Novel alternative tools for metastatic pheochromocytomas/paragangliomas prediction.

OBJECTIVE: The existing prediction models for metastasis in pheochromocytomas/paragangliomas (PPGLs) showed high heterogeneity in different centers. Therefore, this study aimed to establish new prediction models integrating multiple variables based on different algorithms. DESIGN AND METHODS: Data of patients with PPGLs undergoing surgical resection at the Peking Union Medical College Hospital from 2007 to 2022 were collected retrospectively. Patients were randomly divided into the training and testing sets in a ratio of 7:3. Subsequently, decision trees, random forest, and logistic models were constructed for metastasis prediction with the training set and Cox models for metastasis-free survival (MFS) prediction with the total population. Additionally, Ki-67 index and tumor size were transformed into categorical variables for adjusting models. The testing set was used to assess the discrimination and calibration of models and the optimal models were visualized as nomograms. Clinical characteristics and MFS were compared between patients with and without risk factors. RESULTS: A total of 198 patients with 59 cases of metastasis were included and classified into the training set (n = 138) and testing set (n = 60). Among all models, the logistic regression model showed the best discrimination for metastasis prediction with an AUC of 0.891 (95% CI, 0.793-0.990), integrating SDHB germline mutations [OR: 96.72 (95% CI, 16.61-940.79)], S-100 (-) [OR: 11.22 (95% CI, 3.04-58.51)], ATRX (-) [OR: 8.42 (95% CI, 2.73-29.24)] and Ki-67 ≥ 3% [OR: 7.98 (95% CI, 2.27-32.24)] evaluated through immunohistochemistry (IHC), and tumor size ≥ 5 cm [OR: 4.59 (95% CI, 1.34-19.13)]. The multivariate Cox model including the above risk factors also showed a high C-index of 0.860 (95% CI, 0.810-0.911) in predicting MFS after surgery. Furthermore, patients with the above risk factors showed a significantly poorer MFS (P ≤ 0.001). CONCLUSIONS: Models established in this study provided alternative and reliable tools for clinicians to predict PPGLs patients' metastasis and MFS. More importantly, this study revealed for the first time that IHC of ATRX could act as an independent predictor of metastasis in PPGLs.

Composite paraganglioma-ganglioneuroma with atypical catecholamine profile and phenylethanolamine N-methyltransferase expression: a case report and literature review.

Pheochromocytomas and paragangliomas (PPGLs) are rare tumors that secrete catecholamines and arise from the adrenal medulla or extra-adrenal sympathetic ganglia. These tumors secrete adrenaline and noradrenaline, but paragangliomas usually produce only noradrenaline because of the lack of phenylethanolamine N-methyltransferase (PNMT) expression. Composite paragangliomas, which are complex tumors consisting of multiple types of neuroblastic cells, are extremely rare. We present the case of a 46-year-old woman with an atypical catecholamine profile who was preoperatively diagnosed with pheochromocytoma. However, postoperative pathology revealed that the patient had an extra-adrenal paraganglioma accompanied by a ganglioneuroma, which led to the diagnosis of a composite tumor. Interestingly, PNMT is expressed in both paragangliomas and ganglioneuromas. In addition, we reviewed reported composite paragangliomas and compared their clinical features with those of composite pheochromocytomas. We also discuss various aspects of the etiology of composite paragangliomas and the mechanism by which PNMT is expressed in tumors.

Effects of Blood Collection Tubes on the Quantification of Catecholamines and Their O-Methylated Metabolites by Liquid Chromatography Coupled With Tandem Mass Spectrometry.

BACKGROUND: Catecholamines (epinephrine; norepinephrine; and dopamine) and their O-methylated metabolites (metanephrine; normetanephrine; and 3-methoxytyramine) are biomarkers for pheochromocytoma and paraganglioma. Liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) was recommended by Endocrine Society for detecting these compounds. The influence of blood collection tubes on the analysis of the six analytes by LC-MS/MS was not thoroughly investigated, which we want to clarify in our study. METHODS: Blood samples of healthy individuals were collected into serum, lithium heparin, and K2EDTA plasma tubes separately. Samples were subjected to solid phase extraction and then analyzed by LC-MS/MS. The retention behavior and assay performance of the six analytes were assessed for samples from different collection containers. The impacts of potassium and sodium as the counter ions of EDTA on the retention time and matrix effect were also studied. RESULTS: Compared with O-methylated metabolites, the results for catecholamines were more affected by the collection tubes, especially for norepinephrine, which displayed severely suppressed signal and very low extraction efficiency in K2EDTA plasma. Changing the counter ion of EDTA from potassium to sodium dramatically changed the retention behavior and matrix effect of norepinephrine. CONCLUSIONS: It is necessary to evaluate blood collection tubes for catecholamines and their O-methylated metabolites analyzed by LC-MS/MS. In addition, attention should also be paid when the anticoagulant counter ion was changed.

Genetic and Molecular Biomarkers in Aggressive Pheochromocytomas and Paragangliomas.

Pheochromocytomas and paragangliomas (PPGLs) are rare neoplasms producing catecholamines that occur as hereditary syndromes in 25-40% of cases. To date, PPGLs are no longer classified as benign and malignant tumors since any lesion could theoretically metastasize, even if it occurs only in a minority of cases (approximately 10-30%). Over the last decades, several attempts were made to develop a scoring system able to predict the risk of aggressive behavior at diagnosis, including the risk of metastases and disease recurrence; unfortunately, none of the available scores is able to accurately predict the risk of aggressive behavior, even including clinical, biochemical, and histopathological features. Thus, life-long follow-up is required in PPGL patients. Some recent studies focusing on genetic and molecular markers (involved in hypoxia regulation, gene transcription, cellular growth, differentiation, signaling pathways, and apoptosis) seem to indicate they are promising prognostic factors, even though their clinical significance needs to be further evaluated. The most involved pathways in PPGLs with aggressive behavior are represented by Krebs cycle alterations caused by succinate dehydrogenase subunits (SDHx), especially when caused by SDHB mutations, and by fumarate hydratase mutations that lead to the activation of hypoxia pathways and DNA hypermethylation, suggesting a common pathway in tumorigenesis. Conversely, PPGLs showing mutations in the kinase cascade (cluster 2) tend to display less aggressive behavior. Finally, establishing pathways of tumorigenesis is also fundamental to developing new drugs targeted to specific pathways and improving the survival of patients with metastatic disease. Unfortunately, the rarity of these tumors and the scarce number of cases enrolled in the available studies represents an obstacle to validating the role of molecular markers as reliable predictors of aggressiveness.

The importance of perioperative and complication management in the treatment of pheochromocytoma crisis with venoarterial extracorporeal membrane oxygenation (V-A ECMO): a case report and review of the literature.

PURPOSE: In this article, we aimed to elaborate on perioperative and complication management in treatment of pheochromocytoma crisis with extracorporeal membrane oxygenation (ECMO). MATERIAL AND METHODS: We report a case of relatively rare grant paraganglioma-induced pheochromocytoma crisis leading to severe circulatory failure, treated with venoarterial extracorporeal membrane oxygenation (V-A ECMO) as a bridge to curative adrenalectomy. Weaning of ECMO was followed by successful surgical removal of the tumor, and patient survival. However, distal ischemia of the cannulated leg occurred during ECMO operation, which eventually led to amputation. In addition, the patient developed new cerebral infarction and left hemiplegia, half a month after paraganglioma resection. CONCLUSIONS: We believe that patients with pheochromocytoma crisis, who cannot maintain blood circulation, are eligible for V-A ECMO treatment. Moreover, care should be taken to prevent thrombosis and individualized and precise blood pressure management targets. Early detection and treatment of thrombosis is imperative to long-term prognosis of patients with ECMO.

[18F]FDG-PET/CT radiomics for the identification of genetic clusters in pheochromocytomas and paragangliomas.

OBJECTIVES: Based on germline and somatic mutation profiles, pheochromocytomas and paragangliomas (PPGLs) can be classified into different clusters. We investigated the use of [18F]FDG-PET/CT radiomics, SUVmax and biochemical profile for the identification of the genetic clusters of PPGLs. METHODS: In this single-centre cohort, 40 PPGLs (13 cluster 1, 18 cluster 2, 9 sporadic) were delineated using a 41% adaptive threshold of SUVpeak ([18F]FDG-PET) and manually (low-dose CT; ldCT). Using PyRadiomics, 211 radiomic features were extracted. Stratified 5-fold cross-validation for the identification of the genetic cluster was performed using multinomial logistic regression with dimensionality reduction incorporated per fold. Classification performances of biochemistry, SUVmax and PET(/CT) radiomic models were compared and presented as mean (multiclass) test AUCs over the five folds. Results were validated using a sham experiment, randomly shuffling the outcome labels. RESULTS: The model with biochemistry only could identify the genetic cluster (multiclass AUC 0.60). The three-factor PET model had the best classification performance (multiclass AUC 0.88). A simplified model with only SUVmax performed almost similarly. Addition of ldCT features and biochemistry decreased the classification performances. All sham AUCs were approximately 0.50. CONCLUSION: PET radiomics achieves a better identification of PPGLs compared to biochemistry, SUVmax, ldCT radiomics and combined approaches, especially for the differentiation of sporadic PPGLs. Nevertheless, a model with SUVmax alone might be preferred clinically, weighing model performances against laborious radiomic analysis. The limited added value of radiomics to the overall classification performance for PPGL should be validated in a larger external cohort. KEY POINTS: • Radiomics derived from [18F]FDG-PET/CT has the potential to improve the identification of the genetic clusters of pheochromocytomas and paragangliomas. • A simplified model with SUVmax only might be preferred clinically, weighing model performances against the laborious radiomic analysis. • Cluster 1 and 2 PPGLs generally present distinctive characteristics that can be captured using [18F]FDG-PET imaging. Sporadic PPGLs appear more heterogeneous, frequently resembling cluster 2 PPGLs and occasionally resembling cluster 1 PPGLs.

Hypertension in Pheochromocytoma and Paraganglioma: Evaluation and Management in Pediatric Patients.

PURPOSE OF REVIEW: The rare catecholamine-secreting tumors, pheochromocytomas and paragangliomas (PPGL), account for a minority of cases of secondary hypertension in pediatrics. As such, perioperative blood pressure (BP) management in pediatric patients presents a distinct challenge. This review will expand the practitioner's knowledge of antihypertensive treatment options for the pediatric patient with PPGL with a focus on literature in the past several years. RECENT FINDINGS: There continue to be only small case series and single-center experiences to provide guidelines regarding BP management. While phenoxybenzamine has been more routinely used, selective α1-blockers, such as doxazosin, as well as calcium channel blockers, have also been utilized with success in pediatric patients. While the concept of obligatory α-adrenergic blockade for adult patients has been recently challenged, international guidelines and current practice patterns among pediatric clinicians continue to support preoperative α-adrenergic blockade to ensure the best possible patient outcomes. Selective α1-blockers and calcium channel blockers are becoming more commonly used given the high cost, limited availability, and undesirable side effect profile of phenoxybenzamine.

Quantitation of plasma metanephrines using isotope dilution liquid chromatography tandem mass spectrometry (ID-LC/MS/MS): a candidate reference measurement procedure and its application to evaluating routine ID-LC/MS/MS methods.

Accurate measurement of plasma metanephrines (MNs) including metanephrine (MN) and normetanephrine (NMN) is crucial for the screening and diagnosis in pheochromocytomas and paragangliomas (PPGLs). Although the number of laboratories using liquid chromatography tandem mass spectrometry (LC-MS/MS) method to measure MNs has been increasing rapidly, those laboratory-developed assays showed incomparable results. There are no reference measurement procedures (RMPs) or reference materials (RMs) for MNs in Joint Committee for Traceability in Laboratory Medicine (JCTLM), which hindered the standardization of MNs measurement. We established a candidate RMP (cRMP) based on isotope dilution liquid chromatography tandem mass spectrometry (ID-LC/MS/MS) method for plasma MNs measurement. Plasma samples were spiked with MN-D3 and NMN-D3 as internal standards; protein precipitation and ion-exchange solid phase extraction (SPE) were performed to extract samples, eventually analyzed by LC-MS/MS. The cRMP was applied to evaluate two routine ID-LC/MS/MS methods through split-sample comparisons. Fifty-three individual patient samples were determined by cRMP and two routine ID-LC/MS/MS methods; results were analyzed by ordinary linear regression and Bland-Altman plots. The cRMP exhibited desirable imprecision, with intra-run and total imprecision (coefficient variation, CV) for MN being 0.79-1.36% and 1.53-1.87% and for NMN being 1.10-1.34% and 1.15-1.64%. The analytical recoveries of MN and NMN ranged from 98.3 to 101.7% and from 98.5 to 101.9%, respectively. Significant calibrator biases and sample-specific deviations were observed in method comparison. An accurate, precise, and reliable cRMP for plasma MNs was developed, and RMs with value assigned following the cRMP would help minimize the calibration bias and improve the comparability of different measuring systems.

From Diagnosis to Therapy-PET Imaging for Pheochromocytomas and Paragangliomas.

PURPOSE OF REVIEW: Pheochromocytoma and paraganglioma (PPGLs) are neuroendocrine tumors with diverse clinical presentations. PPGLs can be sporadic but often are associated with various syndromes, which can have variable clinical presentations. A thorough workup is therefore critical for staging, treatment, and follow-up. Imaging is an essential part of the workup and diagnosis of PPGLs. RECENT FINDINGS: Improvements in cross-sectional imaging with radionuclides have increased specificity and sensitivity for identifying and treating PPGLs. Furthermore, a variety of targets on PPGLs has allowed for optimal imaging with radionuclides that can be used for staging and treatment. Currently, radionuclides are being evaluated for staging and treatment of PPGLs. Developing novel radionuclides that can identify disease sites and target them simultaneously provides a potential for improving survival and outcomes in patients with PPGLs. Given the clinical diversity among PPGLs, expanding the therapeutic arsenal against locally advanced or metastatic PPGLs can allow clinicians to evaluate and treat PPGLs thoroughly.

Quantitative 18F-DOPA PET/CT in pheochromocytoma: the relationship between tumor secretion and its biochemical phenotype.

INTRODUCTION: 18F-FDOPA illustrates the properties of uptake and storage of catecholamines in pheochromocytomas (PHEOs). Until now, the relationship between 18F-FDOPA quantitative parameters and a PHEO secretory profile has not been specifically evaluated. MATERIALS AND METHODS: Fifty-six patients (56% females, median age: 47.5 yrs) with non-metastatic PHEO, evaluated by 18F-FDOPA PET/CT, were included in this retrospective study. Forty-five patients had negative genetic testing (80.4%); five patients (8.9%) had RET, two patients (3.6%) had SDHB, two had SDHD (3.6%), one patient (1.8%) had NF1, and one patient had a VHL (1.8%) mutation. Correlation between 18F-FDOPA metabolic parameters (tumor SUVmax, tumor SUVmean, tumor SUVmax/liver SUVmax, MTV 42%, total lesion uptake), urinary metanephrines (MNs), and plasma chromogranin A (CgA) were evaluated. RESULTS: All patients had positive 18F-FDOPA PET/CT. On univariate analysis, there was a strong correlation between all metabolic parameters and urinary MNs and plasma chromogranin A (CgA). The highest correlations were observed between total lesion (TL) uptake and the value of urinary MNs regardless of their nature (p = 8.10-15 and r = 0.80) and between MTV 42% and plasma CgA levels (p = 2.10-9, r = 0.74). On multivariate analysis, the correlation of uptake parameters and CgA levels did not persist further due to the relation of CgA and tumor diameter. A correlation between TL uptake and the normetanephrine/metanephrine ratio (NMN/MN) was also found, a finding that was in accordance with in vitro studies, which were found to have a higher catecholamine content in epinephrine producing PHEOs. CONCLUSION: This retrospective study shows a correlation between 18F-FDOPA uptake, especially using TL uptake, urinary MNs, and a PHEO biochemical phenotype. This illustrates that beyond its localization value, 18F-FDOPA PET further enables PHEO characterization at a specific metabolic level.

Pheochromocytomas and Hypertension.

PURPOSE OF REVIEW: Pheochromocytomas and paragangliomas (PPGLs) are uncommon catecholamine-producing neuroendocrine neoplasms that usually present with secondary hypertension. This review is to update the current knowledge about these neoplasms, the pathophysiology, genetic aspects and diagnostic and therapeutic algorithms based on scientific literature mostly within the past 3 years. RECENT FINDINGS: Eighty to eighty-five percent of PPGLs arise from the adrenal medulla (pheochromocytomas; PCCs) and the remainder from the autonomic neural ganglia (paragangliomas; PGLs). Catecholamine excess causes chronic or paroxysmal hypertension associated with sweating, headaches and palpitations, the presenting features of PPGLs, and increases the cardiovascular morbidity and mortality. Genetic testing should be considered in all cases as mutations are reported in 35-40% of cases; 10-15% of PCCs and 20-50% of PGLs can be malignant. Measurements of plasma-free metanephrines or 24-h urine-fractionated metanephrines help biochemical diagnosis with high sensitivity and specificity. Initial anatomical localization after biochemical confirmation is usually with computed tomography (CT) or magnetic resonance imaging (MRI). 123Iodine metaiodobenzylguanidine (123I-MIBG) scintigraphy, positron emission tomography (PET) or single-photon emission computed tomography (SPECT) is often performed for functional imaging and prognostication prior to curative or palliative surgery. Clinical and biochemical follow-up is recommended at least annually after complete tumour excision. Children, pregnant women and older people have higher morbidity and mortality risk. De-bulking surgery, chemotherapy, radiotherapy, radionuclide agents and ablation procedures are useful in the palliation of incurable disease. PPGLs are unique neuroendocrine tumours that form an important cause for endocrine hypertension. The diagnostic and therapeutic algorithms are updated in this comprehensive article.

Heart combined with adrenal multiple pheochromocytomas.

Pheochromocytoma is a kind of rare tumor, occurring at any site in the sympathoadrenal system. Main lesions occur within the adrenal gland; only 1%-2% occur within the chest, and most of these are located in the posterior mediastinum. Intrapericardial pheochromocytoma is extremely rare in clinic, only about 100 cases have been reported in total in both the domestic and foreignliterature since Besterman et al. first reported in 1974. It is often difficult to diagnose and locate these tumors. Hence, we present here a case of adrenal combined with heart multiple pheochromocytomas and discuss about techniques contributed to diagnosis and localization.

Von Hippel-Lindau disease: a single gene, several hereditary tumors.

The Von Hippel-Lindau (VHL) disease is an autosomal dominant disorder characterized by the predisposition for multiple tumors caused by germline mutations in the tumor suppressor gene VHL. This disease is associated with a high morbidity and mortality and presents a variable expression, with different phenotypes from family to family, affecting different organs during the lifetime. The main manifestations of VHL are hemangioblastomas of the central nervous system and retina, renal carcinomas and cysts, bilateral pheochromocytomas, cystic and solid tumors of the pancreas, cystadenomas of the epididymis, and endolymphatic sac tumors. The discovery of any of the syndrome components should raise suspicion of this disease and other stigmas must then be investigated. Due to the complexities associated with management of the various VHL manifestation, the diagnosis and the follow-up of this syndrome is a challenge in the clinical practice and a multidisciplinary approach is needed. The particular relevance to endocrinologists is the detection of pheochromocytomas in 35% and islet cell tumors in 17% of VHL patients, which can be associated with hypertension, hypoglycemia, cardiac arrhythmias, and carcinoid syndrome. The purpose of this review is to define the Von Hippel-Lindau syndrome addressing its clinical aspects and classification, the importance of genetic counseling and to propose a protocol for clinical follow-up.

Hemodynamic instability during percutaneous ablation of extra-adrenal metastases of pheochromocytoma and paragangliomas: a case series.

BACKGROUND: Surgical manipulation of pheochromocytomas and paragangliomas (PPGLs) may induce large hemodynamic oscillations due to catecholamine release. Little is known regarding hemodynamic instability during percutaneous ablation of PPGLs. We examined intraprocedural hemodynamic variability and postoperative complications related to percutaneous ablation of extra-adrenal metastases of PPGL. METHODS: From institutional PPGL registry we identified patients undergoing ablation of extra-adrenal PPGL metastases from January 1, 2000, through December 31, 2016. We reviewed medical records for clinical characteristics and hospital outcomes. Tumors were categorized as functional or nonfunctional based on preprocedural fractionated catecholamine and metanephrine profiles. RESULTS: Twenty-one patients (14 female [67%]) underwent 38 ablations. Twenty-four ablations were performed in patients with functional metastatic lesions, and 14 were in nonfunctional lesions. Intraprocedural use of potent vasodilators for hypertension was higher for patients with functional tumors (P = 0.02); use of vasopressors for hypotension was similar for functional and nonfunctional tumors (P = 0.74). Mean (±SD) intraprocedural blood pressure range (maximum-minimum blood pressure) during 38 procedures was greater for functional than nonfunctional tumors [systolic: 106 (±48) vs 64 (±30) mm Hg, P = 0.005; diastolic: 58 (±22) vs 35 (±14) mm Hg, P = 0.002; mean arterial: 84 (±43) vs 47 (±29) mm Hg, P = 0.007]. Complications included 5 unplanned intensive care unit admissions (3 for precautionary monitoring, 1 for recalcitrant hypotension, and 1 for hypertensive crisis), 1 case of postoperative bleeding, and 1 death. CONCLUSIONS: Substantial hemodynamic instability may develop during ablation of functional and nonfunctional PPGL metastases. When anesthesia is provided for ablation of metastatic PPGLs in radiology suites, preparation for hemodynamic management should match standards used for surgical resection.

Implications of SDHB genetic testing in patients with sporadic pheochromocytoma.

PURPOSE: Succinate dehydrogenase B (SDHB) associated pheochromocytomas (PHEOs) are associated with a higher risk of tumor aggressiveness and malignancy. The aim of the present study was to evaluate (1) the frequency of germline SDHB mutations in apparently sporadic patients with PHEO who undergo preoperative genetic testing and (2) the ability to predict pathogenic mutations. METHODS: From 2012 to 2016, 82 patients underwent a PHEO surgical resection. Sixteen were operated in the context of hereditary PHEO and were excluded from analysis. Among the 66 remaining cases, 48 were preoperatively screened for an SDHB mutation. In addition to imaging studies with specific radiopharmaceuticals (123I-MIBG or 18F-FDOPA) for exclusion of multifocality/metastases, 36 patients underwent 18F-FDG PET/CT. RESULTS: From the 48 genetically screened patients, genetic testing found a germline SDHB variant in two (4.2%) cases: a variant of unknown significance, exon 1, c.14T>G (p.Val5Gly), and a most likely pathogenic mutation, exon 5, c.440A>G (p.Tyr147Cys), according to in silico analysis. Structural and functional analyses of the protein predicted that p.Tyr147Cys mutant was pathogenic. Both tumors exhibited moderate 18F-FDG PET uptake with similar uptake patterns to non-SDHB mutated PHEOs. The two patients underwent total laparoscopic adrenalectomies. Of the remaining patients, 44 underwent a laparoscopic adrenalectomy, and two had an open approach. Pathological analysis of the tumors from patients bearing two germline SDHB variants revealed a typical PHEO (PASS 0 and 2). Ex-vivo analyses (metabolomics, SDHB immunohistochemistry, loss of heterozygosity analysis) allowed a reclassification of the two SDHB variants as probably non-pathogenic variants. CONCLUSIONS: This study illustrates that SDHx mutational analysis can be misleading, even if structural and functional analyses are done. Surgeons should be aware of the difficulty of classifying new SDHB variants prior to implementing SDHB mutation status into a tailored surgical management strategy of a patient.

Low penetrance of paraganglioma and pheochromocytoma in an extended kindred with a germline SDHB exon 3 deletion.

In the Netherlands, the majority of hereditary paragangliomas (PGL) is caused by SDHD, SDHB and SDHAF2 mutations. Founder mutations in SDHD are particularly prevalent, but several SDHB founder mutations have also been described. Here, we describe an extended PGL family with a Dutch founder mutation in SDHB, c.201-4429_287-933del. The proband presented with apparently sporadic head and neck paraganglioma at advanced age. Subsequently, evaluation of the family identified several unaffected mutation carriers, asymptomatic and symptomatic PGL patients, and patients presenting with early-onset malignant pheochromocytoma. The calculated penetrance of the SDHB mutation in this kindred is lower than the risk suggested for SDHB mutations in the literature. This may represent a characteristic of this particular SDHB mutation, but may also be a reflection of the inclusion of relatively large numbers of asymptomatic mutation carriers in this family and adequate statistical correction for ascertainment bias. The low penetrance of SDHB mutations may obscure the hereditary nature of SDHB-linked disease and is important in the counseling of SDHB-linked patients. Risk estimates should preferably be based on the specific mutation involved.

Metastatic pheochromocytoma and paraganglioma.

BACKGROUND: Metastatic pheochromocytomas (PCs) and paragangliomas (PGLs) are rare neuroendocrine tumours with a strong genetic background. DESIGN: We searched the PubMed database through February 2015 to identify studies characterizing metastatic PCs/PGLs as well as currently established and evolving therapies. RESULTS: Large size tumours (> 5 cm), PASS score > 6 and Ki-67 labelling index > 3% are the most robust indices of metastatic PCs/PGLs albeit with great variability. Germline succinate dehydrogenase complex, subunit B (SDHB) mutation constitutes the main reliable molecular predictor of malignancy. Plasma and urinary methoxytyramine are the biochemical markers characterizing metastatic PCs/PGLs along with evolving molecular markers such as miRNAs and SNAIL. Conventional imaging is used for tumour localization, whereas (18)F-FDG-PET for staging of metastatic PCs/PGLs especially those related to SDHB gene mutations. In addition, (68)Ga-DOTATATE PET/CT is emerging as a highly sensitive alternative. Surgery remains the gold standard treatment in reducing tumour bulk and/or controlling the clinical syndrome. Treatment with (131)I-MIBG or radiolabelled somatostatin analogues is considered for unresectable disease. Conventional chemotherapy is reserved for more advanced and refractory to other therapies disease although new schemes are currently evolving. Recent genetic studies have highlighted a number of pathways involved in PCs/PGLs pathogenesis directing towards the use of targeted therapies which have still to be validated in clinical practice. CONCLUSIONS: Metastatic PCs/PGLs remain an orphan disease that is only curable by surgery. However, advances in genomic analyses have improved the pathogenesis of these tumours and may lead to effective and more personalized treatments in the near future.

Successful integration of nonclinical and clinical findings in interpreting the clinical relevance of rodent neoplasia with a new chemical entity.

Canagliflozin, a sodium glucose co-transporter 2 (SGLT2) inhibitor, has been developed for the treatment of adults with type 2 diabetes mellitus (T2DM). During the phase 3 program, treatment-related pheochromocytomas, renal tubular tumors, and testicular Leydig cell tumors were reported in the 2-year rat toxicology study. Treatment-related tumors were not seen in the 2-year mouse study. A cross-functional, mechanism-based approach was undertaken to determine whether the mechanisms responsible for tumorigenesis in the rat were of relevance to humans. Based on findings from nonclinical and clinical studies, the treatment-related tumors observed in rats were not deemed to be of clinical relevance. Here, we describe the scientific and regulatory journey from learning of the 2-year rat study findings to the approval of canagliflozin for the treatment of T2DM.

A Critical Approach to Clinical Biochemistry of Chromogranin A.

Chromogranin A (CGA) is a member of the granin family of proteins which are widespread in endocrine, neuroendocrine, peripheral, and central nervous tissues, where they are typically found in secretory granules. It is well accepted that CGA cooperates to regulate synthesis and secretion of these various granule signaling molecules.Because of its ubiquitous distribution within neuroendocrine tissues, CGA can be a useful diagnostic marker for neuroendocrine neoplasms, including carcinoids, pheochromocytomas, neuroblastomas, medullary thyroid carcinomas (MTC), some pituitary tumors, functioning and nonfunctioning islet cell tumors and other amine precursor uptake and decarboxylation (APUD) tumors. It is also useful as a prognostic marker for detection of recurrence and monitoring of response to different treatments. As other tumor markers, it is imperative to know its physiology and pathophysiology, its sensitivity and specificity in different neuroendocrine tumors (NETs), and carefully integrate these data with the clinical data of the single patient, to maximize its diagnostic/prognostic index.

Reference intervals for urinary metanephrines to creatinine ratios in dogs in Japan.

The urinary normetanephrine to creatinine ratio (uNMN/Cr) and urinary metanephrine to creatinine ratio (uMN/Cr) are commonly evaluated for the diagnosis of pheochromocytomas (PCC) in dogs. This study aimed to establish reference intervals for uNMN/Cr and uMN/Cr in 56 healthy dogs in Japan and to investigate the effect of urine collection methods on these measurements in 15 non-PCC dogs. The upper limits of reference intervals for uNMN/Cr and uMN/Cr were 124.4 nmol/mmol (90% confidence interval [CI] 107.7-137.0) and 121.1 nmol/mmol (90% CI 102.8-145.1), respectively. Both uNMN/Cr and uMN/Cr were significantly higher when urine was collected in the hospital compared to at home. Several factors, including the method of urine collection, should be considered when utilizing these reference intervals.