Pheochromocytomas and Paragangliomas: New Developments with Regard to Classification, Genetics, and Cell of Origin

Fluorescence sensing probe based on functionalized mesoporous MOFs for non-invasive and detection of dopamine in human fluids

Abnormal amount of dopamine (DA) in human body is closely relate to various diseases, such as Parkinson's disease, pheochromocytoma. Real-time monitoring DA is crucial for disease warning, diagnosis and treatment. Currently, most methods rely on invasive blood testing for detecting DA, which is only completed with the aid of the medical staffs in hospitals. Herein, a non-invasive fluorescence visual strategy is developed for the real-time monitoring DA, based on luminescent nanoparticles and modified mesoporous zeolite imidazole framework (ZIF-8-NH2) dodecahedrons. During the reaction process, DA is enriched through the spatial configuration of ZIF-8-NH2 and hydrogen bonding effect. The luminescence of Cr3+-doped zinc gallate (ZnGa2O4:Cr3+, ZGC) is inhibited by the photo-induced electron transfer (PET) mechanism to realize sensitively detecting DA. The intelligent sensing platform based on the designed fluorescence probe and color recognition system is structured for real-time detection of DA in urine. Furthermore, a skin-fitting hydrogel patch is prepared by combining a fluorescent probe with chitosan, which enables sensitive and accurate detection of DA in sweat without the complex sample pretreatment. The non-invasive fluorescence detection method provides an effective strategy for quantitatively monitoring DA in human fluids.

Pheochromocytoma. Preoperative approach

Pheochromocytomas are rare neuroendocrine tumors that derive from the chromaffin cells of the adrenal medulla and secrete catecholamines. The measurement of plasma or fractionated urine metanephrines is the hormonal determination of choice for the biochemical diagnosis. Once the biochemical diagnosis is confirmed, the next step is the localization study. It is recommended to request a genetic study in all patients with pheochromocytomas since 40% of cases are hereditary. Once the diagnostic study is completed, preoperative treatment with alpha blockers should be instituted at least 7-14 days before adrenalectomy. However, in low-risk patients, the omission of presurgical treatment could be considered if the surgery is performed in centers with experience and a strict monitoring of the patient is carried out during the perioperative period. This document offers a practical guide on the diagnosis and perioperative approach in patients with pheochromocytomas.

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.

Paraganglioma of the Neck: A Rare Case With Spinal Metastasis

Paragangliomas are rare neuroendocrine tumors that arise from the paraganglia, which are clusters of neuroendocrine cells associated with the autonomic nervous system. These tumors are commonly found in the adrenal medulla but can also occur in other locations outside the adrenal gland. Here, we present a case report of a slow-growing paraganglioma in the left neck with spinal metastasis in a 60-year-old man. This case highlights the importance of considering paraganglion tumors in the differential diagnosis of neck masses and the need for early diagnosis and management to prevent potential complications. Importantly, both the clinical picture and anatomical location of these tumors is important when determining treatment plans.

[Personalized treatment of pheochromocytoma]

BACKGROUND

Pheochromocytoma is a rare but severe disease of the adrenal glands. The aim of this study is to present and discuss recent developments in the diagnosis and treatment of pheochromocytoma.

MATERIAL AND METHODS

A narrative review article based on the most recent literature is presented.

RESULTS AND DISCUSSION

The proportion of pheochromocytomas as tumors of adrenal origin is about 5% of incidentally discovered adrenal tumors. The classical symptomatic triad of headaches, sweating, and palpitations occurs in only about 20% of patients, while almost all patients show at least 1 of these symptoms. To diagnose pheochromocytoma, levels of free plasma metanephrines or alternatively, fractionated metanephrines in a 24‑h urine collection is required in a first step. In the second step an imaging procedure, computed tomography (CT) or magnetic resonance imaging (MRI), is performed to localize the adrenal tumor. Functional imaging is also recommended to preoperatively detect potential metastases. Genetic testing should always be offered during the course of treatment as 30-40% of pheochromocytomas are associated with genetic mutations. The dogma of preoperative alpha blockade is increasingly being questioned and has been controversially discussed in recent years. Minimally invasive removal of the adrenal tumor is the standard surgical procedure to cure patients with pheochromocytoma. The transabdominal and retroperitoneal laparoscopic approaches are considered equivalent. The choice of the minimally invasive procedure depends on the expertise and experience of the surgeon and should be tailored accordingly. Individualized and regular follow-up care is important after surgery.

PD-L1 Expression is Linked to Tumor-Infiltrating T-Cell Exhaustion and Adverse Pathological Behavior in Pheochromocytoma/Paraganglioma

Pheochromocytoma/paraganglioma (PPGL) is an endocrine-related tumor associated with excessive catecholamine release and has limited treatment options once metastasis occurs. Although recent phase 2 clinical trials of immune checkpoint inhibitors in the treatment of PPGL have preliminarily shown promising results, the fundamentals of immunotherapy for PPGL have not yet been established. In the early research, using bulk RNA sequencing of tumor samples from 7 PPGL patients, we found that PPGL tumor tissues exhibited high PD-L1 mRNA expression compared with adjacent normal adrenal medulla tissues, and this was related to T-cell exhaustion biomarkers. To further validate the association, in this study (n = 60), we first stratified all PPGL samples according to PD-L1 expression as determined by immunohistochemical staining, and then subjected 23 fresh PPGL tumor samples from the cohort to a quantitative polymerase chain reaction (n = 16), flow cytometry (n = 7), and multiplex-immunofluorescence staining. Subsequently, we evaluated the pathological manifestations of all 60 PPGL tumor samples and analyzed the correlation among PD-L1 expression, adverse pathological behavior, various clinicopathological data, and genotypes in PPGL. The results showed that PD-L1-positive expression correlated with the exhaustion of tumor-infiltrating T cells, preoperative abnormal elevation of plasma norepinephrine, high Ki67 index, and adverse pathological behavior in PPGL but not with genetic mutation or metastatic disease, possibly due to the limitation of the small number of patients with metastatic disease (n = 4) in the study cohort. In conclusion, our findings reveal that PD-L1 expression is associated with T-cell exhaustion and adverse pathological behavior in PPGL. These results are expected to provide a new theoretical basis and clinical guidance for the treatment of PPGL.

Lesion-based indicators predict long-term outcomes of pheochromocytoma and paraganglioma- SIZEPASS

Aim

We seek a simple and reliable tool to predict malignant behavior of pheochromocytoma and paraganglioma (PPGL).

Methods

This single-center prospective cohort study assessed size of primary PPGLs on preoperative cross-sectional imaging and prospectively scored specimens using the Pheochromocytoma of the Adrenal Gland Scaled Score (PASS). Multiplication of PASS points with maximum lesion diameter (in mm) yielded the SIZEPASS criterion. Local recurrence, metastasis or death from disease were surrogates defining malignancy.

Results

76 consecutive PPGL patients, whereof 58 with pheochromocytoma and 51 female, were diagnosed at a mean age of 52.0 ± 15.2 years. 11 lesions (14.5%) exhibited malignant features at a median follow-up (FU) of 49 months (range 4-172 mo). Median FU of the remaining cohort was 139 months (range 120-226 mo). SIZEPASS classified malignancy with an area under the curve (AUC) of 0.97 (95%CI 0.93-1.01; p<0.0001). Across PPGL, SIZEPASS >1000 outperformed all known predictors of malignancy, with sensitivity 91%, specificity 94%, and accuracy 93%, and an odds ratio of 72 fold (95%CI 9-571; P<0.001). It retained an accuracy >90% in cohorts defined by location (adrenal, extra-adrenal) or mutation status.

Conclusions

The SIZEPASS>1000 criterion is a lesion-based, clinically available, simple and effective tool to predict malignant behavior of PPGLs independently of age, sex, location or mutation status.

Abdominal nonfunctional paraganglioma in which succinate dehydrogenase subunit B (SDHB) immunostaining was performed: a case report

BACKGROUND

Abdominal nonfunctional paraganglioma is rare. Malignant potential of paraganglioma is assessed by Grading of Adrenal Pheochromocytoma and Paraganglioma score and genetic testing, but genetic testing is not common. We present a case of abdominal nonfunctional paraganglioma whose malignant potential was assessed by grading of adrenal pheochromocytoma and paraganglioma score and succinate dehydrogenase subunit B staining alternative to genetic testing.

CASE PRESENTATION

A 39-year-old Japanese man had a right retroperitoneal tumor without symptoms. Uptake in the tumor was shown by ¹²³I-meta-iodobenzylguanidine scintigraphy. There were no metastases. The results of biochemical workups including blood hormones and urinary metanephrines were normal. We performed retroperitoneoscopic surgery. The tumor was positive for chromogranin A staining but negative for tyrosine hydroxylase. On the basis of the preoperative biochemical workups and pathology results, we diagnosed the tumor as nonfunctional paraganglioma. The Grading of Adrenal Pheochromocytoma and Paraganglioma score classified the tumor as moderately differentiated. Furthermore, negative succinate dehydrogenase subunit B staining suggested the patient has the SDHx (SDHA, SDHB, SDHC and SDHD) mutation.

CONCLUSION

Abdominal nonfunctional PGLs are associated with SDHB mutation, and SDHB staining should be performed as a screening.

A young patient with heart failure was diagnosed with extra-adrenal paraganglioma: a case report

BACKGROUND

We present a case of pelvic paraganglioma that presented with heart failure as the primary symptom.

CASE PRESENTATION

A 35-year-old man was admitted to hospital due to heart failure. Contrast-enhanced pelvic CT showed mass shadows in the posterior wall of the bladder and multiple enlarged lymph nodes in the retroperitoneal area. Ultrasound-guided puncture was performed, and the pathologic diagnosis was extra-adrenal paraganglioma. The patient refused any chemotherapy and died within six months of diagnosis.

CONCLUSION

The possibility of neuroendocrine-related tumors, for example paragangliomas, should be considered in young patients with heart failure, especially those with concomitant hypertension and diabetes.

[Pheochromocytoma and paraganglioma during childhood and adolescence]

BACKGROUND

Pheochromocytoma and paraganglioma belong to the group of rare catecholamine-producing tumours during childhood and adolescence. They occur most frequently in patients with tumour predisposition syndromes. Imaging is essential to assess tumour stage and to plan therapy initiation.

OBJECTIVE

The aim of this review is a summary of the most important characteristics of the aforementioned tumour entities with a special focus on imaging. In particular, magnetic resonance imaging (MRI) as well as nuclear medicine techniques are presented.

MATERIALS AND METHODS

Diagnostic methods in patients with pheochromocytoma and paraganglioma are presented based on the literature and own case reports.

RESULTS

The radiologic modality of choice for the staging of catecholamine-producing tumours during childhood and adolescence is MRI, due to the lack of ionizing radiation and high soft tissue contrast. In addition, 123-I-meta-iodo-benzyl-guanidine (MIBG) scintigraphy and positron emission tomography/computer tomography (PET/CT) are performed. Whole-body MRI is particularly important as a screening tool in patients with a tumour predisposition syndrome.

CONCLUSIONS

Radiologic imaging and nuclear medicine techniques are important for the assessment of disease stage and therapy planning in patients with catecholamine-producing tumours. Detection of metastatic disease is essential, as there are no known histopathologic markers, which can predict the metastatic potential of the tumours.

Fluorescence/Colorimetry/Smartphone Triple-Mode Sensing of Dopamine by a COF-Based Peroxidase-Mimic Platform

Simple and accurate monitoring of urinary dopamine (DA) concentration is significant, which is helpful for the assessment or exclusion of catecholamine-producing tumors, such as pheochromocytoma and paraganglioma. Herein, a fluorescence/colorimetry/smartphone triple-mode sensing platform for DA determination was constructed using copper ion (Cu²⁺)-modified hydrazone-linked covalent organic frameworks (Cu-BTA-COF). Cu-BTA-COF with 21.67 wt % copper content exhibited peroxidase-mimic activity. After adding H₂O₂ and 1,3-dihydroxynaphthalene, the Cu-BTA-COF platform can sensitively and selectively detect DA in three modes with consistent results. In fluorescence/colorimetry/smartphone modes, the linear ranges of DA were 1-10, 0.2-40, and 1-10 μM, with related detection limits of 7.2, 8.6, and 23 nM, respectively. Moreover, the Cu-BTA-COF platform can be explored for DA determination in human urine samples with satisfactory recoveries (97.6-100.4%) in all the three modes, suggesting the potential practical application of the Cu-BTA-COF platform for DA detection in urine.

Computerized tomography texture analysis of pheochromocytoma: relationship with hormonal and histopathological data

OBJECTIVES

Pheochromocytomas are rare tumors which can present with heterogeneous secretion profiles, clinical manifestations, and radiologic appearance. Under a histopathological point of view, they can be characterized as more or less aggressive with the Pheochromocytoma of the Adrenal gland Scaled Score (PASS) and the Grading system for Adrenal Pheochromocytoma and Paraganglioma (GAPP) score. The aim of this study is to analyze the texture analysis characteristics of pheochromocytoma and identify whether the texture analysis can yield information aiding in the diagnosis and the characterization of those tumors.

METHODS

Radiological, biochemical, and histopathological data regarding 30 consecutive patients with histologically confirmed pheochromocytoma were analyzed. Images obtained in the unenhanced, late arterial, venous, and delayed phases were used for the texture analysis.

RESULTS

Urinary epinephrine and metanephrine levels showed a significant correlation (R² = 0.946; R² = 699) in the multivariate linear model with texture features, as well as Ki-67 (R² = 0.397), PASS score (R² = 0.182), GAPP score (R² = 0.705), and cellularity showed a significant correlation (R² = 0.389). The cluster analysis based on radiomic features resulted in 2 clusters, with significative differences in terms of systolic and diastolic blood pressure values at the time of diagnosis (p = 0.025), GAPP score (4 vs 6, p = 0.05), histological pattern (1-2, p = 0.039), and comedonecrosis (0% vs 50%, p = 0.013).

CONCLUSION

In conclusion, our study provides the proof of concept for the use of texture analysis on contrast-enhanced CT images as a noninvasive, quantitative tool for helping in the characterization of the clinical, biochemical, and histopathological features of pheochromocytoma.

Extensive patient-to-patient single nucleus transcriptome heterogeneity in pheochromocytomas and paragangliomas

Pheochromocytoma, neuroendocrine tumor, single cell RNA-sequencing, transcriptome, heterogeneity, SDHB, RET, paraganglinoma; Pheochromocytomas (PC) and paragangliomas (PG) are rare neuroendocrine tumors with varied genetic makeup and are associated with high cardiovascular morbidity and a variable risk of malignancy. The source of the transcriptional heterogeneity of the disease and the underlying biological processes that determine the outcome of PCPG remain largely unclear. We focused on PCPG tumors with germline SDHB and RET mutations, which represent distinct prognostic groups with worse or better prognoses, respectively. We applied single-nuclei RNA sequencing (snRNA-seq) to tissue samples from 11 patients and found high patient-to-patient transcriptome heterogeneity in neuroendocrine tumor cells. The tumor microenvironment also showed heterogeneous profiles, mainly contributed by macrophages of the immune cell clusters and Schwann cells of the stroma. By performing non-negative matrix factorization, we identified common transcriptional programs active in RET and SDHB, as well as distinct modules, including neuronal development, hormone synthesis and secretion, and DNA replication. Similarities between the transcriptomes of the tumor cells and those of the chromaffin- and precursor cell types suggests different developmental stages at which PC and PG tumors appear to be arrested.

Genetic spectrum in a Canadian cohort of apparently sporadic pheochromocytomas and paragangliomas: New data on multigene panel retesting over time

OBJECTIVE

Pheochromocytomas (PHEOs) and paragangliomas (PGLs), collectively known as PPGLs, are tumours with high heritability. The prevalence of germline mutations in apparently sporadic PPGLs varies depending on the study population. The objective of this study was to determine the spectrum of germline mutations in a cohort of patients with apparently sporadic PPGLs over time.

DESIGN

We performed a retrospective review of patients with apparently sporadic PPGLs who underwent genetic testing at our referral centre from 2005 to 2020.

PATIENTS

We included patients with apparently sporadic PPGLs who underwent genetic testing at our referral center.

MEASUREMENTS

Genetic analysis included sequential gene sequencing by Sanger method or next generation sequencing (NGS) with a multigene panel.

RESULTS

The prevalence of germline mutations was 26.2% (43/164); 40.0% (30/75) in PGLs and 14.6% (13/89) in PHEOs. We identified four novel pathogenic variants (two SDHB and two SDHD). Patients carrying germline mutations were younger (38.7 vs. 49.7 years old) than patients with no identified germline mutations. From 2015 to 2020, we performed NGS with a multigene panel on 12 patients for whom the initial genetic analysis was negative. Germline mutations in previously untested genes were found in four (33.3%) of these patients (two MAX and two SDHA), representing 9.3% (4/43) of the mutation carriers.

CONCLUSION

The prevalence of germline mutations in our cohort of patients with apparently sporadic PPGLs was 26.2%. Genetic re-evaluation over time using multigene sequencing by NGS assay in a subgroup of patients leads to an increase in the detection of mutations.

Case Report: Giant Paraganglioma of the Skull Base With Two Somatic Mutations in SDHB and PTEN Genes

Head and neck paragangliomas (HNPGLs) are neuroendocrine tumors. They arise from the parasympathetic ganglia and can be either sporadic or due to hereditary syndromes (up to 40%). Most HNPGLs do not produce significant amounts of catecholamines. We report a case of a giant paraganglioma of the skull base with an unusually severe presentation secondary to excessive release of norepinephrine, with a good outcome considering the severity of disease. A 39-year-old Caucasian woman with no prior medical history was found unconscious and emaciated in her home. In the intensive care unit (ICU) the patient was treated for multi-organ failure with multiple complications and difficulties in stabilizing her blood pressure with values up to 246/146 mmHg. She was hospitalized in the ICU for 72 days and on the 31^st day clinical assessment revealed jugular foramen syndrome and paralysis of the right n. facialis. A brain MRI confirmed a right-sided tumor of the skull base of 93.553 cm³. Blood tests showed high amounts of normetanephrine (35.1-45.4 nmol/L, ref <1.09 nmol/L) and a tumor biopsy confirmed the diagnosis of a paraganglioma. Phenoxybenzamine and Labetalol were used in high doses ((Dibenyline^®, 90 mg x 3 daily) and labetalol (Trandate^®, 200 + 300 + 300 mg daily) to stabilize blood pressure. The patient underwent two tumor embolization procedures before total tumor resection on day 243. Normetanephrine and blood pressure normalized after surgery (0.77 nmol/L, ref: < 1.09 nmol/L). The damage to the cranial nerve was permanent. Our patient was comprehensively examined for germline predisposition to PPGLs, however we did not identify any causal aberrations. A somatic deletion and loss of heterozygosity (LOH) of the short arm (p) of chromosome 1 (including SDHB) and p of chromosome 11 was found. Analysis showed an SDHB (c.565T>G, p.C189G) and PTEN (c.834C>G, p.F278L) missense mutation in tumor DNA. The patient made a remarkable recovery except for neurological deficits after intensive multidisciplinary treatment and rehabilitation. This case demonstrates the necessity for an early tertiary center approach with a multidisciplinary expert team and highlights the efficacy of the correct treatment with alpha-blockade.

Protocol for presurgical and anesthetic management of pheochromocytomas and sympathetic paragangliomas: a multidisciplinary approach

OBJECTIVE

To offer a practical guide for the presurgical and anesthetic management of pheochromocytomas and sympathetic paragangliomas (PGLs).

METHODS

This protocol was based on a comprehensive review of the literature and on our own multidisciplinary team's experience from managing pheochromocytoma and sympathetic PGLs at a referral center.

RESULTS

Patients with pheochromocytomas and sympathetic paragangliomas (PGLs) may develop potentially life-threatening complications, especially during surgical procedures. A complete biochemical, radiological, genetic, and cardiological assessment is recommended in the preoperative stage as it provides an evaluation of the risk of surgical complications and malignancy, allowing individualization of the presurgical treatment. Treatment with α-blockade and proper volume expansion in the preoperative stage significantly reduces the perioperative morbidity. During surgery, the anesthesiologist should look for a deep anesthetic level that inhibits the cardiovascular effects of catecholamines to minimize the risk of intraoperative complications.

CONCLUSIONS

An optimal presurgical evaluation of pheochromocytomas/ sympathetic PGL requires a multidisciplinary approach, including a complete hormonal, radiological, cardiac, genetic, and functioning evaluation in most cases. A proper preoperative evaluation in combination with strict blood pressure and heart rate control, and blood volume status optimization, will significantly reduce the risk of intraoperative and perioperative complications. In those patients who unfortunately develop intraoperative complications, the role of the anesthesiologist is essential since the selection of the appropriate management has a direct impact on morbimortality reduction.

Insights into Mechanisms of Pheochromocytomas and Paragangliomas Driven by Known or New Genetic Drivers

Simple Summary

Pheochromocytomas and paragangliomas are rare neuroendocrine tumors that are often hereditary. Although research has advanced considerably, significant gaps still persist in understanding risk factors, predicting metastatic potential and treating aggressive tumors. The study of rare mutations can provide new insights into how pheochromocytomas and paragangliomas develop. In this review, we provide examples of such rare events and how they can inform our understanding of the spectrum of mutations that can lead to these tumors and improve our ability to provide a genetic diagnosis.

Abstract

Pheochromocytomas and paragangliomas are rare tumors of neural crest origin. Their remarkable genetic diversity and high heritability have enabled discoveries of bona fide cancer driver genes with an impact on diagnosis and clinical management and have consistently shed light on new paradigms in cancer. In this review, we explore unique mechanisms of pheochromocytoma and paraganglioma initiation and management by drawing from recent examples involving rare mutations of hypoxia-related genes VHL, EPAS1 and SDHB, and of a poorly known susceptibility gene, TMEM127. These models expand our ability to predict variant pathogenicity, inform new functional domains, recognize environmental-gene connections, and highlight persistent therapeutic challenges for tumors with aggressive behavior.

Prevalence of Germline Variants in a Large Cohort of Japanese Patients with Pheochromocytoma and/or Paraganglioma

Simple Summary

Pheochromocytoma/paraganglioma (PPGL) has been recognised as one of the most frequent inherited tumours with genetic heterogeneity based on studies in Caucasian populations. Early identification of germline variants is crucial for accurate treatment and follow-up in affected patients and relatives. However, there are only a few large cohort studies in Asia and none from the Japanese population. In this first comprehensive study of Japanese patients with PPGL, we found one in four PPGLs with apparently sporadic presentation harboured germline variant in any of the seven susceptibility genes (MAX, SDHB, SDHC, SDHD, TMEM127, VHL, and RET). SDHB was the most frequently mutated gene and was strongly associated with metastatic PPGLs. Our findings emphasise the importance of genetic testing in determining appropriate treatment and follow-up strategies for patients and relatives.

Abstract

The high incidence of germline variants in pheochromocytoma and paraganglioma (PPGL) has been reported mainly in Europe, but not among Japanese populations in Asia. We aimed to study the prevalence of germline variants in Japanese PPGL patients and the genotype–phenotype correlation. We examined 370 PPGL probands, including 43 patients with family history and/or syndromic presentation and 327 patients with apparently sporadic (AS) presentation. Clinical data and blood samples were collected, and the seven major susceptibility genes (MAX, SDHB, SDHC, SDHD, TMEM127, VHL, and RET) were tested using Sanger sequencing. Overall, 120/370 (32.4%) patients had pathogenic or likely pathogenic variants, with 81/327 (24.8%) in AS presentation. SDHB was the most frequently mutated gene (57, 15.4%), followed by SDHD (27, 7.3%), and VHL (18, 4.9%). The incidence of metastatic PPGL was high in SDHB carriers (21/57, 36.8%). A few unique recurrent variants (SDHB c.137G>A and SDHB c.470delT) were detected in this Japanese cohort, highlighting ethnic differences. In summary, almost a quarter of patients with apparently sporadic PPGL in Japan harboured germline variants of the targeted genes. This study reinforces the recommendation in Western guidelines to perform genetic testing for PPGL and genotype-based clinical decision-making in the Japanese population.

Silent Hypertensive Crisis in an Adolescent: First Case Report of Pediatric Pheochromocytoma from Indonesia

Secondary hypertension in children, to the rare extent, can be caused by endocrine factors such as pheochromocytoma, an adrenal tumor that secretes catecholamine. Only a few cases have been reported in the past 3 decades. To the best of our knowledge, this is the first case report of pediatric pheochromocytoma from Indonesia. We reviewed a case of a 16-year-old Indonesian boy with history of silent hypertensive crisis who was referred from a remote area in an island to the pediatric nephrology clinic at Cipto Mangunkusumo Hospital, Jakarta, Indonesia. Despite medications, his symptoms persisted for 14 months. At the pediatric nephrology clinic, pheochromocytoma was suspected due to symptoms of catecholamine secretion presented, which was palpitation, diaphoresis, and weight loss. However, as the urine catecholamine test was unavailable in Indonesia, the urine sample was sent to a laboratory outside the country. The elevated level of urine metanephrine, focal pathological uptake in the right adrenal mass seen on 131I-MIBG, and histopathology examination confirmed the suspicion of pheochromocytoma. Following the tumor resection, he has been living with normal blood pressure without antihypertensive medications. This case highlights that pheochromocytoma should always be included in the differential diagnoses of any atypical presentation of hypertension. In limited resources setting, high clinical awareness of pheochromocytoma is required to facilitate prompt referral. Suspicion of pheochromocytoma should be followed by measurement of urine metanephrine levels. Early diagnosis of pheochromocytoma would fasten the optimal cure, alleviate the symptoms of catecholamine release, and reverse hypertension.

NIX protein enhances antioxidant capacity of and reduces the apoptosis induced by HSP90 inhibitor luminespib/NVP-AUY922 in PC12 cells

Pheochromocytomas and paragangliomas (PCPGs) are catecholamine-producing neuroendocrine tumors. Accumulating evidences indicate that the blockade of antioxidative pathways might be a novel therapeutic approach to the treatment of PCPG. NIX has been confirmed to play a key role in maintaining redox homeostasis in tumors, while the function of NIX in PCPG remains unclear. In this study, the analyses of the disease-free survival (DFS) showed that high NIX protein level is related to poor prognosis in patients of PCPG. Consistent with this, high level of NIX protein upregulates the level of p-NF-κB and promotes the migration of PC12 cells. In NIX-over-expressing PC12 cells, the level of reactive oxygen species (ROS) is decreased while trolox-equivalent antioxidant capacity (TEAC) increased. But in NIX-silencing cells, ROS level is increased, while TEAC reversely reduced, consequently antioxidase and phase II enzymes of NRF2 signaling were activated, and elevated endoplasmic reticulum (ER) stress was observed. Additionally, the apoptosis induced by luminespib/NVP-AUY922, an inhibitor of heat shock protein 90 (HSP90, a cellular stress response factor), was enhanced in NIX-silencing cells but reduced in the NIX-over-expressing cells. All of these results indicated that high NIX protein level enhances antioxidant capacity of PC12 cells and reduces the apoptosis caused by cell stress, such as induced by luminespib/NVP-AUY922. Therefore, luminespib/NVP-AUY922 might be effective only for PCPG with low NIX level, while targeting NIX could be a further supplement to the therapeutic treatment strategy for PCPG patients with high NIX protein level.

High-specific-activity 131iodine-metaiodobenzylguanidine for therapy of unresectable pheochromocytoma and paraganglioma

Pheochromocytomas and paragangliomas (PPG) are rare cancers arising from the adrenal medulla (pheochromocytoma) or autonomic ganglia (paraganglioma). They have highly variable biological behavior. Most PPG express high-affinity norepinephrine transporters, allowing active uptake of the norepinephrine analog, ¹³¹iodine-metaiodobenzylguanidine (¹³¹I-MIBG). Low-specific-activity forms of ¹³¹I-MIBG have been used since 1983 for therapy of PPG. High-specific-activity ¹³¹I-MIBG therapy improves hypertension management, induces partial radiological response or stable disease, decreases biochemical markers of disease activity and is well tolerated by patients. This drug, approved in the USA in July 2018, is the first approved agent for patients with unresectable, locally advanced or metastatic PPG and imaging evidence of metaiodobenzylguanidine uptake, who require systemic anticancer therapy.

Whole Exome Sequencing Identifies Novel Genetic Alterations in Patients with Pheochromocytoma/Paraganglioma

BACKGROUND

Pheochromocytoma and paragangliomas (PPGL) are known as tumors with the highest level of heritability, approximately 30% of all cases. Clinical practice guidelines of PPGL recommend genetic testing for germline variants in all patients. In this study, we used whole exome sequencing to identify novel causative variants associated with PPGL to improve the detection of rare genetic variants in our cohort.

METHODS

Thirty-six tested negative for pathogenic variants in previous Sanger sequencing or targeted gene panel testing for PPGL underwent whole exome sequencing. Whole exome sequencing was performed using DNA samples enriched using TruSeq Custom Enrichment Kit and sequenced with MiSeq (Illumina Inc.). Sequencing alignment and variant calling were performed using SAMtools.

RESULTS

Among previously mutation undetected 36 patients, two likely pathogenic variants and 13 variants of uncertain significance (VUS) were detected in 32 pheochromocytoma-related genes. SDHA c.778G>A (p.Gly260Arg) was detected in a patient with head and neck paraganglioma, and KIF1B c.2787-2A>C in a patient with a bladder paraganglioma. Additionally, a likely pathogenic variant in BRCA2, VUS in TP53, and VUS in NFU1 were detected.

CONCLUSION

Exome sequencing further identified genetic alterations by 5.6% in previously mutation undetected patients in PPGL. Implementation of targeted gene sequencing consisted of extended genes of PPGL in routine clinical screening can support the level of comprehensive patient assessment.

Head and Neck Paragangliomas-A Genetic Overview

Pheochromocytomas (PCC) and paragangliomas (PGL) are rare neuroendocrine tumors. Head and neck paragangliomas (HNPGL) can be categorized into carotid body tumors, which are the most common, as well as jugular, tympanic, and vagal paraganglioma. A review of the current literature was conducted to consolidate knowledge concerning PGL mutations, familial occurrence, and the practical application of this information. Available scientific databases were searched using the keywords head and neck paraganglioma and genetics, and 274 articles in PubMed and 1183 in ScienceDirect were found. From these articles, those concerning genetic changes in HNPGLs were selected. The aim of this review is to describe the known genetic changes and their practical applications. We found that the etiology of the tumors in question is based on genetic changes in the form of either germinal or somatic mutations. 40% of PCC and PGL have a predisposing germline mutation (including VHL, SDHB, SDHD, RET, NF1, THEM127, MAX, SDHC, SDHA, SDHAF2, HIF2A, HRAS, KIF1B, PHD2, and FH). Approximately 25–30% of cases are due to somatic mutations, such as RET, VHL, NF1, MAX, and HIF2A. The tumors were divided into three main clusters by the Cancer Genome Atlas (TCGA); namely, the pseudohypoxia group, the Wnt signaling group, and the kinase signaling group. The review also discusses genetic syndromes, epigenetic changes, and new testing technologies such as next-generation sequencing (NGS).

Approach to the Patient: Perioperative Management of the Patient with Pheochromocytoma or Sympathetic Paraganglioma

Pheochromocytomas and sympathetic paraganglioma (PPGL) are rare chromaffin cell tumors originating in the adrenal medulla and sympathetic paraganglia, respectively, which share the capacity to synthesize and release catecholamines. The incidence of PPGL has increased in recent years. Surgical resection is the only curative treatment for PPGL. Management of patients with PPGL is complex and should be done by a specialized multidisciplinary team in centers with broad expertise. Surgical resection of a PPGL is a high-risk procedure for which optimal pretreatment with antihypertensive drugs is required in combination with state-of-the-art surgical procedures and anesthesiological techniques. In this article we discuss the underlying evidence and the pros and cons of presurgical medical preparation. Finally, the areas of uncertainty and controversies in this field are addressed.

Recurrent Primary Intrasellar Paraganglioma

We describe a case of an 81-year-old male presenting with bitemporal visual field defects and blurry vision in the right eye. The patient was found to have a recurrent primary paraganglioma in the sellar and suprasellar region requiring a repeat transsphenoidal endoscopic resection. Immunohistochemical examination confirmed paraganglioma with the classic zellballen appearance which stained positive for chromogranin, synaptophysin, and S-100 in the periphery. Paragangliomas (PGLs) in the sella turcica are a rare entity; only 19 cases have ever been reported in the literature. PGLs in the sellar region are often misdiagnosed or diagnosed in a delayed fashion. Earlier diagnosis of this locally aggressive tumor and meticulous debulking can prevent morbidity secondary to the tumor's compressive effects. This report highlights the effectiveness of surgical interventions in treatment of paragangliomas. More research is still needed to determine the need for adjuvant therapies such as radiation.

Clinical Presentation and Treatment Outcomes of Children and Adolescents With Pheochromocytoma and Paraganglioma in a Single Center in Korea

PURPOSE

Pheochromocytoma (PCC) and paraganglioma (PGL) (PPGL) are rare neuroendocrine tumors, and data on managing these conditions in children and adolescents are lacking. The objective of this study was to demonstrate the clinical presentation and treatment outcomes in children and adolescents with PPGL in a single tertiary care center in Korea.

METHODS

This retrospective study included 23 patients diagnosed with PCC (n = 14) and PGL (n = 9) before the age of 21 at Samsung Medical Center (from June 1994 to June 2019). We describe age, gender, family history, clinical characteristics, laboratory findings, pathologic findings, therapeutic approaches, and treatment outcomes.

RESULTS

Of the 23 patients, 14 had PCC and nine had PGL. The median age at diagnosis was 16.8 years (range, 6.8-20.8 years). The common presenting symptoms were hypertension (n = 10), headache (n = 9), palpitation (n = 4), and sweating (n = 4). The plasma or 24-hour urine catecholamine and/or metabolite concentrations were markedly elevated in 22 patients with PPGL, but were normal in one patient with carotid body PGL. All tumors were visualized on computed tomography. Genetic tests were performed in 15 patients, and seven patients showed mutations in RET (n = 3), SDHB (n = 3), and VHL (n = 1). All patients underwent surgery, and complete excision was performed successfully. Three patients with metastasis underwent postoperative adjuvant therapy.

CONCLUSION

This study suggests that pediatric PPGL tends to be extra-adrenal and bilateral and shows a higher potential for genetic mutations. Considering the hereditary predisposition of pediatric PPGL, genetic screening tests are strongly recommended, and lifelong follow-up is needed to detect recurrence and metastasis. Further research with a larger sample size and routine genetic screening is needed to better understand the genetic conditions and long-term prognosis of PPGL.

A Novel MAX Gene Mutation Variant in a Patient With Multiple and "Composite" Neuroendocrine-Neuroblastic Tumors

Introduction: Pheochromocytomas (PCCs), paragangliomas (PGLs), ganglioneuroblastomas (GNBs), and ganglioneuromas (GNs) are neuroendocrine neoplasms (NENs) that were thought to share a common embryologic origin from neural crest cells. However, they rarely occur concurrently and recurrently. We describe the case of a 40-years-old woman with "composite PCC-GN" and multiple NENs and neuroblastic tumors. Case presentation: The patient was first referred to our department at the age of 15 years for paroxysmal hypertension, headache, sweating, and watery diarrhea. Her personal history included the diagnosis of a pelvic GNB with lumbar-aortic lymph node metastases at 11 months. Her family history was positive for cerebral glioblastoma multiforme (father). An abdominal ultrasound showed a right adrenal mass that histologically was a "composite adrenal PCC-GN." The symptoms disappeared after surgery. At the age of 20 years, the symptoms returned: computed tomography (CT) and 131I-metaiodobenzylguanidine (MIBG) scintigraphy showed an inter-aortocaval mass, found histologically to be an inter-aortocaval PGL. Her symptoms reappeared again at 28 years: CT and magnetic resonance imaging revealed four left adrenal gland nodules, found histologically to be multifocal PCCs with some atypia. Genetic screening for VHL, RET, NF1, Tp53, SDHD, SDHB, SDHC, SDHAF2, SDHAF3, SDHA, and TMEM127 was negative. Mutational analysis of the MAX gene revealed the presence of a novel heterozygous variant, c299G>C (p.Arg100Pro, NM_002382.5) that the bioinformatics prediction programs defined as noxious and causative of pathology. Conclusion: This report represents the first description of a co-occurrence of multiple composite PCC-GN and neuroblastic tumors. The long timeline of the presentation of the NENs/neuroblastic tumors from infancy to adulthood requires a lifelong follow-up for this patient. Moreover, the importance of this case lies in the presence of a novel MAX gene variant deleterious, harmful, and causative of pathology, confirmed by Sanger sequencing and never been associated before with multiple composite PCC-GN. The present case underlines the importance of precision medicine and molecular diagnoses for hereditary pheochromocytomas and paragangliomas, suggesting that when they occur in early childhood, it is necessary to perform an extensive genetic investigation and a lifelong follow-up.