Testing for germline mutations in sporadic pheochromocytoma/paraganglioma: a systematic review

Head and Neck Paragangliomas: Overview of Institutional Experience

Head and neck paragangliomas (HNPGLs) are rare and have high rates of genetic mutations. We conducted a retrospective review of 187 patients with 296 PGLs diagnosed between 1974 and 2023. The mean age of diagnosis was 48.8 years (range 10 to 82) with 69.0% female and 26.5% patients with multiple PGLs. Among 119 patients undergoing genetic testing, 70 (58.8%) patients had mutations, with SDHB (30) and SDHD (26) being the most common. The rates of metastasis and recurrence were higher among patients with SDHB mutations or SDHD mutations associated with multiple PGLs. Metabolic evaluation showed elevated plasma dopamine levels were the most common derangements in HNPGL. MRI and CT were the most common anatomic imaging modalities and DOTATATE was the most common functional scan used in this cohort. Most patients (81.5%) received surgery as the primary definitive treatment, while 22.5% patients received radiation treatment, mostly as an adjuvant therapy or for surgically challenging or inoperable cases. Systemic treatment was rarely used in our cohort. Our single-center experience highlights the need for referral for genetic testing and metabolic evaluation and for a team-based approach to improve the clinical outcomes of patients with HNPGLs.

[Metastatic risk factors in pheochromocytoma/paraganglioma]

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

Bilateral Pheochromocytoma with Germline MAX Variant without Family History

Recently, the genetic background of pheochromocytomas/paragangliomas (PPGLs) has been rapidly revealed. These tumors have been referred to as the “ten percent tumor”; however, the frequency of genetic variants of PPGLs has turned out to be more common than expected. PPGLs are potentially hereditary tumors and appear clinically sporadic. Here, we report a case of bilateral pheochromocytoma (PCC) with a variant in the MYC-associated factor X (MAX) gene (c.295 + 1G > A). A male patient was diagnosed with adrenal pheochromocytoma (PCC) and underwent a left adrenalectomy at the age of 40. A new tumor in the right adrenal gland was detected at the age of 43. Urinary metanephrine and normetanephrine concentrations gradually increased. The size of the right adrenal PCC continued to increase one year after detection. Genetic testing of the peripheral blood revealed the presence of a pathogenic variant in MAX. The natural history of adrenal PCCs with the MAX variant has not yet been clarified, because the number of reported cases is not sufficient. Thus, clinicians should consider a MAX variant when they find bilateral or multiple PCCs.

Universal Germline Panel Testing for Individuals With Pheochromocytoma and Paraganglioma Produces High Diagnostic Yield

BACKGROUND

Practice guidelines to identify individuals with hereditary pheochromocytomas and paragangliomas (PPGLs) advocate for sequential gene testing strategy guided by specific clinical features and predate the routine use of multigene panel testing (MGPT).

OBJECTIVE

To describe results of MGPT for hereditary PPGL in a clinically and ancestrally diverse cohort.

SETTING

Commercial laboratory based in the United States.

METHODS

Clinical data and test results were retrospectively reviewed in 1727 individuals who had targeted MGPT from August 2013 through December 2019 because of a suspicion of hereditary PPGL.

RESULTS

Overall, 27.5% of individuals had a pathogenic or likely pathogenic variant (PV), 9.0% had a variant of uncertain significance, and 63.1% had a negative result. Most PVs were identified in SDHB (40.4%), followed by SDHD (21.1%), SDHA (10.1%), VHL (7.8%), SDHC (6.7%), RET (3.7%), and MAX (3.6%). PVs in FH, MEN1, NF1, SDHAF2, and TMEM127 collectively accounted for 6.5% of PVs. Clinical predictors of a PV included extra-adrenal location, early age of onset, multiple tumors, and positive family history of PPGL. Individuals with extra-adrenal PGL and a positive family history were the most likely to have a PV (85.9%). Restricting genetic testing to SDHB/C/D misses one-third (32.8%) of individuals with PVs.

CONCLUSION

Our data demonstrate a high diagnostic yield in individuals with and without established risk factors, a low inconclusive result rate, and a substantial contribution to diagnostic yield from rare genes. These findings support universal testing of all individuals with PPGL and the use of concurrent MGPT as the ideal platform.

Skull Base Tumors: Neuropathology and Clinical Implications

Tumors that arise in and around the skull base comprise a wide range of common and rare entities. Recent studies have advanced our understanding of their pathogenesis, which in some cases, have significantly influenced clinical practice. The genotype of meningiomas is strongly associated with their phenotype, including histologic subtype and tumor location, and clinical outcome. A single molecular alteration, NAB2-STAT6 fusion, has redefined the category of solitary fibrous tumors to include the previous entity hemangiopericytomas. Schwannomas, both sporadic and familial, are characterized by near ubiquitous alterations in NF2 , with additional mutations in SMARCB1 or LZTR1 in schwannomatosis. In pituitary adenohypophyseal tumors, cell lineage transcription factors such as SF-1, T-PIT, and PIT-1 are now essential for classification, providing a more rigorous taxonomy for tumors that were previously considered null cell adenomas. The pituicyte lineage transcription factor TTF-1 defines neurohypophyseal tumors, which may represent a single nosological entity with a spectrum of morphologic manifestations (ie, granular cell tumor, pituicytoma, and spindle cell oncocytoma). Likewise, the notochord cell lineage transcription factor brachyury defines chordoma, discriminating them from chondrosarcomas. The identification of nonoverlapping genetic drivers of adamantinomatous craniopharyngiomas and papillary craniopharyngiomas indicates that these are distinct tumor entities and has led to successful targeted treatment of papillary craniopharyngiomas using BRAF and/or mitogen-activated protein kinase inhibitors. Similarly, dramatic therapeutic responses have been achieved in patients with Langerhans cell histiocytosis, both with BRAF -mutant and BRAF -wildtype tumors. Familiarity with the pathology of skull base tumors, their natural history, and molecular features is essential for optimizing patient care.

Normal and Neoplastic Growth Suppression by the Extended Myc Network

Among the first discovered and most prominent cellular oncogenes is MYC, which encodes a bHLH-ZIP transcription factor (Myc) that both activates and suppresses numerous genes involved in proliferation, energy production, metabolism and translation. Myc belongs to a small group of bHLH-ZIP transcriptional regulators (the Myc Network) that includes its obligate heterodimerization partner Max and six "Mxd proteins" (Mxd1-4, Mnt and Mga), each of which heterodimerizes with Max and largely opposes Myc's functions. More recently, a second group of bHLH-ZIP proteins (the Mlx Network) has emerged that bears many parallels with the Myc Network. It is comprised of the Myc-like factors ChREBP and MondoA, which, in association with the Max-like member Mlx, regulate smaller and more functionally restricted repertoires of target genes, some of which are shared with Myc. Opposing ChREBP and MondoA are heterodimers comprised of Mlx and Mxd1, Mxd4 and Mnt, which also structurally and operationally link the two Networks. We discuss here the functions of these "Extended Myc Network" members, with particular emphasis on their roles in suppressing normal and neoplastic growth. These roles are complex due to the temporal- and tissue-restricted expression of Extended Myc Network proteins in normal cells, their regulation of both common and unique target genes and, in some cases, their functional redundancy.

Pheochromocytoma and paraganglioma: germline genetics and hereditary syndromes

Pheochromocytomas (PCCs) and paragangliomas (PGLs) are neuroendocrine tumors arising from the adrenal medulla and extra-adrenal ganglia, respectively. Approximately 15-25% of PCC/PGL can become metastatic. Up to 30-40% of patients with PCC/PGL have a germline pathogenic variant in a known susceptibility gene for PCC/PGL; therefore, all patients with PCC/PGL should undergo clinical genetic testing. Most of the susceptibility genes are associated with variable penetrance for PCC/PGL and are associated with different syndromes, which include susceptibility for other tumors and conditions. The objective of this review is to provide an overview of the germline susceptibility genes for PCC/PGL, the associated clinical syndromes, and recommended surveillance.

Cost-minimization analysis of sequential genetic testing versus targeted next-generation sequencing gene panels in patients with pheochromocytoma and paraganglioma

INTRODUCTION

Pheochromocytomas and paragangliomas (PPGLs) are highly heritable tumours, with up to 40% of cases carrying germline variants. Current guidelines recommend genetic testing for all patients with PPGLs. Next-generation sequencing (NGS) enables accurate, fast, and inexpensive genetic testing. This study aimed to compare the costs related to PPGL genetic testing between the sequential testing using the decisional algorithm proposed in the 2014 Endocrine Society guidelines and targeted NGS gene panels.

METHODS

Patients with proven PPGLs were enrolled. A gene list covering 17 susceptibility genes related to hereditary PPGLs was developed for targeted sequencing. Validation was carried out by Sanger sequencing. We simulated the diagnostic workflow to examine the anticipated costs based on each strategy for genetic testing.

RESULTS

Twenty-nine patients were included, among whom a germline variant was identified in 34.5%. A total of 22.7% with apparently sporadic PPGL carried a variant. Five genes were involved (RET, n = 3; SDHB, n = 3; SDHD, n = 2; EGLN1, n = 1; and NF1, n = 1). According to the diagnostic workflow, the average cost of the targeted NGS (534.7 US dollars per patient) is lower than that of the sequential testing (734.5 US dollars per patient). The targeted NGS can also reduce the number of hospital visits from 4.1 to 1 per person. The cost can be further reduced to 496.24 US dollars per person (32% reduction) if we apply a new syndromic-driven diagnostic algorithm to establish priorities for specific genetic testing for syndromic and selected cases, and targeted NGS for non-syndromic patients.

CONCLUSIONS

Targeted NGS can reduce both the cost of PPGL genetic testing and the number of hospital visits, compared with the conventional approach. Our proposed algorithm is the preferred approach due to its significant reduction of the cost of genetic testing.Key messagePheochromocytomas and paragangliomas are highly heritable neoplasms.The targeted next-generation sequencing (NGS) gene panels have proven to be fast, accurate, and inexpensive for the genetic analysis.According to this cost analysis, it is economically reasonable to use targeted NGS gene panels for genetic screening.

Patient Interactions With an Automated Conversational Agent Delivering Pretest Genetics Education: Descriptive Study

Background

Cancer genetic testing to assess an individual’s cancer risk and to enable genomics-informed cancer treatment has grown exponentially in the past decade. Because of this continued growth and a shortage of health care workers, there is a need for automated strategies that provide high-quality genetics services to patients to reduce the clinical demand for genetics providers. Conversational agents have shown promise in managing mental health, pain, and other chronic conditions and are increasingly being used in cancer genetic services. However, research on how patients interact with these agents to satisfy their information needs is limited.

Objective

Our primary aim is to assess user interactions with a conversational agent for pretest genetics education.

Methods

We conducted a feasibility study of user interactions with a conversational agent who delivers pretest genetics education to primary care patients without cancer who are eligible for cancer genetic evaluation. The conversational agent provided scripted content similar to that delivered in a pretest genetic counseling visit for cancer genetic testing. Outside of a core set of information delivered to all patients, users were able to navigate within the chat to request additional content in their areas of interest. An artificial intelligence–based preprogrammed library was also established to allow users to ask open-ended questions to the conversational agent. Transcripts of the interactions were recorded. Here, we describe the information selected, time spent to complete the chat, and use of the open-ended question feature. Descriptive statistics were used for quantitative measures, and thematic analyses were used for qualitative responses.

Results

We invited 103 patients to participate, of which 88.3% (91/103) were offered access to the conversational agent, 39% (36/91) started the chat, and 32% (30/91) completed the chat. Most users who completed the chat indicated that they wanted to continue with genetic testing (21/30, 70%), few were unsure (9/30, 30%), and no patient declined to move forward with testing. Those who decided to test spent an average of 10 (SD 2.57) minutes on the chat, selected an average of 1.87 (SD 1.2) additional pieces of information, and generally did not ask open-ended questions. Those who were unsure spent 4 more minutes on average (mean 14.1, SD 7.41; P=.03) on the chat, selected an average of 3.67 (SD 2.9) additional pieces of information, and asked at least one open-ended question.

Conclusions

The pretest chat provided enough information for most patients to decide on cancer genetic testing, as indicated by the small number of open-ended questions. A subset of participants were still unsure about receiving genetic testing and may require additional education or interpersonal support before making a testing decision. Conversational agents have the potential to become a scalable alternative for pretest genetics education, reducing the clinical demand on genetics providers.

[Clinical and laboratory features of hereditary pheochromocytoma and paraganglioma]

The widespread introduction of genetic testing in recent years has made it possible to determine that more than a third of cases of pheochromocytomas and paragangliomas (PPPGs) are caused by germline mutations. Despite the variety of catecholamine-producing tumors manifestations, there is a sufficient number of clinical and laboratory landmarks that suggest a hereditary genesis of the disease and even a specific syndrome. These include a family history, age of patient, presence of concomitant conditions, and symptoms of the disease. Considering that each of the mutations is associated with certain diseases that often determine tactics of treatment and examination of a patient, e.g. high risk of various malignancies. Awareness of the practitioner on the peculiarities of the course of family forms of PPPGs will allow improving the tactics of managing these patients.The article provides up-to-date information on the prevalence of hereditary PPPGs. The modern views on the pathogenesis of the disease induced by different mutations are presented. The main hereditary syndromes associated with PPPGs are described, including multiple endocrine neoplasia syndrome type 2A and 2B, type 1 neurofibromatosis, von Hippel-Lindau syndrome, hereditary paraganglioma syndrome, as well as clinical and laboratory features of the tumor in these conditions. The main positions on the necessity of genetic screening in patients with PPPGs are given.

Hypertensive crisis precatheter ablation for resistant atrial fibrillation: a case of undiagnosed bilateral pheochromocytomas

A 63-year-old man with hypertension was referred for catheter ablation of persistent atrial fibrillation. He was diagnosed with paroxysmal atrial fibrillation approximately 6 years prior. Over the previous 12 months, his atrial fibrillation had become persistent despite medication optimisation for rate control and elective cardioversion. Sinus rhythm was restored briefly. The decision was made to pursue catheter ablation and isolation of the pulmonary veins. On anaesthetic induction, the patient suffered from a hypertensive crisis. The procedure was aborted, and the patient was admitted to hospital for investigations of secondary hypertension. Ultimately, the patient was diagnosed with bilateral pheochromocytomas. This case outlines the diagnostic challenges and cardiac comorbidities associated with bilateral pheochromocytomas.

Composite pheochromocytoma/paraganglioma-ganglioneuroma: analysis of SDH and ATRX status, and identification of frequent HRAS and BRAF mutations

INTRODUCTION

Composite pheochromocytoma/paraganglioma (CP) is a rare neoplasm with most cases presented as single reports. Little is known about its pathogenesis and relationship with ordinary pheochromocytoma (PCC) or paraganglioma (PGL). Our study is aimed at analyzing the status of SDH and ATRX and identifying novel genetic changes in CP.

METHODS

Eighteen CP cases were collected. SDH and ATRX status was screened by immunohistochemistry. Targeted region sequencing (TRS) was successfully performed on formalin-fixed paraffin-embedded tissues in two cases within 3 years. Based on the TRS result, Sanger sequencing of BRAF and HRAS was performed in fifteen cases (including the two cases with TRS performed), with three cases excluded due to the limited amount of tissue.

RESULTS

Histopathologically, all the cases were composite PCC/PGL-ganglioneuroma (GN). The GN components were either closely admixed or juxtaposed with the PCC/PGL components, with a highly variable percentage (10-80%). All cases stained positive for SDHB and ATRX. HRAS and BRAF mutations were identified during TRS. In the subsequent Sanger sequencing, 20.0% (3/15) harbored BRAF mutations (K601E and K601N) and 46.7% (7/15) harbored HRAS mutations (Q61R, Q61L, G13R). The mutation rates were both significantly higher than reported in ordinary PCC/PGL.

CONCLUSIONS

We demonstrated that composite PCC/PGL-GN might be a unique entity with frequent HRAS and BRAF mutations rather than genetic changes of SDH and ATRX. Our findings revealed the possible pathogenesis of composite PCC/PGL-GN and provided clues for potential treatment targets.

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.

Comparing models of delivery for cancer genetics services among patients receiving primary care who meet criteria for genetic evaluation in two healthcare systems: BRIDGE randomized controlled trial

BACKGROUND

Advances in genetics and sequencing technologies are enabling the identification of more individuals with inherited cancer susceptibility who could benefit from tailored screening and prevention recommendations. While cancer family history information is used in primary care settings to identify unaffected patients who could benefit from a cancer genetics evaluation, this information is underutilized. System-level population health management strategies are needed to assist health care systems in identifying patients who may benefit from genetic services. In addition, because of the limited number of trained genetics specialists and increasing patient volume, the development of innovative and sustainable approaches to delivering cancer genetic services is essential.

METHODS

We are conducting a randomized controlled trial, entitled Broadening the Reach, Impact, and Delivery of Genetic Services (BRIDGE), to address these needs. The trial is comparing uptake of genetic counseling, uptake of genetic testing, and patient adherence to management recommendations for automated, patient-directed versus enhanced standard of care cancer genetics services delivery models. An algorithm-based system that utilizes structured cancer family history data available in the electronic health record (EHR) is used to identify unaffected patients who receive primary care at the study sites and meet current guidelines for cancer genetic testing. We are enrolling eligible patients at two healthcare systems (University of Utah Health and New York University Langone Health) through outreach to a randomly selected sample of 2780 eligible patients in the two sites, with 1:1 randomization to the genetic services delivery arms within sites. Study outcomes are assessed through genetics clinic records, EHR, and two follow-up questionnaires at 4 weeks and 12 months after last genetic counseling contactpre-test genetic counseling.

DISCUSSION

BRIDGE is being conducted in two healthcare systems with different clinical structures and patient populations. Innovative aspects of the trial include a randomized comparison of a chatbot-based genetic services delivery model to standard of care, as well as identification of at-risk individuals through a sustainable EHR-based system. The findings from the BRIDGE trial will advance the state of the science in identification of unaffected patients with inherited cancer susceptibility and delivery of genetic services to those patients.

TRIAL REGISTRATION

BRIDGE is registered as NCT03985852 . The trial was registered on June 6, 2019 at clinicaltrials.gov .

Paraganglioma with highly malignant potential involving the rib - Case report and review of the literature

Paragangliomas are rare neuroendocrine tumors arising from paraganglion cells in sympathetic or parasympathetic chains, which may develop in the abdomen, chest, skull base, and neck. As paragangliomas have a wide range of imaging features, the diagnosis often requires tissue sampling. We present a unique case of a paraganglioma which originally presented as a rib tumor.

A 64-year-old male with right flank pain for 2 months’ was referred for a noncontrast renal colic CT. He was found to have a 3.7 × 3.5 cm soft tissue mass invading the left posterior 9th rib and paraspinal muscle. This was fluorodeoxyglucose F 18, (¹⁸F-FDG) avid, with no other distant metabolic activity. He underwent ultrasound-guided core biopsy which revealed a diagnosis of paraganglioma. A right thoracotomy with chest wall resection of 8, 9, and 10 ribs were subsequently performed. The tumor was removed along with a small portion of adherent lung. The tumor was positive for CD56, synaptophysin and chromogranin. S-100 highlighted occasional sustentacular cells, consistent with a pathologic diagnosis of a paraganglioma. The patient remains symptom free for 6 months’ after the operation.

Our case highlights that, when paragangliomas occur within the chest wall, they may present as a rib tumor and can mimic metastasis, myeloma or other primary neoplastic etiologies originating from ribs. Both imaging and pathologic diagnosis can be challenging.

Diagnosis for Pheochromocytoma and Paraganglioma: A Joint Position Statement of the Korean Pheochromocytoma and Paraganglioma Task Force

Pheochromocytoma and paraganglioma (PPGLs) are rare catecholamine-secreting neuroendocrine tumors but can be life-threatening. Although most PPGLs are benign, approximately 10% have metastatic potential. Approximately 40% cases are reported as harboring germline mutations. Therefore, timely and accurate diagnosis of PPGLs is crucial. For more than 130 years, clinical, molecular, biochemical, radiological, and pathological investigations have been rapidly advanced in the field of PPGLs. However, performing diagnostic studies to localize lesions and detect metastatic potential can be still challenging and complicated. Furthermore, great progress on genetics has shifted the paradigm of genetic testing of PPGLs. The Korean PPGL task force team consisting of the Korean Endocrine Society, the Korean Surgical Society, the Korean Society of Nuclear Medicine, the Korean Society of Pathologists, and the Korean Society of Laboratory Medicine has developed this position statement focusing on the comprehensive and updated diagnosis for PPGLs.

Maternal and fetal outcomes in phaeochromocytoma and pregnancy: a multicentre retrospective cohort study and systematic review of literature

BACKGROUND

Phaeochromocytoma or paraganglioma (collectively known as PPGL) in pregnant women can lead to severe complications and death due to associated catecholamine excess. We aimed to identify factors associated with maternal and fetal outcomes in women with PPGL during pregnancy.

METHODS

We did a multicentre, retrospective study of patients with PPGL and pregnancy between Jan 1, 1980, and Dec 31, 2019, in the International Pheochromocytoma and Pregnancy Registry and a systematic review of studies published between Jan 1, 2005, and Dec 27, 2019 reporting on at least five cases. The inclusion criteria were pregnancy after 1980 and PPGL before or during pregnancy or within 12 months post partum. Eligible patients from the retrospective study and systematic review were included in the analysis. Outcomes of interest were maternal or fetal death and maternal severe cardiovascular complications of catecholamine excess. Potential variables associated with these outcomes were evaluated by logistic regression.

FINDINGS

The systematic review identified seven studies (reporting on 63 pregnancies in 55 patients) that met the eligibility criteria and were of adequate quality. A further 197 pregnancies in 186 patients were identified in the International Pheochromocytoma and Pregnancy Registry. After excluding 11 pregnancies due to potential overlap, the final cohort included 249 pregnancies in 232 patients with PPGL. The diagnosis of PPGL was made before pregnancy in 37 (15%) pregnancies, during pregnancy in 134 (54%), and after delivery in 78 (31%). Of 144 patients evaluated for genetic predisposition for phaeochromocytoma, 95 (66%) were positive. Unrecognised PPGL during pregnancy (odds ratio 27·0; 95% CI 3·5-3473·1), abdominal or pelvic tumour location (11·3; 1·5-1440·5), and catecholamine excess at least ten-times the upper limit of the normal range (4·7; 1·8-13·8) were associated with adverse outcomes. For patients diagnosed during pregnancy, α-adrenergic blockade therapy was associated with fewer adverse outcomes (3·6; 1·1-13·2 for no α-adrenergic blockade vs α-adrenergic blockade), whereas surgery during pregnancy was not associated with better outcomes (0·9; 0·3-3·9 for no surgery vs surgery).

INTERPRETATION

Unrecognised and untreated PPGL was associated with a substantially higher risk of either maternal or fetal complications. Appropriate case detection and counselling for premenopausal women at risk for PPGL could prevent adverse pregnancy-related outcomes.

FUNDING

US National Institutes of Health.

Clinical and Biochemical Features of Pheochromocytoma Characteristic of Von Hippel-Lindau Syndrome

BACKGROUND

Approximately 30% of patients with apparent sporadic pheochromocytoma (Pheo) may later prove to have an inherited predisposition syndrome, most commonly Von Hippel-Lindau (VHL) disease. Our aim was to compare the clinical and biochemical features of Pheo in VHL to those in sporadic disease to identify differences that may be used to guide management and surveillance of Pheo in VHL patients.

METHODS

Data of all patients who had adrenalectomy for histologic Pheo from 2000 to 2018 (QIIRB1749) were retrospectively reviewed. VHL patients were diagnosed by standard clinical criteria and/or genetic testing. Patients were classified as having sporadic Pheo (sPheo) if they had no family/personal history consistent with an associated genetic disorder and/or had negative testing for VHL, MAX, MEN1, NF1, RET and SDHAF2/B/C/D/A mutations.

RESULTS

Of 175 patients, 38 (22%) had VHL and 137 (78%) had sPheo including 27 (20%) with negative genetic testing. Compared to sPheo, VHL Pheo patients were younger (mean 25.9 vs. 51.2 years, p < 0.001), less symptomatic (55% vs. 72%, p = 0.074), less hypertensive (46% vs. 64%, p = 0.043) and were more likely to have normal plasma metanephrines (85% vs. 25%, p < 0.001). VHL-related Pheos were smaller (median 2.8 cm vs. 4.4 cm, p < 0.001) but more often multifocal (>1 adrenal Pheo) (16% vs. 0%, p < 0.001). Recurrence >6 months from initial resection was common in VHL (40% vs. 0%, p < 0.001), median time to recurrence 15 years, (range 1-38 years).

CONCLUSIONS

Compared to those with sporadic Pheo, patients with VHL are more likely to be young, asymptomatic and normotensive and to have small, multifocal, normetanephrine-secreting tumors. Because recurrence is common in VHL and arises up to 38 years later, continued surveillance is advised.

Characteristics of germline mutations in Korean patients with pheochromocytoma/paraganglioma

BACKGROUND

Pheochromocytomas and paragangliomas (PPGLs) are catecholamine-producing neuroendocrine tumours. PPGLs are a rare but important cause of secondary hypertension owing to their high morbidity and mortality. Patients with PPGL exhibit an increased prevalence of mutations in one of the PPGL susceptibility genes according to previous studies. We aimed to investigate the characteristics of germline mutations in the largest number of Korean patients with PPGL.

METHODS

In this study, 161 patients with PPGL were evaluated. Phenotype data, including biochemical, pathological and anatomical imaging results, were collected. Germline mutations in 10 PPGL-related genes were tested by targeted next-generation sequencing (NGS), Sanger sequencing and multiplex ligation-dependent probe amplification.

RESULTS

Approximately 21% of apparently sporadic PPGLs harboured germline mutations of the PPGL-related genes. The mutation carriers were younger at the first diagnosis and had more bilateral (28.6% vs 4.0%, p<0.001) and multifocal (11.4% vs 1.6%, p=0.027) PPGLs, but showed no metastatic risk (17.1% vs 11.1%, p=0.504), than non-mutation carriers. Missense mutation of SDHD p.V111I was found in this cohort of Asian patients, which was associated with unilateral pheochromocytoma with dominantly epinephrine production.

CONCLUSION

This study covered the largest number of Korean patients with PPGL. To our knowledge, it is the first to compare results of targeted NGS panel with those of conventional sequencing methods in Asia. We demonstrated that the variant type, as well as the mutated gene, may determine the phenotype and prognosis of PPGLs.

Probability of positive genetic testing in patients diagnosed with pheochromocytoma and paraganglioma: Criteria beyond a family history

BACKGROUND

Genetic testing for germline pheochromocytoma and paraganglioma susceptibility genes is associated with improved patient management. However, data are currently sparse on the probability of a positive testing result based on an individual's clinical presentation. This study evaluates clinical characteristics for association with testing positive for known pheochromocytoma and paraganglioma susceptibility genes.

METHODS

This retrospective analysis examined 111 patients with a diagnosis of pheochromocytoma and paraganglioma who underwent genetic testing. Logistic regression and receiver operating characteristic analyses were performed to identify factors associated with a positive genetic testing result. Probabilities were then calculated for combinations of significant factors to determine the likelihood of a positive test result in each group.

RESULTS

Of 32 patients with a family history of pheochromocytoma and paraganglioma, 31 (97%) had a germline mutation detected. Of 79 patients without a family history, 24 (30%) had a pathogenic germline mutation detected. In multivariate analysis, a positive family history, aged ≤47 years, and tumor size ≤2.9 cm were independent factors associated with a positive genetic testing result. Patients meeting all 3 criteria had a 100% probability compared with 13% in those without any of the criteria. In addition to a positive family history, having either aged ≤47 years or tumor size ≤2.9 cm resulted in a 90% and 100% probability of a positive result, respectively. In the absence of a family history, the probability in patients who were aged ≤47 years and had a tumor size ≤2.9 cm was 60%.

CONCLUSION

In addition to a family history of pheochromocytoma and paraganglioma, aged ≤47 years, and tumor size ≤2.9 cm are associated with a higher probability of testing positive for a pheochromocytoma and paraganglioma susceptibility gene mutation. Patients meeting all 3 criteria have a 100% probability of a positive genetic testing result.

Psychometric Properties of the MICRA Questionnaire in Portuguese Individuals Carrying SDHx Mutations

This study aims to present the translation and cultural adaptation, as well as the psychometric characteristics of the Portuguese version of the Multidimensional Impact of Cancer Risk Assessment (MICRA) questionnaire in individuals with SDHx mutations. The questionnaire was translated and culturally adapted in accordance with the process recommended by the World Health Organization. As per suggestion of the authors of the original instrument, a joint, universal European and Brazilian Portuguese version of the MICRA was created. Ninety-six (asymptomatic or affected) patients with SDHx mutations nationwide completed the adapted version of the MICRA in Portugal. Analyses consisted of confirmatory factor analysis, reliability estimation (alphas), and correlations with two other distress and quality of life instruments. The Portuguese adaptation of the MICRA was understandable to patients from various socioeconomic backgrounds. All items and factor structure of the original version were retained, yielding a good model fit. The MICRA's three subscales and total score showed good internal consistency, and the correlations found between the Portuguese version of the MICRA and the other instruments assessing similar constructs further supported its validity. The adapted version of the MICRA showed good psychometric properties with a representative population of SDHx mutation carriers. This instrument can now be used to study the multidimensional impact of taking a genetic test for these mutations. It can also be used in future studies with other Portuguese populations of patients submitted to genetic tests for cancer risk assessment.

Recent advances in the management of pheochromocytoma and paraganglioma

Pheochromocytomas and paragangliomas (PPGLs) are rare tumors that cause refractory hypertension and hypertensive crisis. Although metastatic disease accounts for 30% of PPGLs, the diagnosis of malignancy is difficult without the presence of metastatic lesions. Here, we review several advancements in the diagnosis and treatment of PPGL. A nationwide epidemiological survey in Japan revealed that the annual number of patients with PPGL was 3000, which was higher than that reported previously. While plasma and urine fractionated metanephrines are recommended for use in specific biochemical testing for diagnosis, creatinine-corrected fractionated metanephrines in spot urine samples that had been widely used in Japan as a convenient screening test were shown to be as useful as 24-h urine fractionated metanephrines. Regarding imaging studies, a more specific functional imaging for PPGLs, ⁶⁸Ga DOTATATE, was newly developed. ⁶⁸Ga DOTATATE provides a clear image with high sensitivity and specificity. Currently, PASS or GAPP histological scores and SDHB immunostaining are clinically used to attempt to discriminate benign from malignant tumors. However, since this distinguishing process remains difficult, all cases were classified as malignant with the possibility of metastasis in the WHO classification of endocrine tumors updated in 2017. Approximately 60% of PPGLs have germline mutations in PPGL-related genes. Currently, the genes are classified into two clusters based on their mechanism for the etiology of tumorigenesis. Based on the possible mechanisms of tumor development associated with gene mutations, several molecular target drugs are under evaluation to explore more promising treatments for malignant PPGL.

Aberrant Splicing of SDHC in Families With Unexplained Succinate Dehydrogenase-Deficient Paragangliomas

Context

Germline mutations in the succinate dehydrogenase genes (SDHA/B/C/D, SDHAF2-collectively, "SDHx") have been implicated in paraganglioma (PGL), renal cell carcinoma (RCC), gastrointestinal stromal tumor (GIST), and pituitary adenoma (PA). Negative SDHB tumor staining is indicative of SDH-deficient tumors, usually reflecting an underlying germline SDHx mutation. However, approximately 20% of individuals with SDH-deficient tumors lack an identifiable germline SDHx mutation.

Methods

We performed whole-exome sequencing (WES) of germline and tumor DNA followed by Sanger sequencing validation, transcriptome analysis, metabolomic studies, and haplotype analysis in 2 Italian-Australian families with SDH-deficient PGLs and various neoplasms, including RCC, GIST, and PA.

Results

Germline WES revealed a novel SDHC intronic variant, which had been missed during previous routine testing, in 4 affected siblings of the index family. Transcriptome analysis demonstrated aberrant SDHC splicing, with the retained intronic segment introducing a premature stop codon. WES of available tumors in this family showed chromosome 1 deletion with loss of wild-type SDHC in a PGL and a somatic gain-of-function KIT mutation in a GIST. The SDHC intronic variant identified was subsequently detected in the second family, with haplotype analysis indicating a founder effect.

Conclusions

This is the deepest intronic variant to be reported among the SDHx genes. Intronic variants beyond the limits of standard gene sequencing analysis should be considered in patients with SDH-deficient tumors but negative genetic test results.

Surveillance of succinate dehydrogenase gene mutation carriers: Insights from a nationwide cohort

OBJECTIVE

Mutations in the genes coding for succinate dehydrogenase (SDHx) are the most frequent germline alterations in pheochromocytomas and paragangliomas. Evidence for the advantages associated with presymptomatic screening for SDHx mutation carriers is scarce. This study describes a nationwide cohort of these mutation carriers and aims to compare patients with clinical manifestations of the disease and those diagnosed through genetic screening.

DESIGN

Cross-sectional study.

PATIENTS

SDHx mutation carriers (n = 118) followed through the Portuguese Oncology referral centres: 41 probands and 77 nonprobands.

MEASUREMENTS

All participants were subjected to biochemical and body imaging examinations for a complete assessment of the extent and spread of disease. Clinical data obtained this way were further analysed.

RESULTS

The mean age of this cohort was 44.5 ± 17.4 years, and more than half carried the same founder SDHB mutation. About 50.8% of the mutation carriers developed pheochromocytomas or paragangliomas. Compared to patients diagnosed through genetic screening, those diagnosed clinically were characterized by larger tumours (P < .001), more frequent metastases (P = .024), were more frequently subjected to surgery (P = .011) and radiotherapy (P = .013), and had worse outcomes, such as macroscopic positive margins (P = .034). Persistent and/or unresectable disease and disease-related mortality were also more frequent in symptomatic patients compared to those diagnosed through genetic screening (P = .014).

CONCLUSIONS

In this nationwide cohort study, a large proportion of mutation carriers were found to develop SDHx-related neoplasia. Genetic testing and subsequent follow-up resulted in the diagnosis of smaller and nonmetastatic tumours, fewer treatment procedures, fewer complications and greater number of disease-free patients.

Genetic testing in endocrine surgery: Opportunities for precision surgery

Recent innovations in molecular and genetic diagnostic techniques have led to rapid advances in genomic medicine and their application to the clinic. The identification and classification of various genetic associations, syndromes, and susceptibility genes in endocrine surgical disorders are increasingly relevant to patient care. Hereditary endocrine disorders represent a significant proportion of disease encountered by endocrine surgeons. Hence, genetic testing has emerged as an important adjunct for the diagnosis and management of patients with endocrine surgical disorders. This article summarizes commonly encountered inherited endocrine disorders and their tumor susceptibility genes, with a focus on the clinical utility of genetic testing and its impact on the surgical management of endocrine disorders.

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

Paragangliomas and pheochromocytomas (PPGL) are rare neuroendocrine tumours characterized by a strong genetic determinism. Over the past 20 years, evolution of PPGL genetics has revealed that around 40% of PPGL are genetically determined, secondary to a germline mutation in one of more than twenty susceptibility genes reported so far. More than half of the mutations occur in one of the SDHx genes (SDHA, SDHB, SDHC, SDHD, SDHAF2), which encode the different subunits and assembly protein of a mitochondrial enzyme, succinate dehydrogenase. These susceptibility genes predispose to early forms (VHL, RET, SDHD, EPAS1, DLST), syndromic (RET, VHL, EPAS1, NF1, FH), multiple (SDHD, TMEM127, MAX, DLST, MDH2, GOT2) or malignant (SDHB, FH, SLC25A11) PPGL. The discovery of a germline mutation in one of these genes changes the patient's follow-up and allows genetic screening of affected families and the presymptomatic follow-up of relatives carrying a mutation.

Tumor-specific prognosis of mutation-positive patients with head and neck paragangliomas

BACKGROUND

Genetic testing to identify succinate dehydrogenase (SDH) mutations in patients with head and neck paraganglioma (HNP) has been in clinical practice for more than a decade. However, the recurrence and metachronous tumor occurrence risks in surgically treated mutation-positive patients are not well studied.

METHODS

Clinical and procedural details of consecutive patients who underwent excision for HNP from January 1996 to October 2016 were retrospectively reviewed. End points included recurrence, metachronous tumor detection, and mortality. Germline DNA was tested to identify mutations in SDHx genes. Patients were divided into three groups on the basis of genetic testing: group I, positive; group II, negative; and group III, unknown or offered but not tested.

RESULTS

HNP was diagnosed in 268 patients, 214 (147 female; mean age, 47 years) included in this study. Directed genetic testing was performed in 68; mutations were detected in SDH in 47 (69%), a majority SDHD. In group I, 47 patients had 64 procedures for 81 tumors (52 carotid body tumors [CBTs]); 17 (36%) were bilateral, 7 (15%) multiple, 3 (6%) functional, and 7 (15%) malignant. Residual tumor in 10 was significant in 2, managed by radiation therapy and reoperation. Local recurrence was detected in 12 patients (25%) at a median of 8 years; 11 metachronous mediastinal and retroperitoneal paragangliomas were detected in 8 (17%) at a median of 13 years. Systemic metastases occurred in five (10%). Six patients (13%) had more than one recurrence. In group II, 21 patients had 22 procedures for 23 tumors, 17 CBTs. Two (9%) were bilateral and two (9%) malignant. Excision was complete in all with no recurrence or systemic metastasis at last follow-up. For group III, 146 patients underwent 153 procedures for 156 tumors, 95 CBTs; 7 (5%) were bilateral, 2 (1%) multiple, 8 (5%) functional, and 1 (0.6%) malignant. Local recurrence was detected in nine (6%) at a median of 9 years and metachronous HNP in three (2%) at a median of 5 years. Systemic metastases occurred in two (1%). Mortality was 4% in group I and 3% in group III, none procedure or tumor related. Group I (mutation positive) had 10-year overall, recurrence-free, and metachronous tumor-free survival rates of 93%, 69.4%, and 73%, respectively, lower than the other groups (P < .001).

CONCLUSIONS

Bilateral, functional, malignant, recurrent, and metachronous tumors are more common in SDH mutation-positive patients with HNP. Overall survival in patients with HNP is high. Metachronous tumors or local recurrences occur late, and long-term follow-up is necessary.

Genetic and Clinical Profiles of Pheochromocytoma and Paraganglioma: A Single Center Study

Pheochromocytoma/paraganglioma (PPGL) has a high genetic heterogeneity with 40% germline variants in known pathogenic genes. Data in Chinese on this aspect are scanty. To detect the genetic and clinical profile of Chinese PPGL patients, we examined the variants of 12 known germline pathogenic genes (SDHA, SDHB, SDHC, SDHD, SDHAF2, FH, VHL, RET, NF1, MAX, TMEM127, and KIF1B) by next-generation sequencing and Sanger sequencing in 314 Chinese PPGL subjects. Twenty nine percent of Chinese PPGL patients had germline variants and SDHB was the most frequently mutated (14.6%). The most frequent SDHB variants were in exon 2, exon 7, and IVS 7. Pathogenic variants were more likely to occur in metastatic PPGL patients, paragangliomas, and patients under 30, with the ratio being 50.7% (35/69), 35.9% (56/156), and 49.5% (52/105), respectively. Our cohort included 314 patients from a single setting. The genetic and clinical features of Chinese PPGL patients were unique in some aspects compared to their non-Chinese counterparts. Identification of genotype-phenotype relation can serve as an effective tool for genetic prioritization and clinical decision-making.

A Guide to Pheochromocytomas and Paragangliomas

Pheochromocytomas and extra-adrenal paragangliomas are rare neuroendocrine neoplasms with characteristic histologic and immunohistochemical features. These tumors can arise in several anatomic locations, necessitating that their diagnostic recognition extends beyond the realm of endocrine disorders. A practical and reproducible risk stratification system for these tumors is still in development. In this rapidly evolving era of molecular medicine, it is essential for pathologists to equip themselves with a framework for understanding the classification of paragangliomas and pheochromocytomas and be informed of how they might advise their colleagues with regard to prognostication and appropriate follow-up.

Mutational profile and genotype/phenotype correlation of non-familial pheochromocytoma and paraganglioma

About 30%-40% of patients with pheochromocytoma (PCC) and paraganglioma (PGL) have underlying germline mutations in certain susceptibility genes despite absent family history of these tumors. Here, we present mutational profile of 101 such patients with PCC/PGL (PPGL) from the highly consanguineous population of Saudi Arabia. Results: Of 101 cases with PPGL, 37/101 (36.6%) had germline mutations. Mutations were detected in 30 cases by PCR and direct Sanger sequencing and in 7 additional cases by NGS. The most commonly mutated gene was SDHB (21/101 cases, 20.8%) and the most common SDHB mutation was c.268C>T, p.R90X occurring in 12/21 (57%) cases. Mutations also occurred in SDHC (4/101, 3.96%), SDHD (3/101, 3%), VHL (2/101, 2%) and MAX (2/101, 2%) genes. The following genes were mutated in 1 patient each (1%), RET, SDHA, SDHAF2, TMEM127 and NF1. Metastatic PPGL occurred in 6/21 cases (28.6%) with SDHB mutations and in 1 case with SDHAF2 mutation. Patients and Methods: DNA was isolated from peripheral blood (53 patients) or from non-tumorous formalin fixed paraffin embedded (FFPE) tissue (48 patients). PCR and direct Sanger sequencing of RET, SDHx, VHL, MAX and TMEM127 genes were performed. Cases without mutations were subjected to whole exome sequencing using next generation sequencing (NGS). Conclusion: About 37% of PPGL without family history of such tumors harbor germline mutations. The most commonly mutated gene is SDHB followed by SDHC, SDHD, VHL, MAX and rarely RET, SDHA, SDHAF2, TMEM127 and NF1. SDHB mutations were associated with metastatic PPGL in more than a quarter of cases.

Pheochromocytoma and paraganglioma: implications of germline mutation investigation for treatment, screening, and surveillance

OBJECTIVE

Paraganglioma (PGL) and pheochromocytoma (PCC) are rare neuroendocrine tumors that were considered to be predominantly sporadic. However, with the identification of novel susceptibility genes over the last decade, it is currently estimated that up to 40% of cases can occur in the context of a hereditary syndrome. We aimed to characterize PGL/PCC families to exemplify the different scenarios in which hereditary syndromes can be suspected and to emphasize the importance for patients and their families of making an opportune genetic diagnosis.

MATERIALS AND METHODS

Retrospective analysis of patients diagnosed with PGL/PCC. Germline mutations were studied using next-generation sequencing panels including SDHA, SDHB, SDHC and SDHD. Clinical data were collected from clinical records, and all patients received genetic counseling.

RESULTS

We describe 4 families with PGL/PCC and germline mutations in SDH complex genes. 2 families have SDHB mutations and 2 SDHD mutations. The clinical presentation of the patients and their families was heterogeneous, with some being atypical according to the literature.

CONCLUSIONS

PGL/PCC are more commonly associated with a germline mutation than any other cancer type, therefore, all individuals with these types of tumors should undergo genetic risk evaluation. NGS multigene panel testing is a cost-effective approach given the overlapping phenotypes. Individuals with germline mutations associated with PGL/PCC should undergo lifelong clinical, biochemical and imaging surveillance and their families should undergo genetic counseling. For all these reasons, it is critical that all medical staff can suspect and diagnose these inherited cancer predisposition syndromes.

Targeted next-generation sequencing detects rare genetic events in pheochromocytoma and paraganglioma

Background

Knowing the genetic status of patients affected by paragangliomas and pheochromocytomas (PPGL) is important for the guidance of their management and their relatives. Our objective was to improve the diagnostic performances of PPGL genetic testing by next-generation sequencing (NGS).

Methods

We developed a custom multigene panel, which includes 17 PPGL genes and is compatible with both germline and tumour DNA screening. The NGS assay was first validated in a retrospective cohort of 201 frozen tumour DNAs and then applied prospectively to 623 DNAs extracted from leucocytes, frozen or paraffin-embedded PPGL tumours.

Results

In the retrospective cohort, the sensitivity of the NGS assay was evaluated at 100% for point and indels mutations and 86% for large rearrangements. The mutation rate was re-evaluated from 65% (132/202) to 78% (156/201) after NGS analysis. In the prospective cohort, NGS detected not only germline and somatic mutations but also co-occurring variants and mosaicism. A mutation was identified in 74% of patients for whom both germline and tumour DNA were available.

Conclusion

The analysis of 824 DNAs from patients with PPGL demonstrated that NGS assay significantly improves the performances of PPGL genetic testing compared with conventional methods, increasing the rate of identified mutations and identifying rare genetic mechanisms.

Clinical Syndromes and Genetic Screening Strategies of Pheochromocytoma and Paraganglioma

Pheochromocytomas (PCCs) are rare neuroendocrine tumors that originate from chromaffin cells of the adrenal medulla, and paragangliomas (PGLs) are extra-adrenal pheochromocytomas. These can be mainly found in clinical syndromes including multiple endocrine neoplasia (MEN), von Hippel–Lindau (VHL) syndrome, neurofibromatosis-1 (NF-1) and familial paraganglioma (FPGL). PCCs and PGLs are thought to have the highest degree of heritability among human tumors, and it has been estimated that 60% of the patients have genetic abnormalities. This review provides an overview of the clinical syndrome and the genetic screening strategies of PCCs and PGLs. Comprehensive screening principles and strategies, along with specific screening based on clinical symptoms, biochemical tests and immunohistochemistry, are discussed.

Exosomal double-stranded DNA as a biomarker for the diagnosis and preoperative assessment of pheochromocytoma and paraganglioma

Pheochromocytomas (PCCs) and paragangliomas (PGLs) are the most heritable endocrine tumors. Genetic testing for 12 driver susceptibility genes is recommended in all PCC and PGL cases. However, detection of somatic mutations in PCC and PGL remains unrealizable for genetic diagnosis and preoperative assessment. We compared the serum exosomal DNA and tumor tissue DNA from patients or mice with PCC or PGL and found double-stranded DNA (dsDNA) fragments in the circulating exosomes of patients with PCC or PGL. Exosomal dsDNA shared the same mutations in the susceptibility genes with that of the parent tumor cells. Moreover, our research showed that serum-derived exosomal dsDNA in PCC and PGL was highly consistent with the paired tumor genome. Our findings provide the first definitive evidence of the presence of exosomal dsDNA that can be used as a noninvasive genetic marker in one of the most effective somatic mutation screens for the diagnosis and preoperative assessment of PCCs and PGLs.

Bilateral Pheochromocytomas in a Patient with Y175C Von Hippel-Lindau Mutation

Von Hippel-Lindau (VHL) disease, caused by germline mutations in the VHL gene, is characterized by metachronously occurring tumors including pheochromocytoma, renal cell carcinoma (RCC), and hemangioblastoma. Although VHL disease leads to reduced life expectancy, its diagnosis is often missed and tumor screening guidelines are sparse. VHL protein acts as a tumor suppressor by targeting hypoxia-inducible factors (HIFs) for degradation through an oxygen-dependent mechanism. VHL mutants with more severely reduced HIF degrading function carry a high risk of RCC, while mutants with preserved HIF degrading capacity do not cause RCC but still lead to other tumors. VHL disease is classified into clinical types (1 and 2A-2C) based on this genotype-phenotype relationship. We report a case of bilateral pheochromocytomas and no other VHL-related tumors in a patient with Y175C VHL and show that this mutant preserves the ability to degrade HIF in normal oxygen conditions but, similar to the wild-type VHL protein, loses its ability to degrade HIF under hypoxic conditions. This study adds to the current understanding of the structure-function relationship of VHL mutations, which is important for risk stratification of future tumor development in the patients.

Identification of IDH-mutant gliomas by a prognostic signature according to gene expression profiling

BACKGROUND

Isocitrate dehydrogenase (IDH) mutations are the most common genetic aberrations in gliomagenesis. We aimed to build a high-efficiency prediction gene signature in patients with IDH-mutant glioma.

METHODS

In total, 167 gliomas from Chinese Glioma Genome Atlas (CGGA) dataset were included for discovery. The Cancer Genome Atlas (TCGA) dataset was used for validation. R language was the main software environment for our statistical operation and graphics.

RESULTS

We applied the Time-Dependent ROC Curve (timeROC) method to estimate the gene prediction accuracy of 3 years and 5 years in two datasets. Seven genes were selected for further analysis (AUC ≥ 0.7 in two datasets). A seven-gene enrichment score was established to predict the overall survival of 3 years and 5 years for IDH- mutant glioma patients. Moreover, the seven-gene signature was an independent prognostic indicator for patients with IDH-mutant glioma. Gene Ontology (GO) Analysis of associated genes revealed signature-related biological process of cell cycle and division.

CONCLUSION

We have identified a seven-gene signature that can provide a more accurate predictor of 3 years and 5 years for patients with IDH-mutant glioma. Moreover, the signature may potentially help neurosurgeons with the clinical personalized management of gliomas.

Pathology and genetics of phaeochromocytoma and paraganglioma

Phaeochromocytoma and paraganglioma (PHEO/PGL) are rare tumours with an estimated annual incidence of 3 per million. Advances in molecular understanding have led to the recognition that at least 30-40% arise in the setting of hereditary disease. Germline mutations in the succinate dehydrogenase genes SDHA, SDHB, SDHC, SDHD and SDHAF2 are the most prevalent of the more than 19 hereditary genetic abnormalities which have been reported. It is therefore recommended that, depending on local resources and availability, at least some degree of genetic testing should be offered to all PHEO/PGL patients, including those with clinically sporadic disease. It is now accepted that that all PHEO/PGL have some metastatic potential; therefore, concepts of benign and malignant PHEO/PGL have no meaning and have been replaced by a risk stratification approach. Although there is broad acceptance that certain features, including high proliferative activity, invasive growth, increased cellularity, large tumour nests and comedonecrosis, are associated with an increased risk of metastasis, it remains difficult to predict the clinical behaviour of individual tumours and no single risk stratification scheme is endorsed or in widespread use. In this review, we provide an update on advances in the pathology and genetics of PHEO/PGL with an emphasis on the changes introduced in the WHO 2017 classification of endocrine neoplasia relevant to practising surgical pathologists.

Trends of genetic screening in patients with pheochromocytoma and paraganglioma: 15-year experience in a high-volume tertiary referral center

BACKGROUND AND OBJECTIVES

Genetic testing for pheochromocytoma and paraganglioma allows for early detection of hereditary syndromes and enables close follow-up of high-risk patient. We investigated the trends in genetic testing among patients at a high-volume referral center and evaluated the prevalence of pheochromocytomas and paragangliomas.

METHODS

We reviewed the charts of 129 patients who underwent adrenalectomy for pheochromocytoma and paraganglioma between January 2000 and July 2015. To evaluate for trends in genetic testing, patients were divided by year of diagnosis: 2000-2005 (group 1, n = 35), 2006-2010 (group 2, n = 44), and 2011-2015 (group 3, n = 50).

RESULTS

Among 129 patients the mean age was 47 years and 56% were women. Groups 2 and 3 were more frequently referred for genetic consultation than group 1, 73%, and 94% versus 26% (P < 0.001). A total of 67% followed up on the referral. The prevalence of genetic mutation was 50% (21/42 tested). The percentage with a genetic syndrome was 23%, 28%, and 22% respectively for groups 1, 2, and 3.

CONCLUSIONS

Referral for genetic counseling significantly increased in the past 15 years. However, only two-thirds of patients followed up with genetic counselors and, therefore, clinicians can do more to improve the adherence rate for genetic counseling.

Routine genetic screening with a multi-gene panel in patients with pheochromocytomas

PURPOSE

Several new gene mutations have been reported in recent years to be associated with a risk of familial pheochromocytoma. However, it is unclear as to whether extensive genetic testing is required in all patients.

METHODS

The clinical data of consecutive patients operated for pheochromocytoma over a decade in a tertiary referral center were reviewed. Genetic screening was performed using a 10-gene panel: RET, VHL, SDHB, SDHD, SDHA, SDHC, SDHAF2, MAX, TMEM127 and FH.

RESULTS

A total of 166 patients were analyzed: 87 of them had genetic screening performed (39 M: 44.8%, 48 F: 55.2%, age range 6-81 years, mean 45±16.8 years). In total, 22/87 (25.3%) patients had germline mutations, while 65/87 (74.7%) patients presented with apparently sporadic tumors. Germline VHL mutations were identified in 11.7% of patients, RET in 6.8% (five MEN2A/MEN2 and one MEN2B/MEN3), SDHD in 2.3%, MAX in 2.3%, SDHB in 1.1%, and TMEM127 in 1.1% of patients. At diagnosis, 15.1% of patients with unilateral non-syndromic pheochromocytoma showed germline mutations. We identified 19.7% of mutations in patients with unilateral-non-recurrent pheochromocytomas within 5 years vs. 50% in the recurrent-bilateral-metastatic group (p = 0.01). Germline mutations were more frequently seen with bilateral pheochromocytomas (p = 0.001): 80% of patients with bilateral disease had germline mutations (4 VHL, 3 RET, 1 MAX).

CONCLUSIONS

The advent of rapid genetic screening using a gene-panel makes it feasible to screen large cohorts of patients and provides a valuable tool to contribute to the prediction of bilateral and malignant disease and to screen family members.

The clinical genetics of phaeochromocytoma and paraganglioma

Phaeochromocytoma and paraganglioma are rare catecholamine-producing tumours, recognised to have one of the richest hereditary backgrounds of all neoplasms, with germline mutations seen in approximately 30% of patients. They can be a part of genetic syndromes such as MEN 2 or Neurofibromatosis type 1, or can be found as apparently sporadic tumours. Germline mutations are almost always found in syndromic patients. Nonetheless, apparently sporadic phaeochromocytoma too show high germline mutation rates. Early detection of a genetic mutation can lead to early diagnosis of further tumours via surveillance, early treatment and better prognosis. Apart from this, the genetic profile has important relevance for tumour location and biochemical profile, and can be a useful predictor of future tumour behaviour. It also enables family screening and surveillance. Moreover, recent studies have demonstrated significant driver somatic mutations in up to 75% of all tumours. Arch Endocrinol Metab. 2017;61(5):490-500.

Systematic genetic screening in a prospective group of Danish patients with pheochromocytoma

Recent guidelines recommend consideration of genetic screening in all newly diagnosed patients with pheochromocytoma. Patients diagnosed with pheochromocytoma in the Region of Southern Denmark during 2006–2013 without previously recognized monogenetic etiology were offered genetic screening for mutations in the VHL, RET, SDHB, SDHC, and SDHD genes. A total of 41 patients were included, and genetic data were available in 35. In four of the 35 patients, a pathogenic variant was identified prior to the diagnosis of pheochromocytoma (von Hippel–Lindau disease, n=2; neurofibromatosis type 1, n=2). The patients carrying a genetic mutation were all younger than 45 years at time of diagnosis of pheochromocytoma, two patients presented with bilateral tumors, and one patient had a positive family history of pheochromocytoma. Genetic screening of the remaining 31 patients did not identify any mutations. The sporadic cases had a median age of 58 years (range 33–80 years). Three of 31 sporadic cases (ages 60, 69, and 76 years at time of diagnosis) presented with bilateral adrenal tumors, one patient had multiple adrenal tumors in both adrenal glands, and no patients had a positive family history of pheochromocytoma. Of the 31 patients, 24 (68.6%) were diagnosed with pheochromocytoma due to evaluation of an adrenal incidentaloma. In conclusion, monogenetic etiology was identified in four of 35 (11.4%) patients diagnosed with pheochromocytoma.

Update on Modern Management of Pheochromocytoma and Paraganglioma

Despite all technical progress in modern diagnostic methods and treatment modalities of pheochromocytoma/paraganglioma, early consideration of the presence of these tumors remains the pivotal link towards the best possible outcome for patients. A timely diagnosis and proper treatment can prevent the wide variety of potentially catastrophic cardiovascular complications. Modern biochemical testing should include tests that offer the best available diagnostic performance, measurements of metanephrines and 3-methoxytyramine in plasma or urine. To minimize false-positive test results particular attention should be paid to pre-analytical sampling conditions. In addition to anatomical imaging by computed tomography (CT) or magnetic resonance imaging, new promising functional imaging modalities of photon emission tomography/CT using with somatostatin analogues such as ⁶⁸Ga-DOTATATE (⁶⁸Ga-labeled DOTA(0)-Tyr(3)-octreotide) will probably replace ¹²³I-MIBG (iodine-123-metaiodobenzylguanidine) in the near future. As nearly half of all pheochromocytoma patients harbor a mutation in one of the 14 tumor susceptibility genes, genetic testing and counseling should at least be considered in all patients with a proven tumor. Post-surgical annual follow-up of patients by measurements of plasma or urinary metanephrines should last for at least 10 years for timely detection of recurrent or metastatic disease. Patients with a high risk for recurrence or metastatic disease (paraganglioma, young age, multiple or large tumors, genetic background) should be followed up lifelong.

Silent genetic alterations identified by targeted next-generation sequencing in pheochromocytoma/paraganglioma: A clinicopathological correlations

AIMS

The goal of this pilot study was to develop a customized, cost-effective amplicon panel (Ampliseq) for target sequencing in a cohort of patients with sporadic phaeochromocytoma/paraganglioma.

METHODS

Phaeochromocytoma/paragangliomas from 25 patients were analysed by targeted next-generation sequencing approach using an Ion Torrent PGM instrument. Primers for 15 target genes (NF1, RET, VHL, SDHA, SDHB, SDHC, SDHD, SDHAF2, TMEM127, MAX, MEN1, KIF1Bβ, EPAS1, CDKN2 & PHD2) were designed using ion ampliseq designer. Ion Reporter software and Ingenuity® Variant Analysis™ software (www.ingenuity.com/variants) from Ingenuity Systems were used to analysis these results.

RESULTS

Overall, 713 variants were identified. The variants identified from the Ion Reporter ranged from 64 to 161 per patient. Single nucleotide variants (SNV) were the most common. Further annotation with the help of Ingenuity variant analysis revealed 29 of these 713variants were deletions. Of these, six variants were non-pathogenic and four were likely to be pathogenic. The remaining 19 variants were of uncertain significance. The most frequently altered gene in the cohort was KIF1B followed by NF1. Novel KIF1B pathogenic variant c.3375+1G>A was identified. The mutation was noted in a patient with clinically confirmed neurofibromatosis. Chromosome 1 showed the presence of maximum number of variants.

CONCLUSIONS

Use of targeted next-generation sequencing is a sensitive method for the detecting genetic changes in patients with phaeochromocytoma/paraganglioma. The precise detection of these genetic changes helps in understanding the pathogenesis of these tumours.

Precision medicine in pheochromocytoma and paraganglioma: current and future concepts

Pheochromocytoma and paraganglioma (PPGL) are rare diseases but are also amongst the most characterized tumour types. Hence, patients with PPGL have greatly benefited from precision medicine for more than two decades. According to current molecular biology and genetics-based taxonomy, PPGL can be divided into three different clusters characterized by: Krebs cycle reprogramming with oncometabolite accumulation or depletion (group 1a); activation of the (pseudo)hypoxia signalling pathway with increased tumour cell proliferation, invasiveness and migration (group 1b); and aberrant kinase signalling causing a pro-mitogenic and anti-apoptotic state (group 2). Categorization into these clusters is highly dependent on mutation subtypes. At least 12 different syndromes with distinct genetic causes, phenotypes and outcomes have been described. Genetic screening tests have a documented benefit, as different PPGL syndromes require specific approaches for optimal diagnosis and localization of various syndrome-related tumours. Genotype-tailored treatment options, follow-up and preventive care are being investigated. Future new developments in precision medicine for PPGL will mainly focus on further identification of driver mechanisms behind both disease initiation and malignant progression. Identification of novel druggable targets and prospective validation of treatment options are eagerly awaited. To achieve these goals, we predict that collaborative large-scale studies will be needed: Pheochromocytoma may provide an example for developing precision medicine in orphan diseases that could ultimately aid in similar efforts for other rare conditions.