BACKGROUND: Lateral neck mass management frequently challenges surgeons. Nerve tissue neoplasms are an uncommon cause of such nodules. Neurogenic tumors form a tiny percentage of the head and neck neoplastic lesions. Considering the number of nerves in this area, it is surprising that such neoplasms are not more frequently seen.
METHODS: A retrospective study was conducted on all patients who presented to the National Cancer Institute of Cairo, Egypt, with head and neck neurogenic neoplasms.
RESULTS: During the last 10 years at the National Cancer Institute of Egypt (2006-2015), 40 cases of neurogenic tumors of the head and neck were treated at the head and neck unit. Patients\' ages ranged from two to 78 years with a mean age of 34.7 years. Childhood neurogenic tumors accounted for nine cases (22.5%) only in this study. Male patients diagnosed with these tumors comprised 16 cases, while female patients comprised 24 cases, with a female-to-male ratio of 1.5:1. Patient presentation depends on the biological behavior of the tumor; for instance, some of them present by slowly growing painless well-circumscribed mobile swelling, and others present by rapidly growing swelling with neurological deficit. Clinical picture and imaging studies such as CT and MRI raise suspicion and may help delineate such tumors, but a definitive diagnosis is obtained by tissue biopsy. Surgery is the mainstay of treatment in most head and neck neurogenic tumors, whereas adjuvant therapy is of limited benefit in some types of neurogenic tumors. The five-year survival rate was 60% for the malignant group, while death was reported in six out of 15 cases (40%).  Conclusion: Most neurogenic head and neck tumors are benign. Accurate preoperative assessment and a high degree of suspicion are the initial steps in the management. Proper treatment involves complete surgical excision; however, debulking procedures have an important role. Malignant neurogenic tumors are aggressive and are treated with combined radical surgical resection and radiation. Chemotherapy is tried for locally advanced unresectable or metastatic disease.

Background and objectives: Paragangliomas of the head and neck are rare, slow-growing neuroendocrine tumors, benign in their vast majority, but with a possibility of developing distant metastases. They show great inheritable character, and their behavior has proven to be unpredictable; therefore, they are considered malignant. Material and methods: This article aims to offer a more comprehensive presentation of the pathogenesis, epidemiology, diagnostic methods, imaging development, and treatment guidelines. We tried to bring together all the necessary data that, in our opinion, a head and neck practitioner should know when managing this type of tumor. Our main focus is on the most recent studies, with the purpose of a homogenous presentation of all current guidelines and approaches to this pathology. Results: Paragangliomas of the head and neck are still a disputed topic. One of the main reasons for that is their low incidence of 0.3 to 1 per 100,000 every year. The most frequent locations are the carotid body, the temporal bone, the jugular and mastoid foramen, and the vagal nerve. Their clinical presentation usually involves a painless lateral mass associated with symptoms such as hoarseness, hearing loss, tinnitus, and cranial nerve deficits. Up to 40% of them are inherited, mostly linked with mutations of succinate dehydrogenase complex. Imaging evaluation consists of CT and MRI, and new functional explorations such as 18F-FDA and 18F-FDG PET/CT, 18F-DOPA PET, 123I-MIBG, and 68Ga-DOTATE PET/CT. Measuring the catecholamine levels in the plasma and urine is mandatory, even though paragangliomas of the head and neck rarely display secretory behavior. Treatment mainly consists of surgery, with different approaches and techniques, but conservative management methods such as wait and scan, radiotherapy, proton therapy, and chemotherapy have proven their efficiency. The therapeutical decision lacks consensus, and current studies tend to recommend an individualized approach. Guidelines regarding long-term follow-up are still a matter of debate.

Metastatic pheochromocytomas and paragangliomas (PPGLs) are rare endocrine malignancies with limited effective treatment options. The association between the tumor microenvironment (TME) with somatostatin receptor 2 (SSTR2) and hypoxia-induced factor-2α (HIF-2α) in PPGLs, critical for optimizing combination therapeutic strategies with immunotherapy, remains largely unexplored. To evaluate the association of SSTR2 and HIF-2α immunoreactivity with the TME in patients with PPGLs, we analyzed the expression of SSTR2A, HIF-2α, and TME components, including tumor-infiltrating lymphocytes (CD4 and CD8), tumor-associated macrophages (CD68 and CD163), and PD-L1, using immunohistochemistry in patients with PPGLs. The primary outcome was to determine the association of the immune profiles with SSTR2A and HIF-2α expression. Among 45 patients with PPGLs, SSTR2A and HIF2α were positively expressed in 21 (46.7%) and 14 (31.1%) patients, respectively. The median PD-L1 immunohistochemical score (IHS) was 2.0 (interquartile range: 0-30.0). Positive correlations were observed between CD4, CD8, CD68, and CD163 levels. A negative correlation was found between the CD163/CD68 ratio (an indicator of M2 polarization) and SSTR2A expression (r = -0.385, p = 0.006). HIF-2α expression showed a positive correlation with PD-L1 IHS (r = 0.348, p = 0.013). The co-expression of PD-L1 (HIS > 10) and HIF-2α was found in seven patients (15.6%). No associations were observed between SDHB staining results and the CD163/CD68 ratio, PD-L1, or SSTR2A expression. Our data suggest the potential of combination therapy with immunotherapy and peptide receptor radionuclide therapy or HIF-2α inhibitors as a treatment option in selected PPGL populations.

BACKGROUND: Hypertension (HT) is one of the most common manifestations in patients with catecholamine-secreting neuroendocrine tumors. Although the cardiovascular manifestations of these tumors have been described, there have been no large-scale investigations of the profile of HT and changes in cardiac structure and function that occur in patients with pheochromocytomas and paragangliomas (PPGL).
METHODS: In this study, we investigated the prevalence of HT and left ventricular remodeling (LVR) in a cohort of 598 patients who underwent surgery for PPGL at our center between January 2001 and April 2022. Information on demographics, reason for hospitalization, medical history, biochemical parameters, findings on echocardiography, and tumor characteristics were recorded. The LVR index was compared according to whether or not there was a history of HT.
RESULTS: The average age was 47.07 ± 15.07 years, and 277 (46.32%) of the patients were male. A history of HT was found in 423 (70.74%) of the 598 patients. Paraganglioma was significantly more common in the group with HT (26.00% vs. 17.71%, P = 0.030) and significantly less likely to be found incidentally during a health check-up in this group (22.93% vs. 59.43%, P < 0.001). Among 365 patients with complete echocardiography data, left ventricular mass index (86.58 ± 26.70 vs. 75.80 ± 17.26, P < 0.001) and relative wall thickness (0.43 ± 0. 08 vs. 0.41 ± 0.06, P = 0.012) were significantly higher in patients with PPGL and a history of HT. The proportions with left ventricular hypertrophy (LVH) (19.40% vs. 8.25%, P = 0.011) and LVR (53.73% vs. 39.18%, P = 0.014) were also higher when there was a history of HT. After adjusting for age, gender, body mass index, alcohol consumption, smoking status, diabetes, stroke, creatinine level, tumor location, and tumor size, a history of HT was significantly correlated with LVH (odds ratio 2.71, 95% confidence interval 1.18-6.19; P = 0.018) and LVR (odds ratio 1.83, 95% confidence interval 1.11-3.03; P = 0.018).
CONCLUSIONS: HT is common in patients with PPGL (70.74% in this cohort). PPGL without a history of HT is more likely to be found incidentally (59.43% in our cohort). HT is associated with LVR in PPGL patients with complete echocardiography data. These patients should be observed carefully for cardiac damage, especially those with a history of HT.

BACKGROUND: Paragangliomas are neuroendocrine tumours commonly located in the abdomen, thorax, head and neck. The definitive treatment for these tumours is surgical resection, which in some cases can be very challenging due to the involvement of critical neurovascular structures and their high vascularity. Therefore, pre-operative embolisation may be performed to reduce the risk of complications. This study aimed to present our experience with endovascular embolisation of head and neck paragangliomas (HNP).
METHODS: In this single-centre study, we reviewed data from consecutive patients with HNP who underwent pre-operative embolisation from 2017 to 2023. The efficacy of embolisation, the method of embolisation, as well as the rate of complications, were noted.
RESULTS: A total of 27 patients (15 females) with an average age of 47 years underwent selective embolisation of HNP. Satisfactory embolisation, defined as occlusion of > 75% of the blood supply, was achieved in 22/27 cases (81.5%). The most commonly used embolic agents included coils and microspheres. With the exception of minor vessel dissections in two patients and embolic agent migration in two patients causing reversible occlusion of the intracranial vessels, there were no other complications associated with embolisation. No neurological deficits occurred in relation to the endovascular procedure.
CONCLUSIONS: The results of our study indicate that endovascular embolisation of HNP prior to surgical resection is a safe and efficacious procedure, with a relatively low complication rate and associated morbidity.

Pheochromocytomas (PCCs) and/or paragangliomas (PGLs) are a challenge to diagnose during pregnancy because of elusive signs and testing difficulties. We report a 25-year-old woman with no pertinent medical history who presented to the hospital with hypertension, vision loss, and weakness and was initially diagnosed with preeclampsia. Imaging showed hemangioblastomas in the medulla and thoracic spine, pancreatic cysts, and a renal cyst. The endocrinology service was consulted for possible PCCs associated with von Hippel-Lindau disease (VHL). Serum and urine normetanephrine levels were elevated despite the lack of overt PCCs/PGLs seen on magnetic resonance imaging and magnetic resonance angiography. The patient was medically managed with doxazosin and then labetalol. Despite successful resection of the hemangioblastoma in the medulla, the patient suffered respiratory distress requiring tracheostomy and venous-venous extracorporeal membrane oxygenation (V-V ECMO) and fetal demise. After 3 months, the patient was discharged to rehabilitation. Follow-up genetics were heterozygous for VHL and Lynch syndrome. DOTATATE positron emission tomography/computed tomography scan showed a small hepatic focus of a maximum standard uptake value of 12.1. Altogether, this case illustrates the importance of prompt diagnosis and proper management of PCCs/PGLs during pregnancy and incorporating genetic information during surveillance to lower morbidity and mortality.

UNASSIGNED: Paragangliomas (PGL) are rare neuroendocrine tumors derived from the autonomic nervous system paraganglia. Urinary bladder paragangliomas (UBPGL) originate from the sympathetic neurons of the urinary bladder wall and represent 0.7% of all paragangliomas and <0.05% of all bladder tumors. PGL and UBPGL can be associated with SDHB, SDHD, NF1, and VHL gene variants, with the most common germline alterations found in SDHB and VHL.
UNASSIGNED: We report a case of a 42-year-old woman who presented with menorrhagia/hematuria, uterine leiomyomas, as well as cardiac and bladder masses. The cardiac mass was favored to be a myxoma based on clinical findings, while the bladder mass was diagnosed as UBPGL. A novel SDHB mutation (c.642G>A, p Q214Q), detected in the UBPGL, was proven to be somatic. Although this variant was seemingly synonymous, it was predicted to have a loss of function due to the splice site effect, which was further supported by the immunohistochemical loss of SDHB.
UNASSIGNED: This case highlights the challenges of diagnosing an extremely rare entity, bladder paraganglioma, with an emphasis on the multidisciplinary approach to navigate various clinical and imaging findings that may initially be misleading. In addition, a novel loss of function SDHB variant that could have been overlooked as a synonymous variant is herein reported, while also illustrating the importance of both germline and somatic mutation testing.

Over the past two decades, research into the genetic susceptibility behind pheochromocytoma and paraganglioma (PPGL) has surged, ranking them among the most heritable tumors. Massive sequencing combined with careful patient selection has so far identified more than twenty susceptibility genes, leading to an over-detection of variants of unknown significance (VUS) that require precise molecular markers to determine their pathogenic role. Moreover, some PPGL patients remain undiagnosed, possibly due to mutations in regulatory regions of already known genes or mutations in undiscovered genes. Accurate classification of VUS and identification of new genes require well-defined clinical and molecular markers that allow effective genetic diagnosis of most PPGLs.

This study aimed to compare tumor lesion detectability and diagnostic accuracy of whole-body magnetic resonance imaging (WB-MRI) and radioiodine-labeled meta-iodo-benzylguanidine (mIBG) imaging techniques in patients with metastatic pheochromocytoma and paraganglioma (PPGL). This retrospective study included 13 patients had pheochromocytoma and 5 had paraganglioma, who were all suspected of having metastatic tumors. Each patient underwent WB-MRI and 123I-mIBG as a pretreatment screening for 131I-mIBG therapy. Two expert reviewers evaluated WB-MRI, 123I-mIBG images, and post-therapy 131I-mIBG images for the presence of metastatic lesions in the lungs, bones, liver, lymph nodes, and other organs. Diagnostic measures for detecting metastatic lesions, including sensitivity, specificity, accuracy, positive predictive value (PPV), negative predictive value (NPV), and receiver operating characteristics (ROC)-area under the curve (AUC), were calculated for each imaging technique. We analyzed WB-MRI images for detecting metastatic lesions, which demonstrated sensitivity, specificity, accuracy, PPV, NPV, and AUC of 82%, 97%, 90%, 96%, 86%, and 0.92, respectively. These values were 83%, 95%, 89%, 94%, 86%, and 0.90 in 123I-mIBG images and 85%, 92%, 89%, 91%, 87%, and 0.91 in post-therapy 131I-mIBG images, respectively. Our results reveal the comparable diagnostic accuracy of WB-MRI to one of the mIBG images.

BACKGROUND: Pheochromocytomas and paragangliomas (PPGLs) typically secrete catecholamines and their metabolites (metanephrines [MN] and normetanephrine [NMN]). Catecholamines are synthesized by several enzymes: phenylalanine hydroxylase (encoded by PAH), tyrosine hydroxylase (TH), aromatic L-amino acid decarboxylase (DDC), dopamine β-hydroxylase (DBH), and phenylethanolamine N-methyltransferase (PNMT). MN/NMN secretion varies between anatomical and molecular subgroups. The aim of this study was to assess the correlation between DNA methylation of catecholamine synthesis genes and MN/NMN secretion.
METHODS: Gene promoter methylation of PAH, TH, AADC, DBH, and PNMT were extracted and calculated based on publicly available data. Comparisons and correlation analysis were performed between MN ± NMN (MN/NMN), NMN only, and neither/unknown secretion patterns. Methylation levels and MN/NMN patterns were compared by three genetic alteration subgroups: pseudohypoxia (PH), kinase signaling (KS), and others.
RESULTS: A total of 178 cases were included. Methylation of PAH CpGs negatively correlated with probability for MN/NMN secretion (p < .05 for all CpGs) and positively with NMN-only secretion. NMN-only secreting tumors had significantly higher promoter methylation of PAH, DBH, and PNMT compared with MN/NMN-secreting tumors. MN/NMN-secreting PPGLs had mainly KS alterations (52.1%), whereas NMN-only PPGLs had PH alterations (41.9%). PPGLs in the PH versus KS group had gene promoter hypermethylation of PAH (p = .002), DBH (p = .02), and PNMT (p = .003).
CONCLUSIONS: Promoter methylation of genes encoding catecholamine synthesis enzymes is strongly and inversely correlated with MN/NMN patterns in PPGLs. KS and PH-related tumors have distinct methylation patterns. These results imply that methylation is a key regulatory mechanism of catecholamine synthesis in PPGLs.