Genetics, diagnosis, management and future directions of research of phaeochromocytoma and paraganglioma: a position statement and consensus of the Working Group on Endocrine Hypertension of the European Society of Hypertension

Case report: Significant liver atrophy due to giant cystic pheochromocytoma

INTRODUCTION

Pheochromocytoma is a neuroendocrine tumor originating from chromaffin cells in the adrenal medulla. Giant pheochromocytomas with a maximum diameter of over 20 cm are particularly rare.

CASE PRESENTATION

We present a case of giant cystic pheochromocytoma in a 64-year-old woman who was found to have a right abdominal mass during an ultrasound examination, which is the largest pheochromocytoma ever documented in China. Meanwhile, obvious atrophy of the right lobe of the liver was found in preoperative CT and during the operation. Our literature review identified 20 cases with a diameter of over 20 cm. The average age at diagnosis was 51.7 (range 17-85), and 35% of cases did not exhibit classic symptoms.

CONCLUSION

Giant pheochromocytoma is an uncommon neoplasm. It can be discovered late due to a lack of clinical manifestations. Diagnosis is dependent on imaging recognition together with catecholamine secretion. Surgical resection is the only curative treatment for such tumors.

Recurrent paraganglioma of the vulva: A rare case report and review of the literature

Purpose

Vulva paragangliomas are rare and usually misdiagnosed or missed, especially in juveniles. Our aim was to summarize the clinical characteristics and treatments of vulva paragangliomas.

Methods and results

We present a case of a 17-year-old Chinese patient with functional paraganglioma from the vulva that was misdiagnosed as clear cell carcinoma. She had suffered from severe headaches, palpitations, sweating, pallor and hypertension. The vaginal wall was invaded by this mass. The tumour was surgically removed smoothly. However, the disease recurred 7 years after surgery, and the patient was treated again. Personalized genetic testing was performed while recovering, and the results suggested that the patient had a germline mutation in the Succinate Dehydrogenase subunit B (SDHB) gene. Now, the patient has been discharged successfully, her blood pressure has returned to normal and some of her clinical symptoms disappeared. A review of the literature concerning the topic is also presented, there have been only 2 cases of paraganglioma of the vulva and 11 cases of vaginal paraganglioma since 1955.

Conclusion

Our case describes a recurrent vulvovaginal paraganglioma with SDHB gene mutation and the largest tumor diameter to date. The diagnosis and treatment process of this case can provide reference for the management of other similar patients.

Novel Germline PHD2 Variant in a Metastatic Pheochromocytoma and Chronic Myeloid Leukemia, but in the Absence of Polycythemia

Background: Pheochromocytoma (Pheo) and paraganglioma (PGL) are rare tumors, mostly resulting from pathogenic variants of predisposing genes, with a genetic contribution that now stands at around 70%. Germline variants account for approximately 40%, while the remaining 30% is attributable to somatic variants. Objective: This study aimed to describe a new PHD2 (EGLN1) variant in a patient affected by metastatic Pheo and chronic myeloid leukemia (CML) without polycythemia and to emphasize the need to adopt a comprehensive next-generation sequencing (NGS) panel. Methods: Genetic analysis was carried out by NGS. This analysis was initially performed using a panel of genes known for tumor predisposition (EGLN1, EPAS1, FH, KIF1Bβ, MAX, NF1, RET, SDHA, SDHAF2, SDHB, SDHC, SDHD, TMEM127, and VHL), followed initially by SNP-CGH array, to exclude the presence of the pathogenic Copy Number Variants (CNVs) and the loss of heterozygosity (LOH) and subsequently by whole exome sequencing (WES) comparative sequence analysis of the DNA extracted from tumor fragments and peripheral blood. Results: We found a novel germline PHD2 (EGLN1) gene variant, c.153G>A, p.W51*, in a patient affected by metastatic Pheo and chronic myeloid leukemia (CML) in the absence of polycythemia. Conclusions: According to the latest guidelines, it is mandatory to perform genetic analysis in all Pheo/PGL cases regardless of phenotype. In patients with metastatic disease and no evidence of polycythemia, we propose testing for PHD2 (EGLN1) gene variants. A possible correlation between PHD2 (EGLN1) pathogenic variants and CML clinical course should be considered.

Predicting Hypertension Subtypes with Machine Learning Using Targeted Metabolites and Their Ratios

Hypertension is a major global health problem with high prevalence and complex associated health risks. Primary hypertension (PHT) is most common and the reasons behind primary hypertension are largely unknown. Endocrine hypertension (EHT) is another complex form of hypertension with an estimated prevalence varying from 3 to 20% depending on the population studied. It occurs due to underlying conditions associated with hormonal excess mainly related to adrenal tumours and sub-categorised: primary aldosteronism (PA), Cushing’s syndrome (CS), pheochromocytoma or functional paraganglioma (PPGL). Endocrine hypertension is often misdiagnosed as primary hypertension, causing delays in treatment for the underlying condition, reduced quality of life, and costly antihypertensive treatment that is often ineffective. This study systematically used targeted metabolomics and high-throughput machine learning methods to predict the key biomarkers in classifying and distinguishing the various subtypes of endocrine and primary hypertension. The trained models successfully classified CS from PHT and EHT from PHT with 92% specificity on the test set. The most prominent targeted metabolites and metabolite ratios for hypertension identification for different disease comparisons were C18:1, C18:2, and Orn/Arg. Sex was identified as an important feature in CS vs. PHT classification.

Management of Patients with Treatment of Pheochromocytoma: A Critical Appraisal

Simple Summary

Preoperative medical preparation with an alpha blockade has been implemented early 1960s to prevent intraoperative hemodynamic instability and consequently decrease morbi-mortality in patients at a high risk of complications. Indeed, surgery at that time consisted of open adrenalectomies with a high morbidity and mortality rate. Current clinical guidelines are based on these early experiences. However, emerging technologies have permitted a drastic reduction of the morbi-mortality rate in patients treated for pheochromocytoma. However, the clinical guidelines have not evolved at the same rate. The aim of this systematic review is to assess the evolution of the management of pheochromocytomas and to appraise the current clinical guidelines to the current clinical practices.

Abstract

The management of pheochromocytomas has significantly evolved these last 50 years, especially with the emergence of new technologies such as laparoscopic procedures in the 1990s. A preoperative blockade using antihypertensive medications to prevent intraoperative hemodynamic instability and cardiocirculatory events is recommended by current clinical guidelines. However, these guidelines are still based on former experiences and are subject to discussion in the scientific community. The aim of this systematic review was to assess the evolution of the management of pheochromocytomas. Laparoscopic procedure is established as the standard of care in current practices. Preoperative medical preparation should be questioned because it does not significantly improve intraoperative events or the risk of postoperative complications in current clinical practice. Current clinical recommendations should be revised and upgraded to current clinical practices.

International initiative for a curated SDHB variant database improving the diagnosis of hereditary paraganglioma and pheochromocytoma

BACKGROUND

SDHB is one of the major genes predisposing to paraganglioma/pheochromocytoma (PPGL). Identifying pathogenic SDHB variants in patients with PPGL is essential to the management of patients and relatives due to the increased risk of recurrences, metastases and the emergence of non-PPGL tumours. In this context, the 'NGS and PPGL (NGSnPPGL) Study Group' initiated an international effort to collect, annotate and classify SDHB variants and to provide an accurate, expert-curated and freely available SDHB variant database.

METHODS

A total of 223 distinct SDHB variants from 737 patients were collected worldwide. Using multiple criteria, each variant was first classified according to a 5-tier grouping based on American College of Medical Genetics and NGSnPPGL standardised recommendations and was then manually reviewed by a panel of experts in the field.

RESULTS

This multistep process resulted in 23 benign/likely benign, 149 pathogenic/likely pathogenic variants and 51 variants of unknown significance (VUS). Expert curation reduced by half the number of variants initially classified as VUS. Variant classifications are publicly accessible via the Leiden Open Variation Database system (https://databases.lovd.nl/shared/genes/SDHB).

CONCLUSION

This international initiative by a panel of experts allowed us to establish a consensus classification for 223 SDHB variants that should be used as a routine tool by geneticists in charge of PPGL laboratory diagnosis. This accurate classification of SDHB genetic variants will help to clarify the diagnosis of hereditary PPGL and to improve the clinical care of patients and relatives with PPGL.

Preoperative Diagnosis of Abdominal Extra-Adrenal Paragangliomas with Fine-Needle Biopsy

Paragangliomas are rare, non-epithelial neuroendocrine neoplasms originating in paraganglia, for instance the adrenal medulla, or at extra-adrenal locations. The aim of this study was to review the literature regarding abdominal extra-adrenal paragangliomas diagnosed pre-operatively with fine-needle biopsy (FNA and/or FNB). The PubMed database was searched to identify such cases, using a specific algorithm and inclusion/exclusion criteria. An unpublished case from our practice was also added to the rest of the data, resulting in a total of 36 cases for analysis. Overall, 24 (67%) lesions were found in females, whereas 12 (33%) in males. Most (21/36; 58.33%) were identified around and/or within the pancreatic parenchyma. FNA and/or FNB reached or suggested a paraganglioma diagnosis in 17/36 cases (47.22%). Of the preoperative misdiagnoses, the most common was an epithelial neuroendocrine tumor (NET). Regarding follow-up, most patients were alive with no reported recurrence; however, 5/36 patients exhibited a recurrence or a widespread disease, whereas one patient died 48 months following her diagnosis. In two patients, transient hypertension was reported during the EUS-FNA procedure. In conclusion, this study showed that the preoperative diagnosis of these lesions is feasible and, while diagnostic pitfalls exist, they could significantly be avoided with the application of immunochemistry.

Clinical and Pathological Tools for Predicting Recurrence and/or Metastasis in Patients with Pheochromocytoma and Paraganglioma

Pheochromocytomas and paragangliomas are endocrine tumors belonging to the family of neural crest cell-derived neoplasms. They have an extremely variable clinical course, characterized by a non-negligible percentage of relapse and/or metastasis after radical surgery. To date, there are no reliable methods to predict the metastatic potential of these neoplasms, despite several clinical, molecular, and histopathological factors that have been extensively studied in the literature as predictors of the recurrence and/or metastasis in these neoplasms with different performances and results. In this review, we aimed to discuss and analyze the most important clinical and histopathological tools for predicting recurrence risk in patients affected by pheochromocytomas or paragangliomas. Thus, we compared the main available predictive models, exploring their applications in stratifying patients’ risks. In conclusion, we underlined the importance of simple and validated tools to better define disease aggressiveness and establish tailored patients’ treatments and follow-ups.

Succinate Dehydrogenase, Succinate, and Superoxides: A Genetic, Epigenetic, Metabolic, Environmental Explosive Crossroad

Research focused on succinate dehydrogenase (SDH) and its substrate, succinate, culminated in the 1950s accompanying the rapid development of research dedicated to bioenergetics and intermediary metabolism. This allowed researchers to uncover the implication of SDH in both the mitochondrial respiratory chain and the Krebs cycle. Nowadays, this theme is experiencing a real revival following the discovery of the role of SDH and succinate in a subset of tumors and cancers in humans. The aim of this review is to enlighten the many questions yet unanswered, ranging from fundamental to clinically oriented aspects, up to the danger of the current use of SDH as a target for a subclass of pesticides.

Preanalytical Pitfalls in Untargeted Plasma Nuclear Magnetic Resonance Metabolomics of Endocrine Hypertension

Despite considerable morbidity and mortality, numerous cases of endocrine hypertension (EHT) forms, including primary aldosteronism (PA), pheochromocytoma and functional paraganglioma (PPGL), and Cushing's syndrome (CS), remain undetected. We aimed to establish signatures for the different forms of EHT, investigate potentially confounding effects and establish unbiased disease biomarkers. Plasma samples were obtained from 13 biobanks across seven countries and analyzed using untargeted NMR metabolomics. We compared unstratified samples of 106 PHT patients to 231 EHT patients, including 104 PA, 94 PPGL and 33 CS patients. Spectra were subjected to a multivariate statistical comparison of PHT to EHT forms and the associated signatures were obtained. Three approaches were applied to investigate and correct confounding effects. Though we found signatures that could separate PHT from EHT forms, there were also key similarities with the signatures of sample center of origin and sample age. The study design restricted the applicability of the corrections employed. With the samples that were available, no biomarkers for PHT vs. EHT could be identified. The complexity of the confounding effects, evidenced by their robustness to correction approaches, highlighted the need for a consensus on how to deal with variabilities probably attributed to preanalytical factors in retrospective, multicenter metabolomics studies.

RET T244I Germline Variant Mutation in a Patient with Pancreatic Paraganglioma and Primary Hyperparathyroidism

INTRODUCTION

Paragangliomas are rare neuroendocrine tumors that arise from chromaffin cells. Often termed extra-adrenal pheochromocytomas, these tumors vary with regards to their functionality, location, and malignant potential. Mutations in the RET proto-oncogene are associated with multiple endocrine neoplasia syndrome type 2 (MEN-2) and paragangliomas. The phenotypes of the individual mutations are documented to help determine prognosis.

CASE PRESENTATION

We report a case of a 64-year-old man with a history of parathyroid adenoma who developed a pancreatic retroperitoneal paraganglioma. Despite having laboratory evidence of excess circulating catecholamines, the patient's only presenting symptom was hip pain. The patient underwent resection, and histologic findings were consistent with paraganglioma with lymph node metastasis. Genetic testing revealed a variant of uncertain significance within the RET gene [c.731C>T (p.T244I)].

CONCLUSIONS

Paragangliomas are rare extra-adrenal neuroendocrine tumors that can be associated with germline mutations. Our patient was diagnosed with a pancreatic paraganglioma associated with a RET T244I mutation. Identifying patients with germline mutations is important for documenting phenotypic presentations of RET gene variants of uncertain significance, which will allow physicians to provide proper management and surveillance of paragangliomas and other associated tumors.

Dysfunction of calcium-regulated exocytosis at a single-cell level causes catecholamine hypersecretion in patients with pheochromocytoma

Neuroendocrine tumors constitute a heterogeneous group of tumors arising from hormone-secreting cells and are generally associated with a dysfunction of secretion. Pheochromocytoma (Pheo) is a neuroendocrine tumor that develops from chromaffin cells of the adrenal medulla, and is responsible for an excess of catecholamine secretion leading to severe clinical symptoms such as hypertension, elevated stroke risk and various cardiovascular complications. Surprisingly, while the hypersecretory activity of Pheo is well known to pathologists and clinicians, it has never been carefully explored at the cellular and molecular levels. In the present study, we have combined catecholamine secretion measurement by carbon fiber amperometry on human tumor cells directly cultured from freshly resected Pheos, with the analysis by mass spectrometry of the exocytotic proteins differentially expressed between the tumor and the matched adjacent non-tumor tissue. In most patients, catecholamine secretion recordings from single Pheo cells revealed a higher number of exocytic events per cell associated with faster kinetic parameters. Accordingly, we unravel significant tumor-associated modifications in the expression of key proteins involved in different steps of the calcium-regulated exocytic pathway. Altogether, our findings indicate that dysfunction of the calcium-regulated exocytosis at the level of individual Pheo cell is a cause of the tumor-associated hypersecretion of catecholamines.

I-131 metaiodobenzylguanidine therapy is a significant treatment option for pheochromocytoma and paraganglioma

AIM

Pheochromocytomas and paragangliomas (PPGLs) are rare neuroendocrine tumours of chromaffin cells. Several modalities are currently available to treat patients with PPGL. These treatment modalities include surgery, chemotherapy, molecular targeted therapy and radiopharmaceuticals.

METHODS

I-131 metaiodobenzylguanidine (mIBG), a classic radiopharmaceutical, can be taken up through specific receptors and sited into many, but not all, PPGL cells.

RESULTS

Many studies have investigated the efficacy and toxicity of I-131 mIBG therapy. These studies reported significant results in terms of objective, hormonal and symptomatic responses as well as tolerable toxicities in patients.

CONCLUSION

This article reviews the reported experiences of patients who underwent I-131 mIBG therapy for PPGL with a focus on functions and deficiencies of the therapy.

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.

Supportive management of patients with pheochromocytoma/paraganglioma undergoing noninvasive treatment

PURPOSE OF REVIEW

Many publications review perioperative management of pheochromocytomas/paragangliomas (PPGLs); however, a large population, including 10-20% of metastatic PPGL patients, have inoperable disease. This has necessitated the development of noninvasive treatments (e.g., radio/chemotherapy), which, in affording disease-modification, have led to an ever-growing population of surviving patients with inoperable PPGL. These patients experience debilitating symptoms arising from discomforts related to the masses themselves (e.g., pain from osseous metastasis) and symptoms from tumoral catecholamine production and release. Unfortunately, management of these conditions is not yet well-defined. Adding further insult-to-injury, these noninvasive treatments can trigger catecholamine release, worsening catecholamine-induced symptoms. Herein, we detail these ailments and their management, especially while patients receive these noninvasive treatments.

RECENT FINDINGS

Improved diagnostic evaluations have allowed for earlier detection of PPGL, prolonging survival in patients with inoperable PPGLs. Accordingly, noninvasive treatment strategies have rapidly evolved alongside state-of- the-art theranostics and genetic testing, which inform ongoing management and therapeutic response.

SUMMARY

While treatments afford improved survival, there must be a corresponding attention to quality-of-life. This is ensured by employing supportive management, which mitigates debilitating symptoms. This is best accomplished with a multidisciplinary approach and familiarity with genetic and biochemical determinants which guide patient education and management.

The Management of Hypertensive Emergencies-Is There a "Magical" Prescription for All?

Hypertensive emergencies (HE) represent high cardiovascular risk situations defined by a severe increase in blood pressure (BP) associated with acute, hypertension mediated organ damage (A-HMOD) to the heart, brain, retina, kidneys, and large arteries. Blood pressure values alone do not accurately predict the presence of HE; therefore, the search for A-HMOD should be the first step in the management of acute severe hypertension. A rapid therapeutic intervention is mandatory in order to limit and promote regression of end-organ damage, minimize the risk of complications, and improve patient outcomes. Drug therapy for HE, target BP, and the speed of BP decrease are all dictated by the type of A-HMOD, specific drug pharmacokinetics, adverse drug effects, and comorbidities. Therefore, a tailored approach is warranted. However, there is currently a lack of solid evidence for the appropriate treatment strategies for most HE. This article reviews current pharmacological strategies while providing a stepwise, evidence based approach for the management of HE.

Perioperative outcomes of pheochromocytoma/paraganglioma surgery preceded by Takotsubo-like cardiomyopathy

BACKGROUND

Pheochromocytomas and paragangliomas can induce severe cardiovascular manifestations such as Takotsubo-like cardiomyopathy. What the perioperative outcomes are of patients presenting with pheochromocytomas/paragangliomas preceded by Takotsubo-like cardiomyopathy remains an unresolved question.

METHODS

From 2006 to 2019, all patients who underwent surgery for pheochromocytomas/paragangliomas preceded by Takotsubo-like cardiomyopathy were included from 3 high-volume centers, with specific attention to perioperative hemodynamic instability and postoperative outcomes.

RESULTS

Overall, 37 patients were included, with a median age of 45 years. Patients were operated on 2 months (1-4) after a Takotsubo-like cardiomyopathy episode; 33 (89%) had a laparoscopic approach. All those who underwent surgery presented in a hemodynamically stable situation. All except 1 of the pheochromocytomas/paragangliomas patients had at least 1 antihypertensive treatment at the time of surgery. The median preoperative systolic blood pressure in the Takotsubo-like cardiomyopathy group was 120 mm Hg (95-132). Overall, 27/34 (79%) of patients required vasoactive drugs during surgery with nicardipine (n = 22), esmolol (n = 12), and/or norepinephrine (n = 8). No patient presented a catecholamine-induced life-threatening complication such as hypertensive crisis, cardiac arrhythmias, pulmonary edema, cardiac ischemia, or Takotsubo-like cardiomyopathy in the perioperative period. Severe morbi-mortality was nil. The systematic review identified 5 studies including 38 pheochromocytomas/paragangliomas patients with at least 1 episode of acute heart failure considered as Takotsubo-like cardiomyopathy before surgery, of which 28 patients had delayed surgery with 1 postoperative death.

CONCLUSION

Hemodynamically stabilized patients with pheochromocytomas/paragangliomas preceded by Takotsubo-like cardiomyopathy can be safely scheduled for an elective pheochromocytomas/paragangliomas surgery, with similar intra and postoperative outcomes as those without Takotsubo-like cardiomyopathy.

Preoperative blood pressure targets and effect on hemodynamics in pheochromocytoma and paraganglioma

Patients with pheochromocytoma and paraganglioma (PPGL) are treated with α-adrenoceptor antagonists to improve peroperative hemodynamics. However, preoperative blood pressure targets differ between institutions. We retrospectively compared per- and postoperative hemodynamics in 30 patients with PPGL that were pretreated with phenoxybenzamine aiming at different blood pressure targets at two separate endocrine departments. All patients were subsequently undergoing laparoscopic surgery at Department of Urology, Herlev University hospital. Fourteen patients were treated targeting to symptomatic and significant orthostatic hypotension and 16 patients to a seated blood pressure below 130/80 mmHg. As a control group, we included 34 patients undergoing laparoscopic adrenalectomy for other reasons. The group titrated to orthostatic hypotension required a higher dose of phenoxybenzamine to achieve the blood pressure target. This group had less intraoperative systolic and diastolic blood pressure fluctuation (Mann-Whitney U test; P < 0.05) and less periods with heart rate above 100 b.p.m. (Mann-Whitney U test; P = 0.04) as compared to the group with a preoperative blood pressure target below 130/80 mmHg. Peroperative use of intravenous fluids were similar between the two groups, but postoperatively more intravenous fluids were administered in the group with a target of ortostatism. Overall, the control group was more hemodynamic stable as compared to either group treated for PPGL. We conclude that phenoxybenzamine pretreatment targeting ortostatic hypotension may improve peroperative hemodynamic stability but causes a higher postoperative requirement for intravenous fluids. Overall, PPGL surgery is related to greater hemodynamic instability compared to adrenalectomy for other reasons.

Management of Pheochromocytomas and Paragangliomas: A Case-Based Review of Clinical Aspects and Perspectives

Paraganglioma and pheochromocytoma are rare medical conditions. Thus, there are still a small number of studies, clinical trials, and evidence-based data in this field. This makes clinical decisions more difficult. In this study, we present a case report enriched with a short review of available essential clinical data, indicating the need for constant metoxycatecholamine level observation and a proper diagnostic imaging approach, especially in terms of ongoing pandemics. Our research also provides a summary of the molecular background of these diseases, indicating their future role in clinical management. We analyzed the ClinicalTrials.gov dataset in order to show future perspectives. In this paper, the use of the PET-CT before MRI or CT is proposed in specific cases during diagnosis processes contrary to the guidelines. PET-CT may be as effective as standard procedures and may provide a faster diagnosis, which is important in periods with more difficult access to health care, such as during the COVID-19 pandemic.

Phase II Study of ONC201 in Neuroendocrine Tumors including Pheochromocytoma-Paraganglioma and Desmoplastic Small Round Cell Tumor

PURPOSE

Tumor dopamine-like DRD2 receptor expression is higher in pheochromocytoma-paraganglioma (PC-PG) compared with other cancers. ONC201 is a bitopic DRD2 antagonist with preclinical ONC201 activity in desmoplastic small round cell tumor (DSRCT).

PATIENTS AND METHODS

Patients (N = 30) with neuroendocrine tumors were treated on this investigator-initiated trial (NCT03034200). ONC201 dose and schedule were 625 mg orally weekly in cohorts A (PC-PG) + B (other neuroendocrine tumors) and 625 mg orally on 2 consecutive days each week in cohort C, which included 5 responding patients. The primary endpoint was radiographic response measured using RECIST. Secondary endpoints included progression-free survival, overall survival, and safety.

RESULTS

In arm A (n = 10; all PC-PG), 50% (5/10) exhibited a partial response (PR) and 2 additional patients had stable disease (SD) >3 months. Median duration of therapy for arm A patients was 9 months (range: 1.5-33 months) with 5 patients treated >1 year. In arm B (n = 12), there were 1 PR (DSRCT) and 2 SD (DSRCT; neuroblastoma) >3 months. Median duration of therapy in arm A was 18 months (range: 1-33 months) and arm B was 3 months (range: 1.5-33 months). Arm C PC-PG (N = 8) showed 1 PR and 7 SD at 3 months, with median duration of therapy >10 months. There was no decline in Karnofsky performance status at week 12 for 28 of 30 patients and no dose modification due to treatment-related adverse events.

CONCLUSIONS

Oral ONC201 was well tolerated in patients with metastatic neuroendocrine tumors and associated with clinical benefit, including tumor responses, particularly in some patients with DSRCT and the majority of patients with PC-PG. See related commentary by Owen and Trikalinos, p. 1748.

Genetic Characteristics of Incidental Pheochromocytoma and Paraganglioma

CONTEXT

Pheochromocytomas and paragangliomas (PPGLs) are being increasingly discovered by imaging performed for unrelated conditions. The genetic landscape of incidental PPGLs remains to be elucidated.

OBJECTIVE

We aimed to describe the genetic characteristics of PPGLs discovered incidentally in a large PPGL cohort.

METHODS

This retrospective cross-sectional study included 697 patients with pathology confirmed PPGLs, including 283 incidentalomas and 414 nonincidentalomas, at 2 tertiary care centers in China in 2009-2019. Tumor DNA samples were sequenced by next-generation sequencing. Identified genetic mutations were confirmed by Sanger sequencing and tested in 277 available matched blood DNA samples.

RESULTS

There was a lower proportion of patients with mutations identified (53% vs 63.3%; P = 0.0067) in incidental than nonincidental PPGLs. In incidental PPGLs, HRAS (11.7%), FGFR1 (11%), and RET (9.2%) were the top 3 mutated genes, whereas HRAS (17.9%), VHL (9.2%), and NF-1 (8.7%) exhibited the highest rate of mutations in nonincidental PPGLs. In incidental pheochromocytomas, the most frequently mutated genes were RET (10.9%), HRAS (10.4%), and VHL (8.6%), while in incidental paragangliomas, FGFR1 (32.8%), HRAS (16.4%), and EPAS1 (9.8%) topped the list. The frequency of NF-1 mutations was significantly lower in incidental than nonincidental pheochromocytomas (4.1% vs 11%; P = 0.0042), while FGFR1 mutations were far more common in incidental than nonincidental paragangliomas (32.8% vs 15.3%; P = 0.0076).

CONCLUSION

More than half of patients with incidental PPGLs had mutations in common susceptibility genes. The search for susceptibility genes should take both the mode of discovery (incidental vs nonincidental) and tumor location (pheochromocytoma vs paraganglioma) into consideration.

The Role of Propranolol as a Repurposed Drug in Rare Vascular Diseases

Rare Diseases (RD) are defined by their prevalence in less than 5 in 10,000 of the general population. Considered individually, each RD may seem insignificant, but together they add up to more than 7000 different diseases. Research in RD is not attractive for pharmaceutical companies since it is unlikely to recover development costs for medicines aimed to small numbers of patients. Since most of these diseases are life threatening, this fact underscores the urgent need for treatments. Drug repurposing consists of identifying new uses for approved drugs outside the scope of the original medical indication. It is an alternative option in drug development and represents a viable and risk-managed strategy to develop for RDs. In 2008, the “off label” therapeutic benefits of propranolol were described in the benign tumor Infantile Hemangioma. Propranolol, initially prescribed for high blood pressure, irregular heart rate, essential tremor, and anxiety, has, in the last decade, shown increasing evidence of its antiangiogenic, pro-apoptotic, vasoconstrictor and anti-inflammatory properties in different RDs, including vascular or oncological pathologies. This review highlights the finished and ongoing trials in which propranolol has arisen as a good repurposing drug for improving the health condition in RDs.

Improved Diagnostic Accuracy of Clonidine Suppression Testing Using an Age-Related Cutoff for Plasma Normetanephrine

BACKGROUND

Moderately elevated plasma normetanephrine (NMN) levels are frequent among patients with suspected pheochromocytoma and paraganglioma (PPGL). Clonidine suppression testing (CST) is recommended to distinguish patients with from those without PPGL. We aimed at evaluating the diagnostic outcome of CST in patients with moderate NMN elevations.

METHODS

Data from patients participating in the PMT study (Prospective Monoamine-Producing Tumor) and the ENSAT (European Network for the Study of Adrenal Tumours) registry in 6 European reference centers were analyzed retrospectively. Eighty-nine patients with suspected PPGL and moderate NMN elevations upon screening were included. During follow-up, PPGL was confirmed in 16 and excluded in 73 cases. Plasma NMN was measured by liquid chromatography tandem mass spectrometry before and 180 minutes after oral clonidine. Receiver operating characteristic analysis was performed to identify optimal cutoffs.

RESULTS

If published diagnostic criteria for CST (ie, NMN ≥112 ng/L and NMN suppression <40%) were applied, a sensitivity of 88% (CI, 61%-98%) and a specificity of 97% (CI, 90%-100%) were observed. An improved cutoff for plasma NMN 180 minutes after clonidine was established at 80% of the age-related upper limit of normal, resulting in a sensitivity of 94% and a specificity of 97%. False-negative CST results occurred in 2 patients with small PPGL.

CONCLUSIONS

This study, involving one of the largest cohorts of patients with suspected PPGL and moderately elevated NMN, confirmed the diagnostic accuracy of CST. The application of an adapted cutoff further improved sensitivity.

Bladder paragangliomas: a pictorial review

Bladder paragangliomas (bPGL) are rare neuroendocrine tumors arising from the sympathetic paraganglia present in the bladder wall. Bladder PGLs are typically submucosal or intramural but when subserosal may not be readily visible at cystoscopy. The average size at presentation is 3.9 cm (range 1.0-9.1 cm). When small, bPGL are usually spherical, well-marginated and homogeneous. Larger bPGL are typically more complex with peri- and intra-tumoral neovascularity and central necrosis. On ultrasound, increased color Doppler signal is typical. The increased soft tissue resolution of MRI enables localization of bPGL within the bladder wall more accurately than CT. Restricted diffusion and avid contrast enhancement help differentiate small bPGLs from leiomyomas, which have similar appearances on ultrasound and CT. Nuclear medicine techniques identify bPGLs and their metastases with high specificity, ⁶⁸Ga-DOTATATE PET/CT having largely replaced ¹²³I-mIBG SPECT/CT as the first line functional investigation. Imaging is essential to aid surgical planning, as endoscopic resection is often not possible or incomplete due to tumor location. For patients with advanced disease, ⁶⁸Ga-DOTATATE PET/CT and ¹²³I-mIBG SPECT/CT assess suitability for peptide receptor radionuclide therapy. Up to 63% of bPGL patients have a germline mutation, most commonly in the SDHB subunit gene, increasing their risk of developing pheochromocytomas and further paragangliomas; lifelong annual biochemical and periodic imaging screening from skull base to pelvis is therefore recommended.

[Succinate dehydrogenase in cancer]

Succinate dehydrogenase (SDH) is a mitochondrial enzyme that participates in both the tricarboxylic acid cycle and the electron transport chain. Mutations in genes encoding SDH are responsible for a predisposition to pheochromocytomas and paragangliomas, and more rarely, to gastrointestinal stromal tumors or renal cell carcinomas. A decrease in SDH activity, not explained by genetics, has also been observed in more common cancers. One of the consequences of the inactivation of SDH is the excessive production of its substrate, succinate, which acts as an oncometabolite by promoting a pseudohypoxic status and an extensive epigenetic rearrangement. Understanding SDH-related oncogenesis now makes it possible to develop innovative diagnostic methods and to consider targeted therapies for the management of affected patients.

Controversies about the systematic preoperative pharmacological treatment before pheochromocytoma or paraganglioma surgery

The question of systematic use of a pharmacological treatment before surgery in patients diagnosed with pheochromocytoma and paraganglioma (PPGL) remains highly controversial. While recent guidelines suggest that this should be used in all patients, some experienced teams consider it unnecessary in some cases, provided the surgery is performed in a dedicated center that has expert endocrinologists, cardiologists, surgeons, and anesthetists. This controversy is aimed at shedding light on the potential benefits and risks of such a treatment, focusing specifically on alpha blockers which are considered as the first-line medical treatments in patients with PPGL. After discussing the rationale for alpha blockers, hemodynamic instability, tolerance, and acute cardiac complications will then be discussed in the first part of the manuscript, defending a systematic use. The second section will focus on blood pressure control, tolerance of alpha blockers, and also the management of normotensive PPGL, examining the daily risks of PPGL and arguing against the systematic use of a preoperative pharmacological treatment before surgery. Finally, we will discuss the concept of expert centers and define the patients in whom the risk/benefit profile would favor the use of this preoperative treatment.

Personalized Management of Pheochromocytoma and Paraganglioma

Pheochromocytomas/paragangliomas are characterized by a unique molecular landscape that allows their assignment to clusters based on underlying genetic alterations. With around 30% to 35% of Caucasian patients (a lower percentage in the Chinese population) showing germline mutations in susceptibility genes, pheochromocytomas/paragangliomas have the highest rate of heritability among all tumors. A further 35% to 40% of Caucasian patients (a higher percentage in the Chinese population) are affected by somatic driver mutations. Thus, around 70% of all patients with pheochromocytoma/paraganglioma can be assigned to 1 of 3 main molecular clusters with different phenotypes and clinical behavior. Krebs cycle/VHL/EPAS1-related cluster 1 tumors tend to a noradrenergic biochemical phenotype and require very close follow-up due to the risk of metastasis and recurrence. In contrast, kinase signaling-related cluster 2 tumors are characterized by an adrenergic phenotype and episodic symptoms, with generally a less aggressive course. The clinical correlates of patients with Wnt signaling-related cluster 3 tumors are currently poorly described, but aggressive behavior seems likely. In this review, we explore and explain why cluster-specific (personalized) management of pheochromocytoma/paraganglioma is essential to ascertain clinical behavior and prognosis, guide individual diagnostic procedures (biochemical interpretation, choice of the most sensitive imaging modalities), and provide personalized management and follow-up. Although cluster-specific therapy of inoperable/metastatic disease has not yet entered routine clinical practice, we suggest that informed personalized genetic-driven treatment should be implemented as a logical next step. This review amalgamates published guidelines and expert views within each cluster for a coherent individualized patient management plan.

Pheochromocytomas and Abdominal Paragangliomas: A Practical Guidance

Simple Summary

Pheochromocytomas and abdominal paragangliomas (PPGLs) are rare. They can be discovered incidentally by imaging with computed tomography or magnetic resonance imaging and during hormonal surveillance in patients with known genetic variants that are associated with PPGLs. As most PPGLs are functioning, a hormonal work-up evaluating for catecholamine excess is recommended. Classical symptoms, such as tachycardia, hypertension and headache, can be present, but when the PPGL is discovered as an incidentaloma, symptoms may be lacking or be more discrete. PPGLs carry malignant potential, and patients should undergo close surveillance, as recurrence of disease or metastasis may develop. Genetic susceptibility for multifocal disease has gained more attention, and germline variants are commonly detected, thus facilitating detection of hereditary cases and afflicted family members. Any patient with a PPGL should be managed by an expert multidisciplinary team consisting of endocrinologists, radiologists, surgeons, pathologists and clinical geneticists.

Abstract

Pheochromocytomas and abdominal paragangliomas (PPGLs) are rare tumors arising from the adrenal medulla or the sympathetic nervous system. This review presents a practical guidance for clinicians dealing with PPGLs. The incidence of PPGLs has risen. Most cases are detected via imaging and less present with symptoms of catecholamine excess. Most PPGLs secrete catecholamines, with diffuse symptoms. Diagnosis is made by imaging and tests of catecholamines. Localized disease can be cured by surgery. PPGLs are the most heritable of all human tumors, and germline variants are found in approximately 30–50% of cases. Such variants can give information regarding the risk of developing recurrence or metastases as well as the risk of developing other tumors and may identify relatives at risk for disease. All PPGLs harbor malignant potential, and current histological and immunohistochemical algorithms can aid in the identification of indolent vs. aggressive tumors. While most patients with metastatic PPGL have slowly progressive disease, a proportion of patients present with an aggressive course, highlighting the need for more effective therapies in these cases. We conclude that PPGLs are rare but increasing in incidence and management should be guided by a multidisciplinary team.

Research on the Damage of Adrenal Pheochromocytoma to Patients’ Cardiovascular Vessels and Its Correlation with Hypertension

Chromaffin cell-centered pheochromocytoma (Pheo) is a rare tumour. Pheochromocytoma and how it affects the heart will be the topic of this article. Due to the comparable symptoms and indications of the sympathetic nervous system, a pheochromocytoma might be difficult to detect early. There are also other frequent differential diagnoses that might delay the detection of a pheochromocytoma. One of the most common side effects of pheochromocytoma is unmanageable hypertension. Hypertensive crisis (extreme increases in blood pressure) can develop, which is a life-threatening condition that leads to strokes or arrhythmia. Estimated to affect African Americans significantly, they frequently go undetected due to a lack of resources or accessibility of services. Because this tumour is difficult to identify and its symptoms often resemble those of other diseases, it is frequently overlooked. A pheochromocytoma's long-term consequences can include cardiac muscle deterioration, congestive heart failure (CHF), a higher diabetes risk and possibly death. Masked hypertension (MH) is more common in people with adrenal pheochromocytoma, which has been related to an increased risk of heart disease. With the use of ambulatory blood pressure monitoring, this research set out to find out how common mental health issues are among people with APs. There were 85 participants in all, 43 of whom had APs and 42 of whom had the same age, gender, BMI, smoking and diabetes as the AP patients. Measurements were made of the BP and AP in both the diseased and control groups. Retrospective data collection was used to gather biochemical, hormonal and radiological information on the patients. The Pearson–Boltzmann CNN method was then used to assess risk based on the diagnosis results. Furthermore, depending on the risk score, more nonselective blockers (e.g., prazosin, doxazosin, terazosin, and metyrosine) have been used to lower perioperative catecholamine levels, hence reducing illness risk. After a successful surgical excision of the tumour, the recommended therapy can usually be stopped quickly.

Perioperative Management of Pheochromocytomas and Sympathetic Paragangliomas

Pheochromocytomas and paragangliomas (PPGLs) are rare neuroendocrine tumors arising from chromaffin cells of the adrenal medulla or extra-adrenal paraganglia, respectively. PPGLs have the highest degree of heritability among endocrine tumors. Currently, ~40% of individuals with PPGLs have a genetic germline and there are at least 12 different genetic syndromes related to these tumors. Metastatic PPGLs are defined by the presence of distant metastases at sites where chromaffin cells are physiologically absent. Approximately 10% of pheochromocytomas and ~40% of sympathetic paragangliomas are linked to metastases, explaining why complete surgical resection is the first-choice treatment for all PPGL patients. The surgical approach is a high-risk procedure requiring perioperative management by a specialized multidisciplinary team in centers with broad expertise. In this review, we summarize and discuss the most relevant aspects of perioperative management in patients with pheochromocytomas and sympathetic paragangliomas.

Contemporary management of paragangliomas of the head and neck

Head and neck paragangliomas (HNPGLs) are rare neuroendocrine tumors typically arising from nonsecretory head and neck parasympathetic ganglia. Historically thought of as aggressive tumors that warranted equally aggressive surgical intervention, evidence has emerged demonstrating that the vast majority of HNPGLs are slow growing and indolent. It is also now recognized that a large proportion of HNPGLs are hereditary with succinate dehydrogenase gene mutations typically implicated. These recent advances have led to significant changes in the way in which clinicians investigate and treat HNPGLs with most now opting for more conservative treatment strategies. However, a proportion of patients present with more aggressive disease and still require nonconservative treatment strategies. Recent studies have sought to determine in which groups of patients the morbidity associated with treatment is justified. We summarize the recent advances in the understanding and management of these tumors and we provide our recommendations regarding the management of HNPGLs.

[Adrenal incidentaloma - differential diagnosis and management]

Adrenal masses are common incidental findings on imaging procedures.In most cases, adrenal incidentalomas are nonfunctioning adrenocortical adenomas, but in up to 20 % they require therapeutic intervention. The aim of this article is to provide essential guidance for clinicians regarding clinical management of patients with adrenal incidentalomas based on the respective current clinical guidelines. The following main questions are addressed: How to distinguish a nonfunctioning incidentaloma from a functioning one and how to assess risk of malignancy? How to define and manage low-level autonomous cortisol secretion, formerly called "subclinical" Cushing's syndrome? Which patients have to be treated surgically and which approach should be used? What follow-up is indicated if the adrenal incidentaloma is not surgically removed?

Genetics of Pheochromocytomas and Paragangliomas Determine the Therapeutical Approach

Pheochromocytomas and paragangliomas are the most heritable endocrine tumors. In addition to the inherited mutation other driver mutations have also been identified in tumor tissues. All these genetic alterations are clustered in distinct groups which determine the pathomechanisms. Most of these tumors are benign and their surgical removal will resolve patient management. However, 5–15% of them are malignant and therapeutical possibilities for them are limited. This review provides a brief insight about the tumorigenesis associated with pheochromocytomas/paragangliomas in order to present them as potential therapeutical targets.

New Insights on the Genetics of Pheochromocytoma and Paraganglioma and Its Clinical Implications

Simple Summary

Pheochromocytoma and paraganglioma (together PPGL) are rare neuroendocrine tumors that arise from chromaffin tissue and produce catecholamines. Approximately 40% of cases of PPGL carry a germline mutation, suggesting that they have a high degree of heritability. The underlying mutation influences the PPGL clinical presentation such as cell differentiation, specific catecholamine production, tumor location, malignant potential and genetic anticipation, which helps to better understand the clinical course and tailor treatment accordingly. Genetic testing for pheochromocytoma and paraganglioma allows an early detection of hereditary syndromes and facilitates a close follow-up of high-risk patients. In this review article, we present the most recent advances in the field of genetics and we discuss the latest guidelines on the surveillance of asymptomatic SDHx mutation carriers.

Abstract

Pheochromocytomas (PHEOs) and paragangliomas (PGLs) are rare neuroendocrine tumors that arise from chromaffin cells. PHEOs arise from the adrenal medulla, whereas PGLs arise from the neural crest localized outside the adrenal gland. Approximately 40% of all cases of PPGLs (pheochromocytomas/paragangliomas) are associated with germline mutations and 30–40% display somatic driver mutations. The mutations associated with PPGLs can be classified into three groups. The pseudohypoxic group or cluster I includes the following genes: SDHA, SDHB, SDHC, SDHD, SDHAF2, FH, VHL, IDH1/2, MHD2, EGLN1/2 and HIF2/EPAS; the kinase group or cluster II includes RET, NF1, TMEM127, MAX and HRAS; and the Wnt signaling group or cluster III includes CSDE1 and MAML3. Underlying mutations can help understand the clinical presentation, overall prognosis and surveillance follow-up. Here we are discussing the new genetic insights of PPGLs.

How to Explore an Endocrine Cause of Hypertension

Hypertension (HTN) is the most frequent modifiable risk factor in the world, affecting almost 30 to 40% of the adult population in the world. Among hypertensive patients, 10 to 15% have so-called “secondary” HTN, which means HTN due to an identified cause. The most frequent secondary causes of HTN are renal arteries abnormalities (renovascular HTN), kidney disease, and endocrine HTN, which are primarily due to adrenal causes. Knowing how to detect and explore endocrine causes of hypertension is particularly interesting because some causes have a cure or a specific treatment available. Moreover, the delayed diagnosis of secondary HTN is a major cause of uncontrolled blood pressure. Therefore, screening and exploration of patients at risk for secondary HTN should be a serious concern for every physician seeing patients with HTN. Regarding endocrine causes of HTN, the most frequent is primary aldosteronism (PA), which also is the most frequent cause of secondary HTN and could represent 10% of all HTN patients. Cushing syndrome and pheochromocytoma and paraganglioma (PPGL) are rarer (less than 0.5% of patients). In this review, among endocrine causes of HTN, we will mainly discuss explorations for PA and PPGL.

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.

Somatostatin analogue pasireotide (SOM230) inhibits catecholamine secretion in human pheochromocytoma cells

Increasingly common, neuroendocrine tumors (NETs) are regarded nowadays as neoplasms potentially causing debilitating symptoms and life-threatening medical conditions. Pheochromocytoma is a NET that develops from chromaffin cells of the adrenal medulla, and is responsible for an excessive secretion of catecholamines. Consequently, patients have an increased risk for clinical symptoms such as hypertension, elevated stroke risk and various cardiovascular complications. Somatostatin analogues are among the main anti-secretory medical drugs used in current clinical practice in patients with NETs. However, their impact on pheochromocytoma-associated catecholamine hypersecretion remains incompletely explored. This study investigated the potential efficacy of octreotide and pasireotide (SOM230) on human tumor cells directly cultured from freshly resected pheochromocytomas using an implemented catecholamine secretion measurement by carbon fiber amperometry. SOM230 treatment efficiently inhibited nicotine-induced catecholamine secretion both in bovine chromaffin cells and in human tumor cells whereas octreotide had no effect. Moreover, SOM230 specifically decreased the number of exocytic events by impairing the stimulation-evoked calcium influx as well as the nicotinic receptor-activated inward current in human pheochromocytoma cells. Altogether, our findings indicate that SOM230 acts as an inhibitor of catecholamine secretion through a mechanism involving the nicotinic receptor and might be considered as a potential anti-secretory treatment for patients with pheochromocytoma.

Pediatric Metastatic Pheochromocytoma and Paraganglioma: Clinical Presentation and Diagnosis, Genetics, and Therapeutic Approaches

Although pediatric pheochromocytomas and paragangliomas (PPGLs) are rare, they have important differences compared to those in adults. Unfortunately, without timely diagnosis and management, these tumors have a potentially devastating impact on pediatric patients. Pediatric PPGLs are more often extra-adrenal, multifocal/metastatic, and recurrent, likely due to these tumors being more commonly due to a genetic predisposition than in adults. This genetic risk results in disease manifestations at an earlier age giving these tumors time to advance before detection. In spite of these problematic features, advances in the molecular and biochemical characterization of PPGLs have heralded an age of increasingly personalized medicine. An understanding of the genetic basis for an individual patient's tumor provides insight into its natural history and can guide clinicians in management of this challenging disease. In pediatric PPGLs, mutations in genes related to pseudohypoxia are most commonly seen, including the von Hippel-Lindau gene (VHL) and succinate dehydrogenase subunit (SDHx) genes, with the highest risk for metastatic disease associated with variants in SDHB and SDHA. Such pathogenic variants are associated with a noradrenergic biochemical phenotype with resultant sustained catecholamine release and therefore persistent symptoms. This is in contrast to paroxysmal symptoms (e.g., episodic hypertension, palpitations, and diaphoresis/flushing) as seen in the adrenergic, or epinephrine-predominant, biochemical phenotype (due to episodic catecholamine release) that is commonly observed in adults. Additionally, PPGLs in children more often present with signs and symptoms of catecholamine excess. Therefore, children, adolescents, and young adults present differently from older adults (e.g., the prototypical presentation of palpitations, perspiration, and pounding headaches in the setting of an isolated adrenal mass). These presentations are a direct result of genetic determinants and highlight the need for pediatricians to recognize these differences in order to expedite appropriate evaluations, including genetic testing. Identification and familiarity with causative genes inform surveillance and treatment strategies to improve outcomes in pediatric patients with PPGL.

Adrenal bleeding due to pheochromocytoma - A call for algorithm

BACKGROUND

Adrenal hemorrhage is a rare, usually life-threating complication. The most common neoplasm resulting in spontaneous adrenal bleeding is pheochromocytoma and it accounts for nearly 50% of cases. Currently, the recommendations for the diagnosis and management of patients with adrenal bleeding due to pheochromocytoma are unavailable.

MATERIALS AND METHODS

We performed a database search for all pheochromocytoma patients, diagnosed and treated from 2005 to 2021 in tertiary endocrinology center. 206 patients were identified, 183 with complete data were included in the analysis. We investigated clinicopathological characteristics, treatment and outcomes of hemorrhagic pheochromocytoma cases and characterize our approach to perioperative diagnosis and medical management. Finally our experiences and data from previously published articles concerning adrenal hemorrhage were analyzed to propose a diagnostic and therapeutic algorithm for hemorrhagic pheochromocytomas.

RESULTS

In the whole group, seven patients (4 men and 3 women) with adrenal bleeding were found, (3.8%). Median patient's age was 49 years (range: 36-78 years). The most common manifestation of adrenal bleeding was acute abdominal pain (5/7). Two patients developed shock. Hormonal assessment was performed in five patients, based on 24-hour urinary fractionated metanephrines with urinary 3-methoxytyramine. Normetanephrine was elevated in all patients, metanephrine and 3-methoxytyramine - in four cases (4/5). Most patients (6/7) had symptoms suggesting pheochromocytoma before hemorrhage - most commonly paroxysmal hypertension (4/7). One patient died, before the diagnosis of adrenal bleeding was made. Diagnostic imaging performed in six out of seven patients revealed adrenal tumor, with median largest diameter equal to 7.4 cm (range: 5-11 cm). Five patients had elective surgery, in one case an urgent surgery was performed. In all cases the diagnosis of pheochromocytoma was confirmed in postoperative histopathology or in autopsy. The perioperative survival rate was 85.7%.

CONCLUSIONS

Diagnosis of pheochromocytoma should be always considered in patients with adrenal bleeding, especially with accompanying abdominal pain, hemodynamic shock and previous history of pheochromocytoma-associated symptoms. Lack of proper diagnosis of pheochromocytoma before surgery is associated with an additional perioperative risk. To improve the decision making in this life-threatening clinical situation, based on our results and literature data, we proposed a diagnostic and treatment algorithm.

Circulating GLP-1 Levels in Patients with Pheochromocytoma/Paraganglioma

The sympathoadrenal system has been shown to stimulate the secretory activity of enteroendocrine cells, although the response is transient. Our aim was to investigate the effects of long-term catecholamine excess on circulating glucagon-likepeptide-1 (GLP-1) levels in patients with pheochromocytoma/paraganglioma (PPGL). Thirty patients diagnosed with PPGL were analyzed. A significant negative association was observed between fasting plasma GLP-1 levels and elevated plasma-free metanephrine (r = -0.407, p = 0.026). After adjustment for age, sex, body mass index (BMI), serum creatinine, and the presence of hyperglycemia, the negative association between plasma GLP-1 and metanephrine persisted by multiple linear regression analysis (β = -0.493, p = 0.013). Positive correlations between fasting glucose and plasma metanephrine (r = 0.380, p = 0.038) and normetanephrine levels (r = 0.450, p = 0.013) were also found. Mean fasting levels of total GLP-1 increased significantly from 25.81 to 39.01 pmol/L (p = 0.017) after PPGL resection. In conclusion, long-term overproduction of catecholamines appears to induce suppression of GLP-1 production compared to an acute response to a stress stimulus. Further studies are required to elucidate the mechanism of GLP-1 secretion with chronic exposure to catecholamine.

Imaging pheochromocytoma in small animals: preclinical models to improve diagnosis and treatment

Pheochromocytomas (PCCs) and paragangliomas (PGLs), together referred to as PPGLs, are rare chromaffin cell-derived tumors. They require timely diagnosis as this is the only way to achieve a cure through surgery and because of the potentially serious cardiovascular complications and sometimes life-threatening comorbidities that can occur if left untreated. The biochemical diagnosis of PPGLs has improved over the last decades, and the knowledge of the underlying genetics has dramatically increased. In addition to conventional anatomical imaging by CT and MRI for PPGL detection, new functional imaging modalities have emerged as very useful for patient surveillance and stratification for therapy. The availability of validated and predictive animal models of cancer is essential for translating molecular, imaging and therapy response findings from the bench to the bedside. This is especially true for rare tumors, such as PPGLs, for which access to large cohorts of patients is limited. There are few animal models of PPGLs that have been instrumental in refining imaging modalities for early tumor detection, as well as in identifying and evaluating novel imaging tracers holding promise for the detection and/or treatment of human PPGLs. The in vivo PPGL models mainly include xenografts/allografts generated by engrafting rat or mouse cell lines, as no representative human cell line is available. In addition, there is a model of endogenous PCCs (i.e., MENX rats) that was characterized in our laboratory. In this review, we will summarize the contribution that various representative models of PPGL have given to the visualization of these tumors in vivo and we present an example of a tracer first evaluated in MENX rats, and then translated to the detection of these tumors in human patients. In addition, we will illustrate briefly the potential of ex vivo biological imaging of intact adrenal glands in MENX rats.

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.

Unclear retroperitoneal tumors, an interdisciplinary challenge - A case report and review of the literature

INTRODUCTION AND IMPORTANCE

Unclear retroperitoneal tumors impose major challenges for clinicians. Tumors can originate primarily from retroperitoneal tissue or secondarily invade into the retroperitoneum. While benign lesions also occur, malignant tumors are far more common. Clinical presentation depends on replacement or invasion of other organs and is therefore highly variable. The heterogeneous tumor composition makes a definitive preoperative diagnosis difficult. Surgical resection is the gold standard for treatment but often proves challenging due to frequent involvement of large retroperitoneal vessels.

CASE PRESENTATION

We present the case of a 70-year old woman diagnosed with a large, unclear retroperitoneal tumor. Initial clinical symptoms were increasing dyspnea and dysphagia in our clinic. Gastroenterologic and cardiologic workup was unremarkable. Computed Tomography (CT) revealed a large retroperitoneal mass in the right upper abdomen with severe displacement of the inferior vena cava and renal veins. The patient was scheduled for primary tumor resection. The procedure was challenging due to the vessel involvement and large blood pressure alterations during tumor mobilization. The post-op pathologic workup then revealed the rare finding of a completely resected paraganglioma. The post-surgical course was uneventful. One year after diagnosis, the patient is relapse-free.

CLINICAL DISCUSSION

Among retroperitoneal tumors, paragangliomas and pheochromocytomas are rare tumor entities. Asymptomatic, sporadic disease is hard to identify preoperatively and can cause unexpected complications in the OR. An experienced team is crucial in achieving best short- and long-term outcomes.

CONCLUSION

This case impressively shows the challenges of retroperitoneal tumors and the importance of interdisciplinary work in these cases.

Diagnosing metastatic pheochromocytoma: Trick lies in attention to details!

Functional metastatic pheochromocytoma (PCC) is a very rare tumour and cytoreductive adrenalectomy with oligo metastatectomy is recommended in cases of low tumour burden. We report a rare case of metastatic PCC with an incidentally detected suspicious nodule seen on the anterior surface of the right lobe of the liver. The adrenal and the lesion were excised and sent for histopathology which was reported as a metastasis from PCC. This lesion was not visualised preoperatively on DOTA-PET-CT, highlighting the importance of keeping a low threshold for suspicion of metastasis in abnormal lesions and taking a biopsy during surgery. Inspection of the liver and rest of the abdomen for any abnormality should be done even when operating for any apparently benign lesions.