Screening and surveillance recommendations for central nervous system hemangioblastomas in pediatric patients with Von Hippel-Lindau disease

PURPOSE

Von Hippel-Lindau (VHL) disease is an autosomal-dominantly inherited tumor predisposition syndrome. One of the most common tumors are central nervous system (CNS) hemangioblastomas. Recommendations on the initiation and continuation of the screening and surveillance program for CNS tumors in pediatric VHL patients are based on small case series and thus low evidence level. To derive more robust screening recommendations, we report on the largest monocentric pediatric cohort of VHL patients.

METHODS

We performed a retrospective analysis on a pediatric cohort of 99 VHL patients consulted at our VHL center from 1992 to 2023. Clinical, surgical, genetic, and imaging data were collected and statistically analyzed.

RESULTS

42 patients (50% male) developed CNS hemangioblastomas, of whom 18 patients (56% male) underwent hemangioblastoma surgery (mean age at first surgery: 14.9 ± 1.9 years; range 10.2-17). The first asymptomatic patient was operated on at the age of 13.2 years due to tumor progress. Truncating VHL mutation carriers had a significantly higher manifestation rate (HR = 3.7, 95% CI: 1.9-7.4, p < 0.0001) and surgery rate (HR = 3.3, 95% CI: 1.2-8.9, p = 0.02) compared with missense mutation carriers.

CONCLUSION

We recommend starting MRI imaging at the age of 12 years with examination intervals every (1-) 2 years depending on CNS involvement. Special attention should be paid to patients with truncating variants. Affected families should be educated regularly on potential tumor-associated symptoms to enable timely MRI imaging and eventually intervention, as CNS hemangioblastoma may develop before screening begins.

GERMAN CLINICAL TRIALS REGISTER REGISTRATION NUMBER

DRKS00029553, date of registration 08/16/2022, retrospectively registered.

Genetic stratification of inherited and sporadic phaeochromocytoma and paraganglioma: implications for precision medicine

Over the past two decades advances in genomic technologies have transformed knowledge of the genetic basis of phaeochromocytoma and paraganglioma (PPGL). Though traditional teaching suggested that inherited cases accounted for only 10% of all phaeochromocytoma diagnosis, current estimates are at least three times this proportion. Inherited PPGL is a highly genetically heterogeneous disorder but the most frequently results from inactivating variants in genes encoding subunits of succinate dehydrogenase. Expanding knowledge of the genetics of PPGL has been translated into clinical practice by the provision of widespread testing for inherited PPGL. In this review, we explore how the molecular stratification of PPGL is being utilized to enable more personalized strategies for investigation, surveillance and management of affected individuals and their families. Translating recent genetic research advances into clinical service can not only bring benefits through more accurate diagnosis and risk prediction but also challenges when there is a suboptimal evidence base for the clinical consequences or significance of rare genotypes. In such cases, clinical, biochemical, pathological and functional imaging assessments can all contribute to more accurate interpretation and clinical management.

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

BACKGROUND

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

METHODS

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

FINDINGS

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

INTERPRETATION

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

FUNDING

US National Institutes of Health.

Primary hyperparathyroidism as first manifestation in multiple endocrine neoplasia type 2A: an international multicenter study

OBJECTIVE

Multiple endocrine neoplasia type 2A (MEN 2A) is a rare syndrome caused by RET germline mutations and has been associated with primary hyperparathyroidism (PHPT) in up to 30% of cases. Recommendations on RET screening in patients with apparently sporadic PHPT are unclear. We aimed to estimate the prevalence of cases presenting with PHPT as first manifestation among MEN 2A index cases and to characterize the former cases.

DESIGN AND METHODS

An international retrospective multicenter study of 1085 MEN 2A index cases. Experts from MEN 2 centers all over the world were invited to participate. A total of 19 centers in 17 different countries provided registry data of index cases followed from 1974 to 2017.

RESULTS

Ten cases presented with PHPT as their first manifestation of MEN 2A, yielding a prevalence of 0.9% (95% CI: 0.4-1.6). 9/10 cases were diagnosed with medullary thyroid carcinoma (MTC) in relation to parathyroid surgery and 1/10 was diagnosed 15 years after parathyroid surgery. 7/9 cases with full TNM data were node-positive at MTC diagnosis.

CONCLUSIONS

Our data suggest that the prevalence of MEN 2A index cases that present with PHPT as their first manifestation is very low. The majority of index cases presenting with PHPT as first manifestation have synchronous MTC and are often node-positive. Thus, our observations suggest that not performing RET mutation analysis in patients with apparently sporadic PHPT would result in an extremely low false-negative rate, if no other MEN 2A component, specifically MTC, are found during work-up or resection of PHPT.

Hemangioblastoma and von Hippel-Lindau disease: genetic background, spectrum of disease, and neurosurgical treatment

INTRODUCTION

Hemangioblastomas are rare, histologically benign, highly vascularized tumors of the brain, the spinal cord, and the retina, occurring sporadically or associated with the autosomal dominant inherited von Hippel-Lindau (VHL) disease. Children or adults with VHL disease have one of > 300 known germline mutations of the VHL gene located on chromosome 3. They are prone to develop hemangioblastomas, extremely rarely starting at age 6, rarely at age 12-18, and, typically and almost all, as adults. There is a plethora of VHL-associated tumors and cysts, mainly in the kidney, pancreas, adrenals, reproductive organs, and central nervous system. Due to a lack of causal treatment, alleviation of symptoms and prevention of permanent neurological deficits as well as malignant transformation are the main task. Paucity of data and the nonlinear course of tumor progression make management of pediatric VHL patients with hemangioblastomas challenging.

METHODS

The Freiburg surveillance protocol was developed by combining data from the literature and our experience of examinations of > 300 VHL patients per year at our university VHL center.

RESULTS

Key recommendations are to start screening of patients at risk by funduscopy with dilated pupils for retinal tumors with admission to school and with MRI of the brain and spinal cord at age 14, then continue biannually until age 18, with emergency MRI in case of neurological symptoms. Indication for surgery remains personalized and should be approved by an experienced VHL board, but we regard neurological symptoms, rapid tumor growth, or critically large tumor/cyst sizes as the key indications to remove hemangioblastomas. Since repeated surgery on hemangioblastomas in VHL patients is not rare, modern neurosurgical techniques should encompass microsurgery, neuronavigation, intraoperative neuromonitoring, fluorescein dye-based intraoperative angiography, intraoperative ultrasound, and minimally invasive approaches, preceded in selected cases by endovascular embolization. Highly specialized neurosurgeons are able to achieve a very low risk of permanent morbidity for the removal of hemangioblastomas from the cerebellum and spinal cord. Small retinal tumors of the peripheral retina can be treated by laser coagulation, larger tumors by cryocoagulation or brachytherapy.

CONCLUSION

We consider management at experienced VHL centers mandatory and careful surveillance and monitoring of asymptomatic lesions are required to prevent unnecessary operations and minimize morbidity.

Variant type is associated with disease characteristics in SDHB, SDHC and SDHD-linked phaeochromocytoma-paraganglioma

BACKGROUND

Pathogenic germline variants in subunits of succinate dehydrogenase (SDHB, SDHC and SDHD) are broadly associated with disease subtypes of phaeochromocytoma-paraganglioma (PPGL) syndrome. Our objective was to investigate the role of variant type (ie, missense vs truncating) in determining tumour phenotype.

METHODS

Three independent datasets comprising 950 PPGL and head and neck paraganglioma (HNPGL) patients were analysed for associations of variant type with tumour type and age-related tumour risk. All patients were carriers of pathogenic germline variants in the SDHB, SDHC or SDHD genes.

RESULTS

Truncating SDH variants were significantly over-represented in clinical cases compared with missense variants, and carriers of SDHD truncating variants had a significantly higher risk for PPGL (p<0.001), an earlier age of diagnosis (p<0.0001) and a greater risk for PPGL/HNPGL comorbidity compared with carriers of missense variants. Carriers of SDHB truncating variants displayed a trend towards increased risk of PPGL, and all three SDH genes showed a trend towards over-representation of missense variants in HNPGL cases. Overall, variant types conferred PPGL risk in the (highest-to-lowest) sequence SDHB truncating, SDHB missense, SDHD truncating and SDHD missense, with the opposite pattern apparent for HNPGL (p<0.001).

CONCLUSIONS

SDHD truncating variants represent a distinct group, with a clinical phenotype reminiscent of but not identical to SDHB. We propose that surveillance and counselling of carriers of SDHD should be tailored by variant type. The clinical impact of truncating SDHx variants is distinct from missense variants and suggests that residual SDH protein subunit function determines risk and site of disease.

Comparison of Pheochromocytoma-Specific Morbidity and Mortality Among Adults With Bilateral Pheochromocytomas Undergoing Total Adrenalectomy vs Cortical-Sparing Adrenalectomy

IMPORTANCE

Large studies investigating long-term outcomes of patients with bilateral pheochromocytomas treated with either total or cortical-sparing adrenalectomies are needed to inform clinical management.

OBJECTIVE

To determine the association of total vs cortical-sparing adrenalectomy with pheochromocytoma-specific mortality, the burden of primary adrenal insufficiency after bilateral adrenalectomy, and the risk of pheochromocytoma recurrence.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study used data from a multicenter consortium-based registry for 625 patients treated for bilateral pheochromocytomas between 1950 and 2018. Data were analyzed from September 1, 2018, to June 1, 2019.

EXPOSURES

Total or cortical-sparing adrenalectomy.

MAIN OUTCOMES AND MEASURES

Primary adrenal insufficiency, recurrent pheochromocytoma, and mortality.

RESULTS

Of 625 patients (300 [48%] female) with a median (interquartile range [IQR]) age of 30 (22-40) years at diagnosis, 401 (64%) were diagnosed with synchronous bilateral pheochromocytomas and 224 (36%) were diagnosed with metachronous pheochromocytomas (median [IQR] interval to second adrenalectomy, 6 [1-13] years). In 505 of 526 tested patients (96%), germline mutations were detected in the genes RET (282 patients [54%]), VHL (184 patients [35%]), and other genes (39 patients [7%]). Of 849 adrenalectomies performed in 625 patients, 324 (52%) were planned as cortical sparing and were successful in 248 of 324 patients (76.5%). Primary adrenal insufficiency occurred in all patients treated with total adrenalectomy but only in 23.5% of patients treated with attempted cortical-sparing adrenalectomy. A third of patients with adrenal insufficiency developed complications, such as adrenal crisis or iatrogenic Cushing syndrome. Of 377 patients who became steroid dependent, 67 (18%) developed at least 1 adrenal crisis and 50 (13%) developed iatrogenic Cushing syndrome during median (IQR) follow-up of 8 (3-25) years. Two patients developed recurrent pheochromocytoma in the adrenal bed despite total adrenalectomy. In contrast, 33 patients (13%) treated with successful cortical-sparing adrenalectomy developed another pheochromocytoma within the remnant adrenal after a median (IQR) of 8 (4-13) years, all of which were successfully treated with another surgery. Cortical-sparing surgery was not associated with survival. Overall survival was associated with comorbidities unrelated to pheochromocytoma: of 63 patients who died, only 3 (5%) died of metastatic pheochromocytoma.

CONCLUSIONS AND RELEVANCE

Patients undergoing cortical-sparing adrenalectomy did not demonstrate decreased survival, despite development of recurrent pheochromocytoma in 13%. Cortical-sparing adrenalectomy should be considered in all patients with hereditary pheochromocytoma.

Co-Inheritance of Autosomal Dominant Polycystic Kidney Disease and Naevoid Basal Cell Carcinoma Syndrome: Effects on Renal Progression

The calcium signalling and hedgehog (HH) signalling pathways operate in the primary cilium. Abnormalities in these pathways cause autosomal dominant polycystic kidney disease (ADPKD) and naevoid basal cell carcinoma syndrome (NBCCS) respectively. Several reports have proposed that hyperactivation of the HH pathway in animal models of polycystic kidney disease affects normal renal development and renal cyst phenotype. A family with 2 cases (a proband and her sister) of ADPKD and NBCCS coinheritance led us to investigate whether interactions may be present in the 2 pathways. The effect of HH pathway hyperactivation (due to c.573C>G mutation on PTCH1 gene that cause NBCCS) on renal ADPKD progression in the proband was compared to 18 age- and sex-matched ADPKD patients in a 9-year, prospective, follow-up study. Blood pressure, total kidney volume, estimated glomerular filtration rate, plasma copeptin, urine excretion of albumin, total protein and monocyte chemoattractant protein-1 (MCP-1) were analysed. Data for the sibling was not available. In the ADPKD group, blood pressure and estimated glomerular filtration rate were within normal values, and total kidney volume and MCP-1 increased (p < 0.01) throughout the study. In comparison, during the 9-year follow-up, the proband showed persistent hypertension (from 125/85 to 140/95 mm Hg), low total kidney volume (75 and 61% of median ADPKD), and a ninefold increase in urine MCP-1. We found no differences in urine excretion of albumin or plasma copeptin values. These results suggest that HH hyperactivation may play a minimal role in ADPKD progression. These observations can help to clarify the clinical impact of affected pathways in renal development and cystogenesis in humans.

Preventive medicine of von Hippel-Lindau disease-associated pancreatic neuroendocrine tumors

Pancreatic neuroendocrine tumors (PanNETs) are rare in von Hippel-Lindau disease (VHL) but cause serious morbidity and mortality. Management guidelines for VHL-PanNETs continue to be based on limited evidence, and survival data to guide surgical management are lacking. We established the European-American-Asian-VHL-PanNET-Registry to assess data for risks for metastases, survival and long-term outcomes to provide best management recommendations. Of 2330 VHL patients, 273 had a total of 484 PanNETs. Median age at diagnosis of PanNET was 35 years (range 10-75). Fifty-five (20%) patients had metastatic PanNETs. Metastatic PanNETs were significantly larger (median size 5 vs 2 cm; P < 0.001) and tumor volume doubling time (TVDT) was faster (22 vs 126 months; P = 0.001). All metastatic tumors were ≥2.8 cm. Codons 161 and 167 were hotspots for VHL germline mutations with enhanced risk for metastatic PanNETs. Multivariate prediction modeling disclosed maximum tumor diameter and TVDT as significant predictors for metastatic disease (positive and negative predictive values of 51% and 100% for diameter cut-off ≥2.8 cm, 44% and 91% for TVDT cut-off of ≤24 months). In 117 of 273 patients, PanNETs >1.5 cm in diameter were operated. Ten-year survival was significantly longer in operated vs non-operated patients, in particular for PanNETs <2.8 cm vs ≥2.8 cm (94% vs 85% by 10 years; P = 0.020; 80% vs 50% at 10 years; P = 0.030). This study demonstrates that patients with PanNET approaching the cut-off diameter of 2.8 cm should be operated. Mutations in exon 3, especially of codons 161/167 are at enhanced risk for metastatic PanNETs. Survival is significantly longer in operated non-metastatic VHL-PanNETs.

Is there any role for minimally invasive surgery in NET?

Neuroendocrine tumors (NET) represent the variability of almost benign lesions either secreting hormones occurring as a single lesion up to malignant lesions with metastatic potential. Treatment of NET is usually performed by surgical resection. Due to the rarity of NET, surgical treatment is mainly based on the experience and recommendations of experts and less on the basis of prospective randomized studies. In addition, the development and establishment of new surgical procedures is made more difficult by their rarity. The development of laparoscopic-assisted surgery has significantly improved the treatment of many diseases. Due to the well-known advantages of laparoscopic surgery, this method has also been increasingly used to treat NET. However, due to limited comparative data, the assumed superiority of laparoscopic surgery in the area NET remains often unclear or not yet proven. This review focuses on the present usage of laparoscopic techniques in the area of NET. Relating to the current literature, this review presents the evidence of various laparoscopic procedures for treatment of adrenal, pancreatic and intestine NET as well as extraadrenal pheochromocytoma and neuroendocrine liver metastases. Further, this review focuses on recent new developments of minimally invasive surgery in the area of NET. Here, robotic-assisted surgery and single-port surgery are promising approaches.

Clinical Characterization of the Pheochromocytoma and Paraganglioma Susceptibility Genes SDHA, TMEM127, MAX, and SDHAF2 for Gene-Informed Prevention

Importance

Effective cancer prevention is based on accurate molecular diagnosis and results of genetic family screening, genotype-informed risk assessment, and tailored strategies for early diagnosis. The expanding etiology for hereditary pheochromocytomas and paragangliomas has recently included SDHA, TMEM127, MAX, and SDHAF2 as susceptibility genes. Clinical management guidelines for patients with germline mutations in these 4 newly included genes are lacking.

Objective

To study the clinical spectra and age-related penetrance of individuals with mutations in the SDHA, TMEM127, MAX, and SDHAF2 genes.

Design, Setting, and Patients

This study analyzed the prospective, longitudinally followed up European-American-Asian Pheochromocytoma-Paraganglioma Registry for prevalence of SDHA, TMEM127, MAX, and SDHAF2 germline mutation carriers from 1993 to 2016. Genetic predictive testing and clinical investigation by imaging from neck to pelvis was offered to mutation-positive registrants and their relatives to clinically characterize the pheochromocytoma/paraganglioma diseases associated with mutations of the 4 new genes.

Main Outcomes and Measures

Prevalence and spectra of germline mutations in the SDHA, TMEM127, MAX, and SDHAF2 genes were assessed. The clinical features of SDHA, TMEM127, MAX, and SDHAF2 disease were characterized.

Results

Of 972 unrelated registrants without mutations in the classic pheochromocytoma- and paraganglioma-associated genes (632 female [65.0%] and 340 male [35.0%]; age range, 8-80; mean [SD] age, 41.0 [13.3] years), 58 (6.0%) carried germline mutations of interest, including 29 SDHA, 20 TMEM127, 8 MAX, and 1 SDHAF2. Fifty-three of 58 patients (91%) had familial, multiple, extra-adrenal, and/or malignant tumors and/or were younger than 40 years. Newly uncovered are 7 of 63 (11%) malignant pheochromocytomas and paragangliomas in SDHA and TMEM127 disease. SDHA disease occurred as early as 8 years of age. Extra-adrenal tumors occurred in 28 mutation carriers (48%) and in 23 of 29 SDHA mutation carriers (79%), particularly with head and neck paraganglioma. MAX disease occurred almost exclusively in the adrenal glands with frequently bilateral tumors. Penetrance in the largest subset, SDHA carriers, was 39% at 40 years of age and is statistically different in index patients (45%) vs mutation-carrying relatives (13%; P < .001).

Conclusions and Relevance

The SDHA, TMEM127, MAX, and SDHAF2 genes may contribute to hereditary pheochromocytoma and paraganglioma. Genetic testing is recommended in patients at clinically high risk if the classic genes are mutation negative. Gene-specific prevention and/or early detection requires regular, systematic whole-body investigation.

Max Schottelius: Pioneer in Pheochromocytoma

First descriptions of diseases attract tremendous interest because they reveal scientific insight even in retrospect. Max Schottelius, the pathologist contributing the first histological description of pheochromocytoma, remains anonymous. We reviewed the description by Schottelius and weighed the report in modern context. Schottelius described the classical diagnostic elements of pheochromocytoma, including the brown appearance after exposure to chromate-containing Mueller’s fixative. This color change, known as chromaffin reaction, results from oxidation of catecholamines and is reflected in the name pheochromocytoma, meaning dusky-colored chromate-positive tumor. Thus Schottelius performed the first known histochemical contribution to diagnosis, which is today standard with immunohistochemistry for chromogranin.

GROWTH RATE OF PARAGANGLIOMAS RELATED TO GERMLINE MUTATIONS OF THE SDHX GENES

OBJECTIVE

The purpose was to determine the growth rate of succinate dehydrogenase subunit (SDHx) gene-related paragangliomas based on computed tomography (CT) measurements.

METHODS

Twenty-seven patients with SDHx mutations who underwent subsequent CT examinations were enrolled in the study. Tumors were classified as head and neck (HNP), thoracic, or abdominal/pelvic paragangliomas (PGLs). The percentage volume increase and volume doubling time were estimated.

RESULTS

We analyzed 56 PGLs (21 with SDHD, 6 with SDHB mutations) in 27 patients (16 men, 11 women; mean age 37.7 years). The estimated median of the follow-up was 23 months. Twenty-two (39.3%) PGLs were located in the abdomen, 8 (14.3%) in the thorax, and 26 (46.4%) in the head and neck region. The median volume growth rate was estimated at 10.4% per year (interquartile range [IQR]: -1.3; 36.3). The volume doubling time was estimated as 7.01 (2.24;+∞) years. By tumor site, the estimated medians of the annual volume growth rates were 13.6% (IQR:0.8 -30.4) for HNP, -6.06% (IQR: -1.79;47.32) for thoracic PGLs, and 10.5% (IQR: -2.2;44.6) for abdominal PGLs. The volume doubling time was 5.44 years (2.61; 87.0) for HNP, 11.8 years (1.79;+∞) for thoracic PGLs, and 6.94 years (1,88;+∞) for abdominal PGLs. There was no significant difference in the volume growth rate according to tumor location or initial size (P>.7 and P = .07, respectively) or gene mutation type (SDHB vs. SDHD, P>.8).

CONCLUSION

PGLs related to SDHx mutations are slowly growing tumors. There were no correlations between tumor location, growth rate or initial size over a 23-month follow-up period.

ABBREVIATIONS

CT = computed tomography HNP = head and neck paraganglioma IQR = interquartile range PGL = paraganglioma PPGL = pheochromocytoma and paraganglioma SDH = succinate dehydrogenase.

Simple and rapid characterization of novel large germline deletions in SDHB, SDHC and SDHD-related paraganglioma

Germline mutations in genes encoding subunits of succinate dehydrogenase (SDH) are associated with hereditary paraganglioma and pheochromocytoma. Although most mutations in SDHB, SDHC and SDHD are intraexonic variants, large germline deletions may represent up to 10% of all variants but are rarely characterized at the DNA sequence level. Additional phenotypic effects resulting from deletions that affect neighboring genes are also not understood. We performed multiplex ligation-dependent probe amplification, followed by a simple long-range PCR 'chromosome walking' protocol to characterize breakpoints in 20 SDHx-linked paraganglioma-pheochromocytoma patients. Breakpoints were confirmed by conventional PCR and Sanger sequencing. Heterozygous germline deletions of up to 104 kb in size were identified in SDHB, SDHC, SDHD and flanking genes in 20 paraganglioma-pheochromocytoma patients. The exact breakpoint could be determined in 16 paraganglioma-pheochromocytoma patients of which 15 were novel deletions. In six patients proximal genes were also deleted, including PADI2, MFAP2, ATP13A2 (PARK9), CFAP126, TIMM8B and C11orf57. These genes were either partially or completely deleted, but did not modify the phenotype. This study increases the number of known SDHx deletions by over 50% and demonstrates that a significant proportion of large gene deletions can be resolved at the nucleotide level using a simple and rapid method.

Paragangliomas in patients with mutations of the SDHD gene

OBJECTIVE:

Paragangliomas represent neoplasms of neural crest origin that arise from paraganglia. Mutations in the gene encoding succinate dehydrogenase subunit D (SDHD) are responsible for a percentage of hereditary paragangliomas. We previously described a group of 271 pheochromocytoma patients, 11 of whom had mutations of the SDHD gene. The objective of this study was to find out whether those 11 patients had additional paragangliomas.

STUDY DESIGN:

Ten patients participated in our clinical screening program that included MRI of the skull base and neck, thorax, and abdomen, as well as an 18Fluoro-DOPA positron emission tomography (DOPA-PET).

RESULTS:

Five patients presented with head and neck paragangliomas, 1 patient with a thoracic paraganglioma, and 2 patients with intraabdominal paragangliomas.

CONCLUSIONS:

The screening for paragangliomas in patients with mutations of the SDHD gene offers the chance to diagnose those tumors in an early stage.

SIGNIFICANCE:

Because morbidity after surgical resection increases with tumor size, early surgery will minimize the potential risks.

MANAGEMENT OF ENDOCRINE DISEASE: Outcome of adrenal sparing surgery in heritable pheochromocytoma

The management of hereditary pheochromocytoma has drastically evolved in the last 20 years. Bilateral pheochromocytoma does not increase mortality in MEN2 or von Hippel-Lindau (VHL) mutation carriers who are followed regularly, but these mutations induce major morbidities if total bilateral adrenalectomy is performed. Cortical sparing adrenal surgery may be proposed to avoid definitive adrenal insufficiency. The surgical goal is to leave sufficient cortical tissue to avoid glucocorticoid replacement therapy. This approach was achieved by the progressive experience of minimally invasive surgery via the transperitoneal or retroperitoneal route. Cortical sparing adrenal surgery exhibits <5% significant recurrence after 10 years of follow-up and normal glucocorticoid function in more than 50% of the cases. Therefore, cortical sparing adrenal surgery should be systematically considered in the management of all patients with MEN2 or VHL hereditary pheochromocytoma. Hereditary pheochromocytoma is a rare disease, and a randomized trial comparing cortical sparing vs classical adrenalectomy is probably not possible. This lack of data most likely explains why cortical sparing surgery has not been adopted in most expert centers that perform at least 20 procedures per year for the treatment of this disease. This review examined recent data to provide insight into the technique, its indications, and the results and subsequent follow-up in the management of patients with hereditary pheochromocytoma with a special emphasis on MEN2.

A registry-based study of thyroid paraganglioma: histological and genetic characteristics

The precise diagnosis of thyroid neoplasias will guide surgical management. Primary thyroid paraganglioma has been rarely reported. Data on prevalence, immunohistochemistry (IHC), and molecular genetics in a systematic series of such patients are pending. We performed a multinational population-based study on thyroid paraganglioma and analyzed prevalence, IHC, and molecular genetics. Patients with thyroid paraganglioma were recruited from the European-American-Head-and-Neck-Paraganglioma-Registry. Demographic and clinical data were registered. Histopathology and IHC were re-investigated. All patients with thyroid paraganglioma underwent molecular genetic analyses of the SDHA, SDHB, SDHC, SDHD, SDHAF2, VHL, RET, TMEM127, and MAX genes. Analyses included Sanger sequencing and multiplex ligation-dependent probe amplification (MLPA) for detection of large rearrangements. Of 947 registrants, eight candidates were initially identified. After immunohistochemical analyses of these eight subjects, 5 (0.5%) were confirmed to have thyroid paraganglioma. IHC was positive for chromogranin, synaptophysin, and S-100 and negative for calcitonin in all five thyroid paragangliomas, whereas the three excluded candidate tumors stained positive for pan-cytokeratin, a marker excluding endocrine tumors. Germline variants, probably representing mutations, were found in four of the five confirmed thyroid paraganglioma cases, two each in SDHA and SDHB, whereas the excluded cases had no mutations in the tested genes. Thyroid paraganglioma is a finite entity, which must be differentiated from medullary thyroid carcinoma, because medical, surgical, and genetic management for each is different. Notably, approximately 80% of thyroid paragangliomas are associated with germline variants, with implications for additional tumors and a potential risk for the family. As opposed to sporadic tumors, surgical management and extent of resection are different for heritable tumors, each guided by the precise gene involved.

Usefulness of Somatostatin Receptor Scintigraphy (Tc-[HYNIC, Tyr3]-Octreotide) and 123I-Metaiodobenzylguanidine Scintigraphy in Patients with SDHx Gene-Related Pheochromocytomas and Paragangliomas Detected by Computed Tomography

AIMS

The aim of this study was to assess the usefulness of somatostatin receptor scintigraphy (SRS) using (99m)Tc-[HYNIC, Tyr3]-octreotide (TOC) and 123I-metaiodobenzylguanidine (mIBG) in patients with SDHx-related syndromes in which paragangliomas were detected by computed tomography and to establish an optimal imaging diagnostic algorithm in SDHx mutation carriers.

METHODS

All carriers with clinical and radiological findings suggesting paragangliomas were screened by SRS and 123I-mIBG. Lesions were classified by body regions, i.e. head and neck, chest, abdomen with pelvis and adrenal gland as well as metastasis.

RESULTS

We evaluated 46 SDHx gene mutation carriers (32 index cases and 14 relatives; 28 SDHD, 16 SDHB and 2 SDHC). In this group, 102 benign tumors were found in 39 studied patients, and malignant disease was diagnosed in 7 patients. In benign tumors, the sensitivity of SRS was estimated at 77% and of 123I-mIBG at 22.0%. The SRS and mIBG sensitivity was found to be clearly region dependent (p < 0.001). The highest SRS sensitivity was found in head and neck paragangliomas (HNP; 91.4%) and the lowest was found in abdominal paragangliomas and pheochromocytomas (40 and 42.9%, respectively). The highest 123I-mIBG sensitivity was found in pheochromocytomas (sensitivity of 100%) and the lowest in HNP (sensitivity of 3.7%). In metastatic disease, SRS was superior to mIBG (sensitivity of 95.2 vs. 23.8%, respectively).

CONCLUSION

SRS and 123I-mIBG single photon emission computed tomography (SPECT) sensitivity in SDHx patients is highly body region dependent. In malignant tumors, SRS is superior to 123I-mIBG SPECT.

Profiling of somatic mutations in phaeochromocytoma and paraganglioma by targeted next generation sequencing analysis

At least 12 genes (FH, HIF2A, MAX, NF1, RET, SDHA, SDHB, SDHC, SDHD, SDHAF2, TMEM127, and VHL) have been implicated in inherited predisposition to phaeochromocytoma (PCC), paraganglioma (PGL), or head and neck paraganglioma (HNPGL) and a germline mutation may be detected in more than 30% of cases. Knowledge of somatic mutations contributing to PCC/PGL/HNPGL pathogenesis has received less attention though mutations in HRAS, HIF2A, NF1, RET, and VHL have been reported. To further elucidate the role of somatic mutation in PCC/PGL/HNPGL tumourigenesis, we employed a next generation sequencing strategy to analyse "mutation hotspots" in 50 human cancer genes. Mutations were identified for HRAS (c.37G>C; p.G13R and c.182A>G; p.Q61R) in 7.1% (6/85); for BRAF (c.1799T>A; p.V600E) in 1.2% (1/85) of tumours; and for TP53 (c.1010G>A; p.R337H) in 2.35% (2/85) of cases. Twenty-one tumours harboured mutations in inherited PCC/PGL/HNPGL genes and no HRAS, BRAF, or TP53 mutations occurred in this group. Combining our data with previous reports of HRAS mutations in PCC/PGL we find that the mean frequency of HRAS/BRAF mutations in sporadic PCC/PGL is 8.9% (24/269) and in PCC/PGL with an inherited gene mutation 0% (0/148) suggesting that HRAS/BRAF mutations and inherited PCC/PGL genes mutations might be mutually exclusive. We report the first evidence for BRAF mutations in the pathogenesis of PCC/PGL/HNPGL.

Role of SDHAF2 and SDHD in von Hippel-Lindau associated pheochromocytomas

BACKGROUND

Pheochromocytomas (PCCs) develop from the adrenal medulla and are often part of a hereditary syndrome such as von Hippel-Lindau (VHL) syndrome. In VHL, only about 30 % of patients with a VHL missense mutation develop PCCs. Thus, additional genetic events leading to formation of such tumors in patients with VHL syndrome are sought. SDHAF2 (previously termed SDH5) and SDHD are both located on chromosome 11q and are required for the function of mitochondrial complex II. While SDHAF2 has been shown to be mutated in patients with paragangliomas (PGLs), SDHD mutations have been found both in patients with PCCs and in patients with PGLs.

MATERIALS AND METHODS

Because loss of 11q is a common event in VHL-associated PCCs, we aimed to investigate whether SDHAF2 and SDHD are targets. In the present study, 41 VHL-associated PCCs were screened for mutations and loss of heterozygosity (LOH) in SDHAF2 or SDHD. Promoter methylation, as well as mRNA expression of SDHAF2 and SDHD, was studied. In addition, immunohistochemistry (IHC) of SDHB, known to be a universal marker for loss of any part the SDH complex, was conducted.

RESULTS AND CONCLUSIONS

LOH was found in more than 50 % of the VHL-associated PCCs, and was correlated with a significant decrease (p < 0.05) in both SDHAF2 and SDHD mRNA expression, which may be suggestive of a pathogenic role. However, while SDHB protein expression as determined by IHC in a small cohort of tumors was lower in PCCs than in the surrounding adrenal cortex, there was no obvious correlation with LOH or the level of SDHAF2/SDHD mRNA expression. In addition, the lack of mutations and promoter methylation in the investigated samples indicates that other events on chromosome 11 might be involved in the development of PCCs in association with VHL syndrome.

Diagnosis of extra-adrenal phaeochromocytoma after nephrectomy

This case describes a 50–yr–old man who was admitted to the Urology Ward upon the suspicion of a left kidney tumor. As part of the pre–operative check–up, an ultrasound and computed tomography of the kidneys were conducted. The results confirmed the initial diagnosis. The postoperative diagnosis was extra-adrenal pararenal phaeochromocytoma (ePCC) with succinate dehydrogenase complex, subunit B (SDHB) gene mutation. During the follow–up, a second tumor was detected by 3,4–dihydroxy–6–F–18–fluoro–L–phenylalanine positron emission tomography/computed tomography F–DOPA–PET CT that resulted in another surgery with complete resection of the tumor. The patient and his family were counseled by a genetic laboratory and remain under surveillance.

Outcomes of adrenal-sparing surgery or total adrenalectomy in phaeochromocytoma associated with multiple endocrine neoplasia type 2: an international retrospective population-based study

BACKGROUND

The prevention of medullary thyroid cancer in patients with multiple endocrine neoplasia type 2 syndrome has demonstrated the ability of molecular diagnosis and prophylactic surgery to improve patient outcomes. However, the other major neoplasia associated with multiple endocrine neoplasia type 2, phaeochromocytoma, is not as well characterised in terms of occurrence and treatment outcomes. In this study, we aimed to systematically characterise the outcomes of management of phaeochromocytoma associated with multiple endocrine neoplasia type 2.

METHODS

This multinational observational retrospective population-based study compiled data on patients with multiple endocrine neoplasia type 2 from 30 academic medical centres across Europe, the Americas, and Asia. Patients were included if they were carriers of germline pathogenic mutations of the RET gene, or were first-degree relatives with histologically proven medullary thyroid cancer and phaeochromocytoma. We gathered clinical information about patients'RET genotype, type of treatment for phaeochromocytoma (ie, unilateral or bilateral operations as adrenalectomy or adrenal-sparing surgery, and as open or endoscopic operations), and postoperative outcomes (adrenal function, malignancy, and death). The type of surgery was decided by each investigator and the timing of surgery was patient driven. The primary aim of our analysis was to compare disease-free survival after either adrenal-sparing surgery or adrenalectomy.

FINDINGS

1210 patients with multiple endocrine neoplasia type 2 were included in our database, 563 of whom had phaeochromocytoma. Treatment was adrenalectomy in 438 (79%) of 552 operated patients, and adrenal-sparing surgery in 114 (21%). Phaeochromocytoma recurrence occurred in four (3%) of 153 of the operated glands after adrenal-sparing surgery after 6-13 years, compared with 11 (2%) of 717 glands operated by adrenalectomy (p=0.57). Postoperative adrenal insufficiency or steroid dependency developed in 292 (86%) of 339 patients with bilateral phaeochromocytoma who underwent surgery. However, 47 (57%) of 82 patients with bilateral phaeochromocytoma who underwent adrenal-sparing surgery did not become steroid dependent.

INTERPRETATION

The treatment of multiple endocrine neoplasia type 2-related phaeochromocytoma continues to rely on adrenalectomies with their associated Addisonian-like complications and consequent lifelong dependency on steroids. Adrenal-sparing surgery, a highly successful treatment option in experienced centres, should be the surgical approach of choice to reduce these complications.

Long-term prognosis of patients with pediatric pheochromocytoma

A third of patients with paraganglial tumors, pheochromocytoma, and paraganglioma, carry germline mutations in one of the susceptibility genes, RET, VHL, NF1, SDHAF2, SDHA, SDHB, SDHC, SDHD, TMEM127, and MAX. Despite increasing importance, data for long-term prognosis are scarce in pediatric presentations. The European-American-Pheochromocytoma-Paraganglioma-Registry, with a total of 2001 patients with confirmed paraganglial tumors, was the platform for this study. Molecular genetic and phenotypic classification and assessment of gene-specific long-term outcome with second and/or malignant paraganglial tumors and life expectancy were performed in patients diagnosed at <18 years. Of 177 eligible registrants, 80% had mutations, 49% VHL, 15% SDHB, 10% SDHD, 4% NF1, and one patient each in RET, SDHA, and SDHC. A second primary paraganglial tumor developed in 38% with increasing frequency over time, reaching 50% at 30 years after initial diagnosis. Their prevalence was associated with hereditary disease (P=0.001), particularly in VHL and SDHD mutation carriers (VHL vs others, P=0.001 and SDHD vs others, P=0.042). A total of 16 (9%) patients with hereditary disease had malignant tumors, ten at initial diagnosis and another six during follow-up. The highest prevalence was associated with SDHB (SDHB vs others, P<0.001). Eight patients died (5%), all of whom had germline mutations. Mean life expectancy was 62 years with hereditary disease. Hereditary disease and the underlying germline mutation define the long-term prognosis of pediatric patients in terms of prevalence and time of second primaries, malignant transformation, and survival. Based on these data, gene-adjusted, specific surveillance guidelines can help effective preventive medicine.

Hemangioblastomas and neurogenic polyglobulia

BACKGROUND

Neurogenic polyglobulia occurs with central nervous system hemangioblastomas. Among the suggested mechanisms are extramedullary hematopoiesis in the tumor tissue and germline mutations of the von Hippel-Lindau (VHL) tumor suppressor gene.

OBJECTIVE

To determine the frequency and driving mechanisms of polyglobulia in central nervous system hemangioblastomas.

METHODS

We performed a retrospective analysis of pre- and postoperative (at 3 and 12 months) hemoglobin levels in a consecutive series of patients with hemangioblastomas operated on in our institution from 1996 to 2009. We performed molecular genetic analyses for mutations of the VHL tumor suppressor gene.

RESULTS

Preoperative hemoglobin levels were available from 164 patients. The average hemoglobin level (15.2 g/dL in males and 13.1 g/dL in females) was within normal range according to our standards. Of 22 patients with increased preoperative hemoglobin levels (>17 g/dL in males and >15 g/dL in females), 8 presented with pathological hemoglobin (>18.5 g/dL in males and >16.5 g/dL in females) according to World Health Organization criteria. Surgical removal of the hemangioblastoma resulted in a permanent cure of polyglobulia in all patients. Six of the 8 patients with pathological hemoglobin elevation carried a germline mutation of the VHL tumor suppressor gene.

CONCLUSION

Neurogenic polyglobulia occurs in a subset of patients with hemangioblastomas. This phenomenon is mostly observed in VHL mutation carriers, but also occurs in patients with sporadic hemangioblastomas. Removal of the tumor results in the permanent cure of polyglobulia. Our observations suggest that polyglobulia is an effect by the tumor itself, either due to paraneoplasia or extramedullary hematopoiesis.

Testing new susceptibility genes in the cohort of apparently sporadic phaeochromocytoma/paraganglioma patients with clinical characteristics of hereditary syndromes

BACKGROUND

Phaeochromocytoma (PCC) and paraganglioma (PGL) can occur sporadically or as a part of familial cancer syndromes. Red flags of hereditary syndromes are young age and multifocal tumours. We hypothesized that such patients are candidates for further molecular diagnosis in case of normal results in 'classical' genes.

MATERIAL AND METHODS

We selected patients with PCC/PGL under the age of 40 and/or with multiple tumours. First, we tested the genes RET, VHL, NF1, SDHB, SDHC and SDHD. Patients without mutations in these genes were tested for mutations in MAX, TMEM127 and SDHAF2.

RESULTS

In 153 patients included, mutations were detected in the classical genes in 72 patients (47%) [RET-22 (14%), VHL-13 (9%), NF1-3 (2%), SDHB-13 (9%), SDHC-3 (2%), SDHD-16 (11%), SDHB large deletions- 2 (1%)]. One patient with MAXc.223C>T (p.R75X) mutation was detected. It was a male with bilateral, metachronous phaeochromocytomas diagnosed in 36 and 40 years of age. Remarkably, he showed in the period before the MAX gene was detected, a RET p. Y791F variant. During 10-year follow-up, we did not find any thyroid abnormalities. LOH examination of tumour tissue showed somatic loss of the wild-type allele of MAX.

CONCLUSION

Analysis of the MAX gene should be performed in selected patients, especially those with bilateral adrenal phaeochromocytoma in whom mutations of the classical genes are absent. Our study provides with further support that Y791F RET is a polymorphism.

Genetics of hereditary head and neck paragangliomas

BACKGROUND

The purpose of this study was to give an overview on hereditary syndromes associated with head and neck paragangliomas (HNPGs).

METHODS

Our methods were the review and discussion of the pertinent literature.

RESULTS

About one third of all patients with HNPGs are carriers of germline mutations. Hereditary HNPGs have been described in association with mutations of 10 different genes. Mutations of the genes succinate dehydrogenase subunit D (SDHD), succinate dehydrogenase complex assembly factor 2 gene (SDHAF2), succinate dehydrogenase subunit C (SDHC), and succinate dehydrogenase subunit B (SDHB) are the cause of paraganglioma syndromes (PGLs) 1, 2, 3, and 4. Succinate dehydrogenase subunit A (SDHA), von Hippel-Lindau (VHL), and transmembrane protein 127 (TMEM127) gene mutations also harbor the risk for HNPG development. HNPGs in patients with rearranged during transfection (RET), neurofibromatosis type 1 (NF1), and MYC-associated factor X (MAX) gene mutations have been described very infrequently.

CONCLUSION

All patients with HNPGs should be offered a molecular genetic screening. This screening may usually be restricted to mutations of the genes SDHD, SDHB, and SDHC. Certain clinical parameters can help to set up the order in which those genes should be tested.

Integrative genetic, epigenetic and pathological analysis of paraganglioma reveals complex dysregulation of NOTCH signaling

Head and neck paragangliomas, rare neoplasms of the paraganglia composed of nests of neurosecretory and glial cells embedded in vascular stroma, provide a remarkable example of organoid tumor architecture. To identify genes and pathways commonly deregulated in head and neck paraganglioma, we integrated high-density genome-wide copy number variation (CNV) analysis with microRNA and immunomorphological studies. Gene-centric CNV analysis of 24 cases identified a list of 104 genes most significantly targeted by tumor-associated alterations. The "NOTCH signaling pathway" was the most significantly enriched term in the list (P = 0.002 after Bonferroni or Benjamini correction). Expression of the relevant NOTCH pathway proteins in sustentacular (glial), chief (neuroendocrine) and endothelial cells was confirmed by immunohistochemistry in 47 head and neck paraganglioma cases. There were no relationships between level and pattern of NOTCH1/JAG2 protein expression and germline mutation status in the SDH genes, implicated in paraganglioma predisposition, or the presence/absence of immunostaining for SDHB, a surrogate marker of SDH mutations. Interestingly, NOTCH upregulation was observed also in cases with no evidence of CNVs at NOTCH signaling genes, suggesting altered epigenetic modulation of this pathway. To address this issue we performed microarray-based microRNA expression analyses. Notably 5 microRNAs (miR-200a,b,c and miR-34b,c), including those most downregulated in the tumors, correlated to NOTCH signaling and directly targeted NOTCH1 in in vitro experiments using SH-SY5Y neuroblastoma cells. Furthermore, lentiviral transduction of miR-200s and miR-34s in patient-derived primary tympano-jugular paraganglioma cell cultures was associated with NOTCH1 downregulation and increased levels of markers of cell toxicity and cell death. Taken together, our results provide an integrated view of common molecular alterations associated with head and neck paraganglioma and reveal an essential role of NOTCH pathway deregulation in this tumor type.

Renal cancer in von Hippel-Lindau disease and related syndromes

Sporadic and hereditary forms of renal cell carcinoma (RCC), von Hippel-Lindau (VHL) disease and the familial paraganglioma syndromes are closely related in terms of their clinical, molecular, and genetic aspects. Most RCCs occur sporadically and the heritable fraction of RCC is estimated to be just 2-4%. An understanding of the molecular genetic basis, the disease-specific and gene-specific biology and the clinical characteristics of these cancer syndromes is of utmost importance for effective genetic diagnosis and appropriate treatment. In addition, such insight will improve our understanding of sporadic RCCs. To date, 10 different heritable RCC syndromes have been described. VHL syndrome is the oldest known hereditary RCC syndrome. Similar to VHL disease, phaeochromocytoma is a major manifestation of the paraganglioma syndromes types 1, 3 and 4 in which RCCs have been reported. These syndromes are therefore regarded as VHL-related disorders and are included in this Review. Multifocal tumours, bilateral occurrence, a young age at diagnosis and/or family history are clinical red flags suggestive of hereditary disease and should trigger referral for genetic and molecular analysis. The identification of an underlying genetic alteration enables gene-specific risk assessment and opens up the possibility of a tailored follow-up strategy and specific surveillance protocols as the basis of effective preventive medicine. The important goals of preventive medicine are to increase the life expectancy of affected patients and to improve their quality of life. The study of seemingly rare hereditary syndromes and their susceptibility genes has consistently revealed clues regarding the aetiology and pathogenesis of these diseases, and can aid diagnosis and the development of therapeutics for patients affected by much more common sporadic counterparts.

Associations of collagen type I α2 polymorphisms with the presence of intracranial aneurysms in patients from Germany

OBJECTIVE

Subarachnoid hemorrhage from ruptured intracranial aneurysms is associated with a severe prognosis. Preventive treatment of unruptured intracranial aneurysms is possible and recommended. However, the identification of risk patients by genetic analyses is not possible because of lack of candidate genes. Collagen type I α2 (COL1A2) has been associated with the presence of aneurysms in patients from Japan, China, and Korea. In this study, we investigate whether COL1A2 is a possible aneurysm candidate gene in the German population.

METHODS

Patients admitted with intracranial aneurysms to our department and collaborating departments were enrolled. Three single-nucleotide polymorphisms (SNPs) of the COL1A2 gene, namely rs42524 in exon 28, rs1800238 in exon 32, and rs2621215 in intron 46 were investigated using restriction enzymes and sequencing. HapMap data were used for comparison of allelic frequencies with the normal population by χ2 test to identify significant associations between genotypes and the presence of aneurysms.

RESULTS

Two hundred sixty-nine patients were enrolled into the study. There was a significant correlation with the presence of aneurysms for the GC allele of the SNP rs42524 in exon 28 (P = .02). The other polymorphisms did not show significant correlations.

CONCLUSIONS

The COL1A2 gene is associated with intracranial aneurysms in a subset of the German population. However, it is not responsible for the majority of aneurysms, and further candidate genes need to be identified to develop sensitive genetic screening for patients at risk.

Autosomal dominant polycystic kidney disease: prevalence of renal neoplasias in surgical kidney specimens

BACKGROUND

The role of autosomal dominant polycystic kidney disease (ADPKD) as a risk factor for renal cell carcinoma (RCC) is still under discussion. Data on prevalence of RCC in ADPKD are limited, especially on a large population scale. The aim of this study was to analyze the prevalence of RCC in ADPKD kidneys and characterize the clinical features of this coincidence.

METHODS

Based on our histopathological registry for ADPKD and the Else Kröner-Fresenius Registry, we retrospectively reviewed malignant and benign renal lesions in patients with ADPKD who had undergone renal surgery from 1988 to 2011.

RESULTS

240 ADPKD patients underwent 301 renal surgeries. Mean age at surgery was 54 years. Overall, 16 malignant and 11 benign lesions were analyzed in 301 kidneys (5.3%; 3.7%), meaning that 12/240 (5%; 1:20) patients presented with malignant renal lesions. 66.7% (8/12) of these patients had undergone dialysis prior to surgery. We found 10/16 (63%) papillary RCC, 5/16 (31%) clear cell RCC, and 1/16 (6%) papillary noninvasive urothelial cancer. Regarding all renal lesions, 6/17 (35.3%) patients had more than one histological finding in their kidneys. In 2 cases, metachronous metastases were removed. Mean follow-up was 66.7 months.

CONCLUSION

Kidney-related prevalence of RCC in ADPKD kidneys was surprisingly high. Whether or not this is due to chronic dialysis or due to the underlying disease is still speculative. Like other cystic renal diseases with an increased risk for RCC, the attending physician should be aware of the malignant potential of ADPKD, especially with concomitant dialysis.

Sequence variations in the von Hippel-Lindau tumor suppressor gene in patients with intracranial aneurysms

BACKGROUND

The rupture of intracranial aneurysms leads to subarachnoid hemorrhage, which is often associated with poor outcome. Preventive treatment of unruptured intracranial aneurysms is possible and recommended. However, the lack of candidate genes precludes identifying patients at risk by genetic analyses. We observed intracranial aneurysms in 2 patients with von Hippel-Lindau (VHL) disease and the known disease-causing mutation c.292T > C (p.Tyr98His) in the VHL tumor suppressor gene. This study investigates whether the VHL gene is a possible candidate gene for aneurysm formation.

METHODS

Patients with intracranial aneurysms admitted to our department between 2006 and 2009 were enrolled. The peripheral leukocyte DNA of 200 patients was investigated for sequence variations in the VHL gene using denaturing high performance liquid chromatography. Peripheral leukocyte DNA of 100 randomly sampled probands was investigated as a control group. The allelic frequencies of sequence variations between both groups were compared using the Fisher exact test.

RESULTS

Fourteen of 200 patients with intracranial aneurysms had sequence variations at 6 different loci in the VHL gene. In contrast, no sequence variations were identified in 100 probands in the control group (P = 0.0062). However, none of the single-sequence variations had a statistically significant difference in the allelic frequencies compared to the control group.

CONCLUSIONS

There is accumulating evidence for a genetic basis of aneurysm development. Our investigations lead to the conclusion that the VHL gene is potentially involved in the formation of intracranial aneurysms in a subset of patients. Additional candidate genes need to be identified in order to develop sensitive genetic screening for at-risk patients.

Carotid body paragangliomas: a systematic study on management with surgery and radiotherapy

The definitive universally accepted treatment for carotid body tumors (CBT) is surgery. The impact of surgery on cranial nerves and the carotid artery has often been underestimated. Alternatively, a few CBTs have been followed without treatment or irradiation. The goal of this study is to summarize the existing evidence concerning the efficacy and safety of surgery and external beam radiotherapy (EBRT) for CBT. Relevant articles were identified using strict criteria for systematic searches. Sixty-seven articles met the criteria which included 2,175 surgically treated patients. On the other hand, 17 articles including 127 patients treated with EBRT were found. Long-term control of the disease was obtained in 93.8% of patients who received surgical treatment and in 94.5% of the radiotherapy group. Surgery resulted in 483 (483/2,175 = 22.2%) new cranial nerve permanent deficits, whereas in the EBRT group, no new deficits were recorded (p = 0.004). The common/internal carotid artery was resected in 271 (12.5%) patients because of injury or tumor encasement, with immediate reconstruction in 212 (9.7%) patients. Three percent (60) of patients developed a permanent stroke and 1.3% (26) died due to postoperative complications. The major complications rates and the mortality after completion of the treatment also were significantly higher in surgical series compared to EBRT series. This systematic analysis highlights evidence that EBRT offers a similar chance of tumor control with lower risk of morbidity as compared to surgery in patients with CBT. This questions the traditional notion that surgery should be the mainstay of treatment.

Epidemiology of autosomal-dominant polycystic kidney disease: an in-depth clinical study for south-western Germany

BACKGROUND

As we emerge into the genomic medicine era, the epidemiology of diseases is taken for granted. Accurate prevalence figures, especially of rare diseases (RDs, ≤50/100,000), will become even more important for purposes of health care and societal planning. We noticed that the numbers of affected individuals in regionally established registries for mainly hereditary RDs do not align with published estimated and expected prevalence figures. We therefore hypothesized that such non-population-based means overestimate RDs and sought to address this by recalculating prevalence for an important 'common' hereditary disease, autosomal-dominant polycystic kidney disease (ADPKD) whereby presumed-prevalence is 100-250/100,000 METHODS: The Else-Kroener-Fresenius-ADPKD-Study in south-west Germany with a population of 2,727,351 inhabitants was established with the cooperation of all nephrology centres. Furthermore, general practitioners, internists, urologists, human geneticists and neurosurgery centres were contacted with questionnaires for demographic, family and kidney function data. Germline-mutation screening of susceptibility genes PKD1 and PKD2 was offered. Official population data for 2010 were used for overall and kidney function-adjusted prevalence estimations.

RESULTS

A total of 891 subjects, 658 index-cases and 233 relatives, aged 10-89 (mean 52), were registered, with >90% response rate, 398 by nephrologists and 493 by non-nephrologists. Molecular-genetic analyses contributed to confirmation of the diagnosis in 57%. The overall prevalence of ADPKD was 32.7/100,000 reaching a maximum of 57.3/100,000 in the 6th decade of life.

CONCLUSIONS

Prevalence of ADPKD is overestimated by 2- to 5-fold and close to the limit of RDs which may be of broad clinical, logistic and policy implications.

Yeast model for evaluating the pathogenic significance of SDHB, SDHC and SDHD mutations in PHEO-PGL syndrome

SDH genes, encoding succinate dehydrogenase, act as tumour suppressor genes, linking mitochondrial dysfunction with tumourigenesis. Heterozygous germline mutations in SDHA, SDHB, SDHC, SDHD and in the assembly factor encoding gene SDHAF2 have all been shown to predispose to heritable endocrine neoplasias such as pheochromocytomas (PHEO) and paragangliomas (PGLs) called 'PHEO-PGL syndrome'. SDH genes mutations, in addition to deletions or truncations which are most likely pathogenic, often include missense substitutions which can be of uncertain significance. Unclassified missense substitutions may be difficult to interpret unless the cause-effect link between mutation and the disease is established by functional and in silico studies or by the familial segregation with the phenotype. Using the yeast model, here, we report functional investigations on several missense SDH mutations found in patients affected by pheochromocytomas or paragangliomas. The aim of this study was to evaluate whether and to which extent the yeast model may be useful for establishing the pathological significance of missense SDH mutations in humans. The results of our study demonstrate that the yeast is a good functional model to validate the pathogenic significance of SDHB missense mutations while, for missense mutations in SDHC and SDHD genes, the model can be informative only when the variation involves a conserved residue in a conserved domain.

Characteristics of intracranial aneurysms in the else kröner-fresenius registry of autosomal dominant polycystic kidney disease

Background

Patients who harbor intracranial aneurysms (IAs) run a risk for aneurysm rupture and subsequent subarachnoid hemorrhage which frequently results in permanent deficits or death. Prophylactic treatment of unruptured aneurysms is possible and recommended depending on the size and location of the aneurysm as well as patient age and condition. IAs are major manifestations of autosomal dominant polycystic kidney disease (ADPKD). Current guidelines do not suggest surveillance of IAs in ADPKD except in the setting of family history if IA was known in any relative with ADPKD. Management of IAs in ADPKD is problematic because limited data exist from large studies.

Methods

We established the Else Kröner-Fresenius Registry for ADPKD in Germany. Clinical data were assessed for age at diagnosis of IAs, stage of renal insufficiency, and number, location and size of IAs as well as family history of cerebral events. Patients with symptomatic or asymptomatic IAs were included. All patients with ADPKD-related IAs were offered mutation scanning of the susceptibility genes for ADPKD, the PKD1 and PKD2 genes.

Results

Of 463 eligible ADPKD patients from the population base of Germany, 32 (7%) were found to have IAs, diagnosed at the age of 2–71 years, 19 females and 13 males. Twenty (63%) of these 32 patients were symptomatic, whereas IAs were detected in an asymptomatic stage in 12 patients. IAs were multifocal in 12 and unifocal in 20 patients. In 26 patients (81%), IAs were diagnosed before end-stage renal failure. Twenty-five out of 27 unrelated index cases (93%) had no IAs or cerebral events documented in their relatives with ADPKD. In 16 unrelated index patients and 3 relatives, we detected germline mutations. The mutations were randomly distributed across the PKD1 gene in 14 and the PKD2 gene in 2 index cases. Questionnaires answered for 320/441 ADPKD patients without IAs revealed that only 45/320 (14%) had MR angiography.

Conclusion

In ADPKD, rupture of IAs occurs frequently before the start of dialysis, is only infrequently associated with a family history of IAs or subarachnoid hemorrhage, and is associated with mutations either of the PKD1 or the PKD2 gene of any type. Screening for IAs is widely insufficiently performed, should not be restricted to families with a history of cerebral events and should be started before end-stage renal failure.

One hundred consecutive kidney transplantations with simultaneous ipsilateral nephrectomy in patients with autosomal dominant polycystic kidney disease

PURPOSE

Surgical management of autosomal dominant polycystic kidney disease (ADPKD) in patients awaiting renal transplantation is a challenging task.

METHODS

From 1998 to 2009, a total of 100 consecutive renal transplantations with simultaneous unilateral nephrectomy were performed in 59 men and 41 women with ADPKD and end-stage renal failure. About 38% received kidney allografts from living donors. The ipsilateral polycystic kidney was removed at the time of renal transplantation. Immunosuppressive therapy was not modified. Cold ischaemia time was 155 (38-204 min) versus 910 min (95-2760 min) for living versus deceased donor transplantation. Mean weight of removed kidneys was 2002 g (414-8850 g). Mean follow-up was 3.0 years (0.8-10.0 years).

RESULTS

Overall patient and graft survival were 97 and 96% at 1 year and 93 and 80% at 5 years, respectively. Serum creatinine at current follow-up was 1.49 (0.8-2.8) mg/dL. Surgical complications, which might be associated with simultaneous nephrectomy requiring re-operation, occurred in 12% (lymphocele 4%, hernia 4%, post-operative haematoma or bleeding 4%). None of the patients died peri-operatively.

CONCLUSION

Renal transplantation with simultaneous unilateral nephrectomy in ADPKD is a reasonable procedure for patients suffering from massively enlarged native kidneys.

Doppler-sonographically guided resection of central nervous system hemangioblastomas

BACKGROUND

Central nervous system (CNS) hemangioblastomas are a benign condition, which can be permanently cured by complete surgical removal. However, the vascular nature of these lesions and difficulties in localizing the tumors account for operative morbidity and recurrence. Power Doppler flow sonography has been proven useful during surgical removal of other vascular lesions.

OBJECTIVE

To evaluate the usefulness of Power Doppler flow sonography for hemangioblastoma.

METHODS

We used the SonoWand Invite (Sonowand AS, Trondheim, Norway) intraoperative navigation system in a consecutive series of hemangioblastomas operated on at our institution. Patients with von Hippel-Lindau (VHL) disease as well as sporadic hemangioblastomas were included.

RESULTS

The system was used on n = 64 consecutive hemangioblastomas operated on at our institution from 2007 to 2009. The tumors were localized in the cerebellum (n = 26), spinal cord (n = 27), brainstem (n = 10), and supratentorial (n = 1). In VHL disease was diagnosed 53 patients, and germline mutations of the VHL tumor suppressor gene were identified in 98%. Average tumor size was 1782 mm and 45% of the tumors were cystic. Forty-two of 64 tumors could be localized by grayscale sonography. All tumors were visible on power Doppler flow sonography. However, in 40 cases, only the pathological vessels and not the solid tumor itself enhanced on power Doppler. Postoperative MRI follow-up revealed remnant/recurrent tumors in 2 cases.

CONCLUSION

Power Doppler flow sonography is a sensitive intraoperative tool to guide the surgical approach and resection and provides reliable resection control in surgery of CNS hemangioblastoma.

[A 47-year-old patient with paroxysmal arterial hypertension and gastric tumors]

Arterial hypertension caused by a paraganglioma is rare and approximately one third of all cases of paraganglioma occur as part of a hereditary syndrome. Among these the Carney-Stratakis syndrome is characterized by the occurrence of paraganglioma/pheochromocytoma and gastrointestinal stromal tumors caused by germline mutations of the succinate dehydrogenase subunit genes (B-D). We report the case of a 47-year-old female patient suffering from Carney-Stratakis syndrome with an endocrine active thoracic paraganglioma which was successfully resected with the assistance of a heart-lung machine and the gastric stromal tumors were removed in a second surgical intervention.

Biallelic inactivation of the SDHC gene in renal carcinoma associated with paraganglioma syndrome type 3

The etiology and pathogenesis of renal cell carcinoma (RCC) are only partially understood. Key findings in hereditary RCC, which may be site specific or a component of a syndrome, have contributed to our current understanding. Important heritable syndromes of RCC are those associated with pheochromocytoma, especially von Hippel-Lindau disease (VHL) associated with germline VHL mutations, and pheochromocytoma and paraganglioma syndrome (PGL) associated with mutations in one of the four genes (SDHA-D) encoding succinate dehydrogenase. A subset of individuals with SDHB and SDHD germline DNA mutations and variants develop RCC. RCC has never been described as a component of SDHC-associated PGL3. The European-American Pheochromocytoma and Paraganglioma Registry comprises 35 registrants with germline SDHC mutations. A new registrant had carotid body tumor (CBT) and his mother had CBT and bilateral RCC. Blood DNA, paragangliomas, and RCCs were analyzed for mutations and loss-of-heterozygosity (LOH) in/flanking SDHC and VHL. The proband with unilateral CBT had a germline SDHC c.3G>A (p.M1I) mutation. His mutation-positive mother had CBT at age 42, clear cell RCC (ccRCC) at age 68, and papillary RCC (pRCC) at age 69. Both paraganglial tumors showed somatic LOH of the SDHC locus. Both ccRCC and pRCC did not have a somatic SDHC mutation but showed LOH for intragenic and flanking markers of the SDHC locus. LOH was also present for the VHL locus. Our findings suggest that RCC is a component of PGL3. Biallelic inactivation of the SDHC gene may represent a new pathway of pathogenesis of syndromic and nonsyndromic RCC, perhaps of both clear cell and papillary histologies.

The endemic paraganglioma syndrome type 1: origin, spread, and clinical expression

CONTEXT

Anecdotal evidence suggests a high incidence in Trentino, Italy, of head and neck paragangliomas (HNPGL), a rare autosomal dominant disease called paraganglioma type 1 syndrome and caused by germ-line mutations of the SDHD gene.

OBJECTIVE

The aim of this study was to investigate the origin, spread, and clinical expression of the disease in this geographic region.

DESIGN, SETTING, AND PARTICIPANTS

Trentino natives with HNPGL were recruited for establishing clinical expression of the disease, presence of a founder effect, and age of common ancestor. A large sample of the local population was recruited for determination of mutation prevalence and spread.

MAIN OUTCOME MEASURES

SDHD genetic testing was offered to first-degree relatives, and clinical surveillance was offered to at-risk carriers. The hypothesis of a founder effect was explored by haplotype analysis, and time to the most recent common ancestor was estimated by decay of haplotype sharing over time.

RESULTS

A total of 287 of the 540 recruited individuals from 95 kindreds carried the SDHD c.341A>G p.Tyr114Cys mutation. The prevalent phenotype was bilateral or multiple HNPGL, with low prevalence of pheochromocytoma and malignant forms. Penetrance was high. A common ancestor was dated between the 14th and 15th century, with the mutation spreading from the Mocheni Valley, a geographic, cultural and, presumably, a genetic isolate to 1.5% of the region's population.

CONCLUSIONS

A combination of particular demographic, geographical, and historical conditions has resulted in the oldest and largest SDHD founder effect so far characterized and has transformed a rare disease into an endemic disease with major public health implications.

Head and neck paragangliomas: clinical and molecular genetic classification

Head and neck paragangliomas are tumors arising from specialized neural crest cells. Prominent locations are the carotid body along with the vagal, jugular, and tympanic glomus. Head and neck paragangliomas are slowly growing tumors, with some carotid body tumors being reported to exist for many years as a painless lateral mass on the neck. Symptoms depend on the specific locations. In contrast to paraganglial tumors of the adrenals, abdomen and thorax, head and neck paragangliomas seldom release catecholamines and are hence rarely vasoactive. Petrous bone, jugular, and tympanic head and neck paragangliomas may cause hearing loss. The internationally accepted clinical classifications for carotid body tumors are based on the Shamblin Class I-III stages, which correspond to postoperative permanent side effects. For petrous-bone paragangliomas in the head and neck, the Fisch classification is used. Regarding the molecular genetics, head and neck paragangliomas have been associated with nine susceptibility genes: NF1, RET, VHL, SDHA, SDHB, SDHC, SDHD, SDHAF2 (SDH5), and TMEM127. Hereditary HNPs are mostly caused by mutations of the SDHD gene, but SDHB and SDHC mutations are not uncommon in such patients. Head and neck paragangliomas are rarely associated with mutations of VHL, RET, or NF1. The research on SDHA, SDHAF2 and TMEM127 is ongoing. Multiple head and neck paragangliomas are common in patients with SDHD mutations, while malignant head and neck paraganglioma is mostly seen in patients with SDHB mutations. The treatment of choice is surgical resection. Good postoperative results can be expected in carotid body tumors of Shamblin Class I and II, whereas operations on other carotid body tumors and other head and neck paragangliomas frequently result in deficits of the cranial nerves adjacent to the tumors. Slow growth and the tendency of hereditary head and neck paragangliomas to be multifocal may justify less aggressive treatment strategies.

Risk profiles and penetrance estimations in multiple endocrine neoplasia type 2A caused by germline RET mutations located in exon 10

Multiple endocrine neoplasia type 2 is characterized by germline mutations in RET. For exon 10, comprehensive molecular and corresponding phenotypic data are scarce. The International RET Exon 10 Consortium, comprising 27 centers from 15 countries, analyzed patients with RET exon 10 mutations for clinical-risk profiles. Presentation, age-dependent penetrance, and stage at presentation of medullary thyroid carcinoma (MTC), pheochromocytoma, and hyperparathyroidism were studied. A total of 340 subjects from 103 families, age 4-86, were registered. There were 21 distinct single nucleotide germline mutations located in codons 609 (45 subjects), 611 (50), 618 (94), and 620 (151). MTC was present in 263 registrants, pheochromocytoma in 54, and hyperparathyroidism in 8 subjects. Of the patients with MTC, 53% were detected when asymptomatic, and among those with pheochromocytoma, 54%. Penetrance for MTC was 4% by age 10, 25% by 25, and 80% by 50. Codon-associated penetrance by age 50 ranged from 60% (codon 611) to 86% (620). More advanced stage and increasing risk of metastases correlated with mutation in codon position (609→620) near the juxtamembrane domain. Our data provide rigorous bases for timing of premorbid diagnosis and personalized treatment/prophylactic procedure decisions depending on specific RET exon 10 codons affected.