting

Tertiary Referral Otolaryngology Centre.

Participants

Twelve family members.

Main outcome measures

Main outcomes were clinical analysis and SDH genotyping

Results and Conclusions

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

The characteristics of carotid body tumors in high-altitude region: Analysis from a single center

OBJECTIVES

Though carotid body tumors are rare, increasing attentions have been given because of malignant transformation and high surgical risk. However, at present, the characteristics and etiology still remain unclear. Our study was designed to describe the clinical features of carotid body tumors in our institution and to compare the results with previous reports.

METHODS

We retrospectively reviewed carotid body tumor patients diagnosed in our institution from January 2015 to May 2020. The demographics, comorbidities, lesion location, anatomic characteristics, complications, and postoperative outcomes were evaluated. Carotid body tumor measurements were determined from computed tomography, magnetic resonance imaging, and carotid arteriography examination. We described and compared the clinical features of carotid body tumors in our institution and other reports.

RESULTS

We totally identified 122 carotid body tumor cases for the present analysis. The mean age was 50.26 years, with the majority being female (82%). The commonest presentation was a painless neck mass (68%). For the distribution of nationality, most patients were the Han nationality (69.7%). The mean altitude of habitat of patients was 2689.4 km; 19.7% patients suffered bilateral lesions. The main blood supply of carotid body tumors was from external carotid artery (54.1%). For patients who received operation, 11 (11.2%) patients experienced cranial nerve injury. The maximal diameter of tumors was 3.99 ± 1.98 cm in male and 3.38 ± 1.36 cm in female. The volume of tumors was 31.49 ± 29.76 cm³ in male and 15.27 ± 13.06 cm³ in female. The distance to base of skull of tumors was 3.39 ± 1.07 cm (3.99 ± 1.98 cm in male vs 3.38 ± 1.36 cm, P < 0.05). Two patients (2.04%) were identified as having malignant carotid body tumor.

CONCLUSIONS

Though carotid body tumor had a low morbidity and multitudinous clinicopathologic features, it was apt to middle-aged women and the main blood supply was from external carotid artery. The painless neck mass was the commonest presentation of carotid body tumors. There were significant difference between male and female patients regarding platelet, hemoglobin, distance to base of skull, tumor volume, altitude of habitat, carotid body tumor location, and hypertension.

Carotid body tumor as a potential cause of paroxysmal hemicrania

A 70-year-old woman presented to our emergency department with a severe left-sided headache. The headache's location and accompanying symptoms are consistent with paroxysmal hemicrania. On workup, a cervical computed tomography scan incidentally revealed a left carotid body tumor, and the patient was referred to vascular surgery. After the resection of the tumor, the patient recovered well in the following months. Furthermore, she no longer experienced any additional headache episodes, which were likely caused by the carotid body tumor.

Carotid Body Tumor Microenvironment

Carotid body tumors (CBTs) are rare paragangliomas, comprising 0.5% of all head and neck tumors, and 65% of head and neck paragangliomas. A majority of CBTs occur sporadically, while 15% are familial or hyperplastic in the setting of chronic hypoxia. They usually present as unilateral, well-circumscribed rubbery masses, arising at the level of the carotid bifurcation. A majority of CBTs are painless and therefore may evade diagnosis for months to years. Symptomatic lesions occur due to progressive cranial nerve IX, X, or XII dysfunction, manifesting as hoarseness, dysphagia, vertigo, coughing, or odynophagia. Other local symptoms include neck discomfort, pulsatile tinnitus, hearing loss, or carotid sinus syndrome. Appropriate workup includes a thorough physical exam followed by radiographic imaging, vascular studies, and biochemical workup with 24 h urinary catecholamine or metanephrine analysis. The management of these tumors, which involves standalone surgical resection or following embolization for larger and more vascular tumors, will also be discussed.

Novel potential causative genes in carotid paragangliomas

Background

Carotid paragangliomas (CPGLs) are rare neuroendocrine tumors that arise from the paraganglion at the bifurcation of the carotid artery and are responsible for approximately 65% of all head and neck paragangliomas. CPGLs can occur sporadically or along with different hereditary tumor syndromes. Approximately 30 genes are known to be associated with CPGLs. However, the genetic basis behind the development of these tumors is not fully elucidated, and the molecular mechanisms underlying CPGL pathogenesis remain unclear.

Methods

Whole exome and transcriptome high-throughput sequencing of CPGLs was performed on an Illumina platform. Exome libraries were prepared using a Nextera Rapid Capture Exome Kit (Illumina) and were sequenced under 75 bp paired-end model. For cDNA library preparation, a TruSeq Stranded Total RNA Library Prep Kit with Ribo-Zero Gold (Illumina) was used; transcriptome sequencing was carried out with 100 bp paired-end read length. Obtained data were analyzed using xseq which estimates the influence of mutations on gene expression profiles allowing to identify potential causative genes.

Results

We identified a total of 16 candidate genes (MYH15, CSP1, MYH3, PTGES3L, CSGALNACT2, NMD3, IFI44, GMCL1, LSP1, PPFIBP2, RBL2, MAGED1, CNIH3, STRA6, SLC6A13, and ATM) whose variants potentially influence their expression (cis-effect). The strongest cis-effect of loss-of-function variants was found in MYH15, CSP1, and MYH3, and several likely pathogenic variants in these genes associated with CPGLs were predicted.

Conclusions

Using the xseq probabilistic model, three novel potential causative genes, namely MYH15, CSP1, and MYH3, were identified in carotid paragangliomas.

A Systematic Review and Meta-Analysis of the Presentation and Surgical Management of Patients With Carotid Body Tumours

OBJECTIVES

The aim was to determine the mode of presentation and 30 day procedural risks in 4418 patients with 4743 carotid body tumours (CBTs) undergoing surgical excision.

METHODS

This is a systematic review and meta-analysis of 104 observational studies.

RESULTS

Overall, 4418 patients with 4743 CBTs were identified. The mean age was 47 years, with the majority being female (65%). The commonest presentation was a neck mass (75%), of which 85% were painless. Dysphagia, cranial nerve injury (CNI), and headache were present in 3%, while virtually no one presented with a transient ischaemic attack (0.26%) or stroke (0.09%). The majority (97%) underwent excision, but only 21% underwent pre-operative embolisation. Overall, 27% were Shamblin I CBTs; 44% were Shamblin II; and 29% were Shamblin III. The mean 30 day mortality was 2.29% (95% CI 1.79-2.93). The mean 30 day stroke rate was 3.53% (95% CI 2.91-4.29), while the mean 30 day CNI rate was 25.4% (95% CI 24.5-31.22). The prevalence of persisting CNI at 30 days was 11.15% (95% CI 8.42-14.64). Twelve series (544 patients) correlated 30 day stroke with Shamblin status. Shamblin I CBTs were associated with a 1.89% stroke rate (95% CI 0.92-3.82), increasing to 2.71% (95% CI 1.43-5.07) for Shamblin II CBTs and 3.99% (95% CI 2.34-6.74) for Shamblin III tumours. Twenty-six series (1075 patients) correlated CNI rates with Shamblin status: 3.76% (95% CI 2.62-5.35) for Shamblin I CBTs, 14.14% (95% CI 11.94-16.68) for Shamblin II, and 17.10% (95% CI 14.82-19.65) for Shamblin III tumours. The prevalence of neck haematoma requiring re-exploration was 5.24% (95% CI 3.45-7.91). The proportion of patients with a neck haematoma requiring re-exploration was not reduced by pre-operative embolisation (5.92%; 95% CI 2.56-13.08) vs. no embolisation (5.82%; 95% CI 2.76-11.88). Pre-operative embolisation did not reduce drainage losses (639 mL vs. 653 mL).

CONCLUSIONS

This is the largest meta-analysis of outcomes after CBT excision. Procedural risks associated with tumour excision were considerable, especially with Shamblin III tumours where 4% suffered a peri-operative stroke and 17% suffered a CNI.

A pediatric carotid body tumor

Carotid body tumors are rare childhood extra-adrenal paragangliomas. We present an 8-year old female with a neck mass mistaken as reactive lymphadenopathy. Computed tomography and magnetic resonance angiography, as well as preoperative embolization and balloon test occlusion, were utilized for planning and management. Surgical excision of the tumor was successful and pathological examination revealed a benign paraganglioma. Surgical treatment is curative for these benign lesions, however rare cases have presented years later with metastatic disease. Therefore, a child, like our patient, will require lifelong surveillance for the development of potential metastasis.

Clinical progression and metachronous paragangliomas in a large cohort of SDHD germline variant carriers

Although it is well established that paternally transmitted germline variants in SDHD are associated with multifocal paragangliomas and lifelong follow-up is generally advised, the risk of metachronous lesions is presently unknown. In a large Dutch cohort of SDHD variant carriers, we studied the development of new paragangliomas, and the evolution of symptoms and cranial nerve impairment. Recurrent event analysis and the Kaplan-Meier product limit estimator were used to study the risk of new lesions. The relation between several predictors and development of new symptoms was assessed using logistic regression. Of the 222 SDHD variant carriers included, 65% presented with symptoms and 11% with cranial nerve dysfunction. Over a median period of 8 years, 42% reported new symptoms, and new cranial nerve impairment was observed in 11% of subjects. The estimated fraction of subjects that developed new HNPGL increased to 73% (95% CI: 52-85%) after 22 years of follow-up. Males were more likely to develop new HNPGL compared to females (HR: 1.63, 95% CI: 1.10-2.40), as were subjects that presented with symptoms, compared to subjects that were asymptomatic at baseline (HR: 1.61, 95% CI: 1.01-2.55). In addition, the risk of new lesions decreased with number of HNPGL present at first diagnosis (HR: 0.68 and 95% CI: 0.56-0.82). Carriers of a paternally inherited SDHD variant face a considerable risk for new HNPGL. In addition, nearly 50% of subjects reported new symptoms. However, new cranial nerve deficits were observed in only 11%, which is less than reported in surgical series. These risks should be taken into account when considering treatment strategies and counseling.

Multi-institutional survey of carotid body tumors in Japan

There has been no attempt to clarify the status of patients with carotid body tumor (CBT) in Japan. This multi-institutional survey analyzed patients with CBT throughout Japan by gathering information on these patients from institutions that performed head and neck surgeries. Information from a total of 150 patients from 25 institutions from the past 20 years was employed in the present survey. There were 87 females and 63 males, and their mean age was 48.0 years old. The most common chief complaint was a neck mass and the mean suffering period was 46.1 months. Eighteen patients had a family history of paragangliomas and fifteen patients had bilateral CBTs. Among the 94 patients who underwent surgery to remove a CBT, 23 patients had tumors classified as Shamblin type I, 59 had type II and 12 had type III. The most frequent feeding artery of these CBTs was the ascending pharyngeal artery. Preoperative embolization of these arteries was effective in reducing blood loss; however, the operation time in Shamblin type I and II tumors was not improved. Thus these results revealed the status of patients with CBT and their treatment throughout Japan.

GROWTH RATE OF PARAGANGLIOMAS RELATED TO GERMLINE MUTATIONS OF THE SDHX GENES

OBJECTIVE

The purpose was to determine the growth rate of succinate dehydrogenase subunit (SDHx) gene-related paragangliomas based on computed tomography (CT) measurements.

METHODS

Twenty-seven patients with SDHx mutations who underwent subsequent CT examinations were enrolled in the study. Tumors were classified as head and neck (HNP), thoracic, or abdominal/pelvic paragangliomas (PGLs). The percentage volume increase and volume doubling time were estimated.

RESULTS

We analyzed 56 PGLs (21 with SDHD, 6 with SDHB mutations) in 27 patients (16 men, 11 women; mean age 37.7 years). The estimated median of the follow-up was 23 months. Twenty-two (39.3%) PGLs were located in the abdomen, 8 (14.3%) in the thorax, and 26 (46.4%) in the head and neck region. The median volume growth rate was estimated at 10.4% per year (interquartile range [IQR]: -1.3; 36.3). The volume doubling time was estimated as 7.01 (2.24;+∞) years. By tumor site, the estimated medians of the annual volume growth rates were 13.6% (IQR:0.8 -30.4) for HNP, -6.06% (IQR: -1.79;47.32) for thoracic PGLs, and 10.5% (IQR: -2.2;44.6) for abdominal PGLs. The volume doubling time was 5.44 years (2.61; 87.0) for HNP, 11.8 years (1.79;+∞) for thoracic PGLs, and 6.94 years (1,88;+∞) for abdominal PGLs. There was no significant difference in the volume growth rate according to tumor location or initial size (P>.7 and P = .07, respectively) or gene mutation type (SDHB vs. SDHD, P>.8).

CONCLUSION

PGLs related to SDHx mutations are slowly growing tumors. There were no correlations between tumor location, growth rate or initial size over a 23-month follow-up period.

ABBREVIATIONS

CT = computed tomography HNP = head and neck paraganglioma IQR = interquartile range PGL = paraganglioma PPGL = pheochromocytoma and paraganglioma SDH = succinate dehydrogenase.

Rapid-sequence MRI for long-term surveillance for paraganglioma and phaeochromocytoma in patients with succinate dehydrogenase mutations

BACKGROUND

Patients with SDHx mutations need long-term radiological surveillance for the development of paragangliomas and phaeochromocytomas, but no longitudinal data exist. The aim of the study was to assess the performance of rapid-sequence non-contrast magnetic resonance imaging (MRI) in the long-term monitoring of patients with SDHx mutations.

METHODS

Retrospective study between 2005 and 2015 at a University Hospital and regional endocrine genetics referral centre. Clinical and imaging data of 47 patients with SDHx mutations (SDHB (36), SDHC (6) and SDHD (5)) who had surveillance for detection of paragangliomas by rapid-sequence non-contrast MRI (base of skull to pubic symphysis) were collected.

RESULTS

Twelve index cases (nine SDHB, one SDHC and two SDHD) and 35 mutation-positive relatives were monitored for a mean of 6.4 years (range 3.1-10.0 years). Mean age at the end of the study: SDHB 46.9 ± 17.6 years; SDHC 42.3 ± 24.4 years; SDHD 54.9 ± 10.6 years. On excluding imaging at initial diagnosis of index cases, 42 patients underwent 116 rapid-sequence MRI scans: 83 scans were negative and 31 scans were positive for sPGL/HNPGL in 13 patients. Most patients had multiple scans (n = number of patients (number of rapid-sequence MRI scans during screening)): n = 9 (2), n = 20 (3), n = 6 (4), n = 1 (6). Nine patients (three index) were diagnosed with new paragangliomas during surveillance and non-operated tumour size was monitored in nine patients. There were two false-positive scans (1.6%). Scans were repeated every 27 ± 9 months.

CONCLUSIONS

Biannual rapid-sequence non-contrast MRI is effective to monitor patients with SDHx mutations for detection of new tumours and monitoring of known tumours.

What happens in vagus: a case of recurrent paraganglioma with malignant transformation and an updated treatment algorithm†

Paragangliomas (PGLs) are rare, extra-adrenal tumors, originating from neural crest cells and can occur anywhere from the skull base to the pelvic floor. Although these tumors are often benign, a fraction of malignant cases exist. Few isolated cases of malignant head and neck PGL are reported in the literature. Treatment algorithms rely heavily on retrospective case studies and institutional experience. We report an unusual case of an extensive, hereditary PGL, with invasive characteristics, that was refractory to radiation therapy. An operative approach was selected for recurrent disease in the setting of critical neurovascular structure compromise. Six months postoperatively, the patient was recovering as expected and had no evidence of recurrent disease. We propose a modified treatment algorithm based on an updated literature review that encompasses the spectrum of PGL, from benign and asymptomatic to invasive and malignant disease.

Multidisciplinary Management of Carotid Body Tumors in a Tertiary Urban Institution

Objective. Aim of this study is to present the experience of our institution in carotid body tumors (CBTs) treatment. Methods. All cases treated in a Vascular Surgery Department within 2.5 years (03/2013-09/2015) were retrospectively evaluated. Demographics, diagnostic, and treatment strategy were recorded. All patients with known CBT underwent ultrasound and magnetic resonance imaging preoperatively. All cases were classified according to the Shamblin type and evaluated by a radiologist, otolaryngologist, and anesthesiologist before and after surgery. Major outcomes included mortality, stroke, cranial nerve injury, and recurrence. Results. Overall, nine patients (mean age: 59.5 ± 16.3 years) with a total of ten CBTs were treated. There was no gender prevalence and most of the cases (55%) were asymptomatic. There were no functional or familial cases. There was only one bilateral case treated in a staged manner. No preoperative embolization of CBTs was performed. Mortality and stroke rates were null. No severe complication was observed in the early and late setting. No malignancy was recorded. Mean follow-up was 15.6 ± 7.8 months. Conclusions. Multidisciplinary management of patients with CBTs is imperative for optimal results, especially in type III tumors, bilateral or functional cases. After careful treatment planning and intraoperative manipulations, complications could be avoided even without preoperative embolization.

Resection of a large carotid paraganglioma in Carney-Stratakis syndrome: a multidisciplinary feat

A 39-year-old man was referred to the vascular surgeons with a right-sided cervical mass, palpitations, headaches and sweating. He had presented with abdominal discomfort 12 months earlier. Investigations had revealed a gastrointestinal stromal tumour (GIST) and left adrenalectomy. CT of the neck with contrast demonstrated a large right carotid paraganglioma, extending superiorly from below the carotid bifurcation to encase the internal carotid artery. Genetic screening confirmed the diagnosis of Carney-Stratakis syndrome, an SDH-D germline mutation leading to GIST and multifocal paragangliomas. Successful surgical excision required considerable multidisciplinary teamwork between neuroendocrinologists, anaesthetists and surgeons. The tumour was highly vascular and involved the right carotid body, hypoglossal and vagus nerves. Access was challenging and maxillofacial surgical expertise were required for division of the mandible. The patient made a good recovery following speech and swallowing rehabilitation.

Sclerosing paraganglioma of the carotid body: a potential pitfall of malignancy

Paragangliomas (PGs) of the head and neck region are typically benign, slow-growing neuroendocrine tumours. At times, they may exhibit unusual histological features, such as prominent stromal sclerosis (sclerosing PG), which may raise concerns of malignancy. We describe a case of sclerosing PG of the carotid body, emphasizing the value of immunohistochemical stains for differential diagnosis. A 43-year-old woman presented with a painless lump on the neck. A magnetic resonance imaging scan demonstrated a hypervascular lesion of the carotid body, which was surgically excised. Grossly, the lesion measured 1.8 cm at maximum diameter. On microscopic examination, irregular nests and tiny bundles of neoplastic cells were found between thick bands of fibrous tissue. Focal nuclear cytomegaly and marked pleomorphism were noted. Neoplastic cells proved to be immunoreactive for chromogranin, synaptophysin and neuron specific enolase, but negative for cytokeratins, smooth muscle actin and CD34. Ultrastructurally, numerous mitochondria, rough endoplasmic reticulum structures and endocrine granules were seen in the cytoplasm of the tumour cells. On consideration of the above-mentioned clinico-pathological and ultrastructural findings a diagnosis of sclerosing PG was established. Sclerosing PG is a rare entity which may mimic a malignant neoplasm. The recognition of this unusual morphological variant of PG, together with appropriate immunostains, leads to the correct diagnosis.

Carotid body tumors: a review of 25 years experience in diagnosis and management of 56 tumors

OBJECTIVE

To report our experience in the management of CBTs and review the literature.

MATERIALS AND METHODS

56 CBTs were operated upon over a period of 25 years. Surgical intervention was planned according to the Shamblin classification. Thirty-nine of the tumors were in males (69.64%), and 17 of the tumors were in females (30.36%). The average age was 42 (ages ranging between 32 and 47). Twenty-two tumors were diagnosed and treated with Shamblin type I, twenty-eight with type II and eight tumors with type III. All patients were unilateral except two had bilateral carotid tumors. Thirty-five lumps were de novo (group A), while 21 lumps were treated after a prior trial of removal (group B).

RESULTS

The incidence of carotid reconstruction was lower among group A (1/35) compared to group B (9/21). Complications were less in group A than group B (23% vs. 30%). There were 4 cases with suspected malignancy and no recurrences during the follow-up period.

CONCLUSION

There is an increased incidence of major vascular reconstruction in cases not properly investigated or diagnosed and in cases with prior attempts of removal in Primary Hospitals. Proper diagnosis of suspicious lumps is mandatory. Resection of CBTs by surgeons with experience in vascular reconstruction is recommended. Vascular reconstructions have to be performed safely without serious complications. Also today, prior attempts of removal are not so common, with preoperative evaluation using the latest diagnostic tools. Cranial nerves injury (especially the Hypoglossal Nv) continues to be the most common complication.

The presence of SDHB mutations should modify surgical indications for carotid body paragangliomas

OBJECTIVE

The aim of this study was to determine whether the genetic background of the disease should be incorporated into treatment decision making.

BACKGROUND

Carotid body paragangliomas are rare tumors that often affect patients with genetic mutations of the succinate dehydrogenase complex (SDHx). Despite growing evidence that germ line genetic mutations alter the aggressiveness of paragangliomas, treatment decisions are currently based only on clinical symptoms and tumor size in patients with carotid body paragangliomas.

METHODS

Retrospective analysis of 34 patients with carotid body paragangliomas who underwent genetic testing and surgical treatment. Recurrence was defined by the return of locoregional disease and/or development of distant metastases. Clinical characteristics and genetic testing results were analyzed as predictors of patient outcomes.

RESULTS

Thirty-four patients underwent 41 primary carotid body paraganglioma resections (median follow-up time of 42 months, range: 1-293). Overall survival was 91.2%. Twelve patients had germ line mutations in SDHB, 17 in SDHD, and 5 carried no known mutation. Surgical resection of larger tumors was associated with higher operative complications (odds ratio: 5.4, P = 0.05). Tumor size at resection was significantly smaller in patients with SDHB mutations than in patients with non-SDHB mutations (2.1 vs 3.3 cm, P = 0.02). Patients with a mutation in the SDHB gene also had significantly worse disease-free survival compared with patients without an SDHB gene mutation (P = 0.03).

CONCLUSIONS

Mutations in the SDHB gene are associated with worse disease-free survival after resection in patients with carotid body paragangliomas despite earlier intervention. This suggests that a more aggressive surgical approach is warranted in patients with SDHB mutations.

Anxiety and depression related to elevated dopamine in a patient with multiple mediastinal paragangliomas

Paragangliomas are rare neuroendocrine tumors. Occasionally they secrete catecholamines in sufficient quantities to cause symptoms. These may include psychiatric symptoms such as anxiety and depression. We describe a patient with multiple mediastinal paragangliomas and persistently elevated dopamine levels who presented with anxiety and depression. She later went on to develop paranoid schizophrenia, which we feel was coincidental. This case illustrates anxiety and depressive symptoms associated with elevated dopamine and the importance of awareness of psychiatric manifestations of neuroendocrine tumors among psychiatrists and physicians.

The management of head-and-neck paragangliomas

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

Results from craniocaudal carotid body tumor resection: should it be the standard surgical approach?

OBJECTIVES

To evaluate results after carotid body tumor (CBT) surgery using a novel dissection technique.

METHODS

A retrospective analysis of all operated CBT in the last 6 years was carried out and results were compared with the current literature and our previous series, which reported another 111 cases operated on until 2005.

RESULTS

Forty-five CBTs were removed in 41 (56% hereditary cases) patients (seven Shamblin I, 22 II, and 16 III). There were no cases of permanent cranial nerve injury or stroke. These pre- and postoperative results compare favorably with our previous series and are superior to, generally smaller, studies reported in the contemporary literature.

CONCLUSIONS

This large series of surgically-treated CBTs supports craniocaudal dissection as the surgical technique of choice as it limits blood loss and facilitates safe CBT resection.