The Additional Value of Somatostatin Receptor Positron Emission Computed Tomography ([68Ga]Ga-DOTATOC PET/CT) Compared with Magnetic Resonance Imaging of the Head and Neck Region in Paraganglioma Patients: A Pilot Study.

The Dutch guideline for patients suspected of head and neck paragangliomas (HNPGLs) recommends magnetic resonance imaging (MRI) and/or computed tomography (CT) of the head and neck area. Additionally, it suggests considering additional nuclear imaging. The aim of this study was to evaluate the outcomes of [68Ga]Ga-DOTATOC PET/CT compared to MRI in patients with suspected HNPGLs and carriers of genetic variations. METHODS: In this single-center pilot study, retrospective data were obtained from consecutive patients between 2016 and 2023. Both MRI and [68Ga]Ga-DOTATOC PET/CT were performed within 12 months. The primary outcome was the location of HNPGLs. RESULTS: A total of 25 consecutive patients were included, and 7 patients (28.0%, p = 0.5) showed differences between the imaging modalities, of whom 5 patients had unexpected localizations with additional uptake by somatostatin receptors (SSTR) on the [68Ga]Ga-DOTATOC PET/CT. CONCLUSIONS: The authors recommend performing baseline imaging with [68Ga]Ga-DOTATOC PET/CT (if available) in variant carriers and using MRI/CT for follow-up according to the regional protocol, thereby shifting the gold standard for baseline imaging from MRI/CT to [68Ga]Ga-DOTATOC PET/CT.

Systematic Review on Botulinum Toxin Injections as Diagnostic or Therapeutic Tool in Thoracic Outlet Syndrome.

BACKGROUND: The optimal diagnostic and treatment algorithm for patients with suspected thoracic outlet syndrome (TOS) remains challenging. Botulinum toxin (BTX) muscle injections have been suggested to shrink muscles in the thoracic outlet reducing neurovascular compression. This systematic review evaluates the diagnostic and therapeutic value of BTX injections in TOS. METHODS: A systematic review of studies reporting BTX as a diagnostic or therapeutic tool in TOS (or pectoralis minor syndrome as TOS subtype) was conducted in PubMed, Embase, and CENTRAL databases on May 26, 2022. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement was followed. Primary end point was symptom reduction after primary procedure. Secondary end points were symptom reduction after repeated procedures, the degree of symptom reduction, complications, and duration of clinical effect. RESULTS: Eight studies (1 randomized controlled trial [RCT], 1 prospective cohort study, and 6 retrospective cohort studies) were included reporting 716 procedures in at least 497 patients (at minimum 350 primary and 25 repeated procedures, residual unclear) diagnosed with presumably only neurogenic TOS. Except for the RCT, the methodological quality was fair to poor. All studies were designed on an intention to treat basis, one also investigated BTX as a diagnostic tool to differentiate pectoralis minor syndrome from costoclavicular compression. Reduction of symptoms was reported in 46-63% of primary procedures; no significant difference was found in the RCT. The effect of repeated procedures could not be determined. Degree of symptom reduction was reported by up to 30-42% on the Short-form McGill Pain scale and up to 40 mm on a visual analog scale. Complication rates varied among studies, no major complications were reported. Symptom relief ranged from 1 to 6 months. CONCLUSIONS: Based on limited quality evidence, BTX may provide short-lasting symptom relief in some neurogenic TOS patients but remains overall undecided. The role of BTX for treatment of vascular TOS and as a diagnostic tool in TOS is currently unexploited.

The upper extremity postthrombotic syndrome score: an international Delphi consensus study to determine the score's functional disability component.

Background: In upper extremity thrombosis research, the occurrence of upper extremity postthrombotic syndrome (UE-PTS) is commonly used as the main outcome parameter. However, there is currently no reporting standard or a validated method to assess UE-PTS presence and severity. In a recent Delphi study, consensus was reached on a preliminary UE-PTS score, combining 5 symptoms, 3 signs, and the inclusion of a functional disability score. However, no consensus was reached on which functional disability score to be included. Objectives: The aim of the current Delphi consensus study was to determine the specific type of functional disability score to finalize UE-PTS score. Methods: This Delphi project was designed as a three-round study using open text questions, statements with 7-point Likert scales, and multiple-choice questions. The CREDES recommendations for Delphi studies were applied. In this context, a systematic review was conducted before the start of the Delphi rounds to identify the available functional disability scores as available in the literature and present these to the expert panel. Results: Thirty-five of 47 initially invited international experts from multiple disciplines completed all the Delphi rounds. In the second round, consensus was reached on the incorporation of the quick disabilities of the arm, shoulder, and hand (QuickDASH) in the UE-PTS score, rendering the third round obsolete. Conclusion: Consensus was reached that the QuickDASH should be incorporated in the UE-PTS score. The UE-PTS score will need to be validated in a large cohort of patients with upper extremity thrombosis before it can be used in clinical practice and future research.

Thoracic outlet syndrome (TROTS) registry: A study protocol for the primary upper extremity deep venous thrombosis section.

INTRODUCTION: There is a lack of comprehensive and uniform data on primary upper extremity deep venous thrombosis (pUEDVT). pUEDVT includes venous thoracic outlet syndrome related upper extremity deep venous thrombosis (UEDVT) and idiopathic UEDVT. Research on these conditions has been hampered by their rarity, lack of uniform diagnostic criteria, and heterogeneity in therapeutic strategies. To improve current research data collection using input of all various pUEDVT treating medical specialists, we initiated the ThoRacic OuTlet Syndrome (TROTS) registry. The aim of the TROTS registry is to a) collect extensive data on all pUEDVT patients through a predefined protocol, b) give insight in the long term outcome using patient reported outcome measures, c) create guidance in the diagnostic and clinical management of these conditions, and thereby d) help provide content for future research. METHODS AND ANALYSIS: The TROTS registry was designed as an international prospective longitudinal observational registry for data collection on pUEDVT patients. All pUEDVT patients, regardless of treatment received, can be included in the registry after informed consent is obtained. All relevant data regarding the initial presentation, diagnostics, treatment, and follow-up will be collected prospectively in an electronic case report form. In addition, a survey containing general questions, a Health-related Quality of Life questionnaire (EQ-5D-5L), and Functional Disability questionnaire (Quick-DASH) will be sent periodically (at the time of inclusion, one and two years after inclusion, and every five years after inclusion) to the participant. The registry protocol was approved by the Medical Ethical Review Board and registered in the Netherlands Trial Register under Trial-ID NL9680. The data generated by the registry will be used for future research on pUEDVT and published in peer reviewed journals. CONCLUSION: TROTS registry data will be used to further establish the optimal management of pUEDVT and lay the foundation for future research and guidelines.

Multicenter Case Series and Literature Review on Durability of Stents in the Thoracic Outlet.

PURPOSE: The aim of this paper was to report our experience with arterial and venous endovascular stent placement in the thoracic outlet (TO) and review available literature. METHODS: All patients that underwent arterial or venous stent placement in the TO between 2013 and 2020 in 5 Dutch vascular teaching-hospitals were retrospectively identified. Primary endpoint was symptomatic stent failure due to stenosis, chronic or posture dependent compression, fracture, or occlusion of the stent. Secondary endpoints were symptoms at last follow-up and re-interventions. For the literature review, we searched studies reporting on stenting in the TO. RESULTS: Twenty-six patients were included with 11 arterial and 15 venous stents implanted to treat angioplasty resistant stenosis in arterial or venous TO syndrome, iatrogenic or traumatic vascular injury, radiotherapy fibrosis, or arterial dissection. Median follow-up was 19 and 14 months in the arterial and venous-group, respectively. Eight (73%) patients in the arterial, and 9 (60%) in the venous-group suffered symptomatic stent failure. Seven (64%) patients in the arterial, and 9 (60%) in the venous-group required at least 1 re-intervention. When comparing all patients with stent placement after TO decompression (TOD) to patients without, there were substantially more symptomatic stent failures and re-interventions required in the patients without TOD. Six patients (54%) in the arterial-group and 11 (73%) in the venous-group were symptom-free at last follow-up. Five articles describing 51 patients with arterial and 6 articles describing 81 patients with venous stents were included in the literature review. In the arterial-group, no TOD prior to stent placement was performed, while in the venous-group all but 1 article performed TOD prior to stent placement. Results showed comparable rates of symptomatic stent failure (24% vs 30%), and patients requiring re-interventions (29% vs 21%) between groups. CONCLUSION: Based on our multicenter series and review, stents in the TO have a considerable risk of failure, both in the venous and the arterial territory. Especially in patients without TOD: the need for re-interventions is high and half the patients eventually undergo TOD. Based on the currently available data, stenting in the TO should be applied cautiously while TOD should be considered.

Editor's Choice - Two Year Results of the Randomised DISCOVER Trial Comparing Covered Versus Bare Metal Stents in the Common Iliac Artery.

OBJECTIVE: It has been suggested that covered stents (CS) may lower restenosis rates compared with bare metal stents (BMS) after endovascular treatment of the common iliac artery. This trial aimed to provide additional evidence on the efficacy of CS vs. BMS in the common iliac artery. METHODS: This multicentre, randomised, single blind controlled superiority trial compared balloon expandable CS and balloon expandable BMS for advanced atherosclerotic lesions in the common iliac artery; this was defined as a stenosis > 3 cm in length or occlusion. The primary end point was freedom from binary restenosis after two years of follow up. The study was conducted according to the principles of the Declaration of Helsinki (version: October 2008) and registered with the Dutch Trial register (NTR3381). RESULTS: One hundred and seventy-four limbs were included between 2012 and 2019 with 87 limbs in each group. Six patients crossed over from the BMS group to the CS group but were analysed according to an intention to treat principle. Freedom from binary restenosis after two years of follow up was 84.7% (95% CI 76.7 - 92.7%) in the BMS group and 89.1% (95% CI 82.4 - 95.8%) in the CS group (p = .40). Freedom from occlusion was 95.0% (95% CI 90.3 - 95.7%) in the BMS group and 96.4% (95% CI 92.5 - 100%) in the CS group (p = .66). Freedom from target lesion revascularisation was 91.1% (95% CI 84.8 - 97.3%) and 95.2% (95% CI 90.7 -99.7%), respectively (p = .31). Technical success, complications, haemodynamic success, and clinical success were also comparable between both groups. Per-protocol analysis did not affect the outcomes of the study. CONCLUSION: No difference was found between balloon expandable CS and BMS for treating advanced atherosclerotic lesions of the common iliac artery.

Post-thrombotic syndrome after upper extremity deep vein thrombosis: An international Delphi consensus study.

OBJECTIVES: Primary deep vein thrombosis of the upper extremity (UEDVT) is a rare condition but up to 60% of patients may develop post-thrombotic syndrome in the upper extremity (UE-PTS) with significant morbidity and decreased quality of life. However, there is no universally accepted method to diagnose and classify UE-PTS, hampering scientific research on UEDVT treatment. Through this international Delphi consensus study we aimed to determine what a clinical score for diagnosing UE-PTS should entail. METHODS: An online focus group survey among 20 patients treated for UEDVT was performed to provide clinical parameters before the start of a four round electronic Delphi consensus study among 25 international experts. The CREDES recommendations on Conducting and Reporting Delphi Studies were applied. Open text questions, multiple selection questions, and 9-point Likert scales were used. Consensus was set at 70% agreement. RESULTS: After four rounds, agreement was reached on a composite score of five symptoms and three clinical signs, combined with a functional disability score. The signs and symptom will each be scored on a severity scale of 0-3 and the total score expressed as an ordinal variable; no/mild/moderate/or severe PTS. The functional disability portion measures the impact of the signs and symptoms on the functionality of the patient's arm. CONCLUSION: Consensus was reached on a composite score of signs and symptoms of UE-PTS combined with a functional disability score. Clinical validation of the UE-PTS score in a large patient cohort is mandatory to facilitate application in future research.

Functional outcome of arterial thoracic outlet syndrome treatment.

Introduction: The low prevalence of Arterial Thoracic Outlet Syndrome (ATOS) and diffuse symptomatology have resulted in limited data on optimal treatment strategies and long-term outcome. The aim of this study was to report and evaluate a single center experience with the treatment of ATOS including midterm patient reported outcome. Methods: All patients treated for ATOS from 2004 to 2020 were retrospectively identified. Patients were divided into two groups based on presenting symptoms; ATOX group (Acute arterial occlusion with ischemia) and ATOS group (claudication symptoms). Baseline characteristics and treatment details were extracted from electronic patient files. A telephone survey was conducted to collect patients' follow-up data including a functional disability score using the Quick Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire. The primary endpoint of this study was symptom-free survival. Secondary endpoints were median QuickDASH scores during follow-up, postoperative complications and possible re-interventions. Results: A total of 20 patients (mean age 44.6 years, median follow-up 50.5 months) were included and divided into two groups (ATOX N = 9, ATOS N = 11). In the ATOX group, eight patients were primarily treated with catheter directed thrombolysis (CDT; N = 5) or surgical thrombectomy (N = 3). All patients received staged thoracic outlet decompression surgery (TOD). In the ATOS group, 10 patients primarily received TOD and one patient was treated conservatively with physiotherapy. Seven ATOX patients and nine ATOS patients were symptom free at follow-up with a median QuickDASH score of 2.3 (IQR 12.5) and 2.3 (IQR 16.5) respectively. Ten complications occurred in the ATOX group; three bleeding complications, five re-occlusions, one arterial dissection and one occipital infarction. In the ATOS group five complications occurred; one perioperative bleeding complication, three re-occlusions and a stent fracture. Seven vs. five re-interventions were required in the ATOX and ATOS groups respectively. Conclusion: The mid-term self-reported symptom free survival in both the ATOX as well as ATOS group seems acceptable while median QuickDASH scores in both groups indicate a very good functional outcome. This however comes at the cost of treatment related bleeding complications in especially the ATOX group presumably due to thrombolysis, and re-interventions required in almost one out of three patients.

Variation in perioperative cerebral and hemodynamic monitoring during carotid endarterectomy.

BACKGROUND: Hemodynamic disturbances cause half of the perioperative strokes following carotid endarterectomy (CEA). Guidelines strongly recommend strict pre- and postoperative blood pressure (BP) monitoring in CEA patients, but do not provide firm practical recommendations. Although in the Netherlands 50 centres perform CEA, no national protocol on perioperative hemodynamic, and cerebral monitoring exists. To assess current monitoring policies of all Dutch CEA-centres, a national survey was conducted. METHODS: Between May and July 2017 all 50 Dutch CEA-centres were invited to complete a 42-question survey addressing perioperative hemodynamic and cerebral monitoring during CEA. Nonresponders received a reminder after 1 and 2 months. By November 2017 the survey was completed by all centres. RESULTS: Preoperative baseline BP was based on a single bilateral BP-measurement at the outpatient-clinic in the majority of centres (n = 28). In 43 centres (86%) pre-operative monitoring (transcranial Doppler (TCD, n = 6), electroencephalography (EEG, n = 11), or TCD + EEG (n = 26)) was performed as a baseline reference. Intraoperatively, large diversity for type of anaesthesia (general: 45 vs. local [LA]:5) and target systolic BP (>100 mm hg - 160 mm hg [n = 12], based on preoperative outpatient-clinic or admission BP [n = 18], other [n = 20]) was reported. Intraoperative cerebral monitoring included EEG + TCD (n = 28), EEG alone (n = 13), clinical neurological examination with LA (n = 5), near-infrared spectroscopy with stump pressure (n = 1), and none due to standard shunting (n = 3). Postoperatively, significant variation was reported in standard duration of admission at a recovery or high-care unit (range 3-48 hr, mean:12 hr), maximum accepted systolic BP (range >100 mm hg - 180 mm Hg [n = 32]), postoperative cerebral monitoring (standard TCD [n = 16], TCD on indication [n = 5] or none [n = 24]) and in timing of postoperative cerebral monitoring (range directly postoperative - 24 hr postoperative; median 3 hr). CONCLUSIONS: In Dutch centres performing CEA the perioperative hemodynamic and cerebral monitoring policies are widely diverse. Diverse policies may theoretically lead to over- or under treatment. The results of this national audit may serve as the baseline dataset for development of a standardized and detailed (inter)national protocol on perioperative hemodynamic and cerebral monitoring during CEA.

Validation of multiparametric MRI by histopathology after nephrectomy: a case study.

OBJECTIVES: Renal multiparametric MRI (mpMRI) is a promising tool to monitor renal allograft health to enable timely treatment of chronic allograft nephropathy. This study aims to validate mpMRI by whole-kidney histology following transplantectomy. MATERIALS AND METHODS: A patient with kidney transplant failure underwent mpMRI prior to transplantectomy. The mpMRI included blood oxygenation level-dependent (BOLD) MRI, T1 and T2 mapping, diffusion-weighted imaging (DWI), 2D phase contrast (2DPC) and arterial spin labeling (ASL). Parenchymal mpMRI measures were compared to normative values obtained in 19 healthy controls. Differences were expressed in standard deviations (SD) of normative values. The mpMRI measures were compared qualitatively to histology. RESULTS: The mpMRI showed a heterogeneous parenchyma consistent with extensive interstitial hemorrhage on histology. A global increase in T1 (+ 3.0 SD) and restricted diffusivity (- 3.6 SD) were consistent with inflammation and fibrosis. Decreased T2 (- 1.8 SD) indicated fibrosis or hemorrhage. ASL showed diminished cortical perfusion (- 2.9 SD) with patent proximal arteries. 2DPC revealed a 69% decrease in renal perfusion. Histological evaluation showed a dense inflammatory infiltrate and fibrotic changes, consistent with mpMRI results. Most interlobular arteries were obliterated while proximal arteries were patent, consistent with ASL findings. DISCUSSION: mpMRI findings correlated well with histology both globally as well as locally.

Timing of Thoracic Outlet Decompression after Thrombolysis for Primary Upper Extremity Deep Venous Thrombosis: A Systematic Review.

BACKGROUND: The optimal timing of decompression surgery after thrombolysis in patients with primary upper extremity deep vein thrombosis (UEDVT) is still a matter of debate. This systematic review compares the safety and efficacy of early intervention versus postponed intervention in patients with primary UEDVT. METHODS: A structured PUBMED, EMBASE, and COCHRANE search was performed for studies reporting on the timing of surgical intervention for primary UEDVT. Studies reporting on timing of decompression surgery in combination with recurrent thrombosis, bleeding complications, and symptom-free survival were included. Two treatment groups were defined; group A received surgical decompression within two weeks after thrombolysis and group B after two weeks or more. All end points were assessed in accordance with the reported outcomes in the included articles. Mean percentages were calculated using descriptive statistics. RESULTS: Six articles (126 patients) were included: 87 patients in group A versus 39 in group B. In group A, bleeding complications occurred in 7% of patients versus 5% in group B. Two-third of the bleeding complications in group A occurred in patients receiving surgical decompression within 24 hr after thrombolysis while kept on intravenous heparin both preoperatively and postoperatively. Reported preoperative recurrent thrombosis was 7% in group A versus 11% in group B, another 13% had postoperative recurrent thrombosis versus 21% in group B. The effectiveness of both treatment strategies was comparable with a total of 89% of patients in group A with minimal or no symptoms at final follow-up compared with 90% in group B. The mean follow-up in group A was 35 months (1-168 months) and 28 months (1-168 months) in group B. CONCLUSIONS: Based on the limited available data presented in this review, early decompression surgery within two weeks after catheter-directed thrombolysis seems as safe and effective as postponed surgical intervention in patients with primary UEDVT.

Adrenal medullary hyperplasia is a precursor lesion for pheochromocytoma in MEN2 syndrome.

Adrenal medullary hyperplasias (AMHs) are adrenal medullary proliferations with a size < 1 cm, while larger lesions are considered as pheochromocytoma (PCC). This arbitrary distinction has been proposed decades ago, although the biological relationship between AMH and PCC has never been investigated. Both lesions are frequently diagnosed in multiple endocrine neoplasia type 2 (MEN2) patients in whom they are considered as two unrelated clinical entities. In this study, we investigated the molecular relationship between AMH and PCC in MEN2 patients. Molecular aberrations of 19 AMHs and 13 PCCs from 18 MEN2 patients were determined by rearranged during transfection (RET) proto-oncogene mutation analysis and loss of heterozygosity (LOH) analysis for chromosomal regions 1p13, 1p36, 3p, and 3q, genomic areas covering commonly altered regions in RET-related PCC. Identical molecular aberrations were found in all AMHs and PCCs, at similar frequencies. LOH was seen for chromosomes 1p13 in 8 of 18 (44%), 1p36 in 9 of 15 (60%), 3p12-13 in 12 of 18 (67%), and 3q23-24 in 10 of 16 (63%) of AMHs, and for chromosome 1p13 in 13 of 13 (100%), 1p36 in 7 of 11 (64%), 3p12-13 in 4 of 11 (36%), and 3q23-24 in 11 of 12 (92%) of PCCs. Our results indicate that AMHs are not hyperplasias and, in clinical practice, should be regarded as PCCs, which has an impact on diagnosis and treatment of MEN2 patients. We therefore propose to replace the term AMH by micro-PCC to indicate adrenal medullary proliferations of less than 1 cm.

An immunohistochemical procedure to detect patients with paraganglioma and phaeochromocytoma with germline SDHB, SDHC, or SDHD gene mutations: a retrospective and prospective analysis.

BACKGROUND: Phaeochromocytomas and paragangliomas are neuro-endocrine tumours that occur sporadically and in several hereditary tumour syndromes, including the phaeochromocytoma-paraganglioma syndrome. This syndrome is caused by germline mutations in succinate dehydrogenase B (SDHB), C (SDHC), or D (SDHD) genes. Clinically, the phaeochromocytoma-paraganglioma syndrome is often unrecognised, although 10-30% of apparently sporadic phaeochromocytomas and paragangliomas harbour germline SDH-gene mutations. Despite these figures, the screening of phaeochromocytomas and paragangliomas for mutations in the SDH genes to detect phaeochromocytoma-paraganglioma syndrome is rarely done because of time and financial constraints. We investigated whether SDHB immunohistochemistry could effectively discriminate between SDH-related and non-SDH-related phaeochromocytomas and paragangliomas in large retrospective and prospective tumour series. METHODS: Immunohistochemistry for SDHB was done on 220 tumours. Two retrospective series of 175 phaeochromocytomas and paragangliomas with known germline mutation status for phaeochromocytoma-susceptibility or paraganglioma-susceptibility genes were investigated. Additionally, a prospective series of 45 phaeochromocytomas and paragangliomas was investigated for SDHB immunostaining followed by SDHB, SDHC, and SDHD mutation testing. FINDINGS: SDHB protein expression was absent in all 102 phaeochromocytomas and paragangliomas with an SDHB, SDHC, or SDHD mutation, but was present in all 65 paraganglionic tumours related to multiple endocrine neoplasia type 2, von Hippel-Lindau disease, and neurofibromatosis type 1. 47 (89%) of the 53 phaeochromocytomas and paragangliomas with no syndromic germline mutation showed SDHB expression. The sensitivity and specificity of the SDHB immunohistochemistry to detect the presence of an SDH mutation in the prospective series were 100% (95% CI 87-100) and 84% (60-97), respectively. INTERPRETATION: Phaeochromocytoma-paraganglioma syndrome can be diagnosed reliably by an immunohistochemical procedure. SDHB, SDHC, and SDHD germline mutation testing is indicated only in patients with SDHB-negative tumours. SDHB immunohistochemistry on phaeochromocytomas and paragangliomas could improve the diagnosis of phaeochromocytoma-paraganglioma syndrome. FUNDING: The Netherlands Organisation for Scientific Research, Dutch Cancer Society, Vanderes Foundation, Association pour la Recherche contre le Cancer, Institut National de la Santé et de la Recherche Médicale, and a PHRC grant COMETE 3 for the COMETE network.

Frequent loss of 17p, but no p53 mutations or protein overexpression in benign and malignant pheochromocytomas.

Genetic changes in the tumorigenesis of sporadic pheochromocytomas are poorly understood, and there are no good markers to discriminate benign from malignant pheochromocytomas. p53 is a tumor suppressor gene and aberrations in this gene are frequently found in many tumor types. The role of p53 in pheochromocytoma tumorigenesis is unclear, with some studies suggesting that p53 mutations can be used to discriminate benign from malignant pheochromocytomas while other studies do not find such an association. Because most of these investigations were hampered by small series of tumors and the use of varying methods, we have performed a comprehensive analysis of p53 aberrations in a large series of pheochromocytomas. Comparative genomic hybridization analysis of 31 benign and 20 malignant tumors showed loss of the p53 locus at chromosome 17p13.1 in 23/51 (45%) cases, and most of these results were confirmed by fluorescence in situ hybridization. Forty-three tumors, including the malignant tumors and the tumors with loss of the p53 locus, were analyzed for p53 mutations in exons 5-8, but none were found. Furthermore, p53 immunohistochemistry on 35 cases revealed strong nuclear p53 expression in only two pheochromocytoma metastases, all other tumors being negative. We conclude that, although there is frequent loss of the p53 locus on 17p, the p53 gene does not appear to play a major role in pheochromocytoma tumorigenesis.

Candidate gene mutation analysis in bilateral adrenal pheochromocytoma and sympathetic paraganglioma.

Pheochromocytomas (PCCs) are rare tumors that arise from chromaffin tissue in the adrenal medulla, but can also occur in the abdomen outside the adrenals and are then called sympathetic paragangliomas (sPGLs). According to the literature, between 15 and 25% of apparently sporadic adrenal PCC and sPGL are caused by germline mutations in RET, von Hippel-Lindau disease (VHL), succinate dehydrogenase subunit B (SDHB), or subunit D SDHD. However, few studies have addressed the mutationfrequency of these candidate genes in selected subgroups of PCC andsPGL, such as bilateral adrenal PCC or extra-adrenal sPGL, and none have looked at somatic mutations by analyzing tumor tissue. Therefore, we have investigated the occurrence of germline and somatic mutations in RET, VHL, SDHB, and SDHD in comparatively large series of bilateral adrenal PCC (n = 33 patients) and sPGL (n = 26 patients), with the aim of determining the mutation frequency of each of these genes and to establish a genetic testing algorithm. Twenty-one RET, two VHL germline, and one SDHD mutations were found in the patients with bilateral adrenal PCC. In sPGL, one novel SDHB germline and one novel SDHB somatic mutation were observed. In addition, two SDHD germline mutations were found. We conclude that germline RET mutations are predominantly found in bilateral PCC, and that somatic and germline SDHB and SDHD mutations usually occur in sPGL, which has practical consequences for genetic testing algorithms. We suggest that sequential mutation analysis should be directed first at RET, followed by VHL and SDHD for patients with bilateral adrenal PCC at diagnosis, and at SDHB and SDHD for patients with sPGL.

Frequent genetic changes in childhood pheochromocytomas.

Pheochromocytomas (PCCs) are rare catecholamine-producing tumors of the adrenal gland which may also occur elsewhere in the abdomen and are then called paragangliomas. A proportion of PCCs occurs in hereditary cancer syndromes, including multiple endocrine neoplasia Type 2 (MEN2), caused by mutations in the RET proto-oncogene, von Hippel-Lindau (VHL) disease, caused by VHL gene abnormalities, and the pheochromocytoma-paraganglioma (PCC-PGL) syndrome, caused by mutations in SDHB and SDHD. Since a proportion of PCCs occurs in children we hypothesized that germline mutations in RET, VHL, succinate dehydrogenase subunit B (SDHB), and subunit D (SDHD) occur more frequently in the pediatric age range. From our single-institution collection of PCCs, we have selected 10 cases that occurred in individuals up to 18 years of age at diagnosis. In these, we have performed mutation analysis on normal and tumor tissues for exons 10, 11, and 16 of RET and for the entire coding sequence of VHL, SDHB, and SDHD. The 10 patients include 7 boys and 3 girls, with an average age of 15.5 years (range 9-18 years). Two patients had germline RET exon 11 mutations (C634R) and 1 patient had an R64P germline mutation in the VHL gene. In the remaining 7 patients there was one patient from a family fulfilling the clinical criteria for VHL disease. All tumors were benign (average follow-up: 12 years) and were located in the adrenal. From our findings we conclude that (a) a large proportion (40%) of pediatric PCC patients is diagnosed in the context of inherited cancer syndromes, and (b) candidate gene analysis appears to be indicated to detect germline mutations.