Case Series: ATRX Variants in Four Patients with Metastatic Pheochromocytoma.

Few reports have highlighted the rare presence of somatic ATRX variants in clinically aggressive, metastatic pheochromocytoma/paraganglioma (PCC/PGL); however, none have addressed detailed clinical presentation (including biochemistry and imaging) and management of these patients. Here, we address these clinical features and management based on four PCC patients with somatic ATRX variants from our National Institutes of Health PCC/PGL cohort. A total of 192 patients underwent exome sequencing (germline, somatic, or both), and four males were found to have somatic ATRX variants (with additional somatic VHL and FH oncogenic variants in patients 2 and 4, respectively). Per-lesion and per-patient comparisons were performed among functional imaging scans performed at the NIH. Biochemical phenotype and response to systemic treatment were evaluated. This mini-series supports prior studies showing aggressive/metastatic PCC in patients with somatic ATRX variants, as all developed widespread metastatic disease. All four PCC patients presented with noradrenergic biochemical phenotype, and some with significant elevation in 3-methoxytyramine. 18F-FDOPA PET/CT was found to be the superior functional imaging modality, with 100% lesion detection rate when compared to that of 68Ga-DOTATATE, 18F-FDG, 18F-FDA, and 123I-MIBG scans. While patients did not respond to chemotherapy or tyrosine kinase inhibitors, they responded to targeted radiotherapy using high-specific-activity 131I-MIBG (Azedra®) or 177Lu-DOTATATE (Lutathera®).

[Off-pump Resection of Dopamine-secreting Cardiac Paraganglioma].

Dopamine-secreting paragangliomas is known to be rare. The average annual incidence rate was reported 0.8 per 100,000 person-years. Approximately 1 to 2% of paragangliomas occur in the chest. We describe a patient with a large dopamine-secreting cardiac paraganglioma, right adrenal tumor and carotid body tumor. A 26-year-old man with progressive exertional dyspnea was referred to our hospital for further management of multiple paragangliomas. Positron emission tomography (PET) and PET-computed tomography (CT) detected those three legions. The diameter of cardiac paraganglioma was over 45 mm and was biggest among three tumors. Firstly, therefore, we planned cardiac paraganglioma resection. Through left lateral thoracotomy in the 4th intercostal space via, cardiac paraganglioma was resected under cardiopulmonary bypass and beating heart. Postoperative course was uneventful. Tumor cells were positive for synaptophysin and chromogranin A. Free metanephrines in the serum and urinary fractionated metanephrines normalized after cardiac surgery while the other two tumors remained untreated.

Metastatic disease and major adverse cardiovascular events preceding diagnosis are the main determinants of disease-specific survival of pheochromocytoma/paraganglioma: long-term follow-up of 303 patients.

Purpose: The natural history in unselected cohorts of patients with pheochromocytoma/ paraganglioma (PPGL) followed for a period >10 years remains limited. We aimed to describe baseline characteristics and outcome of a large cohort and to identify predictors of shorter survival. Methods: This retrospective single-center study included 303 patients with newly diagnosed PPGL from 1968 to December 31, 2023, in 199 prospectively supplemented since July 2020. Mean follow-up was 11.4 (range 0.3-50) years, germline genetic analyses were available in 92.1%. The main outcome measures were overall (OAS), disease-specific (DSS), recurrence-free (RFS) survival and predictors of shorter survival evaluated in patients with metastases at first diagnosis (n=12), metastatic (n=24) and nonmetastatic (n=33) recurrences and without evidence of PPGL after first surgery (n=234). Results: Age at study begin was 49.4 ± 16.3 years. There were 72 (23.8%) deaths, 15 (5.0%), 29 (9.6%) and 28 (9.2%) due to PPGL, cardiovascular disease (CVD) and malignant or other diseases, respectively. Median OAS, DSS1 (tumor-related) and DSS2 (DSS1 and death caused by CVD) were 4.8, 5.9 and 5.2 years (patients with metastases at first diagnosis), 21.2, 21.2 and 19.9 years, and 38.0, undefined and 38.0 years (patients with metastatic and with nonmetastatic recurrences, respectively). Major adverse cardiovascular events (MACE) preceded the first diagnosis in 15% (n=44). Shorter DSS2 correlated with older age (P ≤ 0.001), male sex (P ≤ 0.02), MACE (P ≤ 0.01) and primary metastases (P<0.0001, also for DSS1). Conclusion: The clinical course of unselected patients with PPGL is rather benign. Survival rates remain high for decades, unless there are MACE before diagnosis or metastatic disease.

Tumor volume changes after stereotactic, hypofractionated and conventional radiotherapy in paragangliomas of head and neck.

BACKGROUND: The aim of this study is comparison the effectiveness of stereotactic, hypofractionated and conventional radiotherapy assessed by the tumor volume changes of paraganglioma located in the head and neck region concerning fractional and total doses. METHODS: We analyzed 76 patients after radiotherapy due to paraganglioma who were assigned to 3 groups considering fractional (≤2 Gy, 3-5.5 Gy, ≥6 Gy) and total (≤20 Gy, 21-40 Gy, >40 Gy) doses. The volumes of irradiated tumors were measured and compared based on diagnostic images performed before and after the treatment. RESULTS: The mean tumor volume after the treatment with the lowest fractional dose (≤2 Gy) was decreased by 14.4 cm3. In patients treated with higher fractional doses (>2 Gy), the mean tumor volumes decreased by less than 1 cm3 for hypofractionated and stereotactic radiotherapy. 15.9 cm3 reduction of the mean tumor volume after the treatment with the highest RT total dose (>40 Gy) was stated. In patients treated with total doses ≤20 Gy and 21-40 Gy, the mean tumor volume was stable and reduced by 1.15 cm3, respectively. The analysis demonstrates a statistically significant (p < 0.05) treatment advantage in patients after the lowest fractional and highest total doses. CONCLUSION: The reduction of the tumor's volume was reported after conventional and unconventional radiotherapy. The most significant depletion of the paraganglioma volume was noted after a factional dose ≤2 Gy and a total dose >40 Gy.

Intratumoral Microbiome in Head and Neck Paragangliomas.

Head and neck paragangliomas (HNPGLs) are rare neoplasms arising from paraganglia of the parasympathetic nervous system. HNPGLs are characterized by high vascularity and are located in proximity to major vessels and nerves, which may be potential sources of microbial invasion in these tumors. There have been no studies in the literature on the microbiota in HNPGLs. Investigation of the microbiome associated with paragangliomas is important for understanding tumor pathogenesis. In this study, we investigated the microbiome composition in two sets of HNPGLs. First, 29 fresh frozen (FF) tissues were subjected to 16S rRNA gene sequencing; concurrently, a panel of candidate laboratory-derived contaminants was investigated. Second, we analyzed microbial reads from whole transcriptome sequencing data obtained for 82 formalin-fixed paraffin-embedded (FFPE) HNPGLs. The bacterial diversity in FF tumors was found to be significantly lower than that observed in FFPE HNPGLs. Based on 16S rRNA gene sequencing, only seven bacterial families were identified as potential tumor inhabitants: Bryobacteraceae, Enterococcaceae, Neisseriaceae, Legionellaceae, Vibrionaceae, Obscuribacteraceae, and Mycobacteriaceae. However, RNA-Seq demonstrated higher sensitivity for identifying microbiome composition and revealed abundant bacterial families that partially correlated with those previously described in pheochromocytomas and extra-adrenal paragangliomas. No viruses were found in HNPGLs. In summary, our findings indicated the presence of a microbiome in HNPGLs, comprising a number of bacterial families that overlap with those observed in pheochromocytomas/paragangliomas and glioblastomas.

Prevention and management of hypertensive crises in children with pheochromocytoma and paraganglioma.

Hypertensive crises in pediatric patients are rare conditions. However, determining their precise prevalence is more challenging than in adults due to the heterogeneity in the definition itself. These crises frequently occur without a prior diagnosis of hypertension and may indicate an underlying cause of secondary hypertension, including pheochromocytoma/paraganglioma (PPGL). The mechanisms of hypertensive crises in the pediatric population with PPGL are directly related to different types of catecholamine excess. Noradrenergic tumors typically present with sustained hypertension due to their predominant action on α1-adrenoceptors in the vasculature. Conversely, adrenergic tumors, through epinephrine binding to ß2-adrenoceptors in addition to stimulation of α1- and α2-adrenoceptors, more frequently cause paroxysmal hypertension. Furthermore, the biochemical phenotype also reflects the tumor localization and the presence of a genetic mutation. Recent evidence suggests that more than 80% of PPGL in pediatric cases have a hereditary background. PPGL susceptibility mutations are categorized into three clusters; mutations in cluster 1 are more frequently associated with a noradrenergic phenotype, whereas those in cluster 2 are associated with an adrenergic phenotype. Consequently, the treatment of hypertensive crises in pediatric patients with PPGL, reflecting the underlying pathophysiology, requires first-line therapy with alpha-blockers, potentially in combination with beta-blockers only in the case of tachyarrhythmia after adequate alpha-blockade. The route of administration for treatment depends on the context, such as intraoperative or pre-surgical settings, and whether it presents as a hypertensive emergency (elevated blood pressure with acute target organ damage), where intravenous administration of antihypertensive drugs is mandatory. Conversely, in cases of hypertensive urgency, if children can tolerate oral therapy, intravenous administration may initially be avoided. However, managing these cases is complex and requires careful consideration of the selection and timing of therapy administration, particularly in pediatric patients. Therefore, facing these conditions in tertiary care centers through interdisciplinary collaboration is advisable to optimize therapeutic outcomes.

Cardiac Paraganglioma in a Young Patient Presents with Angina-like Symptoms: A Case Report and Literature Review.

Paragangliomas are rare extra-adrenal neuroendocrine tumors originating from chromaffin tissue that present a diagnostic and therapeutic challenge due to their diverse clinical manifestations and low incidence. While these tumors often manifest as catecholamine-secreting functional tumors, their clinical presentation can vary, leading to delayed diagnosis and challenging management. This study presents the case of a 22-year-old patient with cardiac paraganglioma who initially presented with angina-like symptoms, highlighting the importance of considering this rare condition in young individuals with nonspecific complaints. Diagnostic imaging, including transthoracic echocardiography, CT angiography, and MRI, played a crucial role in identifying the tumor's location and vascularization. Surgical excision, including pulmonary artery graft and CABG, was the primary management approach, which was accompanied by intraoperative complications that later led to CCU admission, followed by postoperative complications, ultimately leading to the patient's death. This case highlights the significance of early recognition and management of complications following a surgical approach to treat paragangliomas.

Management and follow-up strategies for patients with head and neck paraganglioma.

OBJECTIVE: Head-neck paragangliomas (HNPGLs) are rare tumors with approximately half arising due to germline pathogenic variants (PVs) in succinate dehydrogenase genes (SDHx). Patients with HNPGL have heterogeneous propensity to recur and metastasize. Thus, we aim to assess prevalence and predictors of recurrent (RD) and/or metastatic disease in patients with and without SDHx-related HNPGLs. DESIGN AND METHODS: This cross-sectional study used retrospective data of 214 patients enrolled in six referral centers. Data included sex, age, primary tumor treatment, location, and size, biochemical phenotype, germline PVs, presence of RD (locoregional or new tumor), and/or metastasis. RESULTS: Patients with and without SDHx-related HNPGLs showed 74% and 40% prevalence of RD, respectively. Patients without SDHx-related HNPGLs presented with recurrent tumors only in head-neck regions. The only independent predictor for RD in the entire cohort was presence of SDHx PVs. Metastatic prevalence reached 9%-13%. For patients with SDHx-related HNPGLs, large tumor size (>2.3 cm, OR:50.0, CI:2.6-977.6), young age at initial diagnosis (<42years, OR:27.3, CI:1.8-407.2), and presence of SDHB PV (OR:15.6; CI:1.5-164.8) were independent predictors of metastasis. For patients without SDHx-related HNPGLs, only carotid-body location was an independent predictor of metastasis (OR:18.9, CI:2.0-182.5). CONCLUSIONS: Patients without SDHx-related HNPGLs require long-term follow-up due to high prevalence of RD with imaging largely restricted to head-neck regions. As carotid-body HNPGLs have the highest metastatic risk among sporadic tumors, radical treatment with frequent follow-up is suggested until population-based data are available. Importantly, patients with SDHx-related HNPGLs might benefit from early radical treatment when tumors are still small to reduce metastatic risk.

Paraganglioma-induced pheochromocytoma crisis successfully treated by veno-arterial extracorporeal membrane oxygenation: a case report.

Pheochromocytoma crisis is rare but potentially fatal if not recognized early and properly managed. Here, a woman in her 20s with a paraganglioma-induced pheochromocytoma crisis, who was successfully treated by veno-arterial extracorporeal membrane oxygenation (VA-ECMO) and interval tumor resection, is described. In July 2022, the patient was brought to hospital with a complaint of sudden-onset of palpitations with vomiting. The patient developed cardiorespiratory failure with hypoxia. Computed tomography scan showed pulmonary oedema and a mass anterior to the inferior vena cava. She was transferred to the intensive care unit and treated with VA-ECMO. The patient's ECMO was withdrawn after 6 days without any complications. After hemodynamic stabilization, the patient underwent tumor resection 4 months later. The postoperative course was uneventful and she was discharged on postoperative day 7. Histopathological analysis confirmed a paraganglioma. VA-ECMO may play a significant role in saving lives and providing time for accurate diagnosis and specific treatment of a patient with pheochromocytoma crisis. Appropriate individual management can help avoid the occurrence of ECMO complications.

Paediatric renal hilar paraganglioma.

Retroperitoneal neuroendocrine tumours are exceptionally rare. The excision of tumours located in the renal hilum near the renal vessels can be challenging. We report a case of a paraganglioma located at the renal hilum which was excised successfully in a child who presented with abdominal pain, breathlessness, left varicocele and hypertension.

Hybrid Somatostatin Receptor PET/MRI of the Head and Neck.

Hybrid PET/MRI has the potential to transform neuro-oncologic imaging, particularly in diagnosis and treatment planning of somatostatin receptor-expressing tumors of the head and neck. Hybrid PET/MRI combines high-resolution MRI with functional information from PET, providing precise anatomic information and overcoming difficulties in localization inherent to PET alone. There is a range of tumors in the head and neck that overexpress somatostatin receptors and are therefore amenable to evaluation with somatostatin receptor PET/MRI. These include meningiomas, paragangliomas, olfactory neuroblastomas, pituitary neuroendocrine tumors, middle ear neuroendocrine tumors, and medullary thyroid carcinomas. The combination of PET and MRI is superior to either modality alone and can address several unique diagnostic challenges associated with these lesions. The authors discuss the superior capabilities of somatostatin receptor PET/MRI, including improved lesion localization, more sensitive demonstration of disease extent, enhanced surveillance, optimized radiation therapy planning, and accurate prediction of response to somatostatin analog therapy. Although there are only a few dedicated PET/MRI units available in clinical practice, commercial software is now available that can automatically fuse PET/CT data with recently acquired MRI data, increasing the availability of this approach. Radiologists should be aware of the advantages of somatostatin receptor PET/MRI in evaluation of head and neck tumors as well as the potential pitfalls of this approach so that they can accurately advise clinicians and better interpret these studies. ©RSNA, 2024 See the invited commentary by Shatzkes and Strauss in this issue.

Pheochromocytoma/Paraganglioma Syndrome Type 1 Presenting with Atypical Symptoms and a Novel Pathogenic Variant in the SDHD Gene: A Case Report.

This case report presents a 10-year-old patient diagnosed with pheochromocytoma/paraganglioma syndrome type 1 (PPGL1), underlined by a novel heterozygous pathogenic variant (c.154_161del, p.ser52Profster14) in the SDHD gene. Initially, the patient manifested symptoms unusual for pheochromocytoma, including polyuria and polydipsia; however, further diagnostic investigations revealed a pheochromocytoma (PCC) tumor in the adrenal gland. Subsequently, whole exome sequencing (WES) test identified a pathogenic frameshift variant in the SDHD gene, strongly suggestive of PPGL1. This study highlights the importance of considering atypical symptoms in diagnosing rare pediatric pheochromocytoma/paraganglioma tumors and underscores the value of genetic testing in identifying underlying genetic causes, thereby facilitating personalized management of the condition.

Genotype and clinical phenotype characteristics of MAX germline mutation-associated pheochromocytoma/paraganglioma syndrome.

Objective: The aim of this study was to investigate the genotypic and clinical phenotypic characteristics of MAX germline mutation-associated pheochromocytoma (PCC) and paraganglioma (PGL). Methods: We retrospectively analyzed the family investigation data and clinical genetic characteristics of six individuals from three independent families with PCC carrying MAX germline mutations from December 2005 to March 2024. A literature review was then conducted of the six carriers and another 103 carriers from the other 84 families with MAX germline mutations reported previously. Results: There were 109 patients in 87 families with all five exons and 53 types of MAX germline mutations. p.R33* (c.97C>T; 21.1%), p.R75* (c.223C>T; 13.8%), and p.A67D (c.200C>A; 7.3%), which accounted for 42.2% of mutations detected, were the most common mutations. Moreover, 101 (92.7%) patients developed PCCs, including 59 bilateral PCCs and 42 unilateral PCCs, and 19 (18.8%) patients showed metastasis. The mean age at diagnosis was 32.8 ± 12.6 (13-80) years. The male-to-female ratio was 1.3:1. In 11 (10.9%) patients, the PCC was accompanied by chest or abdominal PGL, and one other patient had sole head and neck PGL. Nine (8.3%) patients also had functional pituitary adenomas, 11 (10.9%) developed other neuroendocrine tumors (NETs), and 7 (6.4%) presented with concomitant non-NET. Meanwhile, MAX-p.Q82Tfs*89 and p.E158A mutations are reported for the first time in this study. Conclusion: MAX germline mutations may cause new types of multiple endocrine neoplasia. A comprehensive baseline assessment of neural crest cell-derived diseases is recommended for all individuals with MAX germline mutations. The risk of bilateral and metastatic PCCs should also be considered.

Total loss of VHL gene function impairs neuroendocrine cancer cell fitness due to excessive HIF2α activity.

Loss-of-function germline von Hippel-Lindau (VHL) tumor suppressor mutations cause VHL disease, which predisposes individuals to kidney cancer, hemangioblastomas, and paragangliomas. The risk that a given VHL disease family will manifest some or all these tumor types is profoundly influenced by the VHL allele it carries. For example, almost all VHL disease families that develop paraganglioma have missense VHL mutations. VHL families with null VHL alleles develop kidney cancer and hemangioblastomas without a high risk of paraganglioma. The latter is surprising because the VHL gene product, pVHL, suppresses the HIF2 transcription factor and gain-of-function HIF2 mutations are also linked to paraganglioma. Paragangliomas arise from the sympathetic or parasympathetic nervous system. Given the lack of human paraganglioma cell lines, we studied the effects of inactivating VHL in neuroblastoma cell lines, which also arise from the sympathetic nervous system. We found that total loss of pVHL function profoundly impairs the fitness of neuroblastoma cell lines in a HIF2-dependent manner both ex vivo and in vivo. This fitness defect can be rescued by pVHL variants linked to paraganglioma, but not by pVHL variants associated with a low risk of paraganglioma. These findings suggest that HIF2 activity above a critical threshold prevents the development of paraganglioma.

[Endothelial cells and fibroblasts mediate the microenvironmental regulatory network of carotid body paraganglioma].

Objective:To explore the gene expression characteristics of endothelial cells and fibroblasts in the microenvironment of SDHD-mutated carotid body tumors（SDHD-CBT）, to fine the functional enrichment of each subcluster, and to further explore the network of cell-cell interactions in the microenvironment of SDHD-CBT. Methods:The bioinformatics analysis was used to download and reanalyze the single-nuclear RNA sequencing data of SDHD-CBT, SDHB mutated thoracic and abdominal paraganglioma（SDHB-ATPGL）, SDHB-CBT, and normal adrenal medulla（NAM）, to clarify the information of cell populations of the samples. We focused on exploring the gene expression profiles of endothelial cells and fibroblasts subclusters, and performed functional enrichment analysis based on Gene Ontology（GO） resources. CellChat was used to compare the cell-cell interactions networks of different clinical samples and predict significant signaling pathways in SDHD-CBT. Results:A total of 7 cell populations were profiled. The main subtypes of endothelial cells in SDHD-CBT are arterial and venous endothelial cells, and the main subtypes of fibroblasts are myofibroblasts and pericytes. Compared to NAM, SDHB-CBT and SDHB-ATPGL, cell communication involving endothelial cells and fibroblasts in SDHD-CBT is more abundant, with significant enrichment in pathways such as FGF, PTN, WNT, PROS, PERIOSTIN, and TGFb. Conclusion:Endothelial cells and fibroblasts in SDHD-CBT are heterogeneous and involved in important cellular interactionprocesses, in which the discovery of FGF，PTN，WNT，PROS，PERIOSTIN and TGFb signals may play an important role in the regulation of microenvironment of SDHD-CBT.

[Application of internal carotid artery stent in glomus jugular paraganglioma surgery].

Objective:To summarize the application of internal carotid artery stent in glomus jugular paraganglioma surgery, and to provide an effective strategy for reducing the risk of internal carotid artery injury. Methods:This article reviewed the surgical cases of internal carotid artery stent implanting from 2018.06 to 2022.12, and discussed the stent placement method, treatment protocols, and perioperative management strategies. Results:A total of 5 patients underwent a comprehensive evaluation of the degree of internal carotid artery invasion using imaging techniques such as MRI, carotid CT angiography （CTA）, and digital silhouette angiography （DSA）. All patients were found to have varying degrees of internal carotid artery involvement. Stenting of the internal carotid artery was performed in all patients before surgery, and the stenting process went smoothly without any internal carotid artery injury. Three months after stenting, tumor resection or subtotal resection surgery was performed to avoid internal carotid artery injury during the surgery, and the surgical process was successfully completed. Postoperative follow-up from 4 months to 2 years showed that the internal carotid artery was patent after stent placement, with great endothelialization process and no stent-related complications. Conclusion:In patients with glomus jugular paraganglioma, when preoperative imaging shows internal carotid artery involvement, preoperative stenting is a safe and effective therapeutic strategy to reinforce the arterial wall structure, protect and maintain the integrity of the artery, and reduce the risk of vascular injury during the surgery. This article summarizes the experience of internal carotid artery stent in glomus jugular paraganglioma surgery, which provides an important reference for clinical practice.

[Review and prospect of the diagnosis and treatment of head and neck paragangliomas].

ead and neck paraganglioma（HNPGL） often originates from the parasympathetic ganglia and is a highly invasive benign tumor. The diagnosis and treatment of this disease with strong heterogeneity is still a challenge. In the future, deep exploration is needed in genetic typing, grading diagnosis and treatment decisions, protection of cranial nerves and new drug treatments to better treat this disease.

[The surgical outcomes in management of jugular foramen paragangliomas with tension free anterior rerouting of the facial never and tunnel packing of the inferior petrous sinus].

Objective:The aim of this study is to evaluate the safety and efficacy of surgical interventions ofjugular foramen paragangliomas（JFP） utilizing modified surgical techniques, tensionfree anterior rerouting of the facial nerve and tunnel-packing or push-packing of the inferior petrous sinus. Methods:A retrospective analysis was conducted on a cohort of 88 patients diagnosed with JFP and treated at the Eye Ear Nose and Throat Hospital of Fudan University（in Shanghai, China） from October 2010 to June 2021. The surgical outcomes were analyzed for tumor classification, intraoperative conditions, and function of the postoperative facial nerve（FN） and lower cranial nerve（LCN）. Results:The study included a total of 88 patients, gross total resection was achieved in 70 patients（79.5%）, near total resection was obtained in 17 patients（19.3%）, and one patient undergoing subtotal resection. The average of intraoperative blood loss was 448.3 mL. Additionally, 24 patients underwent surgical total anterior rerouting（TAR）, 18 patients underwent surgical total FN tension free anterior rerouting（TF-TAR）, and 18 patients underwent surgical FN partial FN tension free anterior rerouting（TF-PAR）. Good postoperative FN function（House-Brackmann Ⅰ-Ⅱ） was achieved in 62.5% of TAR group. In the TF-TAR and PF_TAR groups, good postoperative FN function was demonstrated in 88.9% patients. It showed a significantly improvement of the FN function following application of tension-free FN anterior rerouting technique（P=0.007）. Twenty patients（22.7%） suffered from at least one LCN deficit in the preoperative evaluation. The postoperative LCN deficits was correlated with the Fisch classification of tumors, which showed a lower incidence of LCN dysfunction in classes C1-C2（4.9%, 2/41cases） and poorer outcomes of LCN dysfunction in classes C3-D（8.5%,4/47cases ）, it was likely less impacted the LCN function in the early stage tumor. Conclusion:The application of modified surgical techniques of FN tension-free anterior rerouting and tunnel-packing of the inferior petrous sinus has been shown to effectively preserve the function of the FN and LCN, decrease intraoperative blood loss, and ultimately improve patients' postoperative quality of life.

[Reconstruction of internal carotid artery in the resection of paraganglioma of head and neck].

Objective:This study aims to discuss the necessity，surgical method and effect of reconstruction of internal carotid artery （ICA） in the resection of paraganglioma of head and neck. Methods:We retrospectively analyzed the data of the patients who underwent head and neck paraganglioma resection and ICA reconstruction in Peking Union Medical College Hospital from May 2015 to August 2023. The demographic characteristics, preoperative examinations, diagnoses, surgical techniques, and follow-up information were collected. Results:Six patients were enrolled, including four females and two males, with an average age of（39.8±13.0） years. All the patients presented mainly complaining local masses with or without pain. Four cases underwent surgery through Fisch infratemporal fossa approach type A+B, and one through approach type A and one through transcervical approach. Five patients had vascular reconstruction using the great saphenous vein while one patient used an artificial vessel. The average follow-up period was（43.8±31.6） months. One patient had tumor recurrence after 3 years and underwent second surgery to remove the residual tumor, and the other 5 patients had no tumor recurrence. One patient had acute bridging vessel embolism, and the other was found to have occlusion of the bridging vessel at follow-up. Conclusion:Carotid revascularization during resection of paraganglioma of head and neck is an important technique to completely remove the tumor, cure the disease, ensure intracranial blood supply, and reduce cerebrovascular complications. The "pre-reconstruction technique " is an effective method to minimize the duration of brain blood flow interruption, compared to traditional carotid revascularization. Close observation is necessary, along with regular radiological examinations to assess the patency of transplanted vessels, and the residual or recurrent tumors.