An overview of 20 years of genetic studies in pheochromocytoma and paraganglioma

Retrospective analysis of robotic versus laparoscopic surgery in the treatment of giant pheochromocytoma and paraganglioma

To compare the safety and effectiveness of robot-assisted laparoscopic surgery and traditional laparoscopic surgery in the treatment of giant pheochromocytomas and paragangliomas (PPGL). A retrospective analysis was conducted using the data of patients who underwent surgery at our institution between January 2013 and November 2023 and whose postoperative pathological examination confirmed PPGL (n = 84). Patients were divided into the robot-assisted (n = 33) and laparoscopic (n = 51) groups. Baseline data and intraoperative and postoperative recovery conditions of the two groups were compared. There was no significant difference in the baseline data between the two groups. The time to resume food intake in the robot-assisted group was shorter than that in the laparoscopic group [2 (1-2) vs. 3 (2-3) days, p < 0.001], and the incidence of postoperative morbidity was also lower (15.2% vs. 43.1%, p = 0.009); however, operating room time was longer [265 (240-370) vs. 245 (205-297.5) min, p = 0.039], and overall hospitalization costs were higher [80336.38 (72,014.3-101,555.39) vs. 60,102.13 (43,059.205-88085.35) CNY, p = 0.003]. This study results indicate that robot-assisted laparoscopic surgery has a lower postoperative complication rate and faster postoperative gastrointestinal function recovery. However, the surgery is costlier and operating room time is longer than with traditional laparoscopic surgery. Robotic surgery can be considered for giant PPGL if the patient's financial condition permits.

SLC25A11, a Novel Gene Associated With Carney-Stratakis Syndrome

Background

Carney-Stratakis syndrome (CSS), a rare condition characterized by paragangliomas and/or pheochromocytomas and gastrointestinal stromal tumors (GIST), is caused by germline heterozygous pathogenic variants in the succinate dehydrogenase subunit genes (SDHB, SDHC, SDHD).

Methods

Histological, genetic, and functional analyses were conducted in a 59-year-old female with CSS (9 cm left pheochromocytoma, 4.8 cm paraganglioma, and 9.3 cm GIST). Whole-exome sequencing (WES) of germline DNA paired with tumor DNA was performed.

Results

WES identified a rare heterozygous germline variant (c.293G>A/p.Arg98His) in the mitochondrial 2-oxoglutarate/malate carrier gene (SLC25A11). This variant, located in a highly conserved residue of the SLC25A11 mitochondrial carrier domain, is predicted to be deleterious in silico (REVEL score = 0.81). WES of pheochromocytoma, paraganglioma, and GIST did not reveal somatic pathogenic variants in genes previously associated with these tumors. A significant reduction in SLC25A11 expression was observed in the tumors of this patient with the SLC25A11 c.293G>A variant (0.69 ± 0.003) compared to tumors from cluster 1 (1.39 ± 0.45; P = 0.0229) and cluster 2 (1.79 ± 0.71; P = .0154). Consistent with the mRNA findings, SLC25A11 protein levels were markedly reduced in the pheochromocytoma and paraganglioma compared to other tumors. Negative staining for 5-hydroxymethylcytosine in all 3 tumors suggests a DNA hypermethylation profile characteristic of cluster 1A, despite normal SDHB expression levels. However, genome-wide copy number variation analysis did not reveal any loss of heterozygosity at the SLC25A11 locus.

Conclusion

The loss of SLC25A11 expression in tumors, the absence of somatic drivers, and the hypermethylation status strongly support the role of SLC25A11 in CSS pathogenesis.

Triggering tumorigenic signaling: Succinate dehydrogenase inhibitor (SDHi) fungicides induce oncometabolite accumulation and metabolic shift in human colon cells

Succinate dehydrogenase inhibitors (SDHi) are fungicides used worldwide to control the proliferation of fungi in crops. They act by blocking the activity of succinate dehydrogenase (SDH), a universal enzyme involved in mitochondrial functions and metabolism. While SDH-encoding genes are tumour suppressors, which loss-of-function mutations predispose to different types of rare tumors in humans, the consequences of chemical inactivation of SDH by SDHi remain largely unknown, particularly regarding their carcinogenic potential. Here, we investigated the metabolic and cellular impact of SDHi on human non-cancer and transformed colon cells. We show that SDHi inhibit SDH activity and increase the level of succinate, known to act as an oncometabolite in SDH-deficient cancers. SDHi exposure also induces a Warburg-like metabolic reprogramming typical of cancer cells, associated with transcriptomic and morphological changes promoting cell migration and invasion. These effects are enhanced in transformed colon cells carrying mutations in colorectal cancer (CRC) driver genes. These findings provide the first evidence that SDHi-mediated chemical inactivation of SDH mimics some metabolic and phenotypic features previously described in human tumors with SDH genetic deficiencies. Given that loss of SDH expression in CRC patients correlates with a poor prognosis, these patients could represent a population sensitive to SDHi exposure. Therefore, it would be wise to include them in biomonitoring programs. Finally, our work highlights the need to improve regulatory assessment procedures to take better account of SDHi mode of action, by developing relevant tests to cover the multiple key events linked to SDH inactivation and assess the resulting mitochondrial toxicity.

Approaches to reduce succinate accumulation by restoration of succinate dehydrogenase activity in cultured adrenal cells

The rare human neuroendocrine tumors pheochromocytoma and paraganglioma (PPGL) can result from loss of mitochondrial succinate dehydrogenase. The resulting succinate accumulation is tumorigenic in certain neuroendocrine cells. Here, we explore two theoretical approaches to mitigate tumorigenic succinate accumulation in a cell culture model of PPGL. We first study a gene replacement strategy using transposition technology, and conclude that many of the changes in mitochondrial morphology, oxidative cell metabolism and succinate accumulation can be reversed by this process. We then investigate whether riboflavin supplementation has the potential to rescue succinate dehydrogenase activity in the intact SDHA catalytic subunit to suppress succinate accumulation even in the absence of SDHB. We show that this latter strategy is not successful.

Genetic Testing Referral Rates for Pheochromocytoma and Paraganglioma in an Academic Tertiary Centre

BACKGROUND

Clinical guidelines recommend genetic counselling for all patients with pheochromocytoma or paraganglioma (PPGL). Barriers to accessing genetics evaluation are incompletely understood. The objective of this study was to identify individual- and provider-level barriers to genetic testing.

METHODS

Retrospective study of patients with PPGL who underwent resection at a tertiary academic centre. Study outcomes included referral rates for genetic counselling and completion of germline testing.

RESULTS

Of 224 patients who underwent resection of PPGL, 75% were referred for genetic counselling, and 49% completed testing. Genetic testing was highest after 2019. More individuals 50 years or younger underwent testing compared to over 50 (65% vs. 37%, p < 0.001). Medicare insurance was associated with lower rates of testing compared to commercial insurances (32% vs. 64%, p = 0.006). Controlling for individual and temporal factors, head and neck paragangliomas were least likely to undergo genetic testing (OR 0.13, 95% CI: 0.05-0.31). Reasons for not undergoing testing included insurance denial, time constraints, and patient uncertainty. Twenty-two percent (14/68) of patients with pheochromocytoma had a positive finding (FH, MSH3, MUTYH, NF1, RET, SDHD and VHL), while 46% (19/41) of patients with paraganglioma had a positive finding (MSH6, SDHA, SDHB, SDHD, TMEM127 and VHL).

CONCLUSION

Germline testing was performed in less than half of patients with PPGL, and 30% who underwent tested carried a pathogenic mutation, reinforcing the importance of genetics evaluation. Older age, Medicare coverage, and head and neck paragangliomas were associated with lower rates of genetic testing, presenting opportunities to improve education and equity in the management of patients with PPGL.

Metastatic pheochromocytoma complicated with Langerhans cell histiocytosis: a case report

Pheochromocytoma is a neuroendocrine neoplasm that originates from chromaffin cells of the adrenal medulla. Langerhans cell histiocytosis (LCH) is a proliferative disease of histiocyte-like cells, often associated with activating mutations of the mitogen-activated protein kinase (MAPK) pathway. We present a case of a 49-year-old male with a history of pheochromocytoma, which metastasized to the inferior vena cava eight years after left adrenalectomy. At the same time, it was found that the pheochromocytoma in the metastasis was complicated with LCH, a combination that has not been previously reported. Genetic analysis was carried out by next-generation sequencing (NGS) technology. Somatic mutations of BRAF and RAD54B were detected in Langerhans cells and EPAS1 in pheochromocytoma.

Surgical resection of a recurrent retroperitoneal paraganglioma: A case report

BACKGROUND

Paraganglioma (PGL) is a neuroendocrine tumor originating from paraganglia that can occur in various locations, such as the head, neck, chest, abdomen, and pelvis. Retroperitoneal PGLs are rare, and recurrent cases in this area are particularly uncommon, posing considerable surgical complexities. Owing to their neuroendocrine activity, PGLs are capable of secreting hormones like catecholamines, thereby presenting significant challenges in hemodynamic management during the perioperative period.

CASE SUMMARY

We report a 64-year-old man with a recurrent retroperitoneal PGL. The patient underwent retroperitoneal mass resection in 2013, with postoperative pathology revealing a PGL. Regular follow-up was not conducted until April 2024, when a computed tomography scan revealed a huge mass in the retroperitoneum, closely adjacent to the abdominal aorta. Laboratory examinations revealed elevated levels of catecholamines in the patient's blood serum. Upon admission, volume expansion and blood pressure (BP) monitoring were carried out for one week, with catecholamine levels reviewed and normalized. Adequate preoperative preparation was conducted, including central venous access, arterial BP monitoring, and the preparation of vasoactive agents. During tumor resection, the patient experienced acute, significant fluctuations in BP. The timely intervention of the anesthesiologist stabilized the BP, facilitating the successful resection of the tumor which was confirmed as a recurrent PGL. Postoperative follow-up revealed no evidence of tumor residual or recurrence.

CONCLUSION

PGL recurrence is rare but non-negligible. PGLs adjacent to major arteries complicate surgery, and perioperative hemodynamic stability demands meticulous attention.

Progress in surgical approaches and outcomes of patients with pheochromocytoma and paraganglioma

Significant advances have been made in the past few decades in surgical management and outcomes of patients with pheochromocytoma and paraganglioma. Improvements in preoperative hypertensive control with the implementation of alpha- and beta-adrenergic blockade has resulted in better intra-operative blood pressure control and less incidence of hypertensive crises, which had been a large source of morbidity in the past. Emphasis on anesthesia and surgical team communication has also assisted in minimizing intraoperative hypertensive events at critical points of the operation. Shifting away from open resection, the now standard-of-care laparoscopic and minimally invasive adrenalectomy offers less pain, shorter hospitalizations, and quicker recoveries. Patient underlying germline mutations can guide the timing, approach, and extent of surgery. Postoperative outcomes have significantly improved with recent advancements in perioperative care in addition to regimented biochemical and radiographic surveillance. Here, we highlight the recent advancements in surgical approaches and outcomes for patients with pheochromocytoma and paraganglioma.

Clinical practice guideline for the management of hypertension in China

In China, hypertension is the most common chronic non-communicable disease and the most significant risk factor for cardiovascular mortality among urban and rural residents. To standardize the clinical diagnosis and treatment of hypertension and to improve the prevention and control level of hypertension in China, Chinese Society of Cardiology, Chinese Medical Association; Hypertension Committee of Cross-Straits Medicine Exchange Association; Cardiovascular Disease Prevention and Rehabilitation Committee, Chinese Association of Rehabilitation Medicine, jointly collaborated to formulate the Clinical Practice Guideline for Hypertension Management in China. The Grading of Recommendation, Assessment, Development, and Evaluation (GRADE) approach was used to rate the quality of evidence and strength of recommendations, and the reporting items for practice guidelines in healthcare (RIGHT) were followed to establish the guideline. Detailed evidence-based recommendations for the diagnosis, evaluation, and treatment of 44 clinical questions in the field of hypertension, including essential and secondary hypertension, have been provided to guide clinical practice.

REGISTRATION

International Practice Guidelines Registry Platform, http://www.guidelines-registry.cn/ , No. IPGRP-2021CN346.

Facts, Dogmas, and Unknowns About Mitochondrial Reactive Oxygen Species in Cancer

Cancer metabolism is sustained both by enhanced aerobic glycolysis, characteristic of the Warburg phenotype, and oxidative metabolism. Cell survival and proliferation depends on a dynamic equilibrium between mitochondrial function and glycolysis, which is heterogeneous between tumors and even within the same tumor. During oxidative phosphorylation, electrons from NADH and FADH2 originated in the tricarboxylic acid cycle flow through complexes of the electron transport chain. Single electron leaks at specific complexes of the electron transport chain generate reactive oxygen species (ROS). ROS are a concentration-dependent double-edged sword that plays multifaceted roles in cancer metabolism. ROS serve either as signaling molecules favoring cellular homeostasis and proliferation or damage DNA, protein and lipids, causing cell death. Several aspects of ROS biology still remain unsolved. Among the unknowns are the actual levels at which ROS become cytotoxic and if toxicity depends on specific ROS species or if it is caused by a cumulative effect of all of them. In this review, we describe mechanisms of mitochondrial ROS production, detoxification, ROS-induced cytotoxicity, and the use of antioxidants in cancer treatment. We also provide updated information about critical questions on the biology of ROS on cancer metabolism and discuss dogmas that lack adequate experimental demonstration. Overall, this review brings a comprehensive perspective of ROS as drivers of cancer progression, inducers of cell death, and the potential use of antioxidants as anticancer therapy.

Durable and deep response to CVD chemotherapy in SDHB-mutated metastatic paraganglioma: case report

INTRODUCTION

Succinate dehydrogenase subunit B (SDHB)-mutated paragangliomas (PGLs) are rare neuroendocrine tumors characterized by increased malignancy, readily metastasizing, and poorer prognosis. Here we report a case of SDHB-mutated metastatic PGL, wherein the patient showed significant tumor shrinkage and complete symptom remission following chemotherapy. We aim to contribute additional evidence to the existing knowledge associated with SDHB-mutated PGLs.

CASE REPORT

A 40-year-old male patient presented with recurrent hypoglycemia and hypertension crisis. Imaging revealed a huge left retroperitoneal tumor and multiple diffuse metastases in lungs. Catecholamine was also elevated, aligning with a diagnosis of metastatic PGL. Pathology also confirmed this diagnosis. Additionally, the immunohistochemistry indicated negative expression of SDHB and gene test showed somatic SDHB mutation. Given the SDHB mutation, cyclophosphamide-vincristine-dacarbazine (CVD) chemotherapy was initiated in critical conditions. Subsequently, a significant tumor shrinkage and complete biochemical response were observed after two treatment cycles. In September 2024, CT scan revealed new pulmonary lesions. The progression-free survival (PFS) with CVD chemotherapy was 24 months.

CONCLUSION

This report reviews the distinct clinical and biochemical characteristics and treatment approaches of SDHB-mutated paragangliomas, emphasizing that the significance of incorporating both genetic testing and immunohistochemical analysis in clinical practice.

SDHB-Associated Pheochromocytomas: What is Their Clinical Behavior?

INTRODUCTION

Germline pathogenic variants in succinate dehydrogenase subunit B (SDHB) cause paraganglioma/pheochromocytoma syndrome type 4 (PGL-4). SDHB-associated pheochromocytomas (PCC) are thought to be rare and little data exist about their clinical behavior.

PATIENTS AND METHODS

Retrospective review of patients treated (1993-2023) at a tertiary cancer center for SDHB-associated PCC. Clinical and demographic variables were retrieved to characterize disease-free survival, disease progression, and overall survival.

RESULTS

In total, 90 SDHB-carriers were identified, 18% had PCC (n = 16). Median age at diagnosis of was 40 (19-76) years, 50% (n = 8) of patients were male, 25% (n = 4) had distant metastasis (DM) at diagnosis, and 13% (n = 2) had synchronous PGL. No patients had bilateral disease, and 94% of patients underwent surgery as initial treatment with a curative intent in 75%. Overall, 64% of patients underwent open resection. Recurrence occurred in 77% of patients (n = 10), 75% in minimally invasive surgery (MIS) versus 77% open, p = 0.63. Bone was the most common site of DM (100%, n = 13). Metaidobenzyleguanidine (MIBG) imaging was performed in 69% of patients, 91% of which were positive. Median time from surgery until recurrence was 36 months (1-295 months). Radiation therapy was the most common adjuvant treatment (44%) followed by Iobenguane I-131 (31%) and systemic therapy (31%). Median follow-up time was 56 months (1-408 months). Overall, 33% of patients were alive, 19% of patients were disease-free, and 50% of the patients with DM had stable disease at last follow-up.

CONCLUSIONS

Overall, 18% of germline SDHB mutation-carriers were diagnosed with PCC, all of which were unilateral. SDHB-associated PCC was associated with advanced and recalcitrant disease and was often MIBG positive. More studies are needed to better understand the clinical behavior of PCC in PGL-4.

Genetic landscape of Romanian PPGLs

Pheochromocytomas and paragangliomas (PPGLs) are rare neuroendocrine tumours that originate from chromaffin cells and occur in the adrenal medulla and in the sympathetic or parasympathetic ganglia. Nearly 70% of PPGLs result from germline or somatic mutations in a single driver gene. The aim of this study was to characterize the genetic background and clinical characteristics related to genetic profile of patients with PPGLs from Romania. We retrospectively retrieved data of 125 patients consecutively registered, diagnosed with PPGLs in a tertiary referral center of endocrinology from Romania, between 1976 and 2022. We identified 88 (70.4%) women, and 37 (29.6%) men, with a mean age at diagnosis of 48.5 ± 15 years. From these 125 patients, 80 (64%) were submitted to the genomic study; 35% (n = 28) had a germline mutation (20 RET, 3 VHL, 1 SDHB, 1 NF1, 1 SDHD, 1 FANCA, 1 CASR) while 65% (n = 52) presented sporadic disease. Patients with hereditary disease had significantly lower age at diagnosis comparing to sporadic cases (37 ± 15 vs. 49.9 ± 12.2 years, p = 0.001). Bilateral tumors developed in twelve patients from the hereditary group. Metastatic disease was described in 4 out of 80 patients (2 of them with hereditary disease). Patients from sporadic group tended to have a right lateralisation of the tumour compared to hereditary cases, where the tumour was more often left sided. RET pathogenic variant (p.Cys634Trp) associated with MEN2A syndrome was the most prevalent in Romanian population with PPGLs and could be considered as a founder effect. Patients with hereditary disease are diagnosed at a younger age and develop bilateral tumors more frequently compared to sporadic cases.

Multiple Endocrine Neoplasia with Multiple PGLs in Two Boxer Dogs: Morphological Features, Immunohistochemical Profile and SDHD Gene Mutation Screening

This study aimed to describe the gross and histological features of multiple endocrine and non-endocrine neoplasia, including multiple PGLs found in two Boxer dogs. Additionally, the identified PGLs were immunohistochemically evaluated, and the subunits 2, 3, and 4 of the SDHD gene were screened for possible mutations. The tumors identified include aortic and carotid body PGLs, thyroid follicular-compact carcinoma, and subcutaneous lipomas. One case also had a Leydig cell tumor and adrenal cortex hyperplasia, while the other had H-type pancreatic carcinoma. Three out of 4 PGLs appeared benign, but one aortic body tumor showed malignant features with neoplastic emboli at its edge. Immunohistochemical analysis confirmed the neuroendocrine origin of all PGLs, with positive staining for Chromogranin A, NSE, and variable positivity for S100. No somatic mutations were found in exons 2, 3, and 4 of the SDHD gene in any of the evaluated PGLs. The absence of mutations in the evaluated SDHD gene subunits suggests the involvement of other genetic factors or pathways in the development of these tumors, warranting further investigation in this field.

Novel Gene Variants in a Nationwide Cohort of Patients with Pheochromocytoma and Paraganglioma

Pheochromocytomas (PCCs) and paragangliomas (PGLs), denoted PPGLs, are rare neuroendocrine tumours and are highly heterogeneous. The phenotype-genotype correlation is poor; therefore, additional studies are needed to understand their pathogenesis. We describe the clinical characteristics of 63 patients with PPGLs and perform a genetic study. Genetic screening was performed via a targeted gene panel, and clinical variables were compared among patients with a positive molecular diagnosis and negative ones in both PCC and PGL cohorts. The mean age of patients with PCC was 50.0, and the mean age of those with PGL was 54.0. Disease-causing germline variants were identified in 16 individuals (25.4%), twelve and five patients with PCC and PGL, respectively. Genetically positive patients were younger at diagnosis in both cohorts. Variants in genes associated with either isolated PPGLs or syndromic forms of the disease were detected in a cohort of PPGLs. We have identified novel variants in known genes and set the importance of genetic screening to every patient with PPGLs, with a special focus on the young. A longer follow up of patients with variants in genes associated with syndromic forms is of clinical value.

Robot-Assisted Surgery and Multigene Panel Testing for Pheochromocytoma and Paraganglioma Syndrome

Pheochromocytoma and paraganglioma are often associated with hereditary syndromes, particularly those involving genes such as RET, which is linked to multiple endocrine neoplasia type 2A. Genetic testing plays a crucial role in diagnosing these conditions, guiding treatment strategies, and providing early intervention options for the affected families. A 57-year-old man presenting with back pain was found to have a left adrenal tumor and a retroperitoneal tumor near the left renal hilum. Hormonal studies and imaging confirmed the diagnosis of pheochromocytoma and paraganglioma. The patient underwent robot-assisted laparoscopic surgery to remove the tumors. Postoperative multigene panel testing identified a mutation in RET c.1901G > T (p.Cys634Phe) leading to the diagnosis of multiple endocrine neoplasia type 2A. Despite this genetic finding, no other endocrine tumors, such as medullary thyroid cancer or hyperparathyroidism, were detected at the time of diagnosis. The patient remains under close surveillance for the potential development of associated conditions. This case highlights the importance of comprehensive genetic testing in patients with pheochromocytoma and paraganglioma, particularly when hereditary syndromes are suspected. Genetic insights ensure precise management, allowing for tailored treatment and improved outcomes in patients with hereditary pheochromocytoma and paraganglioma.

Familial and early recurrent pheochromocytoma in a child with a novel in-frame duplication variant of VHL

Pheochromocytomas and paragangliomas (PPGLs) are rare neuroendocrine tumors often linked to underlying genetic variants. Genetic analysis can promote gene-adjusted, specific follow-up, and surveillance protocols for both patients and their families at risk. We report the case of a 7-yr-old boy with bilateral pheochromocytoma, which recurred a year after partial adrenalectomy. The patient's father developed bilateral pheochromocytomas at 25 yr of age. Both individuals possessed a novel heterogeneous in-frame duplication germline variant of VHL, yet neither exhibited other clinical manifestations of von Hippel-Lindau disease (VHL). Traditionally, VHL missense mutations have been associated with a higher risk of PPGL development, whereas truncating mutations typically confer a lower risk. In-frame duplication variants are rarely observed in patients with VHL but may lead to changes in the three-dimensional structure of the translated protein, similar to truncating variants. Our analysis suggests that these in-frame duplications of amino acids in specific regions may cause pheochromocytomas in a manner similar to missense variants. Further accumulation of VHL cases with various genotypes and standardized open-access worldwide databases, including longitudinal and specific clinical data linked to genotypes, is required. It is crucial to consider genetic analyses for pediatricians who may diagnose childhood-onset PPGL.

Anesthesia Management in Hereditary Pheochromocytoma and Paraganglioma: Updated Insights into Clinical Features and Perioperative Care

Approximately 40% of pheochromocytoma and paraganglioma (PPGL) cases are familial, typically presenting earlier with more complex symptoms. This paper synthesizes literature and guidelines to inform on clinical characteristics and perioperative care for PPGL. Pheochromocytoma in von Hippel-Lindau (VHL) disease exhibits heightened secretion activity without significant perioperative hemodynamic changes. Tumors in multiple endocrine neoplasia type 2 (MEN2) have a stronger endocrine function, which may induce hemodynamic fluctuations during surgery. Therefore, pheochromocytoma screening is essential at all stages of MEN2. Neurofibromatosis type 1 (NF1) often presents multisystem lesions and can result in difficult airway. Pheochromocytoma should be evaluated when NF1 patients present hypertension. Pheochromocytoma and paraganglioma type 5 may present multiple lesions of pheochromocytoma or paraganglioma. In summary, hereditary PPGLs may present with severe lesions in other systems, beyond tumor function. A multi-disciplinary team (MDT) approach is often invaluable in perioperative management.

Mouse developmental defects, but not paraganglioma tumorigenesis, upon conditional Complex II loss in early Sox10+ cells

In humans, loss of heterozygosity for defective alleles of any of the four subunits of mitochondrial tricarboxylic acid cycle enzyme succinate dehydrogenase (SDH, also Complex II of the electron transport chain) can lead to paraganglioma tumors in neuroendocrine cells. With the goal of developing mouse models of this rare disorder, we have developed various SDH conditional loss strategies. Based on recent lineage tracing studies, we hypothesized that conditional SDHC loss in early embryogenesis during migration of primordial neural crest cells that form the susceptible chromaffin cells of the adrenal medulla might induce paraganglioma. We triggered low levels of detectable SDHC loss in Sox10+ cells at E11.5 of mouse development. We report that, rather than developing adrenal medulla paraganglioma (pheochromocytoma), offspring survived with evidence of neural crest cell dysfunction. Phenotypes included mild lower extremity gait anomalies suggestive of neural tube closure defects and patches of unpigmented fur consistent with neural crest-derived melanocyte dysfunction. These defects were not observed in mice lacking Sdhc knockout. Our results add to existing data suggesting that, unlike humans, even early embryonic (Sox10-driven) SDHx loss is inadequate to trigger paraganglioma in mice of the genetic backgrounds that have been investigated. Instead, low levels of tricarboxylic acid cycle-deficient neural crest cells cause mild developmental defects in hind limb and melanocyte function. This new model may be of interest for studies of metabolism during early neural crest cell development.

Tricarboxylic Acid Cycle Relationships with Non-Metabolic Processes: A Short Story with DNA Repair and Its Consequences on Cancer Therapy Resistance

Metabolic changes involving the tricarboxylic acid (TCA) cycle have been linked to different non-metabolic cell processes. Among them, apart from cancer and immunity, emerges the DNA damage response (DDR) and specifically DNA damage repair. The oncometabolites succinate, fumarate and 2-hydroxyglutarate (2HG) increase reactive oxygen species levels and create pseudohypoxia conditions that induce DNA damage and/or inhibit DNA repair. Additionally, by influencing DDR modulation, they establish direct relationships with DNA repair on at least four different pathways. The AlkB pathway deals with the removal of N-alkylation DNA and RNA damage that is inhibited by fumarate and 2HG. The MGMT pathway acts in the removal of O-alkylation DNA damage, and it is inhibited by the silencing of the MGMT gene promoter by 2HG and succinate. The other two pathways deal with the repair of double-strand breaks (DSBs) but with opposite effects: the FH pathway, which uses fumarate to help with the repair of this damage, and the chromatin remodeling pathway, in which oncometabolites inhibit its repair by impairing the homologous recombination repair (HRR) system. Since oncometabolites inhibit DNA repair, their removal from tumor cells will not always generate a positive response in cancer therapy. In fact, their presence contributes to longer survival and/or sensitization against tumor therapy in some cancer patients.

Proteomic characterization of head and neck paraganglioma and its molecular classification

Background

Head and neck paragangliomas (HNPGLs) are rare neuroendocrine tumors that pose significant challenges in both diagnosis and treatment. The pathogenic mechanism remains unclear, and there is no proteomic analysis-based molecular classification. Therefore, gaining a deeper understanding of this disease from the protein level is crucial because proteins play a fundamental role in the occurrence and development of tumors.

Methods

We collected 44 tumor samples from patients diagnosed with HNPGL. The adrenal paraganglioma tissue (N = 46) was used as the disease control group and the chorda tympani nerves (N = 18) were used as the control group. High-pH reversed-phase liquid chromatography and liquid chromatography with tandem mass spectrometry analyses were used to build an integrated protein database of tumor samples. We then obtained two sets of differentially expressed proteins between the tumor group and the control group to identify the unique proteomic signatures of HNPGLs. Ingenuity pathway analysis annotations were used to perform the functional analysis. Subsequently, we developed a clinically relevant molecular classification for HNPGLs that connected the clinical characteristics with meaningful proteins and pathways to explain the varied clinical manifestations.

Results

We identified 6,640 proteins in the HNPGL group, and 314 differentially expressed proteins unique to HNPGL were discovered via inter-group comparison. We identified two HNPGL subgroups that significantly differed in clinical manifestation and proteomic characteristics. On the basis of the proteomic results, we proposed a pathogenic mechanism underlying HNPGL.

Conclusion

We conducted a comprehensive analysis of the molecular mechanisms of HNPGL to build, for the first time, a clinically relevant molecular classification. By focusing on differential proteomic analyses between different types of paragangliomas, we were able to obtain a comprehensive description of the proteomic characteristics of HNPGL, which will be valuable for the search for significant biomarkers as a new treatment method for HNPGL.

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

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

Analysis of clinical and pathological characteristics of retroperitoneal paraganglioma and associated prognostic factors

BACKGROUND AND OBJECTIVES

The aim of this study is to explore the long-term prognostic risk factors associated with patients diagnosed with retroperitoneal paraganglioma (RPGL) and examine their clinical and pathological characteristics.

METHODS

Expressions of biomarkers were identified using immunohistochemistry (IHC) and case databases were retrospectively searched. Survival analysis was performed using Kaplan-Meier and Cox risk regression to identify the factors that influence the postoperative progression-free survival of patients with RPGL.

RESULTS

A total of 105 patients, most of whom had tumors situated in the paraaortic region, and whose average tumor size was 8.6 cm, were enrolled in this study. The average follow-up duration was 51 months, with a mortality rate of 19% and a recurrence and metastasis rate of 41.9%. Tumors were assessed using the modified Grading system for Adrenal Pheochromocytoma and Paraganglioma (GAPP), and SDHB, S-100, and Ki-67 were stained using IHC in all cases. Out of the total cases examined, negative in SDHB expression were observed in 18.1% of cases, S-100 expression was negative in 36.2% of cases, and endovascular tumor enboluswas present in approximately 25.7% of cases. The results of the univariate analysis indicated that several factors significantly influenced the progression-free survival of patients with PGL as follow: maximum tumor diameter (>5.5 cm), tumor morphological features, tumor grading (modified GAPP score > 6), SDHB negative, S-100 negative, and expression of proliferation index Ki-67 (>3%) (X2 = 4.217-27.420, p < 0.05). The results of the multivariate analysis indicated that negative of S-100 (p = 0.021) and SDHB (p = 0.038), as well as intravascular tumor thrombus (p = 0.047) expression were independent risk factors for progression-free survival in patients.

CONCLUSION

RPGL is characterized by diverse biological features and an elevated susceptibility to both recurrence and metastasis. Both SDHB and S-100 can be employed as traditional IHC indicators to predict the metastatic risk of PGL, whereas the tumor histomorphology-endovascular tumor enbolus assists in determining the metastasis risk of RPGL.

Current management of carotid body tumors

Carotid body tumors (CBTs) are neoplasms that occur at the bifurcation of the carotid artery and are pathologically classified as paragangliomas. In the 4th edition of the WHO classification, paragangliomas are categorized as neoplasms with malignant potential. Clinically, about 5% of CBTs present with malignant features such as metastasis. Currently, it is challenging to distinguish between tumors with benign courses and those that present malignantly. Recent advances in genetic testing have elucidated the genetic characteristics of paragangliomas, including carotid body tumors. Over 20 genes have been identified as being involved in tumor development. Particularly in head and neck paragangliomas, abnormalities in genes related to succinate dehydrogenase are frequently observed. Research is ongoing to understand the mechanisms by which these genes contribute to tumor development. The definitive treatment for CBTs is surgical resection. These tumors are prone to bleeding and often adhere firmly to the carotid artery, making intraoperative bleeding control challenging. The risk of lower cranial nerve paralysis is relatively high, and there is a risk of stroke because of manipulation of the carotid artery. Preoperative evaluation with angiography is essential, and a multi-disciplinary surgical team approach is necessary. In cases where the tumor is difficult to resect or has metastasized, radiation therapy or chemotherapy are employed. Clinical trials involving targeted molecular therapies and radiopharmaceuticals have recently been conducted, with some applied clinically. The development of various new treatments is anticipated, providing hope for therapeutic options in refractory cases.

Case report: A rare DLST mutation in patient with metastatic pheochromocytoma: clinical implications and management challenges

Background

Pheochromocytoma is one of the most hereditary human tumors with at least 20 susceptible genes undergoing germline and somatic mutations, and other mutations less than 1% -2%. In recent years, other rare mutations have gradually been discovered to be possibly related to the pathogenesis and metastasis of pheochromocytoma. Most patients with pheochromocytoma experience common symptoms like headaches, palpitations, and sweating, while some may have less common symptoms. The diversity of symptoms, genetic mutations, and limited treatment options make management challenging.

Case presentation

A 53-year-old woman was hospitalized after experiencing episodic epigastric pain for one month. A mass was found in her right adrenal gland and she underwent robot-assisted laparoscopic surgery, revealing a pheochromocytoma. At the 16-month follow-up, multiple metastatic lesions consistent with metastatic pheochromocytoma were found. A germline mutation in the dihydrolipoamide succinyltransferase (DLST) gene (c.330 + 14A>G) was detected, and despite trying chemotherapy and adjuvant therapy, the patient had a limited response with an overall survival of 27 months.

Conclusions

DLST mutation is one of the rare pheochromocytoma-related mutated genes, and genetic sequencing is crucial for effective clinical management.

Giant Cystic Pheochromocytoma Associated With Neurofibromatosis Type 1: A Case Report

Pheochromocytomas are tumors that develop from the chromaffin cells of the adrenal medulla. More than 40% of cases of pheochromocytomas are associated with genetic conditions such as neurofibromatosis type 1 (NF1) or von Hippel-Lindau syndrome. Cystic pheochromocytomas are rare, generally asymptomatic, and thus of bigger size at the time of diagnosis. Surgical treatment is necessary to prevent cardiovascular morbidity and malignancy risk. We report the case of a 27-year-old patient admitted for further examination of a left adrenal mass that was discovered by an abdominal CT scan in the context of abdominal pain associated with hypertension evolving for three years. The clinical examination showed the presence of multiple café au lait spots, axillary and inguinal freckling with two dermal neurofibromas diagnosed clinically, as well as Lisch nodules on bilateral ophthalmic examination, thus meeting the clinical criteria for the diagnosis of NF1. The clinical laboratory investigation showed elevated urinary metanephrine and normetanephrine levels. CT scan examination showed a 10 cm left adrenal cystic mass on abdominal CT. This mass uptake of the radioligand in metaiodobenzylguanidine (MIBG) scintigraphy without secondary extra-adrenal localization allowed the diagnosis of a seemingly benign cystic pheochromocytoma to be made. The patient was put on presurgical drug preparation with volume expansion and then underwent left unilateral adrenalectomy. The histopathological study was in favor of a rather aggressive cystic pheochromocytoma with a pheochromocytoma of the adrenal gland scaled (PASS) score of 9. Blood pressure and urine catecholamines at seven days, three months, six months, and one year after surgery were normalized. Cystic pheochromocytoma is a rare tumor with a potentially poor prognosis. It is characterized by a more insidious evolution and a larger volume at diagnosis. It should be considered a diagnosis in patients with a cystic adrenal mass or an extra-adrenal mass with fluctuating blood pressure during surgery. This case illustrates the importance of both presurgical preparation and screening for pheochromocytoma in neurofibromatosis type 1.

Comprehensive Investigation of Angiogenesis, PASS Score and Immunohistochemical Factors in Risk Assessment of Malignancy for Paraganglioma and Pheochromocytoma

A challenging task in routine practice is finding the distinction between benign and malignant paragangliomas and pheochromocytomas. The aim of this study is to conduct a comparative analysis of angiogenesis by assessing intratumoral microvascular density (MVD) with immunohistochemical (IHC) markers (CD31, CD34, CD105, ERG), and S100 immunoreactivity, Ki67 proliferative index, succinate dehydrogenase B (SDHB) expressiveness, tumor size with one the most utilized score Pheochromocytoma of Adrenal Gland Scales Score (PASS), using tissue microarray (TMA) with 115 tumor samples, 61 benign (PASS < 4) and 54 potentially malignant (PASS ≥ 4). We found no notable difference between intratumoral MVD and potentially malignant behavior. The group of potentially malignant tumors is significantly larger in size, has lower intratumoral MVD, and a decreased number of S100 labeled sustentacular cells. Both groups have low proliferative activity (mean Ki67 is 1.02 and 1.22, respectively). Most tumors maintain SDHB expression, only 6 cases (5.2%) showed a loss of expression (4 of them in PASS < 4 group and 2 in PASS ≥ 4). PASS score is easily available for assessment and complemented with markers of biological behavior to complete the risk stratification algorithm. Size is directly related to PASS score and malignancy. Intratumoral MVD is extensively developed but it is not crucial in evaluating the malignant potential.

Pan-cancer molecular signatures connecting aspartate transaminase (AST) to cancer prognosis, metabolic and immune signatures

Background

Serum aspartate transaminase (sAST) level is used routinely in conjunction with other clinical assays to assess liver health and disease. Increasing evidence suggests that sAST is associated with all-cause mortality and has prognostic value in several cancers, including gastrointestinal and urothelial cancers. Here, we undertake a systems approach to unravel molecular connections between AST and cancer prognosis, metabolism, and immune signatures at the transcriptomic and proteomic levels.

Methods

We mined public gene expression data across multiple normal and cancerous tissues using the Genotype Tissue Expression (GTEX) resource and The Cancer Genome Atlas (TCGA) to assess the expression of genes encoding AST isoenzymes (GOT1 and GOT2) and their association with disease prognosis and immune infiltration signatures across multiple tumors. We examined the associations between AST and previously reported pan-cancer molecular subtypes characterized by distinct metabolic and immune signatures. We analyzed human protein-protein interaction networks for interactions between GOT1 and GOT2 with cancer-associated proteins. Using public databases and protein-protein interaction networks, we determined whether the subset of proteins that interact with AST (GOT1 and GOT2 interactomes) are enriched with proteins associated with specific diseases, miRNAs and transcription factors.

Results

We show that AST transcript isoforms (GOT1 and GOT2) are expressed across a wide range of normal tissues. AST isoforms are upregulated in tumors of the breast, lung, uterus, and thymus relative to normal tissues but downregulated in tumors of the liver, colon, brain, kidney and skeletal sarcomas. At the proteomic level, we find that the expression of AST is associated with distinct pan-cancer molecular subtypes with an enrichment of specific metabolic and immune signatures. Based on human protein-protein interaction data, AST physically interacts with multiple proteins involved in tumor initiation, suppression, progression, and treatment. We find enrichments in the AST interactomes for proteins associated with liver and lung cancer and dermatologic diseases. At the regulatory level, the GOT1 interactome is enriched with the targets of cancer-associated miRNAs, specifically mir34a - a promising cancer therapeutic, while the GOT2 interactome is enriched with proteins that interact with cancer-associated transcription factors.

Conclusions

Our findings suggest that perturbations in the levels of AST within specific tissues reflect pathophysiological changes beyond tissue damage and have implications for cancer metabolism, immune infiltration, prognosis, and treatment personalization.

A Woman with Bilateral Pheochromocytoma and Tuberous Sclerosis Complex

Background/Objective

Pheochromocytoma and paraganglioma (PPGL) are rare neuroendocrine tumors. Here, we report an unusual case of synchronous PPGL in an asymptomatic patient with tuberous sclerosis complex (TSC).

Case Report

A 49-year-old woman with a history of TSC and end-stage renal disease was referred for evaluation of bilateral adrenal and retroperitoneal masses. She denied chest pain, palpitations, headaches, or previous hypertensive crisis. The laboratory test results showed a plasma normetanephrine level of 20.20 nmol/L (normal range, 0.00-0.89 nmol/L) and plasma chromogranin A level Chromogranin A (CgA) levels of 1518 ng/mL (normal range, 0-103 ng/mL). The plasma metanephrine level was normal. After α-blockade, the patient underwent bilateral adrenalectomy and retroperitoneal mass excision. Pathology confirmed these lesions to be pheochromocytoma and composite paraganglioma/ganglioneuroma, respectively. Her plasma normetanephrine level normalized postoperatively, and the chromogranin A levels improved to 431 ng/mL.

Discussion

Routine imaging has increased the incidental diagnosis of PPGL. Diagnostic workup includes measurement of the urinary and/or plasma metanephrine and catecholamine levels followed by tumor localization. Patients with young age, syndromic lesions, bilateral PPGL, or unilateral disease with a positive family history should have genetic testing. Definitive treatment is surgical after α-blockade.

Conclusion

This case highlights a rare presentation of bilateral PPGL in a patient with TSC.

Hypoxic Signaling Pathways in Carotid Body Tumors

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

IL-6-Producing Pheochromocytoma Associated With Von Hippel Lindau Disease: A Case Report With Literature Review

We present a first case report of an IL-6-producing pheochromocytoma associated with von Hippel Lindau (vHL) disease. Pheochromocytomas are rare tumors that produce catecholamines, leading to various symptoms. In this case, a 28-year-old woman with a family history of vHL disease presented with a prolonged fever. Laboratory examinations revealed elevated C-reactive protein levels, and notably, a significantly increased serum IL-6 level. Imaging studies confirmed bilateral adrenal tumors with increased uptake on fluorodeoxyglucose-positron emission tomography and 123I-metaiodobenzylguanidine scintigraphy in the right adrenal gland. Despite partial relief with nonsteroidal anti-inflammatory drugs and alpha-blockers, her fever persisted until prednisolone administration, which promoted a complete resolution. A histopathological analysis following a right laparoscopic adrenalectomy revealed a typical pheochromocytoma. We conducted further analyses, including an enzyme-linked immunosorbent assay (ELISA), a quantitative real-time polymerase chain reaction (PCR) test, and immunoblot assays from the resected tumor tissues. We compared the current case with other cases of pheochromocytoma that presented neither elevated serum IL-6 nor high fever. Using ELISA, we found that this patient exhibited more IL-6 secretion than that seen in other cases. Additionally, quantitative real-time PCR and immunoblot found that both the phosphorylated signal transducer and activator of transcription 3 (STAT3) messenger RNA (mRNA) and protein expression levels exceeded those of the other cases. Thus, we surmised that IL-6 was produced directly from the tumor tissue and IL-6 expression was potentiated through the IL-6/STAT3 signaling pathway. Our findings contribute to the understanding of IL-6-producing pheochromocytomas and their distinct clinical characteristics.

Mastering bladder paraganglioma for optimal treatment: a case report of robot-assisted surgery

Bladder paraganglioma is a rare neuroendocrine neoplasm, either functional or non-functional, arising from the urinary bladder. Functional variants present with catecholamine-related symptoms, while non-functional variants pose diagnostic challenges, mimicking urothelial carcinoma. Misdiagnosis risks underscore the importance of accurate identification for appropriate patient management. In this case, a 52-year-old man, diagnosed incidentally with hypertension and reported occasional post-micturition tachycardia, underwent abdominal ultrasound for known hepatic cyst follow-up, revealing an oval hypoechoic bladder mass. Initial consideration of bladder urothelial carcinoma prompted further investigation with contrast-enhanced CT scan and cystoscopy that confirmed extrinsic mass nature, and subsequent robotic-assisted partial cystectomy was performed. Histologically, the removed mass exhibited characteristic features of bladder paraganglioma. Postoperative recovery was uneventful, with resolution of post-micturition tachycardia at 1 month. Follow-up includes endocrinological evaluation and a 6-month CT scan. In conclusion, bladder paraganglioma should be considered in para-vesical mass differentials. This case highlights the importance of meticulous history collection, even in asymptomatic patients, the need for a multidisciplinary approach for accurate diagnosis and management of this rare condition, and the robotic approach as a viable option.

A comprehensive characterisation of phaeochromocytoma and paraganglioma tumours through histone protein profiling, DNA methylation and transcriptomic analysis genome wide

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.

Somatic EPAS1 Variants in Pheochromocytoma and Paraganglioma in Patients With Sickle Cell Disease

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.

[Corticotropin-producing pheochromocytoma in multiple endocrine neoplasia type 1]

A clinical case of a man 66 y.o. who was diagnosed with hormone-inactive pituitary macroadenoma complicated by corneal erosion and partial atrophy of the optic nerve of the left eye due to exophthalmos. The increase in prolactin level was regarded due to a «stalk-effect». The patient underwent a transnasal pituitary adenomectomy with subsequent regression of symptoms. After 4 years, against the background of a new coronavirus infection, increasing general weakness, headaches, a crisis increase in blood pressure and tachycardia attacks appeared. Computed tomography (CT) accidentally revealed an adrenal incidentaloma, in laboratory tests - hypercortisolism, elevated ACTH levels, hypokalemia, hyperglycemia, increased levels of metanephrine and normetanephrine. The patient developed acute steroid psychosis, after which an adrenalectomy with a tumor was performed, a pheochromocytoma was histologically confirmed. After surgery, there was a regression of symptoms, the development of adrenal insufficiency with reduced levels of ACTH and cortisol. Upon further examination, a polynodose euthyroid goiter was established, the biopsy of the nodes - Hashimoto's thyroiditis (Bethesda II). Meanwhile, primary hyperparathyroidism was detected. According to ultrasound, scintigraphy with Ts99m-Technetril and CT revealed an increase of left parathyroid gland. A bilateral revision of the neck, removal of the right upper and left upper parathyroid adenomas were performed. In the postoperative period, the levels of calcium and parathyroid hormone were normalized. Given the presence of a combination of multiple tumors of the endocrine system (primary hyperparathyroidism, corticotropin-producing pheochromocytoma, hormone-inactive pituitary macroadenoma, polynodose euthyroid goiter), the MEN1 syndrome was clinically established. The study of 2 and 10 exons of the MEN1 gene revealed no mutations, which does not exclude the presence of a hereditary syndrome. The patient continues observation. In the available literature in Russian and English languages the case of ACTH pheochromocytoma as part of the MEN type 1 syndrome have not been found. Therefore, we consider the presented case to be the first one.

Research in the genetics of pheochromocytoma and paraganglioma: a bibliometric analysis from 2002 to 2022

Over the past two decades, there has been a significant growth in articles focusing on the genetics of pheochromocytoma and paraganglioma (PPGL). We used bibliometric methods to investigate the historical changes and trend in PPGL research. There was a total of 1263 articles published in English from 2002 to 2022 included in our study. The number of annual publications and citations in this field has been increasing in the past 20 years. Furthermore, most of the publications originated from the European countries and the United States. The co-occurrence analysis showed close cooperation between different countries, institutions, or authors. The dual-map discipline analysis revealed that majority articles focused on four disciplines: #2 (Medicine, Medical, Clinical), #4 (Molecular, Biology, Immunology), #5 (Health, Nursing, Medicine), and #8 (Molecular, Biology, Genetics). The hotspot analysis revealed the keywords that have been landmark for PPGL genetics research in different time periods, and there was continued interest in gene mutations, especially on SDHX family genes. In conclusion, this study displays the current status of research and future trends in the genetics of PPGL. In future, more in-depth research should concentrate on crucial mutation genes and their specific mechanisms to assist in molecular target therapy. It is hoped that this study may help to provide directions for future research on genes and PPGL.

Current Status of Cancer Genomics and Imaging Phenotypes: What Radiologists Need to Know

Ongoing discoveries in cancer genomics and epigenomics have revolutionized clinical oncology and precision health care. This knowledge provides unprecedented insights into tumor biology and heterogeneity within a single tumor, among primary and metastatic lesions, and among patients with the same histologic type of cancer. Large-scale genomic sequencing studies also sparked the development of new tumor classifications, biomarkers, and targeted therapies. Because of the central role of imaging in cancer diagnosis and therapy, radiologists need to be familiar with the basic concepts of genomics, which are now becoming the new norm in oncologic clinical practice. By incorporating these concepts into clinical practice, radiologists can make their imaging interpretations more meaningful and specific, facilitate multidisciplinary clinical dialogue and interventions, and provide better patient-centric care. This review article highlights basic concepts of genomics and epigenomics, reviews the most common genetic alterations in cancer, and discusses the implications of these concepts on imaging by organ system in a case-based manner. This information will help stimulate new innovations in imaging research, accelerate the development and validation of new imaging biomarkers, and motivate efforts to bring new molecular and functional imaging methods to clinical radiology. Keywords: Oncology, Cancer Genomics, Epignomics, Radiogenomics, Imaging Markers Supplemental material is available for this article. © RSNA, 2023.

Pheochromocytoma: a changing perspective and current concepts

This article aims to review current concepts in diagnosing and managing pheochromocytoma and paraganglioma (PPGL). Personalized genetic testing is vital, as 40-60% of tumors are linked to a known mutation. Tumor DNA should be sampled first. Next-generation sequencing is the best and most cost-effective choice and also helps with the expansion of current knowledge. Recent advancements have also led to the increased incorporation of regulatory RNA, metabolome markers, and the NETest in PPGL workup. PPGL presentation is highly volatile and nonspecific due to its multifactorial etiology. Symptoms mainly derive from catecholamine (CMN) excess or mass effect, primarily affecting the cardiovascular system. However, paroxysmal nature, hypertension, and the classic triad are no longer perceived as telltale signs. Identifying high-risk subjects and diagnosing patients at the correct time by using appropriate personalized methods are essential. Free plasma/urine catecholamine metabolites must be first-line examinations using liquid chromatography with tandem mass spectrometry as the gold standard analytical method. Reference intervals should be personalized according to demographics and comorbidity. The same applies to result interpretation. Threefold increase from the upper limit is highly suggestive of PPGL. Computed tomography (CT) is preferred for pheochromocytoma due to better cost-effectiveness and spatial resolution. Unenhanced attenuation of >10HU in non-contrast CT is indicative. The choice of extra-adrenal tumor imaging is based on location. Functional imaging with positron emission tomography/computed tomography and radionuclide administration improves diagnostic accuracy, especially in extra-adrenal/malignant or familial cases. Surgery is the mainstay treatment when feasible. Preoperative α-adrenergic blockade reduces surgical morbidity. Aggressive metastatic PPGL benefits from systemic chemotherapy, while milder cases can be managed with radionuclides. Short-term postoperative follow-up evaluates the adequacy of resection. Long-term follow-up assesses the risk of recurrence or metastasis. Asymptomatic carriers and their families can benefit from surveillance, with intervals depending on the specific gene mutation. Trials primarily focusing on targeted therapy and radionuclides are currently active. A multidisciplinary approach, correct timing, and personalization are key for successful PPGL management.

The connection between tricarboxylic acid cycle enzyme mutations and pseudohypoxic signaling in pheochromocytoma and paraganglioma

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.

[French recommendations for malignant pheochromocytomas and paragangliomas by the national ENDOCAN-COMETE network]

Pheochromocytomas and paragangliomas are rare neuroendocrine tumors, developed respectively in the adrenal medulla and in extra-adrenal locations. Their malignancy is defined by the presence of distant metastases. Forty percent of them are inherited and can be part of different hereditary syndromes. Their management is ensured in France by the multidisciplinary expert centers of the ENDOCAN-COMETE national network "Cancers of the Adrenal gland", certified by the National Cancer Institute and discussed within multidisciplinary team meetings. The diagnostic and therapeutic work-up must be standardized, based on an expert analysis of clinical symptoms, hormonal biological secretions, genetics, morphological and specific metabolic imaging. In the context of a heterogeneous survival sometimes beyond seven to ten years, therapeutic intervention must be justified. This is multidisciplinary and relies on surgery, interventional radiology, external or internal radiotherapy and medical treatments such as sunitinib or dacarbazine and temodal chemotherapy. The personalized approach based on functional imaging fixation status and genetics is progressing despite the extreme rarity of this disease.

Assembly of mitochondrial succinate dehydrogenase in human health and disease

Mitochondrial succinate dehydrogenase (SDH), also known as electron transport chain (ETC) Complex II, is the only enzyme complex engaged in both oxidative phosphorylation and the tricarboxylic acid (TCA) cycle. SDH has received increasing attention due to its crucial role in regulating mitochondrial metabolism and human health. Despite having the fewest subunits among the four ETC complexes, functional SDH is formed via a sequential and well-coordinated assembly of subunits. Along with the discovery of subunit-specific assembly factors, the dynamic involvement of the SDH assembly process in a broad range of diseases has been revealed. Recently, we reported that perturbation of SDH assembly in different tissues leads to interesting and distinct pathophysiological changes in mice, indicating a need to understand the intricate SDH assembly process in human health and diseases. Thus, in this review, we summarize recent findings on SDH pathogenesis with respect to disease and a focus on SDH assembly.

Single-cell transcriptome sequencing reveals tumor heterogeneity in family neuroblastoma

Neuroblastoma(NB) is the most common extracranial solid tumor in childhood, and it is now believed that some patients with NB have an underlying genetic susceptibility, which may be one of the reasons for the multiplicity of NB patients within a family line. Even within the same family, the samples show great variation and can present as ganglioneuroblastoma or even benign ganglioneuroma. The genomics of NB is still unclear and more in-depth studies are needed to reveal its key components. We first performed single-cell RNA sequencing(sc-RNAseq) analysis on clinical specimens of two family neuroblastoma(FNB) and four sporadic NB cases. A complete transcriptional profile of FNB was constructed from 18,394 cells from FNB, and we found that SDHD may be genetically associated with FNB and identified a prognostic related CAF subtype in FNB: Fib-4. Single-cell flux estimation analysis (scFEA) results showed that malignant cells were associated with arginine spermine, oxaloacetate and hypoxanthine, and that malignant cells metabolize lactate at lower levels than T cells. Our study provides new resources and ideas for the development of the genomics of family NB, and the mechanisms of cell-to-cell interactions and communication and the metabolic landscape will provide new therapeutic targets.

Spotlight on GOT2 in Cancer Metabolism

GOT2 is at the nexus of several critical metabolic pathways in homeostatic cellular and dysregulated cancer metabolism. Despite this, recent work has emphasized the remarkable plasticity of cancer cells to employ compensatory pathways when GOT2 is inhibited. Here, we review the metabolic roles of GOT2, highlighting findings in both normal and cancer cells. We emphasize how cancer cells repurpose cell intrinsic metabolism and their flexibility when GOT2 is inhibited. We close by using this framework to discuss key considerations for future investigations into cancer metabolism.

Case Report: A novel EPAS1 mutation in a case of paraganglioma complicated with polycythemia and atrial septal defect

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.

Rare presentation of vagal paraganglioma in an early age: A case report and literature review

INTRODUCTION AND IMPORTANCE

Vagal paragangliomas of neck are rare tumours of neural crest origin usually arising in elderly age with female predominance. They have a vague clinical presentation therefore difficult to diagnose preoperatively. We hope that this case report and literature review would add to the existing literature and help devise a comprehensive diagnostic and therapeutic plan for vagal paragangliomas.

CASE PRESENTATION

We report a case of vagal paraganglioma occurring in a 13-year-old male which is an extremely rare presentation in this age group. The patient presented with a large solitary painless progressively growing mass in posterior triangle of neck. External jugular vein was stretched and trachea was deviated medially. The mass was arising via a twig from vagus nerve and was surgically excised. Diagnosis was established post-operatively through histopathological analysis.

CLINICAL DISCUSSION

Vagal paraganglioma is a rare occurrence in male teenagers and may mimic schwannoma, neuroma, jugular meningioma, or other gangliomas. Surgical excision is mainstay of treatment but resultant vagal complications and neurological consequences are usually unavoidable. Nonetheless, the prognosis may be easily improved with sound surgical judgement, skill, and routine follow-up.

CONCLUSIONS

Vagal paraganglioma usually presents as a swelling in neck and cannot be diagnosed on simple clinical examination. CT scan and MRI are imaging modalities of choice and can be coupled with angiography to increase diagnostic accuracy. Although both radiation therapy and surgical excision have both been found to be successful treatment options, it is still unclear which is more beneficial.

[Rare forms of hereditary endocrine neoplasia: co-existence of pituitary adenoma and pheochromocytoma/paraganglioma]

Functioning pituitary adenomas and pheochromocytomas/paragangliomas are rare in the general population. Pituitary adenomas occur in the familial setting in approximately 5% of cases, whereas pheochromocytomas/paragangliomas can be hereditary in 30-40% of cases. Hereditary syndromes associated with pituitary adenomas include multiple endocrine neoplasia types 1 and 4, familial isolated pituitary adenomas, and Carney complex. Hereditary syndromes associated with pheochromocytomas/paragangliomas and genes, mutations in which predispose to their development, are more numerous. The first clinical descriptions of the co-occurrence of pituitary adenoma and pheochromocytoma/paraganglioma in one patient date back to the mid 20th century, however delineating such a co-occurrence into a particular syndrome («3PAs» (pituitary adenoma, pheochromocytoma, paraganglioma)) was suggested only in 2015. To date, approximately 100 cases of such a co-occurrence have been described in the literature. Mutations in genes encoding subunits of succinate dehydrogenase complex II (SDHx) are revealed in the majority of cases, much less common are mutations in MAX, MEN1 and some other genes. This review summarizes the current information on the «3PAs» syndrome.

Management of pheochromocytomas and paragangliomas: Review of current diagnosis and treatment options

Pheochromocytomas (PCCs) are rare neuroendocrine tumors derived from the chromaffin cells of the adrenal medulla. When these tumors have an extra-adrenal location, they are called paragangliomas (PGLs) and arise from sympathetic and parasympathetic ganglia, particularly of the para-aortic location. Up to 25% of PCCs/PGLs are associated with inherited genetic disorders. The majority of PCCs/PGLs exhibit indolent behavior. However, according to their affiliation to molecular clusters based on underlying genetic aberrations, their tumorigenesis, location, clinical symptomatology, and potential to metastasize are heterogenous. Thus, PCCs/PGLs are often associated with diagnostic difficulties. In recent years, extensive research revealed a broad genetic background and multiple signaling pathways leading to tumor development. Along with this, the diagnostic and therapeutic options were also expanded. In this review, we focus on the current knowledge and recent advancements in the diagnosis and treatment of PCCs/PGLs with respect to the underlying gene alterations while also discussing future perspectives in this field.

Succinate Dehydrogenase Mutations as Familial Pheochromocytoma Syndromes

It is recognized that a large portion of pheochromocytoma and paraganglioma cases will have an underlying germline mutation, supporting the recommendation for universal genetic testing in all patients with PPGLs. A mutation in succinate dehydrogenase subunit B is associated with increased rates of developing synchronous and/or metachronous metastatic disease. Patients identified with this mutation require meticulous preoperative evaluation, a personalized surgical plan to minimize the risk of recurrence and tumor spread, and lifelong surveillance.