Clinical outcomes and challenges of surgical extirpation for carotid body paraganglioma in South Korea: a single-center retrospective study.

BACKGROUND: Carotid body paraganglioma (CBP) is a rare, highly vascularized, and slow-growing neuroendocrine tumor. Surgical resection is the definitive treatment for CBP, however, it remains challenging due to the tumor's proximity to critical blood vessels and cervical cranial nerves. This study aimed to document the characteristics of CBP and examine the clinical outcomes of patients following surgical extirpation of CBP. METHODS: This is a single-center retrospective review analyzed patients who underwent CBP extirpation. We examined the patient demographics, preoperative clinical features, tumor characteristics, levels of catecholamines and their metabolites in the serum and urine. Surgeries were performed by one vascular surgeon with follow-ups at 1,3,6 months and yearly thereafter. Logistic regression analysis was conducted to identify risk factors associated with the occurrence of either permanent or temporary cervival cranial nerve palsy (CNP). RESULTS: From September 2020 to February 2023, this study examined 21 cases of CBP removal surgeries that were carried out in 19 patients. The mean age of the patients was 38.9 ± 10.9 years and the percentage of males was 57.1% (n = 12). The most common preoperative clinical feature was painless neck mass (n = 12; 57.1%). Complete resection was achieved in 20 cases; excluding one case with pathologically proven sclerosing paraganglioma. Vascular procedures were performed in four cases (ECA resection, n = 2; primary repair of ICA tear without carotid shunting, n = 1; and ICA patch angioplasty with carotid shunting, n = 1). Temporary cranial neurologic complications, specifically aspiration and hoarseness occurred in four (19.0%), and three (14.3%) cases, respectively. Hoarseness associated with permanent CNP persisted for more than 6 months in two cases (9.5%). No recurrence or mortality was observed during the follow-up period. CONCLUSIONS: Surgical resection is the primay treatment approach for CBP; however, it poses risks of vascular or cervical CNP. The intraoperative estimated blood loss was the only identified risk factor for CNP.

Novel insights into the classification of Shamblin III carotid body tumors from a neurosurgical perspective.

BACKGROUND AND PURPOSE: The classic Shamblin system fails to provide valuable guidance in many Shamblin's III carotid body tumors (III-CBTs) due to the variable forms of carotid arteries and the complex anatomic relationships in parapharyngeal space. We proposed a modified classification to separately divide III-CBTs into different subgroups on the basis of arterial relevant features and anatomical relevant features. MATERIALS AND METHODS: From 2020 to 2023, a total of 129 III-CBTs at a single institution were retrospectively analyzed. All cases were independently classified as arterial-relevant and anatomical-relevant subgroups. The pre-, peri- and postoperative data were summarized and compared accordingly. RESULTS: Among the 129 cases, 69 cases were identified as "Classical type", 23 cases as "Medial type", 27 cases as "Lateral type" and 10 cases as "Enveloped type" according to arterial morphologies. Besides, 76 cases were identified as "Common type", 15 cases as "Pharynx- invasion type", 18 cases as "Skull base-invasion type" and 20 cases as "Mixed type" according to anatomical relationships. "Enveloped type" of tumors in arterial-relevant classification and "Mixed type" of tumors in anatomical-relevant classification are the most challenging cases for surgeons with the lowest resection rate, highest incidence of carotid arteries injury and postoperative stroke. CONCLUSION: The modified classifications provide comprehensive understanding of different III-CBTs which are applicable for individualized treatment in clinical practice.

Single-cell transcriptome analysis reveals tumoral microenvironment heterogenicity and hypervascularization in human carotid body tumor.

Carotid body tumor (CBT) is a rare neck tumor located at the adventitia of the common carotid artery bifurcation. The prominent pathological features of CBT are high vascularization and abnormal proliferation. However, single-cell transcriptome analysis of the microenvironment composition and molecular complexity in CBT has yet to be performed. In this study, we performed single-cell RNA sequencing (scRNA-seq) analysis on human CBT to define the cells that contribute to hypervascularization and chronic hyperplasia. Unbiased clustering analysis of transcriptional profiles identified 16 distinct cell populations including endothelial cells (ECs), smooth muscle cells (SMCs), neuron cells, macrophage cells, neutrophil cells, and T cells. Within the ECs population, we defined subsets with angiogenic capacity plus clear signs of later endothelial progenitor cells (EPCs) to normal ECs. Two populations of macrophages were detectable in CBT, macrophage1 showed enrichment in hypoxia-inducible factor-1 (HIF-1) and as well as an early EPCs cell-like population expressing CD14 and vascular endothelial growth factor. In addition to HIF-1-related transcriptional protein expression, macrophages1 also display a neovasculogenesis-promoting phenotype. SMCs included three populations showing platelet-derived growth factor receptor beta and vimentin expression, indicative of a cancer-associated fibroblast phenotype. Finally, we identified three types of neuronal cells, including chief cells and sustentacular cells, and elucidated their distinct roles in the pathogenesis of CBT and abnormal proliferation of tumors. Overall, our study provided the first comprehensive characterization of the transcriptional landscape of CBT at scRNA-seq profiles, providing novel insights into the mechanisms underlying its formation.

The value of color doppler ultrasonography combined with computed tomography angiography and magnetic resonance angiography in the preoperative quantification and classification of carotid body tumors: a retrospective analysis.

BACKGROUND: Computed tomography angiography (CTA) and magnetic resonance angiography (MRA) provide accurate vascular imaging information, but their use may be contraindicated. Color Doppler ultrasonography (CDU) provides simple, safe, noninvasive, and reproducible imaging. We therefore investigated the role of preoperative CDU combined with CTA and MRA in the quantification, typing, and diagnosis of carotid body tumors (CBTs). METHODS: We retrospectively analyzed patients with CBTs categorized into group A (type I [n = 1] and type II [n = 10]) or group B (type III [n = 56]) per the intraoperative Shamblin classification. CDU, CTA, and MRA characteristics of CBTs were observed, surgical results were correlated, and the diagnostic threshold of the CBT classification was calculated. RESULTS: CBTs were usually located at the common carotid artery bifurcation, encircling the carotid artery. An increased angle was found between the internal and external carotid arteries. On CDU, CBTs primarily presented as homogeneous hypoechoic masses with clear boundaries, rich flow signals, and a high-speed, low-resistance artery-like flow spectrum. CTA showed uniform or heterogeneous marked enhancement. MRA showed mixed T1 and slightly longer T2 signals and uniform or uneven obvious enhancement. With increases in the lesion size, amount of blood transfused, and operation time, the intraoperative classification level and possibility of skull-base invasion increased. When the maximum diameter of the lesion, the volume of the tumor, the distance between the upper margin of the tumor to the mastoid and the mandibular angle were 3.10 cm, 10.15 cm3, - 3.26 cm, and 0.57 cm, respectively, the largest Youden index was the best diagnostic boundary value for Shamblin type III tumors. CONCLUSIONS: CDU combined with CTA and MRA can accurately evaluate the size and classification of CBTs.

Outcomes and Predictors of Morbidity after Carotid Body Tumor Resection.

BACKGROUND: Carotid body tumors (CBTs) are uncommon neuroendocrine tumors at the carotid bifurcation treated with resection. The goal of this study was to examine patient outcomes after CBT resection and establish predictors of morbidity. METHODS: Patients undergoing CBT resection were identified from the National Surgical Quality Improvement Program (NSQIP) database over 11 years. Demographics, past medical history, preoperative labs, procedural details, morbidity and mortality were recorded. Multivariable logistic regression (MLR) analysis was performed to determine independent predictors of morbidity. RESULTS: From 2010 to 2020, 668 CBT resections were identified. The majority of patients were female (65%) and White (72%) with a mean age of 56 (standard deviation [SD] ± 16). Average body mass index (BMI) was 29.9 (SD ± 7.1). Arterial resection occurred in 81 patients (12%). 6% of patients experienced morbidity, most commonly re-operation (2.4%). Morbidity was more common in patients with higher BMI (33.1 vs. 29.7, P = 0.005), chronic obstruction pulmonary disease (10% vs. 1.9%, P = 0.012), higher American Society of Anesthesiologists (P = 0.005), and lower albumin (3.7 vs. 4, P = 0.016). Morbidity was not increased with arterial resection (P = 1) or based on length of operation (P = 0.169). Morbidity did not impact mortality (P = 0.06) though led to longer length of stay [LOS] (8 days vs. 2.4, P < 0.001). On MLR, preoperative BMI was the only risk factor for morbidity (odds ratio 1.06, 95% confidence interval 1.02-1.1, P = 0.005). CONCLUSIONS: CBT resection is very well tolerated with low stroke rates, morbidity, and mortality. Arterial resection leads to increased transfusion requirements and LOS but did not increase stroke rates, mortality, or overall morbidity. Within the NSQIP database, preoperative BMI was the only predictor of postoperative morbidity, which leads to significantly longer LOS.

Surgical Management of Carotid Body Tumors: Experience of Two Centers.

BACKGROUND: Carotid body tumors (CBTs) are rare but require surgical resection given their potential for growth and malignancy. For some surgical teams, tumor hypervascularity justifies preoperative embolization to facilitate resection and limit complications. The objective of our study was to evaluate 2 different practices of surgical resection with or without preoperative embolization in a 2-center cohort. METHODS: A consecutive series of patients who underwent CBT surgery, from January 2011 to June 2019, were divided into 2 groups, as to whether they were (embolized CBT [ECBT]) or not (nonembolized CBT [NECBT]) preoperatively embolized. Both groups were compared specifically according to the duration of operation, postoperative complications, and length of stay. RESULTS: Twenty-two patients with a mean age of 48.5 ± 14.3 years were included. In the series, 23 CBTs were resected: 13 were embolized preoperatively; the mean time between embolization and surgery was 2.62 ± 1.50 days. Both groups were comparable based on characteristics of population and tumor, with a mean size of 33.2 ± 11.9 mm. We noted a significant increase in operation duration in the ECBT group: 151 min (±40.9) vs. 87.0 min (±21); P < 0.01. There was no difference between the 2 groups regarding cranial nerve (50% vs. 46%; P = 1), sympathetic nervous system (20% vs. 23%; P = 1), or vascular nerve (20% vs. 23%; P = 0.18) complications. No cerebrovascular accident was identified. The length of stay was 3.60 days (±1.78) vs. 3.73 days (±1.19; P = 0.44). CONCLUSIONS: This study reflects the experience of 2 centers in the management of CBT which is a rare pathology with no standardized treatment. Our series showed no significant difference between the ECBT and NECBT groups regarding postoperative complications and length of hospital stay. The reduction in operating time in the NECBT group remains to be demonstrated.

Proteomics analysis of carotid body tumor revealed potential mechanisms and molecular differences among Shamblin classifications.

Carotid body tumors (CBTs) are a rare type of paraganglioma, and surgical resection is the only effective treatment. Because of the proximity of CBTs to the carotid artery, jugular vein, and cranial nerve, surgery is extremely difficult, with high risks of hemorrhage and neurovascular injury. The Shamblin classification is used for CBT clinical evaluation; however, molecular mechanisms underlying classification differences remain unclear. This study aimed to investigate pathogenic mechanisms and molecular differences between CBT types. In Shamblin I, II, and III tumors, differentially expressed proteins (DEPs) were identified using direct data-independent acquisition (DIA). DEPs were validated using immunohistochemistry. Proteomics profiling of three Shamblin subtypes differed significantly. Bioinformatics analysis showed that adrenomedullin signaling, protein kinase A signaling, vascular endothelial growth factor (VEGF) signaling, ephrin receptor signaling, gap junction signaling, interleukin (IL)-1 signaling, actin cytoskeleton signaling, endothelin-1 signaling, angiopoietin signaling, peroxisome proliferator-activated receptor (PPAR) signaling, bone morphogenetic protein (BMP) signaling, hypoxia-inducible factor 1-alpha (HIF-1α) signaling, and IL-6 signaling pathways were significantly enriched. Furthermore, 60 DEPs changed significantly with tumor progression. Immunohistochemistry validated several important DEPs, including aldehyde oxidase 1 (AOX1), mediator complex subunit 22 (MED22), carnitine palmitoyltransferase 1A (CPT1A), and heat shock transcription factor 1 (HSF1). To our knowledge, this is the first application of proteomics quantification in CBT. Our results will deepen the understanding of CBT-related pathogenesis and aid in identifying therapeutic targets for CBT treatment.

Study on the Influencing Factors of Short-Term Recovery of Neurological Symptoms after Carotid Body Tumor Resection.

OBJECTIVE: To compare the differences in the short-term recovery from neurological symptoms (SRN) (≤ 6 months) and clinical characteristics of patients with different Shamblin classifications carotid body tumor (CBT) resection and to analyze the risk factors affecting SRN after surgery. METHODS: Patients who underwent CBT resection between June 2018 and September 2022 were recruited. Perioperative factors and indicators of the nature of the tumor were recorded. The risk factors affecting SRN after CBT resection were analyzed using logistic regression analysis. RESULTS: Eighty-five patients (43.86 ± 12.7 years, 46 females) were included, 40 (47.06%) of whom exhibited SRN. Univariate logistic regression showed that preoperative symptoms, surgical side, bilateral posterior communicating artery (PcoA) opening, some indicators of tumor size, operative/anesthesia time, and Shamblin III classification were correlated with postoperative neurological prognosis (all p < 0.05). After adjusting for confounders, preoperative symptoms (OR, 5.072; 95% CI 1.027-25.052; p = 0.046), surgical side (OR, 0.025; 95% CI 0.003-0234; p = 0.001), bilateral PcoA opening (OR, 22.671; 95% CI 2.549-201.666; p = 0.005), distance from the tip of the C2 dens to the superior aspect (dens-CBT) (OR, 0.918; 95% CI 0.858-0.982; p = 0.013) and Shamblin III classification (OR, 28.488; 95% CI 1.986-408.580; p = 0.014) were correlated with postoperative neurological symptom recovery. CONCLUSION: Preoperative symptoms, surgical side (right), bilateral PcoA opening, a short dens-CBT and Shamblin III classification are risk factors affecting SRN after CBT resection. Early resection is recommended for small-volume CBTs without neurovascular compression or invasion to obtain SRN.

Carotid body paraganglioma metastatic to spine causing cord compression: a case report.

BACKGROUND: Carotid body tumors (CBTs) are rare neuroendocrine neoplasms arising near the carotid bifurcation with a reported incidence of 1 to 2 cases in 100,000 patients. Most CBTs are sporadic, benign, slow-growing, and non-secreting, but untreated CBTs can grow locally to compress the nearby blood vessels, esophagus, and airway. Regional metastases can occur in 5% to 10% of cases, but distant metastases are exceedingly rare, occurring in roughly 1-2% of cases. As such, the optimal treatment for metastatic CBTs is not well-defined. We report a rare case of a patient with CBT distant metastases causing spinal cord compression. CASE PRESENTATION: A 40-year-old African American female presented with a right neck mass, headaches, vertigo, tinnitus, hoarseness, and dysphagia. Imaging demonstrated a Shamblin II right neck mass; subsequent transcervical resection and pathology showed a carotid body paraganglioma. The patient recurred locally near the carotid bifurcation, so she underwent Stereotactic Body Radiation Therapy to the recurrent right neck disease. She later re-presented with new onset bilateral lower extremity weakness, dysmetria, and numbness. She was found to have metastatic disease to the thoracic spine causing spinal cord compression. She underwent laminectomy, tumor resection, and posterior fixation followed by adjuvant radiation therapy. She was started on systemic therapy with sunitinib. She eventually progressed with metastatic disease to the right iliac bone, which was treated with palliative radiotherapy. Second line systemic therapy with capecitabine and temozolomide was started. At last follow up, the patient was asymptomatic with stable persistent disease. CONCLUSIONS: Paragangliomas often exhibit a prolonged interval to the development of progression; locoregional recurrences or rare distant metastases have been reported to occur as many as 20 years from diagnosis. The natural course of CBTs in other cases as well as the present case call into question the idea that CBTs are truly benign; instead CBTs may be indolent tumors with metastatic potential. Treatment choices for CBTs include surgical resection, radiation therapy, and systemic therapy, though the optimal treatment regimen for metastatic CBTs is not well-defined. A more advanced understanding of CBT pathophysiology, disease classification, risk stratification, and treatment options is needed to improve outcomes for patients.

Carotid body tumors: A retrospective case series of 11 patients.

BACKGROUND: Carotid body tumors (CBTs) are uncommon neuroendocrine tumors located near the carotid bifurcation within the carotid body. CBTs are slow-growing; affected individuals may remain asymptomatic for years and are often diagnosed incidentally following imaging studies. When present, symptoms are nonspecific. Because incidence is low, retrospective review of CBT case series is an ideal study design for investigating common symptomology, identifying successful diagnostic tools, and evaluating treatment outcomes. METHODS: This article describes a case series of 11 patients treated for CBTs at an academic medical center in the Southeastern US. A retrospective chart review of 11 patients who had been discharged from the hospital following treatment for CBTs between 2017 and 2021 was conducted. Descriptive statistics were used to delineate the case series. RESULTS: There were four males (36%) and seven females (64%) included in the retrospective case series. The age range was 34 to 79 with a mean of 56.73 (standard deviation 16.038). Three patients were found to have a neck mass on physical exam. Additional symptoms included vocal cord paralysis, facial paralysis, ischemic stroke, Bell palsy, dysphonia, and dizziness. Two patients had familial CBTs. Ten patients underwent surgical excision. CONCLUSION: This case series showed that patients with CBTs should be assessed with a combination of history and physical exams along with imaging studies to confirm the diagnosis. Because CBTs may become malignant and metastasize, it is important for NPs to be knowledgeable about presenting symptoms and appropriate diagnostic studies to be able to refer patients to vascular surgeons early to prevent complications.

Management of Multiple Head and Neck Paragangliomas With Assistance of a 3-D Model.

INTRODUCTION: Extirpation of multiple head and neck paragangliomas carries challenge due to close anatomic relationships with critical neurovascular bundles. OBJECTIVES: This study aims to assess whether the application of 3-D models can assist with surgical planning and treatment of these paragangliomas, decrease surgically related morbidity and mortality. METHODS: Fourteen patients undergoing surgical resection of multiple head and neck paragangliomas were enrolled in this study. A preoperative 3-D model was created based on radiologic data, and relevant critical anatomic relationships were preoperatively assessed and intraoperatively validated. RESULTS: All 14 patients presented with multiple head and neck paragangliomas, including bilateral carotid body tumors (CBT, n = 9), concurrent CBT with glomus jugulare tumors (GJT, n = 4), and multiple vagal paragangliomas (n = 1). Ten patients underwent genomic analysis and all harbored succinate dehydrogenase complex subunit D (SDHD) mutations. Under guidance of the 3-D model, the internal carotid artery (ICA) was circumferentially encased by tumor on 5 of the operated sides, in 4 (80%) of which the tumor was successfully dissected out from the ICA, whereas ICA reconstruction was required on one side (20%). Following removal of CBT, anterior rerouting of the facial nerve was avoided in 3 (75%) of 4 patients during the extirpation of GJT with assistance of a 3-D model. Two patients developed permanent postoperative vocal cord paralysis. There was no vessel rupture or mortality in this study cohort. CONCLUSION: The 3-D model is beneficial for establishment of a preoperative strategy, as well as planning and guiding the intraoperative procedure for resection of multiple head and neck paragangliomas.

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.

Paraganglioma cuerpo carotídeo: experiencia en 20 años y revisión de la literatura / Carotid body paraganglioma: 20-year experience and literature review

Resumen El paraganglioma carotideo es un tumor infrecuente, originado de las células de la cresta neural. Raramente son secretores y tienen un bajo potencial maligno. El diagnóstico es difícil y requiere una alta sospecha clínica, combinada con estudios imagenológicos. Su tratamiento está basado en la cirugía, con especial cuidado de las estructuras vasculonerviosas que se encuentran en intimo contacto. Se describe la casuística de paragangliomas de cuerpo carotídeo en Clínica Las Condes y compararla con una revisión de la literatura actualizada del tema.

Abstract Carotid paraganglioma is a rare tumor, originated from neural crest cells. Usually they lack hormone secretion function, and have a low malignant potential. Diagnosis is difficult, and requires high clinical suspicious, combined with image and pathologic findings. Its treatment is based on surgery, with special care of close anatomic relation with important vascular-nervous structures. Here, we present cases of carotid paragangliomas evaluated at Clinica Las Condes comparing them with an updated literature review.

Clinical Characteristics and Surgical Outcomes of Carotid Body Tumors: Data from the Carotid Paraganglioma Cooperative International Registry (CAPACITY) Group.

BACKGROUND: This study's objective was to conduct a multinational registry of patients with carotid body tumors (CBTs) and to analyze patients' clinical characteristics, treatments, and outcomes. METHODS: Retrospective study from the Carotid Paraganglioma Cooperative International Registry involving eleven medical centers in Bolivia, Ecuador, Mexico, and Spain, of all patients with a CBT who underwent resection between 2009 and 2019. RESULTS: A total of 1432 patients with a CBT surgically treated were included. Median patient age was 54 years (range: 45-63 years), and 82.9% (1184) of the study cohort were female. While at low altitude, the proportion of female-to-male cases was 2:1, at high altitude, this proportion increased to 8:1, with statistically significant differences (p = .022). Median operative time was 139 min (range: 110-180 min), while median operative blood loss was 250 ml (range: 100-500 ml), with statistically significant difference in increased blood loss (p = .001) and operative time (p = .001) with a higher Shamblin classification. Eight (0.6%) patients suffered stroke. Univariate analysis analyzing for possible factors associated with increased odds of stroke revealed intraoperative vascular lesion to present an OR of 2.37 [CI 95%; 1.19-4.75] (p = 0.001). In 245 (17.1%), a cranial nerve injury was reported. Seven (0.5%) deaths were recorded. CONCLUSION: The most common CBT type on this cohort was hyperplasic, which might be partially explained by the high altitudes where these patients lived. Increased blood loss and operative time were associated with a higher Shamblin classification, and the risk of stroke was associated with patients presenting transoperative vascular lesions.

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

BACKGROUND: To assess the efficacy and safety of preoperative embolization (PE) in patients with carotid body tumor (CBTs). METHODS: In a single-center retrospective cohort study, 127 patients underwent surgical resection of CBTs from January 2003 to December 2019. One-to-one propensity score matching was conducted between patients with or without PE. RESULTS: Thirty-two (25.2%) patients received PE. After propensity score matching, no statistically significant differences were found in the baseline characteristics of 28 patients in each group. Compared with NPE group, operative time and estimated blood loss (EBL) were significantly reduced in the PE group. The incidence of stroke, perioperative complications, intraoperative blood transfusion, vascular reconstruction, hospital stay, tumor recurrence, and all-cause mortality were not different between the PE and NPE group. CONCLUSIONS: Preoperative embolization was efficient and safe with a reduction of intraoperative blood loss and operative time during CBT resection.

Challenges of Surgical Resection of Carotid Body Tumors - Multiple Feeding Arteries and Preoperative Embolization.

BACKGROUND: Carotid body tumor is a hypervascular tumor with multiple feeding arteries and unique orientation at the carotid bifurcation. Although resection is a radical therapy for this tumor, complete resection is challenging. MATERIALS AND METHODS: Articles reporting carotid body tumor treatment and surgical resection were reviewed including case-control series and review articles. RESULTS: Selected reports were reviewed and discussed focusing on choice of treatment, surgical difficulties and preoperative embolization of feeding arteries. CONCLUSION: Multiple feeding arteries and adhesion of the tumor to the carotid arterial wall are causes of difficulties in carotid body tumor resection. The effectiveness of preoperative embolization remains controversial due to the varied situations in performing surgical resection among the institutions. However, perfect embolization and resection immediately after embolization reduce blood loss and operative time of surgery for carotid body tumor.

Is Preoperative Embolization Necessary for Carotid Paraganglioma Resection: Experience of a Tertiary Center.

PURPOSE: This study was designed to investigate whether preoperative embolization is a useful procedure to decrease blood loss and neurovascular complications for carotid body tumor (CBT) surgery or not. METHODS: Medical records of our tertiary care center from 2012 to 2019 were scanned for patients who underwent surgery for CBT, retrospectively. Age, gender, complaint and head and neck examination findings at the time of presentation, preoperative complete blood count parameters, imaging records (cervical magnetic resonance imaging and carotid artery angiography), Shamblin classification, tumor size, intraoperative findings, and postoperative complications were noted. RESULTS: A total of 26 patients were operated due to CBT between 2012 and 2019 in our clinic; preoperative arterial embolization was performed to 15 (57.7%) patients, and 11 (42.3%) patients were operated without embolization. Youngest patient was 24 years old, while oldest was 69 years and mean age was 44.35 ± 12.73. (embolization group: ages ranging between 24 and 64 with a mean of 41.5 ± 11.02 years; in nonembolization group: ages ranging between 26 and 69 with a mean of 48.1 ± 14.3). Embolization status was not significantly related to cranial nerve injury, vascular injury, overall complications, and hematocrit decrease. Arterial injury is more likely to occur with increasing Shamblin class (r = .39; P = .04). Tumor size is not found to be significantly related to cranial nerve injury, vascular injury, overall complications, and hematocrit decrease, but cranial nerve injury and vascular injury were more likely to occur in large tumors (r = .34; P = .089 and r = .34; P = .087, respectively). Age was significantly and negatively correlated to vascular injury (r = -.51; P = .05). Vascular injury was significantly correlated with gender (male predominance: r = -.64; P = .000). CONCLUSION: Although preoperative arterial embolization is considered to attenuate the complication risk, we found that there was no significant difference among the patients with or without embolization.

Necessity of Intraoperative Level IIA Lymph Node Dissection in Patients with Carotid Body Tumors: A Retrospective Study of 126 Cases.

BACKGROUND: Carotid body tumors (CBTs) are relatively uncommon neoplasms that rarely have malignant potential. However, malignant CBTs (MCBTs) are still associated with a poor prognosis and the treatment is still challenging clinically. Therefore, we evaluated the necessity of intraoperative level IIA lymph node dissection in patients with CBT. METHODS: The clinical characteristics, intraoperative details, and pathological diagnosis of 126 CBT patients who had undergone surgery were retrospectively reviewed. The patients were divided into 2 groups according to whether level IIA lymph node dissection was performed. The prognosis was analyzed using Kaplan-Meier curves and Cox model multivariate survival analysis. RESULTS: Among the 126 patients, 7 patients (10.3%) in the selective lymph node dissection (SLND) group (68 patients) were diagnosed with MCBTs with evidence of lymph node metastasis. Two patients (3.4%) in the lymph node nondissection (LNND) group (58 patients) were diagnosed with MCBTs later after the second operation because they could not be diagnosed as malignant initially because of the lack of lymph node pathology results although the pathology of the primary lesion showed features of malignancy. The SLND group had a significantly higher relapse-free survival rate than the LNND group (94.1% vs. 79.3%, p = 0.021). Patients with a confirmed diagnosis had a better prognosis than those with insufficient evidence of a malignancy due to the lack of lymph node information. Twenty-nine patients in the SLND group and 26 patients in the LNND group had postoperative nerve injuries, with no significant difference between the groups (p = 0.879). CONCLUSION: Intraoperative dissection of level IIA lymph nodes around the tumor in CBT patients can help improve the diagnosis and prognosis of MCBTs without causing additional cranial nerve injury.

Identification of Isocitrate Dehydrogenase 2 (IDH2) Mutation in Carotid Body Paraganglioma.

Carotid body paragangliomas (PGLs) are rare neuroendocrine tumors that develop within the adventitia of the medial aspect of the carotid bifurcation. Carotid body PGLs comprise about 65% of head and neck paragangliomas, however, their genetic background remains elusive. In the present study, we report one case of carotid body PGL with a somatic mutation in the gene encoding isocitrate dehydrogenase 2 (IDH2). The missense mutation in IDH2 resulted in R172G amino acid substitution, which exhibits neomorphic activity and production of D-2-hydroxyglutarate.