Current trends in carotid body tumors: Comprehensive review

A 37-year-old female with a carotid body tumor (paraganglioma): A rare case report from Syria

INTRODUCTION AND IMPORTANCE

This case study presents the clinical details of a 37-year-old woman who presented with an asymptomatic swelling in the right supraclavicular region, ultimately diagnosed as a carotid body tumor (CBT).

CASE PRESENTATION

The patient's medical background, which included her brother's CBT, prompted further investigation. Upon clinical examination and imaging studies, a tissue mass surrounding the right internal carotid artery was identified. Subsequent surgical resection of the tumor was performed, and histological analysis confirmed a neoplastic proliferation consistent with paraganglioma.

CLINICAL DISCUSSION

This case highlights the significance of taking into account familial history and conducting comprehensive diagnostic assessments for patients exhibiting similar symptoms. The successful multidisciplinary management of this rare tumor underscores the importance of early detection and appropriate therapeutic interventions.

CONCLUSION

This report offers valuable insights into the clinical presentation, diagnostic process, and treatment of CBTs, emphasizing the necessity for a comprehensive approach to managing this uncommon neoplasm.

Carotid body tumor: characteristics and surgical outcome

BACKGROUND

Carotid body tumors are uncommon neuroendocrine growths near the carotid bifurcation. While some advocate preoperative embolization to minimize bleeding, others avoid it due to complications. This study shares the experience of a single center in managing patients with carotid body tumors without practicing preoperative embolization.

METHODS

This was a cross-sectional study of patients with carotid body tumors managed between 2020 and 2024. Data were collected from the hospital's registry. When necessary, routine blood tests, neck ultrasonography, and computed tomography scans were conducted. The tumors were categorized according to Shamblin's classification. The average duration of follow-up was 20 months.

RESULTS

The study involved 25 patients, 22 (88%) females and 3 (12%) males. Their ages ranged from 27 to 85 years old. Twenty (80%) cases presented with neck swelling, and six (24%) had a positive medical history. Tumors were mainly on the right side (52%), with 20 (80%) showing ill-defined neck masses. Tumor sizes ranged from 1.5 to 7 cm, with Shamblin type II tumors being discovered in the majority of cases (72%). Types of tumors were significantly associated with the tumor size (p-value < 0.05). Blood transfusion was required in five cases (20%), three from type III and two from type II, with none from type I (p-value = 0.001). Temporary neurological deficits occurred in 3 cases (12%). No functional impairment or mortality was recorded.

CONCLUSIONS

Carotid body tumors are rare tumors with an unknown etiology. Operation without practicing preoperative embolization may be feasible with an acceptable outcome.

Stereotactic radiotherapy for head and neck paragangliomas: How long should we wait for treatment response?

BACKGROUND AND PURPOSE

Stereotactic radiotherapy (SRT) is an effective treatment for head & neck (H&N) paragangliomas. Nevertheless, the timeline for achieving a tumor-volume-reduction (TVR) remains unclear.

MATERIALS AND METHODS

Sixty-three cases with H&N paragangliomas received definitive SRT and were evaluated retrospectively. Statistical Package for the Social Sciences (SPSS) v23.0 (IBM, Armonk, NY, USA) was used for statistics.

RESULTS

Sixty-eight lesions were irradiated, with glomus jugulotympanicum being the most common location (44 %). Median tumor diameter and volume were 3 cm (range, 1-7.6 cm) and 15.4 cm3 (range,1-185 cm3), respectively. Median dose was 25 Gy (range, 12-37.5 Gy) in 5 fractions (range, 1-5 fractions). Median follow-up was 40 months (range, 3-184 months). Treatment response, evaluated at a median 4.6 months post-SRT (range: 3-11 months), revealed TVR in 26 cases (41 %). During follow-up, 13 additional cases showed TVR, resulting in an overall TVR rate of 62 %. The median duration for attaining TVR was 9 months (range, 3-36 months) after SRT, and TVR occurred ≥ 12 months in 42 % of cases. Patients without prior surgery (p = 0.03) and with a longer follow-up (p = 0.04) demonstrated a higher rate of TVR. The likelihood of TVR tends to increase as the SRT dose increases (p = 0.06). Overall local control (LC) rate was 100 %. No ≥ grade 3 acute or late toxicities were observed.

CONCLUSION

While SRT demonstrates an excellent LC rate for H&N paragangliomas, it's important to note that the response to treatment may require time. TVR may last beyond the initial year of treatment in a substantial proportion of patients.

The Radiosurgery Society Case-Based Discussion of the Management of Head and Neck or Skull Base Paragangliomas with Stereotactic Radiosurgery and Radiotherapy

Stereotactic radiosurgery (SRS) and fractionated stereotactic radiotherapy (FSRT) have been used for the treatment of head and neck or skull base paraganglioma for a considerable time, demonstrating promising local control rates and a favorable safety profile compared with surgical approaches. Nevertheless, the choice of treatment must be carefully tailored to each patient's preferences, tumor location, and size, as well as anticipated treatment-related morbidity. This case-based review serves as a practical and concise guide for the use of SRS and FSRT in the management of head and neck or skull base paragangliomas, providing information on the diagnosis, treatment, follow-up considerations, and potential pitfalls.

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.

Microsurgery in carotid body paraganglioma

Objectives

In carotid paraganglioma surgery, magnification is crucial to properly evaluate the anatomical relationships between mass, carotid wall, cranial nerves, tumour vascular supply and fascial envelope. The aims of this study are to describe the microsurgical technique, along with the underlying microsurgical anatomy, and to assess outcomes in terms of disease control, complications and functional results.

Methods

Twenty-six patients, accounting for 29 carotid paragangliomas, treated with microsurgery by the same senior surgeon over a 35-year period, were included.

Results

No carotid injury requiring repair, nor peri- or post-operative stroke occurred in this series. No surgical injury of the main trunk of VII to XII cranial nerves occurred. Complete excision was obtained in all cases and no recurrence was observed during follow-up.

Conclusions

The small study size and its retrospective nature suggests caution; however, our results show that microsurgery can allow a safe and precise dissection of the carotids and nerves.

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.

Hypoxic Signaling Pathways in Carotid Body Tumors

Carotid body tumors (CBTs) are rare tumors with a 1-2 incidence per 100,000 individuals. CBTs may initially present without apparent symptoms, and symptoms begin to arise since tumors grow bigger to compress surrounding tissue, such as recurrent laryngeal nerve and esophagus. Also, the etiology of CBTs remains unclear since it is more likely to occur in those who live in high-altitude areas or suffer from chronic hypoxic diseases such as COPD. SDH mutations and familial inheritance have been reported to be related to CBTs. SDH complexes play crucial roles in aerobic respiration, and SDH mutations in CBTs have been reported to be associated with hypoxia. Hypoxic signaling pathways, specifically hypoxic markers, have attracted more research attention in tumor exploration. However, the existing literature on these signaling and markers lacks a systematic review. Also, therapeutic approaches in CBTs based on hypoxic signaling are rarely used in clinics. In this review, we concluded the role of hypoxic signaling and markers and their potential implications in the initiation and progression of CBTs. Our findings underscore the involvement of the SDH family, the HIF family, VEGFs, and inflammatory cytokines (ICs) in tumorigenesis and treatment. Of particular interest is the role played by SDHx, which has recently been linked to oxygen sensing through mutations leading to hereditary CBTs. Among the SDH family, SDHB and SDHD exhibit remarkable characteristics associated with metastasis and multiple tumors. Besides SDH mutations in CBTs, the HIF family also plays crucial roles in CBTs via hypoxic signaling pathways. The HIF family regulates angiogenesis during mammalian development and tumor growth by gene expression in CBTs. HIF1α could induce the transcription of pyruvate dehydrogenase kinase 1 (PDK1) to inhibit pyruvate dehydrogenase kinase (PDH) by inhibiting the TCA cycle. Then, carotid body cells begin to hyperplasia and hypertrophy. At the same time, EPAS1 mutation, an activating mutation, could decrease the degradation of HIF2α and result in Pacak-Zhuang syndrome, which could result in paraganglioma. HIFs can also activate VEGF expression, and VEGFs act on Flk-1 to control the hyperplasia of type I cells and promote neovascularization. ICs also play a pivotal signaling role within the CB, as their expression is induced under hypoxic conditions to stimulate CB hyperplasia, ultimately leading to CBTs detecting hypoxic areas in tumors, and improving the hypoxic condition could enhance photon radiotherapy efficacy. Moreover, this review offers valuable insights for future research directions on understanding the relationship between hypoxic signaling pathways and CBTs.

Risk Factors for Stroke After Carotid Paraganglioma Surgery

BACKGROUND

The Carotid Paraganglioma Cooperative International Registry (CAPACITY) is an international registry composed of 1,432 patients with carotid body tumors (CBT) from 11 centers from 4 countries. The aim of this study was to identify risk factors for patients who presented stroke after carotid paraganglioma resection.

METHODS

Clinical characteristics and demographics of patients who presented transoperatively and postoperatively stroke from the CAPACITY database were retrospectively gathered. Regression analysis was performed using single logistic regression with Omnibus' test for possible factors that might contribute to present stroke.

RESULTS

Out of 1,432 patients, 8 (0.5%) female patients presented stroke. Median age was 53 years (range: 41-70 years). Six strokes occurred transoperatively, diagnosed clinically in the immediate postoperative period. Of them, none of the patients received any further treatment. Three of them died on postoperative day 2, 3, and 4. Two patients developed stroke during the first 24 postoperative hours, patients showed dysarthria, and aphasia. One of them was reintervened with thrombectomy due to thrombosis of the common carotid artery the other patient was treated conservatively. Median follow-up was 16 months (range: 2-72 months). Single logistic regression analysis revealed a history of diabetes mellitus (odds ratio (OR) 7.62), carotid artery disease (OR 17.51), and vascular lesion (OR 2.37) to have significantly increased odds of stroke during CBT surgery.

CONCLUSIONS

In the present study history of diabetes mellitus, carotid artery disease, and vascular lesion had increased odds of stroke during CBT surgery. Findings are limited by low event rate and even larger cohorts are needed to fully define preventive preoperative strategies for preventing stroke.

High Altitude Carotid Body Tumors Growth During active Surveillance

BACKGROUND

The gold standard for patients with carotid body tumors (CBT) is surgical resection; nevertheless, some patients are unfit for surgery or, for other reasons, could not be operated on. Active surveillance has been known to be a reasonable strategy for these cases. This study aimed to evaluate tumor growth in unoperated patients with CBTs.

METHODS

A retrospective review of all unoperated patients with CBT from a single academic hospital diagnosed between 2014 and 2021 was performed. Results of nonparametric testing were presented using the median and ranges for Mann-Whitney-U or Kruskal-Wallis. Significance was defined as a 2-tailed P < .05.

RESULTS

The cohort included a total of 31 patients, with a median age of 60 years (range: 37-80 years), of which 27 (87.1%) were females. The patients live at a median altitude of 2800 meters (range: 2756-2980 meters) above sea level. Twenty (64.5%) patients had Shamblin I tumors, eight (25.8%) patients had Shamblin II tumors, and three (9.7%) patients had Shamblin III tumors. Median CBT volume at diagnosis was 14.1 cm3 (range: .9 - 213.3 cm³). Median volume at diagnosis of symptomatic tumors was substantially larger than asymptomatic tumors, 49.2 cm³ vs 7.9 cm³, respectively (P = .03). Median growth of the tumors during a median 15-month follow-up (range: 3-43 months) was 3.3 cm³ (range: 0-199.9 cm³). Overall, 77% (n = 24) of the CBTs grew at least 1 cm³.

CONCLUSION

Most patients in the present study had tumor growth by at least 1 cm³, with a median tumor growth of 3.3 cm.³ In the present study tumor growth was shown to be greater than other low altitude CBT active surveillance studies; therefore, surgical resection should be recommended in patients with CBT living at high altitudes.

Case report: Cardiac arrest during carotid body tumor resection indicating carotid sinus hypersensitivity

Background

Carotid body tumor surgery is associated with various complications. However, intraoperative cardiac arrest is very rare and no more than 10 cases have been reported.

Case description

A 58-year-old woman diagnosed with bilateral carotid body tumors underwent right carotid body tumor surgery. Sudden cardiac arrest occurred during the resection and was attributed to carotid sinus hypersensitivity. The patient recovered after prompt treatment and the tumor was removed completely with no complications.

Conclusion

Cardiac arrest attributed to carotid sinus hypersensitivity during carotid body tumor resection is very rare. Proper treatments can reverse intraoperative cardiac arrest. If carotid sinus hypersensitivity is detected preoperatively, prophylactic temporary pacemaker implantation may be appropriate.

Schwannoma of the Hypoglossal Nerve Mimicking Carotid Body Paraganglioma

Carotid body paragangliomas (CBPs) clinically present as highly vascularized cervical masses with a pathognomonic localization at the carotid artery bifurcation. Following ultrasonography and MRI/CT imaging, surgical resection with optional preoperative embolization is considered as the treatment of choice in most cases. We herein present the case of a 60-year-old female with characteristic clinical signs and imaging findings of a right-sided CBP who finally went to surgical treatment. Intraoperatively, the tumor showed an adherent growth to the hypoglossal nerve that had to be partially resected, resulting in a postoperative nerve palsy. Histological examination of the resected tumor revealed the unexpected diagnosis of a hypoglossal nerve schwannoma. To the best of our knowledge, we herein present the third case reported in the literature of a unilateral hypoglossal schwannoma located at the carotid bifurcation mimicking clinical symptoms, imaging and intraoperative findings of a CBP.