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Abstract: We present a case of a 48-year-old woman who had previously undergone surgical resection for bladder paraganglioma. An 18 F-FDOPA PET/CT scan performed for suspected colorectal paraganglioma showed intense colorectal uptake associated with adenopathy. Histological examination did not support the presence of a neuroendocrine tumor but instead confirmed the presence of moderately differentiated colorectal adenocarcinoma. Colorectal adenocarcinoma belongs to the list of nonneuroendocrine false-positive tumors that can be detected using 18 F-FDOPA. Therefore, a morphological analysis is important. Thus, 18 F-FDOPA may be a marker for the aggressiveness of colorectal adenocarcinoma., Competing Interests: Conflicts of interest and sources of funding: none declared., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Introduction: Pheochromocytomas and paragangliomas (PPGLs) are rare neuroendocrine tumours that produce catecholamines. [131I] metaiodobenzylguanidine (MIBG)-avid unresectable or metastatic PPGLs are treated with [131I] MIBG radionuclide therapy. A high metabolic tumour volume (MTV) and total lesion glycolysis (TLG) can be poor prognostic factors. Therefore, we evaluated the metabolic responses to [131I] MIBG therapy with respect to other clinical factors., Methods: A retrospective study was performed on a series of 20 patients who underwent FDG-PET before and after [131I] MIBG therapy. We administered a single dose comprising 5.5 GBq of [131I] MIBG (usually three times; for some cases, the number was increased or decreased considering treatment efficacy and side effects). Semi-quantitative parameters (SUVmax, MTV, and TLG) were calculated using the liver SUV (mean + 3 × standard deviation) as a threshold on Metavol software. The semi-quantitative FDG-PET parameters for determining response were complete response (CR), partial remission (PR), stable disease (SD), and progressive disease (PD). We divided our study participants into the PD and non-PD groups (i.e., SD + PR + CR) and compared the overall survival (OS) between the two groups. Subsequently, we evaluated the relationships between metabolic response and age, sex, tumour type, metastatic site, chemotherapy or external radiation history, and 24-h urine catecholamine levels by univariate logistic regression analyses., Results: Both MTV-based and TLG-based criteria for PD versus non-PD were significant prognostic factors (p = 0.014). However, treatment response as evaluated based on the SUVmax was not a significant predictor. Higher urinary dopamine levels were associated with poor metabolic response as assessed by MTV and TLG (OR 1.002, p = 0.029). The other clinical parameters were non-significant., Conclusion: Poor metabolic response (measured with MTV and TLG) to [131I] MIBG therapy in unresectable or metastatic PPGLs was related to shorter OS. The poor metabolic response can be predicted using the urinary dopamine level., (© 2023 The Author(s). Published by S. Karger AG, Basel.)

Pheochromocytoma and abdominal paraganglioma (PPGL) are rare catecholamine-producing, keratin-negative, non-epithelial neuroendocrine neoplasms characterized by a unique association with syndromic diseases caused by constitutional mutations in a wide range of susceptibility genes. While PPGLs are recognized for their malignant potential, the risk of metastatic disease varies depending on several clinical, histological, and genetic factors. Accurate diagnosis and prognosis of these tumors require a multidisciplinary approach, integrating insights from various medical specialties. Pathologists play a crucial role in this complex task, as numerous morphological, immunohistochemical, and genetic findings can be linked to worse outcomes. Therefore, it is vital to stay informed about the latest advancements in PPGL pathology. This brief review provides an overview of the challenges associated with PPGLs and highlights the most recent developments in tumor prognostication.

Paragangliomas of the thyroid gland are rare and usually they originate from the inferior laryngeal paraganglia. In this case report, we describe the case of a 78-year-old woman who presented with an incidental finding of thyroid nodule dislocating the trachea. After a systemic and radiological evaluation, right lobo-isthmectomy was performed, and the definitive diagnosis of paraganglioma was reached. Diagnosis of these thyroidal lesions could be difficult due to their rarity, to their specific radiological aspects and the need of employing specific histological staining techniques. Once the definitive diagnosis is reached, patients should undergo a systemic and genetic evaluation. Surgery is the gold standard treatment; radiotherapy should be considered when aggressive behavior is suspected. Regular long-lasting follow-up should be proposed to these patients considering the unpredictable behavior of these lesions., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Purpose: This study aimed to compare the diagnostic performances of 18 F-FDOPA PET/CT and 123 I-MIBG scintigraphy with SPECT/CT for detection of pheochromocytoma and paraganglioma (PPGL)., Patients and Methods: We conducted a prospective, single-institution comparative study. Patients suspected of having PPGL or those showing recurrence and/or distant metastasis of PPGL were enrolled. The primary objective was to affirm the noninferiority of 18 F-FDOPA PET/CT for diagnostic sensitivity. Both 123 I-MIBG scintigraphy with SPECT/CT (at 4 and 24 hours) and 18 F-FDOPA PET/CT (at 5 and 60 minutes after radiotracer administration) were performed. The final diagnosis was established either pathologically or via clinical follow-up. Nuclear physicians, unaware of the clinical data, undertook image analysis., Results: Thirty-two patients were evaluated: 14 of 21 with an initial diagnosis and 9 of 11 with recurrence/metastasis had PPGLs in their final diagnoses. In patient-based analyses, 18 F-FDOPA PET/CT (95.7%) exhibited noninferior sensitivity compared with 123 I-MIBG SPECT/CT (91.3%), within the predetermined noninferiority margin of -12% by a 95% confidence interval lower limit of -10%. Both modalities showed no significant difference in specificity (88.9% vs 88.9%). In the region-based analysis for the recurrence/metastasis group, 18 F-FDOPA PET/CT demonstrated significantly higher sensitivity compared with 123 I-MIBG SPECT/CT (86.2% vs 65.5%, P = 0.031) and superior interobserver agreement (κ = 0.94 vs 0.85). The inclusion of an early phase in dual-phase 18 F-FDOPA PET/CT slightly improved diagnostic performance, albeit not to a statistically significant degree., Conclusions: 18 F-FDOPA PET/CT demonstrated noninferior sensitivity and comparable specificity to 123 I-MIBG SPECT/CT in the diagnosing PPGL. Notably, in the assessment of PPGL recurrence and metastasis, 18 F-FDOPA PET/CT outperformed 123 I-MIBG SPECT/CT in terms of both sensitivity and interobserver agreement., Competing Interests: Conflicts of interest and sources of funding: The authors declare that they have no conflict of interest. This research was partly supported by a grant of the Korea Health Technology R&D Project through the Korea Health Industry Development Institute, funded by the Ministry of Health and Welfare, South Korea (grant number HR18C0016)., (Copyright © 2023 The Author(s). Published by Wolters Kluwer Health, Inc.)

Paraganglioma, a catecholamine-producing tumor originating in extra-adrenal paraganglion cells, is rare in children. Although diagnosis of paraganglioma is based on the presence of catecholamine symptoms, some patients lack such symptoms. Delayed diagnosis is associated with tumor growth and invasion of surrounding vessels. Herein, we report a case of pediatric retroperitoneal paraganglioma invading the inferior vena cava. The tumor was completely resected and the patient has been free of recurrence for 2 years. Our findings suggest that complete resection can help prevent recurrence in cases of invasion of the inferior vena cava.

Aim: To develop and internally validate a novel predictive model for SDHB mutations in pheochromocytomas and retroperitoneal paragangliomas (PPGLs)., Methods: Clinical data of patients with PPGLs who presented to Peking Union Medical College Hospital from 2013 to 2022 and underwent genetic testing were retrospectively collected. Variables were screened by backward stepwise and clinical significance and were used to construct multivariable logistic models in 50 newly generated datasets after the multiple imputation. Bootstrapping was used for internal validation. A corresponding nomogram was generated based on the model. Sensitivity analyses were also performed., Results: A total of 556 patients with PPGLs were included, of which 99 had a germline SDHB mutation. The prediction model revealed that younger age of onset [Odds ratio (OR): 0.93, 95% CI: 0.91-0.95], synchronous metastasis (OR: 6.43, 95% CI: 2.62-15.80), multiple lesion (OR: 0.22, 95% CI: 0.09-0.54), retroperitoneal origin (OR: 5.72, 95% CI: 3.13-10.47), negative 131I-meta-iodobenzylguanidine (MIBG) (OR: 0.34, 95% CI: 0.15-0.73), positive octreotide scintigraphy (OR: 3.24, 95% CI: 1.25-8.43), elevated 24h urinary dopamine (DA) (OR: 1.72, 95% CI: 0.93-3.17), NE secretory type (OR: 2.83, 95% CI: 1.22- 6.59), normal secretory function (OR: 3.04, 95% CI: 1.04-8.85) and larger tumor size (OR: 1.09, 95% CI: 0.99-1.20) were predictors of SDHB mutations in PPGLs, and showed good and stable predictive performance with a mean area under the ROC curve (AUC) of 0.865 and coefficient of variation of 2.2%., Conclusions: This study provided a novel and useful tool for predicting SDHB mutations by integrating easily obtained clinical data. It may help clinicians select suitable genetic testing methods and make appropriate clinical decisions for these high-risk patients., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Zhou, Gao, Ma, Li, Cui, Wang, Li, Zhang and Tong.)

Background: Phaeochromocytomas and paragangliomas (PPGLs) are rare neuroendocrine tumours. Pathogenic variants have been identified in more than 15 susceptibility genes; associated tumours are grouped into three Clusters, reinforced by their transcriptional profiles. Cluster 1A PPGLs have pathogenic variants affecting enzymes of the tricarboxylic acid cycle, including succinate dehydrogenase. Within inherited PPGLs, these are the most common. PPGL tumours are known to undergo epigenetic reprograming, and here, we report on global histone post-translational modifications and DNA methylation levels, alongside clinical phenotypes., Results: Out of the 25 histone post-translational modifications examined, Cluster 1A PPGLs were distinguished from other tumours by a decrease in hyper-acetylated peptides and an increase in H3K4me2. DNA methylation was compared between tumours from individuals who developed metastatic disease versus those that did not. The majority of differentially methylated sites identified tended to be completely methylated or unmethylated in non-metastatic tumours, with low inter-sample variance. Metastatic tumours by contrast consistently had an intermediate DNA methylation state, including the ephrin receptor EPHA4 and its ligand EFNA3. Gene expression analyses performed to identify genes involved in metastatic tumour behaviour pin-pointed a number of genes previously described as mis-regulated in Cluster 1A tumours, as well as highlighting the tumour suppressor RGS22 and the pituitary tumour-transforming gene PTTG1., Conclusions: Combined transcriptomic and DNA methylation analyses revealed aberrant pathways, including ones that could be implicated in metastatic phenotypes and, for the first time, we report a decrease in hyper-acetylated histone marks in Cluster 1 PPGLs., (© 2023. The Author(s).)

Purpose: To evaluate the rate of recurrence among patients with pheochromocytomas and sympathetic paragangliomas (PGLs; together PPGLs) and to identify predictors of recurrence (local recurrence and/or metastatic disease)., Methods: This retrospective multicenter study included information of 303 patients with PPGLs in follow-up in 19 Spanish tertiary hospitals. Recurrent disease was defined by the development of local recurrence and/or metastatic disease after initial complete surgical resection., Results: A total of 303 patients with PPGLs that underwent 311 resections were included (288 pheochromocytomas and 15 sympathetic PGLs). After a median follow-up of 4.8 years (range 1-19), 24 patients (7.9%) had recurrent disease (3 local recurrence, 17 metastatic disease and 4 local recurrence followed by metastatic disease). The median time from the diagnosis of the PPGL to the recurrence was of 11.2 months (range 0.5-174) and recurrent disease cases distributed uniformly during the follow-up period. The presence of a pathogenic variant in SDHB gene (hazard ratio [HR] 13.3, 95% CI 4.20-41.92), higher urinary normetanephrine levels (HR 1.02 per each increase in standard deviation, 95% CI 1.01-1.03) and a larger tumor size (HR 1.01 per each increase in mm, 95% CI 1.00-1.02) were independently associated with disease recurrence., Conclusion: The recurrence of PPGLs occurred more frequently in patients with SDHB mutations, with larger tumors and with higher urinary normetanephrine levels. Since PPGL recurrence may occur at any time after the initial PPGL diagnosis is performed, we recommend performing a strict follow-up in all patients with PPGLs, especially in those patients with a higher risk of recurrent disease., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Araujo-Castro, García Sanz, Mínguez Ojeda, Hanzu, Mora, Vicente, Blanco Carrera, de Miguel Novoa, López García, Lamas, Manjón-Miguélez, del Castillo Tous, Rodríguez de Vera, Barahona San Millán, Recasens, Tomé Fernández-Ladreda, Valdés, Gracia Gimeno, Robles Lazaro, Michalopoulou, Álvarez Escolá, García Centeno, Barca-Tierno, Herrera-Martínez and Calatayud.)

A 55-year-old man was referred for the close examination of an abdominal mass noted on abdominal ultrasonography during a physical examination. A contrast-enhanced computed tomography(CT)scan of his abdomen revealed a 36-mm heterogeneously contrast-enhanced mass on the left side of the aorta. He was referred for laparoscopic tumor resection without preoperative histological examination. The tumor was identified from the dorsal aspect of the mesentery of the transverse colon and was resected only because it was detachable from the duodenum. A temporary abnormal hypertension was observed intraoperatively. However, he exhibited a favorable postoperative course and was discharged on the 8th postoperative day. Grossly, it was a nodular tumor with a diameter of 38 mm. Histopathological examination revealed that the tumor cells having abundant cytoplasm formed large foci and were surrounded by sinusoidal vessels. Immunohistochemistry results were positive for chromogranin A, synaptophysin, and neural cell adhesion molecule; thus, paraganglioma was diagnosed. Herein, we report a case of laparoscopic resection of an asymptomatic paraganglioma.

Background: Paragangliomas are tumours of extra-adrenal paraganglia. They may metastasize to the brain but primary paragangliomas are exceedingly rare in the supratentorial region and long-term outcomes after surgery is largely unknown. This description of an excellent outcome 13 years following surgery in a 40-year-old gentleman with a primary paraganglioma near the falx provides an important perspective on the value of gross total resection in these tumours. We also review the options for adjuvant therapy in tumours that cannot be excised completely., Case Description: We describe a supratentorial paraganglioma in the parasagittal region in a 40-year-old gentleman who presented with clinical and radiological features suggestive of a right parafalcine meningioma. Histopathological examination following gross total excision of the tumour revealed histological and immunochemical features of a paraganglioma. A detailed search for a systemic primary was negative and the patient remains disease-free 13 years after the surgery., Conclusions: Differentiating between tumours arising primarily and those that are metastatic deposits in the central nervous system requires long-term follow-up and monitoring for the appearance of occult primary tumours. Gross total resection is likely to provide good long-term outcomes.

Rational: Paragangliomas are rare and can occur in many places throughout the body, but mediastinal paragangliomas are even rarer, accounting for less than 0.3% of mediastinal masses. Extremely susceptible to misdiagnosis and mistreatment, which may lead to the death of the patient., Patient Concerns: We report a case of a giant paraganglioma of the middle mediastinum. A 40-year-old woman was admitted to the hospital with a rib fracture and a chest computed tomography suggesting a giant occupying tumor in the middle mediastinum., Diagnosis: Immunohistochemistry revealed positive for S100 fraction and Syn, focally positive for CgA, while negative for CKp and succinate dehydrogenase complex iron sulfur subunit B gene, and Ki67index ≈ 5%. The imaging and immunohistochemical features suggested a final diagnosis of Paragangliomas., Interventions: This patient underwent lateral open heart surgery to remove a mediastinal mass., Outcomes: One month after being discharged, the patient was contacted by phone for a follow-up visit and reported feeling OK. Unfortunately, as of the date of submission, the patient did not come to our hospital for review., Lessons: Mediastinal paraganglioma as a rare and potentially malignant tumor susceptible to misdiagnosis and mistreatment. Organ pathology examination is the gold standard for diagnosis, and surgery is an important treatment method. A clear diagnosis and thorough preoperative examination are important guarantees for the success of surgery., Competing Interests: The authors have no conflicts of interest to disclose., (Copyright © 2023 the Author(s). Published by Wolters Kluwer Health, Inc.)

Context: Somatic EPAS1 variants account for 5% to 8% of all pheochromocytoma and paragangliomas (PPGL) but are detected in over 90% of PPGL in patients with congenital cyanotic heart disease, where hypoxemia may select for EPAS1 gain-of-function variants. Sickle cell disease (SCD) is an inherited hemoglobinopathy associated with chronic hypoxia and there are isolated reports of PPGL in patients with SCD, but a genetic link between the conditions has yet to be established., Objective: To determine the phenotype and EPAS1 variant status of patients with PPGL and SCD., Methods: Records of 128 patients with PPGL under follow-up at our center from January 2017 to December 2022 were screened for SCD diagnosis. For identified patients, clinical data and biological specimens were obtained, including tumor, adjacent non-tumor tissue and peripheral blood. Sanger sequencing of exons 9 and 12 of EPAS1, followed by amplicon next-generation sequencing of identified variants was performed on all samples., Results: Four patients with both PPGL and SCD were identified. Median age at PPGL diagnosis was 28 years. Three tumors were abdominal paragangliomas and 1 was a pheochromocytoma. No germline pathogenic variants in PPGL-susceptibility genes were identified in the cohort. Genetic testing of tumor tissue detected unique EPAS1 variants in all 4 patients. Variants were not detected in the germline, and 1 variant was detected in lymph node tissue of a patient with metastatic disease., Conclusion: We propose that somatic EPAS1 variants may be acquired through exposure to chronic hypoxia in SCD and drive PPGL development. Future work is needed to further characterize this association., (© The Author(s) 2023. Published by Oxford University Press on behalf of the Endocrine Society.)

With the improvement of genetic testing technology in diseases in recent years, researchers have a more detailed and clear understanding of the source of cancers. Succinate dehydrogenase B (SDHB), a mitochondrial gene, is related to the metabolic activities of cells and tissues throughout the body. The mutations of SDHB have been found in pheochromocytoma, paraganglioma and other cancers, and is proved to affect the occurrence and progress of those cancers due to the important structural functions. The importance of SDHB is attracting more and more attention of researchers, however, reviews on the structure and function of SDHB, as well as on the mechanism of its carcinogenesis is inadequate. This paper reviews the relationship between SDHB mutations and related cancers, discusses the molecular mechanism of SDHB mutations that may lead to tumor formation, analyzes the mutation spectrum, structural domains, and penetrance of SDHB and sorts out some of the previously discovered diseases. For the patients with SDHB mutation, it is recommended that people in SDHB mutation families undergo regular genetic testing or SDHB immunohistochemistry (IHC). The purpose of this paper is hopefully to provide some reference and help for follow-up researches on SDHB., Competing Interests: Declaration of Competing Interest The authors declare no competing interests. Chang Liu: wrote the manuscript and gathered the document. Dayang Zhou and Kexin Yang: modified the manuscript and edited of the manuscript. Jibang Peng: collected the literatures. Zhu Zhu and Ning Xu: gave direction and reviewed., (Copyright © 2023 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)

Pheochromocytomas and paragangliomas (PPGLs) are rare neuroendocrine tumors originating from chromaffin cells, holding significant clinical importance due to their capacity for excessive catecholamine secretion and associated cardiovascular complications. Roughly 80% of cases are associated with genetic mutations. Based on the functionality of these mutated genes, PPGLs can be categorized into distinct molecular clusters: the pseudohypoxia signaling cluster (Cluster-1), the kinase signaling cluster (Cluster-2), and the WNT signaling cluster (Cluster-3). A pivotal factor in the pathogenesis of PPGLs is hypoxia-inducible factor-2α (HIF2α), which becomes upregulated even under normoxic conditions, activating downstream transcriptional processes associated with pseudohypoxia. This adaptation provides tumor cells with a growth advantage and enhances their ability to thrive in adverse microenvironments. Moreover, pseudohypoxia disrupts immune cell communication, leading to the development of an immunosuppressive tumor microenvironment. Within Cluster-1a, metabolic perturbations are particularly pronounced. Mutations in enzymes associated with the tricarboxylic acid (TCA) cycle, such as succinate dehydrogenase (SDHx), fumarate hydratase (FH), isocitrate dehydrogenase (IDH), and malate dehydrogenase type 2 (MDH2), result in the accumulation of critical oncogenic metabolic intermediates. Notable among these intermediates are succinate, fumarate, and 2-hydroxyglutarate (2-HG), which promote activation of the HIFs signaling pathway through various mechanisms, thus inducing pseudohypoxia and facilitating tumorigenesis. SDHx mutations are prevalent in PPGLs, disrupting mitochondrial function and causing succinate accumulation, which competitively inhibits α-ketoglutarate-dependent dioxygenases. Consequently, this leads to global hypermethylation, epigenetic changes, and activation of HIFs. In FH-deficient cells, fumarate accumulation leads to protein succination, impacting cell function. FH mutations also trigger metabolic reprogramming towards glycolysis and lactate synthesis. IDH1/2 mutations generate D-2HG, inhibiting α-ketoglutarate-dependent dioxygenases and stabilizing HIFs. Similarly, MDH2 mutations are associated with HIF stability and pseudohypoxic response. Understanding the intricate relationship between metabolic enzyme mutations in the TCA cycle and pseudohypoxic signaling is crucial for unraveling the pathogenesis of PPGLs and developing targeted therapies. This knowledge enhances our comprehension of the pivotal role of cellular metabolism in PPGLs and holds implications for potential therapeutic advancements., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Wang, Liu, Li, Zhang, Gao, Wang and Zhou.)

Currently, all pheochromocytoma/paraganglioma (PPGLs) are considered malignant due to metastatic potential. Consequently, PPGLs are divided into «metastatic» and «non-metastatic». Metastatic PPGLs can be with synchronous metastasis (metastases appear simultaneously with the identified primary tumor) or metachronous (metastases develop after removal of the primary tumor). The term metastatic PPGLs is not used in the presence of tumor invasion into surrounding organs and tissues, without the presence of distant metastases of lymphogenic or hematogenic origin. It is generally believed that about 10% of pheochromocytomas and about 40% of sympathetic paragangliomas have metastatic potential. On average, the prevalence of PPGLs with the presence of metastases is 15-20%. Risk factors for metastatic PPGLs are widely discussed in the literature, the most significant of which are groups of clinical, morphological and genetic characteristics. The review presents a discussion of such risk factors for metastatic PPGLs as age, localization and type of hormonal secretion of the tumor, the size and growth pattern of the adrenal lesion, the presence of necrosis and invasion into the vessels, the tumor capsule surrounding adipose tissue, high cellular and mitotic activity, Ki-67 index, expression of chromogranin B and S100 protein, the presence of genetic mutations of three main clusters (pseudohypoxia, kinase signaling and Wnt signaling).Over the past two decades, a number of authors have proposed various predictor factors and scales for assessing a probability of metastatic PPGLs. The review contains detailed description and comparison of sensitivity and specificity of such predictor scales as PASS, GAPP, M-GAPP, ASES and COPPS.

Pheochromocytoma and paraganglioma (PPGL) require prompt consideration and efficient diagnosis and treatment to minimize associated morbidity and mortality. Once considered, appropriate biochemical testing is key to diagnosis. Advances in understanding catecholamine metabolism have clarified why measurements of the O-methylated catecholamine metabolites rather than the catecholamines themselves are important for effective diagnosis. These metabolites, normetanephrine and metanephrine, produced respectively from norepinephrine and epinephrine, can be measured in plasma or urine, with choice according to available methods or presentation of patients. For patients with signs and symptoms of catecholamine excess, either test will invariably establish the diagnosis, whereas the plasma test provides higher sensitivity than urinary metanephrines for patients screened due to an incidentaloma or genetic predisposition, particularly for small tumors or in patients with an asymptomatic presentation. Additional measurements of plasma methoxytyramine can be important for some tumors, such as paragangliomas, and for surveillance of patients at risk of metastatic disease. Avoidance of false-positive test results is best achieved by plasma measurements with appropriate reference intervals and preanalytical precautions, including sampling blood in the fully supine position. Follow-up of positive results, including optimization of preanalytics for repeat tests or whether to proceed directly to anatomic imaging or confirmatory clonidine tests, depends on the test results, which can also suggest likely size, adrenal vs extra-adrenal location, underlying biology, or even metastatic involvement of a suspected tumor. Modern biochemical testing now makes diagnosis of PPGL relatively simple. Integration of artificial intelligence into the process should make it possible to fine-tune these advances., (© The Author(s) 2023. Published by Oxford University Press on behalf of the Endocrine Society. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Background: Pheochromocytomas and paragangliomas have up to a 20% rate of metastatic disease that cannot be reliably predicted. This study prospectively assessed whether the dopamine metabolite, methoxytyramine, might predict metastatic disease, whether predictions might be improved using machine learning models that incorporate other features, and how machine learning-based predictions compare with predictions made by specialists in the field., Methods: In this machine learning modelling study, we used cross-sectional cohort data from the PMT trial, based in Germany, Poland, and the Netherlands, to prospectively examine the utility of methoxytyramine to predict metastatic disease in 267 patients with pheochromocytoma or paraganglioma and positive biochemical test results at initial screening. Another retrospective dataset of 493 patients with these tumors enrolled under clinical protocols at National Institutes of Health (00-CH-0093) and the Netherlands (PRESCRIPT trial) was used to train and validate machine learning models according to selections of additional features. The best performing machine learning models were then externally validated using data for all patients in the PMT trial. For comparison, 12 specialists provided predictions of metastatic disease using data from the training and external validation datasets., Findings: Prospective predictions indicated that plasma methoxytyramine could identify metastatic disease at sensitivities of 52% and specificities of 85%. The best performing machine learning model was based on an ensemble tree classifier algorithm that used nine features: plasma methoxytyramine, metanephrine, normetanephrine, age, sex, previous history of pheochromocytoma or paraganglioma, location and size of primary tumours, and presence of multifocal disease. This model had an area under the receiver operating characteristic curve of 0·942 (95% CI 0·894-0·969) that was larger (p<0·0001) than that of the best performing specialist before (0·815, 0·778-0·853) and after (0·812, 0·781-0·854) provision of SDHB variant data. Sensitivity for prediction of metastatic disease in the external validation cohort reached 83% at a specificity of 92%., Interpretation: Although methoxytyramine has some utility for prediction of metastatic pheochromocytomas and paragangliomas, sensitivity is limited. Predictive value is considerably enhanced with machine learning models that incorporate our nine recommended features. Our final model provides a preoperative approach to predict metastases in patients with pheochromocytomas and paragangliomas, and thereby guide individualised patient management and follow-up., Funding: Deutsche Forschungsgemeinschaft., Competing Interests: Declaration of interests CP, AF, and GE declare a filed German patent A5914/TUD 017, with the title “Verfahren zur Vorhersage eines Nebennierentumours sowie eines Metastaserisikos mithilfe klinisch relevanter Parameter”, relevant to this manuscript. All other authors declare no competing interests., (Copyright © 2023 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY-NC-ND 4.0 license. Published by Elsevier Ltd.. All rights reserved.)

Context: Pheochromocytomas and paragangliomas (PPGLs) with SDHx pathogenic variants (PVs) are characterized by a higher intratissular succinate/fumarate ratio (RS/F) than non-SDHx-mutated ones. Also, an increase in serum succinate levels has been reported in patients with germline SDHB or SDHD PV., Objective: To assess whether measurement of serum succinate, fumarate levels, and RS/F might aid identification of an SDHx germline PV/likely pathogenic variant (LPV) in patients with PPGL or in asymptomatic relatives; and to guide identification of a PV/LPV among the variants of unknown significance (VUS) identified in SDHx by next-generation sequencing., Methods: This prospective monocentric study included 93 patients attending an endocrine oncogenetic unit for genetic testing. Succinate and fumarate were measured in serum by gas chromatography coupled to mass spectrometry. The RS/F was calculated to assess SDH enzymatic function. Diagnostic performance was assessed by receiver operating characteristic analysis., Results: RS/F had a higher discriminant power than succinate alone to identify an SDHx PV/LPV in patients with PPGL. However, SDHD PVs/LPVs are frequently missed. Only RS/F differed between asymptomatic SDHB/SDHD PV/LPV carriers and SDHB/SDHD-linked patients with PPGL. Finally RS/F could be helpful to easily evaluate the functional impact of VUS in SDHx., Conclusion: Measurement of serum RS/F in patients with PPGL and in asymptomatic relatives is a valuable initial workup tool to detect those carrying a germline PV/LPV in SDHx. Its discriminative power is equal or superior to those of succinate measured alone. SDHD PVs/LPVs are less frequently identified by these biochemical tools. Use of RS/F for SDHx VUS reclassification needs to be evaluated further., (© The Author(s) 2023. Published by Oxford University Press on behalf of the Endocrine Society. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

This article is a summary of the plenary lecture presented by Jared Rosenblum that was awarded the Manger Prize at the Sixth International Symposium on Pheochromocytoma/Paraganglioma held on 19-22 October 2022 in Prague, Czech Republic. Herein, we review our initial identification of a new syndrome of multiple paragangliomas, somatostatinomas, and polycythemia caused by early postzygotic mosaic mutations in EPAS1, encoding hypoxia-inducible factor 2 alpha (HIF-2α), and our continued exploration of new disease phenotypes in this syndrome, including vascular malformations and neural tube defects. Continued recruitment and close monitoring of patients with this syndrome as well as the generation and study of a corresponding disease mouse model as afforded by the pheochromocytoma/paraganglioma translational program at the National Institutes of Health has provided new insights into the natural history of these developmental anomalies and the pathophysiologic role of HIF-2α. Further, these studies have highlighted the importance of the timing of genetic defects in the development of related disease phenotypes. The recent discovery and continued study of this syndrome has not only rapidly evolved our understanding of pheochromocytoma and paraganglioma but also deepened our understanding of other developmental tumor syndromes, heritable syndromes, and sporadic diseases.

Background: Paraganglioma is a rare neuroendocrine tumor and is highly associated with hereditary susceptibility genes, often occurring as part of a genetic syndrome. The genetic heterogeneity of paraganglioma poses challenges in diagnosis, counseling, and clinical management., Case Summary: We present the case of a 60-year-old woman with hypertension, atrial septal defect, and polycythemia, who experienced paroxysmal palpitations, sweating, headache, abdominal pain, nausea, and vomiting. Her blood pressure was severely unstable. Blood laboratory tests revealed elevated catecholamine levels, contrast-enhanced CT of her whole abdomen showed a round retroperitoneal mass with soft tissue density, and somatostatin receptor imaging (68Ga PET-CT) indicated a retroperitoneal mass with abnormally increased expression of somatostatin receptor. It is interesting to note that whole exome sequencing (WES) analyses on both blood and tumor samples revealed a novel EPAS1 mutation, specifically the c.2501A > G; p.Tyr834Cys variant, which has never been reported. The patient was diagnosed with paraganglioma and underwent successful Da Vinci robot-assisted laparoscopic resection of the retroperitoneal tumor. During a 3-month follow-up period, her blood pressure stabilized, and her symptoms significantly improved., Conclusion: This case reveals that the EPSA1 mutation may be the primary driver of paraganglioma complicated by atrial septal defect and polycythemia. Additionally, the utilization of Da Vinci robot-assisted laparoscopic surgery contributed to a favorable prognosis for the patient., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Yang, Chen, Liu and Zhao.)

Pheochromocytomas (PCCs) and paragangliomas (PGLs) are rare neuroendocrine tumors. PGLs can further be divided into sympathetic (sPGLs) and head-and-neck (HN-PGLs). There are virtually no treatment options, and no cure, for metastatic PCCs and PGLs (PPGLs). Here, we composed a tissue microarray (TMA) consisting of 149 PPGLs, reflecting clinical features, presenting as a useful resource. Mutations in the pseudohypoxic marker HIF-2α correlate to an aggressive tumor phenotype. We show that HIF-2α localized to the cytoplasm in PPGLs. This subcompartmentalized protein expression differed between tumor subtypes, and strongly correlated to proliferation. Half of all sPGLs were metastatic at time of diagnosis. Cytoplasmic HIF-2α was strongly expressed in metastatic sPGLs and predicted poor outcome in this subgroup. We propose that higher cytoplasmic HIF-2α expression could serve as a useful clinical marker to differentiate paragangliomas from pheochromocytomas, and may help predict outcome in sPGL patients., (© 2023. The Author(s).)

Background: Due to the location of paragangliomas (PGLs) behind the retrohepatic segment of inferior vena cava (IVC), it is difficult to expose and resect the tumor., Case Presentation: A tumor measuring 50×45×62cm behind the retrohepatic portion of IVC was found in a 51-year-old female with hypertention and diabetes mellitus. Although the test for catecholamines revealed no signs of disease, the enhanced computed tomography (CT) scan, somatostatin receptor imaging and iodine-131-labeled metaiiodo-benzylguanidine ( 131 I-MIBG) imaging revealed that the tumor was PGL. A three-dimensional printing was performed to visualize the tumor. The laparoscpic surgery for the PGL behind the retrohepatic segment of IVC was performed and the tumor was resected completely without causing any tissues injury. The pathologic diagnosis was PGL and the patient was able to recover well., Conclusions: This case demonstrates that laparoscopic surgery may be helpful in tumor accessibility, and could be used in the appropriate cases to remove PGLs that are located behind the retrohepatic segment of the IVC., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Wang, Deng, Li, Ji and Wen.)

Context: Limited information is available concerning the genetic spectrum of pheochromocytoma and paraganglioma (PPGL) patients in South America. Germline SDHB large deletions are very rare worldwide, but most of the individuals harboring the SDHB exon 1 deletion originated from the Iberian Peninsula., Objective: Our aim was to investigate the spectrum of SDHB genetic defects in a large cohort of Brazilian patients with PPGLs., Methods: Genetic investigation of 155 index PPGL patients was performed by Sanger DNA sequencing, multiplex ligation-dependent probe amplification, and/or target next-generation sequencing panel. Common ancestrality was investigated by microsatellite genotyping with haplotype reconstruction, and analysis of deletion breakpoint., Results: Among 155 index patients, heterozygous germline SDHB pathogenic or likely pathogenic variants were identified in 22 cases (14.2%). The heterozygous SDHB exon 1 complete deletion was the most frequent genetic defect in SDHB, identified in 8 out of 22 (36%) of patients. Haplotype analysis of 5 SDHB flanking microsatellite markers demonstrated a significant difference in haplotype frequencies in a case-control permutation test (P = 0.03). More precisely, 3 closer/informative microsatellites were shared by 6 out of 8 apparently unrelated cases (75%) (SDHB-GATA29A05-D1S2826-D1S2644 | SDHB-186-130-213), which was observed in only 1 chromosome (1/42) without SDHB exon 1 deletion (X2 = 29.43; P < 0.001). Moreover, all cases with SDHB exon 1 deletion had the same gene breakpoint pattern of a 15 678 bp deletion previously described in the Iberian Peninsula, indicating a common origin., Conclusion: The germline heterozygous SDHB exon 1 deletion was the most frequent genetic defect in the Brazilian PPGL cohort. Our findings demonstrated a founder effect for the SDHB exon 1 deletion in Brazilian patients with paragangliomas., (© The Author(s) 2023. Published by Oxford University Press on behalf of the Endocrine Society. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Pheochromocytoma and paraganglioma (PPGL), are rare neuroendocrine tumors arising from the adrenal medulla and extra-adrenal paraganglia, respectively. Up to about 60% are explained by germline or somatic mutations in one of the major known susceptibility genes e.g., inNF1,RET,VHL, SDHx,MAXandHRAS. Targeted Next Generation Sequencing was performed in 14 sporadic tumors using a panel including 26 susceptibility genes to characterize the mutation profile. A total of 6 germline and 8 somatic variants were identified. The most frequent somatic mutations were found in NF1(36%), four have not been reported earlier in PCC or PGL. Gene expression profile analysis showed that NF1 mutated tumors are classified into RTK3 subtype, cluster 2, with a high expression of genes associated with chromaffin cell differentiation, and into a RTK2 subtype, cluster 2, as well with overexpression of genes associated with cortisol biosynthesis. On the other hand, by analyzing the entire probe set on the array and TCGA data, ALDOC was found as the most significantly down regulated gene in NF1-mutated tumors compared to NF1-wild-type. Differential gene expression analysis showed a significant difference between Nt - and Ct-NF1 domains in mutated tumors probably engaging different cellular pathways. Notably, we had a metastatic PCC with a Ct-NF1 frameshift mutation and when performing protein docking analysis, Ct-NF1 showed an interaction with Nt-FAK suggesting their involvement in cell adhesion and cell growth. These results show that depending on the location of the NF1-mutation different pathways are activated in PPGLs. Further studies are required to clarify their clinical significance., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Author(s). Published by Elsevier B.V. All rights reserved.)

Two normotensive male patients came with complaints of low back pain. Contrast-enhanced magnetic resonance imaging of the lumbosacral spine revealed an enhancing intradural extramedullary lesion (at the L4-L5 vertebral level in the first patient and at the L2-L3 vertebral level in the second patient). The tumor resembled the head and caudal blood vessels the tail of a tadpole, thereby giving the "tadpole sign." This sign is an important radiologic and histopathologic correlate, which is helpful in preoperative diagnosis of spinal paraganglioma., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Laryngeal paragangliomas are neural crest derived rare neuroendocrine tumors which originates from either superior or inferior laryngeal paraganglia. It arises most commonly in supraglottis with mean age of 44 years and it is three times more common in females. This is a case of 39 years female who underwent endoscopic debulking and excision of tumor for histopathological examination which proved to be poorly differentiated squamous cell carcinoma and received a cycle of chemotherapy that probably resulted in complete resolution of initial mass which was confirmed in subsequent follow up. Futher immunohistochemistry examination diagnosed the case as Laryngeal paraganglioma. With this consideration, how effective is the role of chemotherapy in the management of proven case of Laryngeal paragangliomas?

Background: Adrenal tumors, including benign cortical adenoma (BCA) and pheochromocytoma (PCC) or paraganglioma (PGL), have been more frequently detected during imaging examinations in recent years. However, the associated clinical or laboratory characteristics, especially on the Chinese population, still need to be investigated., Methods: We conducted a retrospective analysis of 491 patients pathologically diagnosed with adrenal tumors, from Jan 19, 2018 to Dec 17, 2019, at a tertiary referral hospital in Wuhan of China. Our findings including 247 (50.3%) BCA cases, and 92 (18.7) PCC/PGL cases and other cases. Both the clinical and laboratory parameters were reviewed and analyzed., Results: Compared with other adrenal tumors, PCC/PGL showed larger tumor diameters and more frequently located on the right side, and were with higher levels of urinary catecholoamines and plasma metanephrines, especially for the 24 h urinary vanilmandelic acid (VMA) and plasma normetanephrine (NMN). The optimal diagnostic thresholds were 29.40 ug/24 h for VMA (sensitivity, 85%; specificity, 91%) and 0.63 nmol/L for NMN (sensitivity, 91%; specificity, 92%). The 24 h urinary VMA and plasma NMN also shared abilities to differentiate between different tumor laterality and different tumor size in PCC/PGL cases. In addition, compared with the other benign tumors, BCA were smaller in diameters (20 vs 35 mm, p < 0.001), and seemed to be lower in levels of plasma epinephrine, dopamine and serum ACTH., Conclusion: 24 h Urinary catecholoamines and plasma metanephrines, especially for the 24 h urinary VMA and plasma MNM, showed higher diagnostic efficacies for PCC/PGL, and were tightly associated with the tumor laterality and tumor size., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: Pheochromocytoma (PHEO) and paraganglioma (PGL) are rare neuroendocrine tumors characterized by hemodynamic instability, caused by the paroxysmal release of catecholamines. Patients may develop cardiovascular complications in the perioperative phase due to the massive release of catecholamines, particularly during anesthetic induction and surgical manipulation of the tumor. The aim of this retrospective study was to evaluate the risk factors involved in perioperative hemodynamic instability in patients who underwent surgery for chromaffin tumors., Methods: Forty patients (median age 55 [36.50-64.50]) undergone surgery for PHEO/abdominal PGL from January 2011 to December 2016 at the AOU Careggi (Florence, Italy) were retrospectively evaluated. Systolic, diastolic, and mean blood pressure were considered at baseline and during surgery. Patients with blood pressure steadily < 140/90 mmHg before surgery were considered "adequately prepared". A preoperative therapy with doxazosin, a selective alpha-1 blocker, was started in all patients for at least 14 days prior to the surgery. The presence of hemodynamic instability was reported., Results: Comparing males and females, a significant difference in doxazosin daily dose (p = 0.018), systolic blood pressure (p = 0.048), and in the proportion of adequately prepared patients (p = 0.031) emerged. A positive correlation between preoperative daily dose of doxazosin, tumor size (B = 0.60, p < 0.001), and urinary normetanephrine levels (B = 0.64, p < 0.001) was also observed. Hemodynamic instability occurred in 30.0% of patients. The absence of adequate preparation (p = 0.012) before surgery, urinary normetanephrine levels (NMNur p = 0.039), and surgery time (minutes) (p = 0.021) resulted as risk factors of hemodynamic instability in our series. The use of intraoperative drugs was higher in patients with hemodynamic instability (p < 0.001). A pre-surgical SBP level of > 133 mmHg (OR = 6 CI95% 1.37-26.20, p = 0.017) and an intraoperative SBP and MBP levels of > 127 mmHg (OR = 28.80 CI95% 2.23-371.0, p = 0.010) and > 90 mmHg (OR = 18.90 CI95% 1.82-196.0, p = 0.014), respectively, were identified as effective thresholds to recognize patients at higher risk of HI., Conclusions: A preoperative therapy with alpha-blockers is useful, but not sufficient to avoid surgical risks. Patients with higher pre-surgical levels of NMNur, pre-surgical SBP > 133 mmHg, and/or intraoperative SBP > 127 mmHg and MBP > 90 mmHg, should be carefully monitored. A multidisciplinary approach is indispensable to optimize the management of PHEOs/abdominal PGLs in order to reduce surgical complications., (© 2023. The Author(s).)

Background: Paragangliomas are rare neuroendocrine tumors. While paragangliomas of the spine are rare, those located in non-cauda equina areas with spinal canal extension are even rarer., Case Presentation: We present a case of a 23-year-old female of African descent with a primary thoracic paraganglioma with intervertebral extension resulting in displacement and compression of the spinal cord and extensive local invasion of the surrounding structures. This paraganglioma was functional with typical symptoms of catecholamine excess. Despite the aggressive nature of the paraganglioma, the patient only had isolated sensory symptoms in the left shoulder. Adequate alpha and beta-blockade were instituted prior to her undergoing surgery with near-total resection and complete preserved neurology. There was no underlying pathogenic genetic mutation found., Conclusions: Even though rare, paraganglioma should be considered in the differential diagnosis of spinal tumors. Genetic testing should be performed in patients with paragangliomas. One should exercise extreme caution in treating such rare tumors that may cause neurological deficits and careful surgical planning should be undertaken to avoid possible catastrophic complications., (© 2023. The Author(s).)

Core needle biopsy (CNB) has been used with caution in pheochromocytoma and paraganglioma (PPGL) due to concerns about catecholamine-related complications. While it is unclear what scientific evidence supports this claim, it has limited the acquisition of biological samples for diagnostic purposes and research, especially in metastatic PPGL. We performed a systematic review and individual patient meta-analysis to evaluate the risk of complications after CNB in PPGL patients. The primary and secondary objectives were to investigate the risk of death and the occurrence of complications requiring intervention or hospitalization, respectively. Fifty-six articles describing 86 PPGL patients undergoing CNB were included. Of the patients (24/71), 34% had metastases and 53.4% (31/58) had catecholamine-related symptoms before CNB. Of the patients (14/41), 34.1% had catecholamine excess testing prior to the biopsy. No CNB-related deaths were reported. Four patients (14.8%, 4/27) experienced CNB-related complications requiring hospitalization or intervention. One case had a temporary duodenal obstruction caused by hematoma, two cases had myocardial infarction, and one case had Takotsubo cardiomyopathy. Eight patients (32%, 8/25) had CNB-related catecholamine symptoms, mainly transient hypertension, excessive diaphoresis, tachycardia, or hypertensive crisis. The scientific literature does not allow us to make any firm conclusion on the safety of CNB in PPGL. However, it is reasonable to argue that CNB could be conducted after thorough consideration, preparation, and with close follow-up for PPGL patients with a strong clinical indication for such investigation.

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.

Malignant middle ear paraganglioma (MEPGL) is an exceedingly rare tumor of the neuroendocrine system. In general, MEPGLs represent as slow growing and hypervascularized benign neoplasms. The genetic basis of MEPGL tumorigenesis has been poorly investigated. We report a case of malignant MEPGL accompanied by the comprehensive genetic analysis of the primary tumor and metastasis. Based on whole-exome sequencing data, the germline pathogenic mutation p.R230H in the SDHB gene, encoding for subunit B of mitochondrial complex II, was found in a patient. Analysis of somatic mutation spectra revealed five novel variants in different genes, including a potentially deleterious variant in UNC13C that was common for the tumor and metastasis. Identified somatic variants clustered into SBS1 and SBS5 mutational signatures. Of note, the primary tumor was characterized by Ki-67 4% and had an elevated mutational load (1.4/Mb); the metastasis' mutational load was about 4.5 times higher (6.4/Mb). In addition, we revealed somatic loss of the wild-type SDHB allele, as well as loss of heterozygosity (LOH) at the 11p locus. Thus, germline mutation in SDHB combined with somatic LOH seem to be drivers that lead to the tumor's initiation and progression. Other somatic changes identified can be additional disease-causing factors. Obtained results expand our understanding of molecular genetic mechanisms associated with the development of this rare tumor.

Pheochromocytomas (PCC)/paragangliomas (PGL) are catecholamine (CA) -secreting neuroendocrine tumors, which are known as PPGL due to their histological and pathophysiological similarities. In addition to the typical triad of paroxysmal headache, palpitation, and sweating, PPGL may also be accompanied by symptoms and signs involving multiple organs and systems such as the cardiovascular system, digestive system, endocrine system, and nervous system. Currently, surgical resection is the first choice for PPGL. Safe and effective surgical management of complicated PPGL is the goal of clinical work. In this paper, we discuss this hot issue based on complicated PPGL cases, aiming to share our experience of the surgical management strategy of PPGL., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Wang, Zhao, Liao and Zhang.)

Context: IDH1 is a pheochromocytoma/paraganglioma (PPGL) susceptibility gene; however, its role, especially in the Chinese population, has not been characterized., Objective: To determine the prevalence of somatic IDH1 hotspot variants in a large cohort of Chinese patients with PPGLs and to summarize associated phenotypes., Methods: This retrospective cross-sectional study was based on a main cohort of 1141 patients with PPGLs from 2 tertiary-care centers in China. We included 50 cases with urinary bladder paragangliomas (UBPGLs), of whom 29 were part of the main cohort and 21 were from other centers. Two additional cases with IDH1 hotspot variants not part of the main cohort were also included for summarizing IDH1-associated phenotypes. Next-generation sequencing of tumor DNA was used to analyze a customized panel of genes., Results: The overall prevalence of IDH1 hotspot variants in the main cohort was 0.5% (6/1141). Among those PPGLs without mutations in 15 common driver genes, the prevalence of IDH1 variants was 0.9% (4/455). When restricted to paraganglioma (PGL) without mutations, the prevalence reached 4.7% (4/86). Among UBPGLs, IDH1 hotspot variants accounted for 8% (4/50). Together, all 10 patients (9 PGLs and 1 pheochromocytoma) with IDH1 hotspot variants, including 3 females with concurrent EPAS1 hotspot variants, had apparently sporadic tumors, without metastasis or recurrence. There were 3 patients with biochemical data, all showing a non-adrenergic phenotype., Conclusions: The somatic IDH1 hotspot variants cause PPGL development in some Chinese patients, especially among those apparently sporadic PGLs with a non-adrenergic phenotype and without mutations in major PPGL driver genes., (© The Author(s) 2022. Published by Oxford University Press on behalf of the Endocrine Society. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Purpose: To compare the intraoperative and surgical outcomes of normotensive pheochromocytomas and sympathetic paragangliomas (PPGLs), hypertensive PPGLs and non-PPGL adrenal lesions., Methods: This a retrospective multicenter cohort study of patients with PPGLs from 18 tertiary hospitals. A control group of histologically confirmed adrenocortical adenomas (non-PPGL group) was selected to compare intraoperative and surgical outcomes with of the normotensive PPGLs., Results: Two hundred and ninety-six surgeries performed in 289 patients with PPGLs were included. Before surgery, 209 patients were classified as hypertensive PPGLs (70.6%) and 87 as normotensive PPGLs. A higher proportion of normotensive PPGLs than hypertensive PPGLs did not receive alpha presurgical blockade (P = 0.009). When we only considered those patients who received presurgical alpha blockers (200 hypertensive PPGLs and 76 normotensive PPGLs), hypertensive PPGLs had a threefold higher risk of intraoperative hypertensive crisis (OR 3.0 [95% 1.3-7.0]) and of hypotensive episodes (OR 2.9 [95% CI 1.2-6.7]) than normotensive PPGLs. When we compared normotensive PPGLs (n = 76) and non-PPGLs (n = 58), normotensive PPGLs had a fivefold higher risk of intraoperative complications (OR 5.3 [95% CI 1.9-14.9]) and a six times higher risk of postoperative complications (OR 6.1 [95% CI 1.7-21.6]) than non-PPGLs., Conclusion: Although the risk of intraoperative hypertensive and hypotensive episodes in normotensive PPGLs is significantly lower than in hypertensive PPGLs, normotensive PPGLs have a greater risk of intraoperative and postoperative complications than non-PPGL adrenal lesions. Therefore, it is recommended to follow the standard of care for presurgical and anesthetic management of PPGLs also in normotensive PPGLs., (© 2022. The Author(s), under exclusive licence to Italian Society of Endocrinology (SIE).)

Molecular imaging evaluation of pheochromocytomas and paragangliomas depends on multiple factors, such as localized versus metastatic disease, the genetic, and biochemical profile of tumors. Positron emission tomography/computed tomography (PET/CT) imaging of these tumors outperforms Meta-Iodo-Benzyl-Guanidine (MIBG) scintigraphy in most cases. A few PET radiotracers have been studied in evaluating these patients with somatostatin receptor PET imaging and have shown superior performance compared with other agents in most of these patients. 18F-fluorodeoxyglucose PET/CT imaging is useful in select patients, such as those with succinate dehydrogenase complex subunit B-associated disease. Treatment strategy depends on multiple factors and necessitates a multidisciplinary approach., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Purpose: The predominant symptom of pheochromocytomas and paragangliomas (PPGLs) is variable hypertension (HTN); however, not all patients with PPGLs develop HTN. Studies of the clinical characteristics of normotensive patients and which patients are more likely to develop HTN in PPGLs are rare. This study was performed to identify the clinical features to better understand this clinical entity., Methods: All consecutive adult patients with PPGLs were retrospectively enrolled from January 2018 to June 2020. The clinical characteristics of the patients were investigated. Multivariate logistic regression analysis was used to identify risk factors and receiver operating characteristic curves were used to evaluate the diagnostic performance of the variables., Results: There were 203 patients in the analysis, including 115 patients with normotension. Fewer patients with normotensive PPGLs had diabetes (p < 0.001) and clinical symptoms (p < 0.001). The 24-h urinary epinephrine (p = 0.002) and 24-h urinary norepinephrine (24hU-NE) concentrations (p < 0.001) were lower, and tumor diameter (p < 0.001) was smaller in patients with normotensive PPGLs. Multivariate logistic regression analysis showed that diabetes and 24hU-NE concentration were independent and negative risk factors for normotensive PPGLs. The area under the curve of 24hU-NE concentration and diabetes for predicting normotensive PPGLs was 0.788 and 0.634, respectively. Combining diabetes and 24hU-NE concentration into one model, the area under the curve of the model for predicting normotensive PPGLs was 0.817., Conclusions: Normal blood pressure could not exclude PPGLs. Identifying the clinical characteristics of normotensive and hypertensive patients in PPGLs is helpful for risk stratification and individualized assessment and treatment., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Purpose of Review: This review summarizes practical recommendations for screening, work-up, and management of hereditary head and neck paragangliomas based on the growing molecular and empirical understanding of this disease., Recent Findings: The proportion of hereditary cases among head and neck paragangliomas is significant (∼33 to 50%), and specific genetic alterations may increase the risk of malignancy. Genotyping should be performed for each case, and patients carrying a pathological mutation should be regularly screened for new tumors. Computed tomography (CT), magnetic resonance imaging (MRI), digital subtraction angiography (DSA), and functional positron emission tomography (PET) can provide a reliable preoperative diagnosis in the absence of histology. Comparative data on therapeutic outcome and morbidity now render radiation, stereotactic radiosurgery, and active surveillance preferable over surgery in highly advanced cases of jugulotympanic and vagal paragangliomas, whereas surgery remains the first choice for most carotid body paragangliomas., Summary: Complete paraganglioma removal continues to be the primary therapeutic goal; however, this is sometimes impossible to accomplish with acceptable morbidity. In these cases, therapy selection should focus on preserving cranial nerve function and minimizing both tumor-associated and therapy-associated complications, particularly in genetically predisposed patients. An interdisciplinary approach to the management of hereditary head and neck paragangliomas is strongly recommended., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Abstract: High-specific-activity 131 I-MIBG (Azedra) is the only Food and Drug Administration-approved therapy for metastatic pheochromocytomas and paragangliomas, which are rare neuroendocrine tumors with limited treatment options. Based on our experience, we proposed here functional imaging-based tumor response criteria for these patient cohorts. Each response category was illustrated with typical sample cases, and clinical correlation was provided., Competing Interests: Conflicts of interest and sources of funding: none declared., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Pheochromocytomas and Paragangliomas (Pheo/PGL) are rare catecholamine-producing tumours derived from adrenal medulla or from the extra-adrenal paraganglia respectively. Around 10-15% of Pheo/PGL develop metastatic forms and have a poor prognosis with a 37% of mortality rate at 5 years. These tumours have a strong genetic determinism, and the presence of succinate dehydrogenase B (SDHB) mutations are highly associated with metastatic forms. To date, no effective treatment is present for metastatic forms. In addition to cancer cells, the tumour microenvironment (TME) is also composed of non-neoplastic cells and non-cellular components, which are essential for tumour initiation and progression in multiple cancers, including Pheo/PGL. This review, for the first time, provides an overview of the roles of TME cells such as cancer-associated fibroblasts (CAFs) and tumour-associated macrophages (TAMs) on Pheo/PGL growth and progression. Moreover, the functions of the non-cellular components of the TME, among which the most representatives are growth factors, extracellular vesicles and extracellular matrix (ECM) are explored. The importance of succinate as an oncometabolite is emerging and since Pheo/PGL SDH mutated accumulate high levels of succinate, the role of succinate and of its receptor (SUCNR1) in the modulation of the carcinogenesis process is also analysed. Further understanding of the mechanism behind the complicated effects of TME on Pheo/PGL growth and spread could suggest novel therapeutic targets for further clinical treatments., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Martinelli, Amore, Canu, Maggi and Rapizzi.)

Introduction: Pheochromocytomas and paragangliomas (PCC/PGL) are rare neuroendocrine tumors and can secrete catecholamine. Previous studies have found that SDHB immunohistochemistry (IHC) can predict SDHB germline gene mutation, and SDHB mutation is closely associated with tumor progression and metastasis. This study aimed to clarify the potential effect of SDHB IHC as a predictive marker for tumor progression in PCC/PGL patients., Methods: We included PCC/PGL patients diagnosed in Ruijin Hospital, Shanghai Jiao Tong University School of Medicine from 2002 to 2014 for retrospective analysis and discovered that SDHB (-) staining patients had poorer prognoses. Then we examined SDHB protein expression by IHC on all tumors in the prospective series, which was composed of patients from 2015 to 2020 in our center., Results: In the retrospective series, the median follow-up was 167 months, and during follow-up, 14.4% (38/264) patients developed metastasis or recurrence, and 8.0% (22/274) patients died. Retrospective analysis revealed that 66.7% (6/9) of participants in the SDHB (-) group and 15.7% (40/255) of those in the SDHB (+) group developed progressive tumors (OR: 10.75, 95% CI: 2.72-52.60, P=0.001), and SDHB (-) was independently associated with poor outcomes after adjusting by other clinicopathological parameters (OR: 11.68, 95% CI: 2.58-64.45, P=0.002). SDHB (-) patients had shorter disease-free survival (DFS) and overall survival (OS) (P<0.001) and SDHB (-) was significantly associated with shorter median DFS (HR: 6.89, 95% CI: 2.41-19.70, P<0.001) in multivariate cox proportional hazard analysis. In the prospective series, the median follow-up was 28 months, 4.7% (10/213) patients developed metastasis or recurrence, and 0.5% (1/217) patient died. For the prospective analysis, 18.8% (3/16) of participants in the SDHB (-) group had progressive tumors compared with 3.6% (7/197) in the SDHB (+) group (RR: 5.28, 95% CI: 1.51-18.47, P=0.009), statistical significance remained (RR: 3.35, 95% CI: 1.20-9.38, P=0.021) after adjusting for other clinicopathological factors., Conclusions: Our findings demonstrated patients with SDHB (-) tumors had a higher possibility of poor outcomes, and SDHB IHC can be regarded as an independent biomarker of prognosis in PCC/PGL., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Su, Yang, Jiang, Xie, Zhong, Wu, Jiang, Zhang, Zhou, Ye, Ning and Wang.)

Background: Pheochromocytomas and paragangliomas (PPGLs) are neuroendocrine tumors, most of which are characterized by the release of catecholamine, and range in diameters from less than 1 cm to 10 cm or more. However, knowledge of the differences in clinical features between small and large PPGLs is insufficient., Methods: A retrospective analysis of patients with PPGLs treated at our institution between January 2018 and June 2020 was performed. The clinical characteristics of patients were investigated, and comparisons were made between patients with large and small PPGLs. The logistic regression analysis was used to confirm the risk factors, and the receiver operating characteristic curve was used to evaluate the diagnostic performance of the variables., Results: Totally 263 patients were included, including 110 patients in small tumor group and 153 patients in large tumor group. There were more male patients in the large tumor group (p=0.009). More patients had hypertension (p<0.001) and diabetes (p=0.002) in the large tumor group. The 24-h urinary epinephrine (24hU-E) (p < 0.001) and 24-h urinary norepinephrine (24hU-NE) (p=0.002) concentrations were higher in the large tumor group. In terms of tumor location, adrenal-PPGLs were more frequent in the large tumor group (p<0.001). Multivariate logistic regression analysis showed that male sex [odds ratio (OR): 2.871, 95% confidence interval (CI): 1.444-5.711, p=0.003], 24hU-E concentrations (OR: 1.025, 95% CI:1.004-1.047, p=0.020), 24hU-NE concentrations (OR: 1.002, 95%CI: 1.001-1.004, p=0.045), and adrenal-PPGLs (OR: 2.510, 95% CI:1.256-5.018, p=0.009) were positive risk factors for large tumors. Taking above variables into the same model, the area under the receiver operating characteristic curve of the model for predicting the large tumor was 0.772 (95% CI: 0.706-0.834). After the short-term follow-up, there was no significant difference in tumor recurrence between the two groups (p=0.681)., Conclusions: Significant differences in numerous clinical characteristics exist between large and small PPGLs. The male patients were more likely to be with large tumors, and such tumors were more likely to reside on the adrenal glands. Catecholamine measurements also help predict tumor size of PPGLs. Clinical decision-making will benefit from this information., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Zhao, Li, Meng, Fan, Zhang, Zhang, Liu, Zhou and Zhu.)

Glycemic alterations are frequent in patients with pheochromocytoma and paraganglioma (PPGL), but the real incidence of secondary diabetes mellitus (DM) is uncertain, because prospective multicenter studies on this topic are lacking in the literature. The main pathophysiological mechanisms of glucose homeostasis alterations in PPGL, related to catecholamine hypersecretion, are impaired insulin and glucagon-like peptide type 1 (GLP-1) secretion and increased insulin resistance. Moreover, it has been reported that different pathways leading to glucose intolerance may be related to the secretory phenotype of the chromaffin tumor. Predictive factors for the development of glucose intolerance in PPGL patients are a higher age at diagnosis, the need for a higher number of anti-hypertensive drugs, and the presence of secreting neoplasms. Tumor resection is strongly related to the resolution of DM in PPGL patients, with a significant improvement of glycemic control in most cases. We can hypothesize a different personalized therapeutic approach based on the secretory phenotype. The adrenergic phenotype is more closely related to reduced insulin secretion, so insulin therapy may be required. On the other hand, the noradrenergic phenotype mainly acts by increasing insulin resistance and, therefore, insulin-sensitizing antidiabetic agents can find a greater application. Regarding GLP-1 receptor agonists, the data suggest a possible promising therapeutic effect, based on the assumption that GLP-1 secretion is impaired in patients with PPGL. The principal predictors of remission of glycemic alterations after surgery for PPGL are a lower preoperative body mass index (BMI), a larger tumor, higher preoperative catecholamine levels, and a shorter duration of the disease (under three years). Otherwise, after resection of PPGL, hypoglycemia can occur as the result of an excessive rebound of preoperative hyperinsulinemia. It is a rare, but potentially severe complication reported in a lot of case reports and a few small retrospective studies. Higher 24-h urinary metanephrine levels, longer operative times and larger tumors are predictive factors for hypoglycemia in this setting. In conclusion, alterations of carbohydrate metabolism are clinically relevant manifestations of PPGL before and after surgery, but there is the need to conduct multicenter prospective studies to obtain an adequate sample size, and to allow the creation of shared strategies for the clinical management of these potentially severe manifestations of PPGL.

Objectives: Head & Neck Paragangliomas have been historically relying on surgery mostly, with worsened quality of life and major sequelae. Conventional external radiation therapy seems to offer an equivalent control rate with a low toxicity profile. The aim of this study was to assess the safety and efficiency of intensity-modulated radiation therapy in Head & Neck paragangliomas., Methods: This is a retrospective monocentric study conducted in a referral center, including all patients treated with IMRT, whether as an exclusive or post-operative treatment for a tympanic and jugular, carotid, or vagal paraganglioma. Data collection was performed through the manuscript and computerized medical files, including consultation, operative, imaging, pathological analyses, delineation, and treatment planning reports. Success was defined as the complete or partial regression or stabilization without progression, or relapse in accordance with the RECIST criteria. Acute toxicities and long-term sequelae were assessed., Results: Our cohort included 39 patients included between 2011 and 2021: 18 patients treated for a TJ PG (45.9%), 11 patients for a carotid PG (28.4%), and 9 for a vagal PG (23.1%). Twenty-nine patients had IMRT as an exclusive treatment (74.4%), whereas 10 patients had a post-operative complementary treatment (25.6%). Median follow-up in our cohort was 2318 days (average = 2200 days, 237-5690, sd = 1281.9). Among 39 patients, 37 were successfully controlled with IMRT (94.8%), and the toxicity profile was low without any major toxicity., Conclusion: IMRT seems an ideal treatment, whether exclusive or post-operative for Head & Neck paragangliomas., Level of Evidence: 3 Laryngoscope, 133:607-614, 2023., (© 2022 The Authors. The Laryngoscope published by Wiley Periodicals LLC on behalf of The American Laryngological, Rhinological and Otological Society, Inc.)