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Patients harboring germline mutations in the succinate dehydrogenase complex subunit B (SDHB) gene present with pheochromocytomas and paragangliomas (PPGL) that are more likely malignant and clinically aggressive. The combination chemotherapy cyclophosphamide, vincristine, and dacarbazine (CVD) was retrospectively evaluated in patients with SDHB-associated metastatic PPGL.Query Twelve metastatic PPGL patients harboring SDHB mutations/polymorphisms with undetectable SDHB immunostaining were treated with CVD. CVD therapy consisted of 750 mg/m 2 cyclophosphamide with 1.4 mg/m 2 vincristine on day 1 and 600 mg/m 2 dacarbazine on days 1 and 2, every 21-28 days. Treatment outcome was determined by RECIST criteria as well as determination of response duration and progression-free and overall survivals. A median of 20.5 cycles (range 4-41) was administered. All patients had tumor reduction (12-100% by RECIST). Complete response was seen in two patients, while partial response was observed in 8. The median number of cycles to response was 5.5. Median duration of response was 478 days, with progression-free and overall survivals of 930 and 1190 days, respectively. Serial [ 18 F]-fluorodeoxyglucose positron emission tomography and computed tomography imaging demonstrated continued incremental reduction in maximal standardized uptake values (SUV max ) values in 26/30 lesions. During treatment administration, the median SUV decreased from > 25 to < 6, indicating the efficacy of chemotherapy over a prolonged period of time. Prolonged therapy results in continued incremental tumor reduction, and is consistent with persistent drug sensitivity. CVD chemotherapy is recommended to be considered part of the initial management in patients with metastatic SDHB-related PPGL.

The aim of the study is to evaluate if there is an association between attention deficit hyperactivity disorder (ADHD) and the diagnosis of pheochromocytoma/paraganglioma (PHEO/PGL) in pediatric patients. A case series study of 43 patients under the age of 18 with PHEO/PGL tumors who were evaluated at the National Institute of Health between January 2006 and May 2014 is reported. Prior diagnosis of ADHD and treatment course with stimulant medications was recorded. Patient symptoms, catecholamine and metanephrine levels, tumor characteristics, and genetic analyses for syndromes associated with PHEO/PGL were evaluated. A chi-squared test was used to assess the prevalence of ADHD in the PHEO/PGL patients compared to the general population. Nine out of 43 (21%) of patients diagnosed with PHEO/PGL had been diagnosed with ADHD prior to tumor identification. Four of the 9 patients had been treated with amphetamine, dextroamphetamine, and/or methylphenidate, potentially exacerbating an adrenergic crisis. In addition, 4 patients exhibited hypertension at the initial diagnosis of their PHEO/PGL. Three patients had resolution of their ADHD symptoms after successful surgical removal of PHEO/PGL. Our study found a prevalence of ADHD in 21% of our PHEO/PGL patients, significantly higher than 7.2% seen in the general pediatric population. Symptoms of anxiety and difficulty in concentration in these patients may have been related to their underlying PHEO/PGL and were not recognized as part of the constellation of symptoms in a child with PHEO/PGL. In pediatric patients with hypertension and ADHD symptomatology, an evaluation to rule out PHEO/PGL is warranted prior to treatment with stimulant medications., (© Georg Thieme Verlag KG Stuttgart · New York.)

Objective: Pharmacological treatment is mandatory in patients with hormonally functional phaeochromocytoma and paraganglioma (PHAEO/PGL). We evaluated if patients initially diagnosed with hormonally functional PHAEO/PGL by various medical subspecialties received proper adrenoceptor blockade, and analysed factors predicting the prescription of adequate treatment., Methods: In a retrospective cohort study, we reviewed data from patients initially diagnosed with hormonally functional PHAEO/PGL outside the National Institutes of Health and Cedars-Sinai Medical Center, who were referred to these institutions between January 2001 and April 2015. Logistic regression was used to assess factors associated with proper adrenoceptor blockade., Results: A total of 381 patients were included. Adequate pharmacological treatment was prescribed to 69·3%, of which 93·1% received α-adrenoceptor blockers. Regarding patients who were inappropriately treated, 53% did not receive any medication. Independent predictors of the prescription of a proper blockade were the diagnosis by endocrinologists [odds ratio (OR) 4·14; 95% confidence interval (CI), 2·51-6·85; P < 0·001], the presence of high blood pressure (OR 5·94; 95% CI, 3·11-11·33; P < 0·001) and the evidence of metastasis (OR 5·96; 95% CI, 1·93-18·46; P = 0·002)., Conclusions: Although most patients received adequate pharmacological treatment, almost one-third were either not treated or received inappropriate medications. The diagnosis by endocrinologists, the presence of high blood pressure and the evidence of metastatic disease were identified as independent predictors of a proper blockade. These results highlight the need to educate physicians about the importance of starting adequate adrenoceptor blockade in all patients with hormonally functional PHAEO/PGL., (© 2016 John Wiley & Sons Ltd.)

Germline mutations occur in up to 30-40% of pheochromocytoma/paraganglioma, with mutations in the succinate dehydrogenase (SDH) subunits B (SDHB) and D (SDHD) being the most common. Blood samples are favored for obtaining high quality DNA, however, leukocytes can also be obtained by collecting saliva. The aim of this study was to determine whether SDHB and SDHD gene mutations in patients with pheochromocytoma/paraganglioma could be determined using a salivary sample. Paired blood and salivary samples were collected from 30 patients: 9 SDHB mutation positive, 13 with a SDHD mutation, and 8 without any SDHx mutations. The Oragene DISCOVER kit was used to collect and extract DNA from saliva. Blood DNA was extracted from EDTA blood samples. The DNA purification and concentration were measured by spectrophotometry. The 8 exons of SDHB and the 4 exons of SDHD were amplified and sequenced by PCR-based bidirectional Sanger sequencing. Total DNA yields from blood DNA were similar to those obtained from saliva DNA [mean (±SD) saliva vs. blood DNA concentration 514.6 (±580.8) ng/µl vs. 360.9 (±262.7) ng/µl; p=0.2)]. The purity of the saliva DNA samples was lower than that of blood [mean OD260/OD280 ratio 1.78 (±0.13) vs. 1.87 (±0.04); p=0.001, respectively], indicating more protein contamination in the saliva-extracted DNA. This study shows that salivary DNA collected from patients with pheochromocytoma/paraganglioma is a good alternative for extraction of genomic DNA for its high DNA concentration and acceptable purity and can be used as an alternative to blood derived DNA in screening for SDHB and SDHD mutations., (© Georg Thieme Verlag KG Stuttgart · New York.)

Objective: Overall about 10 to 20% of pheochromocytomas/paragangliomas (PHEOs/PGLs) are metastatic, with higher metastatic potential observed in succinate dehydrogenase subunit B/fumarate hydratase (SDHB/FH)-related tumors. Due to the improved availability of biochemical and genetic testing and the frequent use of anatomical/functional imaging, there is currently a higher detection rate of metastatic PHEO/PGL., Methods: A retrospective analysis of 132 patients (27 children, 105 adults) with metastatic PHEO/PGL diagnosed and treated from 2000 to 2014 was conducted., Results: Seventy-seven (58%) males and 55 (42%) females were included; 39 (30%) have died, with no sex preference. Seventy-three (55%) patients had SDHB mutations; 59 (45%) patients had apparently sporadic tumors (AST). SDHB patients had an average age at primary tumor diagnosis of 31 ± 16 years compared to 40 ± 15 years in AST patients (P<.001). The average metastatic interval (MI) decreased with increasing age in both SDHB and AST patients (P = .013 for both). Only 16% of all primary tumors were smaller than 4.5 cm. Eleven percent of patients had biochemically silent disease, more with SDHB. Of SDHB patients, 23% had metastatic tumors at first diagnosis, compared to 15% of AST patients. Five- and 10-year survival rates were significantly better for metastatic AST than SDHB patients (P = .01). Overall survival was significantly different between children and adults (P = .037); this was mostly attributed to the SDHB patients, in whom children had statistically significantly longer survival than adults (P = .006). The deceased patients all died due to the PHEO/PGL and mainly had noradrenergic phenotypes., Conclusion: In children, metastatic PHEOs/PGLs are mainly due to SDHB mutations; in adults they are equally distributed between in SDHB mutations and AST, with better 5- and 10-year survival rates for ASTs. In SDHB patients, children survive longer than adults. Primary metastatic tumors, most presenting as noradrenergic PGLs, are larger than 4.5 cm in >80% of patients. The frequency of metastatic tumors from primary AST increases with age, including a decreased MI compared to SDHB tumors. These results support several recommendations that are summarized in the Discussion.

Purpose: Patients with succinate dehydrogenase subunit B(SDHB) mutation-related pheochromocytoma/paraganglioma (PHEO/PGL) are at a higher risk for metastatic disease than other hereditary PHEOs/PGLs. Current therapeutic approaches are limited, but the best outcomes are based on the early and proper detection of as many lesions as possible. Because PHEOs/PGLs overexpress somatostatin receptor 2 (SSTR2), the goal of our study was to assess the clinical utility of [(68)Ga]-DOTA(0)-Tyr(3)-octreotate ([(68)Ga]-DOTATATE) positron emission tomography/computed tomography (PET/CT) and to evaluate its diagnostic utility in comparison with the currently recommended functional imaging modalities [(18)F]-fluorodopamine ([(18)F]-FDA), [(18)F]-fluorodihydroxyphenylalanine ([(18)F]-FDOPA), [(18)F]-fluoro-2-deoxy-d-glucose ([(18)F]- FDG) PET/CT as well as CT/MRI., Experimental Design: [(68)Ga]-DOTATATE PET/CT was prospectively performed in 17 patients with SDHB-related metastatic PHEOs/PGLs. All patients also underwent [(18)F]-FDG PET/CT and CT/MRI, with 16 of the 17 patients also receiving [(18)F]-FDOPA and [(18)F]-FDA PET/CT scans. Detection rates of metastatic lesions were compared between all these functional imaging studies. A composite synthesis of all used functional and anatomical imaging studies served as the imaging comparator., Results: [(68)Ga]-DOTATATE PET/CT demonstrated a lesion-based detection rate of 98.6% [95% confidence interval (CI), 96.5%-99.5%], [(18)F]-FDG, [(18)F]-FDOPA, [(18)F]-FDA PET/CT, and CT/MRI showed detection rates of 85.8% (CI, 81.3%-89.4%; P < 0.01), 61.4% (CI, 55.6%-66.9%; P < 0.01), 51.9% (CI, 46.1%-57.7%; P < 0.01), and 84.8% (CI, 80.0%-88.5%; P < 0.01), respectively., Conclusions: [(68)Ga]-DOTATATE PET/CT showed a significantly superior detection rate to all other functional and anatomical imaging modalities and may represent the preferred future imaging modality in the evaluation of SDHB-related metastatic PHEO/PGL., (©2015 American Association for Cancer Research.)

Background: Succinate dehydrogenase subunit B (SDHB) mutations are associated with aggressive pheochromocytoma (PHEO)/paraganglioma (PGL) behavior, often resulting in metastatic disease and fatal outcomes. These tumors are often larger, extra-adrenal, and contain lower catecholamine concentrations than other hereditary PHEOs/PGLs. This study evaluated the size and age at diagnosis of primary SDHB-related PHEOs/PGLs as independent predictors of their metastatic behavior and outcome (survival)., Methods: One hundred six patients with SDHB mutation-related PHEO/PGL were included in this retrospective study. The recorded largest diameters, locations, and patient ages at initial diagnosis of SDHB-related primary tumors were analyzed in the context of time to metastasis and patient survival., Results: First, the development of metastatic disease in patients with primary tumors ≥4.5 cm was significantly earlier than in patients with smaller tumors (P = 0.003). Second, patients with primary tumors larger than 5.5 cm also had worse overall survival than patients with smaller tumors (P = 0.008). Third, age at initial diagnosis was found to be an independent predictor of patient survival (PHEOs: P = 0.041; PGLs: P < 0.001). Fourth, we did not observe a significant difference in survival based on the specific SDHB mutations or patient sex., Conclusion: Receiver operating characteristic curves established 4.5 cm as the best value to dichotomize the primary SDHB-related PHEO/PGL in order to evaluate the development of metastatic disease and 5.5 cm as the best value for survival prediction. Subsequently, the size of the primary tumor was found as an age-independent predictor of patient survival and metastases development in PGL. In both PHEO and PGL, age at diagnosis was found to be a size-independent predictor of patient survival. No significant difference was found in metastases development or patient survival between males and females or among specific SDHB mutations. This data further extends and supports previous recommendations that carriers with SDHB mutations must undergo early and regular evaluations to detect PHEO/PGL in order to achieve the best clinical outcome.

Background: Aggressive surgical resection with intent to cure and surgical debulking procedures are commonly recommended in patients with metastatic pheochromocytoma and paraganglioma. To date there are no data on operative outcomes of patients after surgical resection of metastatic pheochromocytoma and paraganglioma to determine if such an approach is appropriate and what factors may be associated with a favorable outcome., Study Design: We performed a retrospective analysis of 30 patients with metastatic pheochromocytoma/paraganglioma who underwent surgical treatment. Clinical characteristics and genetic factors were analyzed as predictors of biochemical response to surgery., Results: Thirty patients underwent a total of 42 operations, with a median follow-up time of 24 months (range 1 to 114 months). Complete disease resection (R0/R1) was achieved in 18 (42.9%) cases; 24 cases (57.1%) were debulking (R2) procedures without intent to cure. Complete biochemical remission was achieved in 10 (23.8%) cases and partial biochemical response was achieved in 23 (54.8%) cases. Patients with disease confined to the abdomen were more likely to achieve and maintain a biochemical response postoperatively than those with extra-abdominal disease (p = 0.0003). Debulking operations were significantly less likely to achieve or maintain biochemical palliation, with only 1 patient maintaining a biochemical response 12 months postoperatively (p < 0.0001). Patients were less likely to obtain pharmacologic independence after debulking (p = 0.0003), with only 2 (8.3%) not requiring pharmacotherapy 6 months after the intervention. Factors not associated with biochemical response to surgery include sex, family history, SDHB mutation status, systemic therapy, and preoperative biochemical profile., Conclusions: Depending on the extent of disease, patients with metastatic pheochromocytoma/paraganglioma can benefit from aggressive operative intervention and resection with intent to cure. Debulking procedures are unlikely to achieve clinically significant biochemical response, with any biochemical response achieved being very short-lived., (Published by Elsevier Inc.)

Background: There are currently no reliable biomarkers for malignant pheochromocytomas and paragangliomas (PPGLs). This study examined whether measurements of catecholamines and their metabolites might offer utility for this purpose., Methods: Subjects included 365 patients with PPGLs, including 105 with metastases, and a reference population of 846 without the tumour. Eighteen catecholamine-related analytes were examined in relation to tumour location, size and mutations of succinate dehydrogenase subunit B (SDHB)., Results: Receiver-operating characteristic curves indicated that plasma methoxytyramine, the O-methylated metabolite of dopamine, provided the most accurate biomarker for discriminating patients with and without metastases. Plasma methoxytyramine was 4.7-fold higher in patients with than without metastases, a difference independent of tumour burden and the associated 1.6- to 1.8-fold higher concentrations of norepinephrine and normetanephrine. Increased plasma methoxytyramine was associated with SDHB mutations and extra-adrenal disease, but was also present in patients with metastases without SDHB mutations or those with metastases secondary to adrenal tumours. High risk of malignancy associated with SDHB mutations reflected large size and extra-adrenal locations of tumours, both independent predictors of metastatic disease. A plasma methoxytyramine above 0.2nmol/L or a tumour diameter above 5cm indicated increased likelihood of metastatic spread, particularly when associated with an extra-adrenal location., Conclusion: Plasma methoxytyramine is a novel biomarker for metastatic PPGLs that together with SDHB mutation status, tumour size and location provide useful information to assess the likelihood of malignancy and manage affected patients., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Background: Pheochromocytomas are rare catecholamine-producing tumors derived in more than 30% of cases from mutations in 9 tumor-susceptibility genes identified to date, including von Hippel-Lindau tumor suppressor (VHL); succinate dehydrogenase complex, subunit B, iron sulfur (Ip) (SDHB); and succinate dehydrogenase complex, subunit D, integral membrane protein (SDHD). Testing of multiple genes is often undertaken at considerable expense before a mutation is detected. This study assessed whether measurements of plasma metanephrine, normetanephrine, and methoxytyramine, the O-methylated metabolites of catecholamines, might help to distinguish different hereditary forms of the tumor., Methods: Plasma concentrations of O-methylated metabolites were measured by liquid chromatography with electrochemical detection in 173 patients with pheochromocytoma, including 38 with multiple endocrine neoplasia type 2 (MEN 2), 10 with neurofibromatosis type 1 (NF1), 66 with von Hippel-Lindau (VHL) syndrome, and 59 with mutations of SDHB or SDHD., Results: In contrast to patients with VHL, SDHB, and SDHD mutations, all patients with MEN 2 and NF1 presented with tumors characterized by increased plasma concentrations of metanephrine (indicating epinephrine production). VHL patients usually showed solitary increases in normetanephrine (indicating norepinephrine production), whereas additional or solitary increases in methoxytyramine (indicating dopamine production) characterized 70% of patients with SDHB and SDHD mutations. Patients with NF1 and MEN 2 could be discriminated from those with VHL, SDHB, and SDHD gene mutations in 99% of cases by the combination of normetanephrine and metanephrine. Measurements of plasma methoxytyramine discriminated patients with SDHB and SDHD mutations from those with VHL mutations in an additional 78% of cases., Conclusions: The distinct patterns of plasma catecholamine O-methylated metabolites in patients with hereditary pheochromocytoma provide an easily used tool to guide cost-effective genotyping of underlying disease-causing mutations.

Pheochromocytomas are rare tumors in children arising from chromaffin cells of adrenal medullary or extra-adrenal paraganglionic tissue. The tumors are characterized by synthesis, metabolism, and secretion of catecholamines. The formerly used guidelines for pheochromocytoma have been changed by recent discoveries, implementation of new approaches, and understanding of biochemistry, genetics, imaging, pathophysiology, and nomenclature of these tumors. In children, pheochromocytomas are more frequently familial, extra-adrenal, bilateral, and multifocal than in adults. Because of a highly variable clinical presentation, pheochromocytoma is often referred to as the great mimic. Measurements of plasma or urinary fractionated metanephrines are recommended as first-line biochemical tests for diagnosis, with optimum diagnostic sensitivity to be preferred over specificity. In general, localization studies must be used secondary to clinical and biochemical evidence. Adequate preoperative treatment with alpha-blockade is mandatory, including for pheochromocytomas that do not secrete but only synthesize catecholamines. Because approximately 40% of pheochromocytomas in children have a hereditary basis, proper genetic testing should be performed, with appropriate implications for future follow-up and treatment options. The risk for development of malignant disease depends highly on the underlying mutation, which may also impact recommendations concerning screening and surgical or systemic treatment. This article reviews recent advances in biochemistry, genetics, and imaging and outlines recommendations for improved evaluation and treatment of children with benign or malignant pheochromocytomas.

Approximately 50% of patients with multiple endocrine neoplasia (MEN) 2A or 2B develop pheochromocytoma. These tumours are almost exclusively benign and localized in the adrenal glands. About one-third are bilateral at initial diagnosis. Amongst patients with pheochromocytoma, those with MEN 2A have subtler symptoms compared to those with sporadic disease. Since pheochromocytomas in patients with MEN 2 often secrete catecholamines episodically (but metabolize them continuously to metanephrines), the first choice for biochemical diagnosis is the measurement of free metanephrines in plasma, with urinary fractionated metanephrines being the second choice. In patients with pheochromocytomas that produce exclusively normetanephrine, MEN 2 can be excluded. In patients with biochemically proven MEN 2-related pheochromocytoma, anatomical imaging of the adrenals (with either computerized tomography or magnetic resonance) should be obtained next. Functional imaging with specific ligands (e.g. scintigraphy with [(123)I]-metaiodobenzylguanidine or, if available, positron emission tomography with [(18)F]-fluorodopamine, [(18)F]-dihydroxyphenylalanine, [(11)C]-adrenaline or [(11)C]-hydroxyephedrine) may then be particularly useful in patients with distorted anatomy from previous surgery, in cases of equivocal biochemical data despite high clinical suspicion for a tumour, to rule out multifocal disease, or where there is suspicion of metastatic disease (e.g. tumours larger than 5 cm). Laparoscopic surgery is the treatment of choice and subtotal (cortical-sparing) adrenalectomy is the procedure of choice in bilateral pheochromocytomas.

Mutations in the gene encoding subunit B of the mitochondrial enzyme succinate dehydrogenase (SDHB) are inherited in an autosomal dominant manner and are associated with hereditary paraganglioma (PGL) and pheochromocytoma. The phenotype of patients with SDHB point mutations has been previously described. However, the phenotype and penetrance of gross SDHB deletions have not been well characterized as they are rarely described. The objective was to describe the phenotype and estimate the penetrance of an exon 1 large SDHB deletion in one kindred. A retrospective and prospective study of 41 relatives across five generations was carried out. The main outcome measures were genetic testing, clinical presentations, plasma catecholamines and their O-methylated metabolites. Of the 41 mutation carriers identified, 11 were diagnosed with PGL, 12 were found to be healthy carriers after evaluation, and 18 were reportedly healthy based on family history accounts. The penetrance of PGL related to the exon 1 large SDHB deletion in this family was estimated to be 35% by age 40. Variable expressivity of the phenotype associated with a large exon 1 SDHB deletion was observed, including low penetrance, diverse primary PGL tumor locations, and malignant potential. [ABSTRACT FROM AUTHOR]