The North American Neuroendocrine Tumor Society consensus guideline for the diagnosis and management of neuroendocrine tumors: pheochromocytoma, paraganglioma, and medullary thyroid cancer

Continuous renal replacement therapy for haemodynamic collapse and rhabdomyolysis induced by pheochromocytoma crisis

Pheochromocytoma associated with pregnancy is not common. Caesarean section may induce pheochromocytoma crisis, resulting in a lethal condition. The clinical picture of pheochromocytoma crisis is extremely variable. In this report, we describe a case of severe pheochromocytoma crisis induced by caesarean section presenting with hyperpyrexia, haemodynamic collapse, muscle weakness, heart failure, and acute kidney injury. Furthermore, we report that the muscle weakness was a manifestation of rhabdomyolysis, resulting from the pheochromocytoma crisis. Standard medical therapy failed to halt the patient's rapidly deteriorating condition. Continuous renal replacement therapy removed catecholamines from the circulation, resulting in improvement of haemodynamics and abrogation of rhabdomyolysis.

Trends in the presentation, treatment, and survival of patients with medullary thyroid cancer over the past 30 years

BACKGROUND

The impact of recent medical advances on disease presentation, extent of operation, and disease-specific survival for patients with medullary thyroid cancer is unclear.

METHODS

We used the Surveillance, Epidemiology, and End Results registry to compare trends over 3 time periods, 1983-1992, 1993-2002, and 2003-2012.

RESULTS

There were 2,940 patients diagnosed with medullary thyroid cancer between 1983 and 2012. The incidence of medullary thyroid cancer increased during this time period from 0.14 to 0.21 per 100,000 population, and mean age at diagnosis increased from 49.8 to 53.8 (P < .001). The proportion of tumors ≤1 cm also increased from 11.4% in 1983-1992, 19.6% in 1993-2002, to 25.1% in 2003-2012 (P < .001), but stage at diagnosis remained constant (P = .57). In addition, the proportion of patients undergoing a total thyroidectomy and lymph node dissection increased from 58.2% to 76.5% during the study period (P < .001). In the most recent time interval, 5-year, disease-specific survival improved from 86% to 89% in all patients (P < .001) but especially for patients with regional (82% to 91%, P = .003) and distant (40% to 51%, P = .02) disease.

CONCLUSION

These data demonstrate that the extent of operation is increasing for patients with medullary thyroid cancer. Disease-specific survival is also improving, primarily in patients with regional and distant disease.

Interest of systematic screening of pheochromocytoma in patients with neurofibromatosis type 1

OBJECTIVE

Pheochromocytoma (PHEO) may occur in 0.1-5.7% of patients presenting with a neurofibromatosis type 1 (NF1). Current recommendations are to explore only symptomatic patients. The objective of the study is to evaluate the prevalence and the interest of a systematic PHEO screening in this population.

DESIGN

A prospective study in a French tertiary center including consecutive NF1 patients older than 18 years.

METHODS

A systematic screening combining abdominal imaging and urinary fractionated metanephrines was proposed. In case of positivity of one or both exams, (123)I-metaiodobenzylguanidine scintigraphy or [(18)F]-fluoro-dihydroxyphenylalanine PET imaging was performed. The diagnosis of secreting PHEO was retained in case of elevated urinary metanephrines associated with positive scintigraphy and non-secreting PHEO when urinary metanephrines were normal with a positive scintigraphy.

RESULTS

Between January 2014 and August 2015, 234 patients were included and 156 patients (66.7%) completed both exams. In these 156 patients, 12 PHEOs were diagnosed, representing a prevalence of 7.7%. Of these, six PHEOs were secreting, with only two symptomatic patients. The tumor size of these PHEOs were bigger than that of non-secreting PHEO (25.2 ± 6.6 vs 14 ± 6.9 mm, P = 0.0165). One lesion was bilateral. Mean metanephrine and normetanephrine levels were 3.2 ± 2.6N and 2.8 ± 1N respectively. Three patients underwent surgery. The six patients with non-secreting PHEO were asymptomatic. One of them had bilateral lesion and one underwent surgery.

CONCLUSIONS

PHEO in NF1, whether or not secreting, are mostly asymptomatic. The current strategy to explore only symptomatic patients leads to an underestimation of prevalence with the risks inherent to the existence of an unrecognized PHEO.

PATIENTS' SAFETY AND FEASIBILITY OF INTRAVENOUS URAPIDIL IN THE PRETREATMENT OF PHEOCHROMOCYTOMA PATIENTS IN A NORMAL WARD SETTING - AN ANALYSIS OF 20 CONSECUTIVE CASES

Context

The intravenously administered selective α1 antagonist urapidil represents an alternative to phenoxybenzamine in the preoperative treatment of pheochromocytoma patients.

Objective

The aim of the study was to investigate the blood pressure changes in pheochromocytoma patients with urapidil pretreatment with special regards to the need for interventions in order to estimate the safety of this treatment in a normal ward setting.

Design

The medical records of all patients who underwent adrenalectomy for PCC were reviewed retrospectively. Systolic blood pressure values >180mmHg were defined as hypertensive episodes and systolic blood pressure values < 50mmHg as hypotensive episodes. Episodes of blood pressure instabilities were considered significant and recorded as intervention if they led to a direct action.

Results

Twenty consecutive patients who received urapidil pretreatment were enrolled in this retrospective study. Preoperatively, a median of 9 blood pressure measurements per day have been performed on the ward. A total of 2 episodes of hypertension occurred, and 1 episode of hypotension has been recorded. In the period from 25-72 hours postoperatively the median number of blood pressure measurements was 5 per 24 hours. The blood pressure deviations led to a total of 3 interventions for hypertension in 1 (5%) patients and 5 interventions for hypotension in 3 (15%) patients. All interventions could be managed on the normal ward, without the need to transfer the patient to an ICU.

Conclusions

Intravenous urapidil can safely be administered on a normal ward without putting patients at risk. Intensive monitoring beyond 24 hours postoperatively was not necessary, the blood pressure measurements during the shift on a normal ward were sufficient for maintaining patients' safety.

Laparoscopic adrenalectomy for pheochromocytoma-does size matter? A single surgeon comparative study

Background

Surgical difficulty in laparoscopic adrenalectomy for pheochromocytoma increases with tumor size. We compared single surgeon outcomes of laparoscopic adrenalectomy for pheochromocytomas in patients with tumors smaller or greater than 4 cm to assess safety of the procedure.

Methods

A retrospective review was performed of laparoscopic adrenalectomies for pheochromocytoma by a single surgeon over a 3-year period. All patients underwent lateral transperitoneal surgery. Operative and outcome data was retrieved and compared for tumors >4 cm versus smaller tumors.

Results

We performed 28 laparoscopic adrenalectomies on 24 patients including four simultaneous bilateral surgeries. Fifteen tumors were greater than 4 cm in size (mean 6.3 cm) while 13 were smaller (mean 2.9 cm). Both groups had similar operating time (138 vs. 116 min; P=0.2) and blood loss (181 vs. 143 mL; P=0.41). The small tumor group had four Clavien-Dindo grade 1 and one grade 3a complication while the large tumor group had three grade 1 complications. There were no conversions to open surgery. Eighteen patients (75%) did not require any anti-hypertensive medications post-operatively.

Conclusions

Tumor size does not impact outcomes of laparoscopic adrenalectomy for pheochromocytomas. Larger tumors are associated with similar operative time, blood loss and complications as smaller ones.

Systemic treatment and management approaches for medullary thyroid cancer

Although rare, medullary thyroid cancer (MTC) exemplifies the value that ever-expanding knowledge of molecular pathways and mechanisms brings to managing challenging cancers. Although surgery can be curative for MTC in many patients, a substantial proportion of patients present with locoregional or distant metastatic disease. Once distant disease occurs, treatment options are limited, and conventional cancer treatments such as cytotoxic chemotherapy are of minimal benefit. Biomarkers such as calcitonin and carcinoembryonic antigen are important correlates of disease burden as well as predictors of disease progress, including recurrence and survival. MTC is either sporadic (∼75%) or inherited (∼25%) as an autosomal dominant disease. Regardless, germline and somatic mutations, particularly in the rearranged during transfection (RET) proto-oncogene, are key factors in the neoplastic process. Gain-of-function RET mutations result in overactive proteins that lead to abnormal activation of downstream signal transduction pathways, resulting in ligand-independent growth and resistance to apoptotic stimuli. Specific RET mutation variants have been found to correlate with phenotype and natural history of MTC with some defects portending a more aggressive clinical course. Greater understanding of the consequence of the aberrant signaling pathway has fostered the development of targeted therapies. Two small-molecule tyrosine kinase inhibitors, vandetanib and cabozantinib, are currently available as approved agents for the treatment of advanced or progressive MTC and provide significant increases in progression-free survival. Since there have been no head-to-head comparisons, clinicians often select between these agents on the basis of familiarity, patient characteristics, comorbidities, and toxicity profile.

Thyroid Gland Malignancies

Surgery remains the most important effective treatment for differentiated (DTC) and medullary thyroid cancer (MTC). Radioactive iodine (RAI) is another important treatment but is reserved only for DTC whose disease captures RAI. Once patients fail primary therapy, observation is often recommended, as most DTC and MTC patients will have indolent disease. However, in a fraction of patients, systemic therapy must be considered. In recent decades 4 systemic therapies have been approved by the United States FDA for DTC and MTC. Sorafenib and lenvatinib are approved for DTC and vandetanib and cabozantinib for MTC. Anaplastic thyroid cancer (ATC) is a rare and rapidly progressive form of thyroid cancer with a very high mortality rate. Treatment of ATC remains a challenge. Most patients are not surgical candidates at diagnosis due to advanced disease. External beam radiation and radiosensitizing radiation are the mainstay of therapy at this time. However, exciting new drugs and approaches to therapy are on the horizon but it will take a concerted, worldwide effort to complete clinical trials in order to find effective therapies that will improve the overall survival for this devastating disease.

Flushing in (neuro)endocrinology

Cutaneous flushing is a common presenting complaint in endocrine disorders. The pathophysiology of flushing involves changes in cutaneous blood flow triggered by multiple intrinsic factors that are either related to physiology or disease. Flushing can be divided into episodic or persistent causes. Episodic flushing is mediated by the release of endogenous vasoactive mediators or medications, while persistent flushing results in a fixed facial erythema with telangiectasia and cyanosis due to slow-flowing deoxygenated blood in large cutaneous blood vessels. The differential diagnosis of cutaneous flushing in neuroendocrine disorders is limited, yet encompasses a broad spectrum of benign and malignant entities, including carcinoid syndrome, pheochromocytoma, Cushing syndrome, medullary thyroid cancer, and pancreatic neuroendocrine tumors. In this review, we provide a concise and up-to-date discussion on the differential diagnosis and approach of flushing in neuroendocrinology.

Diagnosis and Management of Hereditary Phaeochromocytoma and Paraganglioma

About 30% of phaeochromocytomas or paragangliomas are genetic. Whilst some individuals will have clinical features or a family history of inherited cancer syndrome such as neurofibromatosis type 1 (NF1) or multiple endocrine neoplasia 2 (MEN2), the majority will present as an isolated case. To date, 14 genes have been described in which pathogenic mutations have been demonstrated to cause paraganglioma or phaeochromocytoma . Many cases with a pathogenic mutation may be at risk of developing further tumours. Therefore, identification of genetic cases is important in the long-term management of these individuals, ensuring that they are entered into a surveillance programme. Mutation testing also facilitates cascade testing within the family, allowing identification of other at-risk individuals. Many algorithms have been described to facilitate cost-effective genetic testing sequentially of these genes, with phenotypically driven pathways. New genetic technologies including next-generation sequencing and whole-exome sequencing will allow much quicker, cheaper and extensive testing of individuals in whom a genetic aetiology is suspected.

The results of molecular genetic testing for RET proto-oncogene mutations in patients with medullary thyroid carcinoma in a referral center after the two decade period

BACKGROUND

Medullary thyroid carcinoma (MTC) is a type of thyroid neoplasm which originates from parafollicular cells, and it is commonly diagnosed by calcitonin screening. Besides the sporadic form, the heritable form of MTC is characterized by constitutive activation of the RET (REarranged during Transfection) proto-oncogene caused by different mutations.

METHOD

We collected data regarding RET genetic screening performed in the Center for Endocrine Surgery in Belgrade during a 20-year-period. The study group included 249 MTC patients who were genetically tested for RET mutations by Sanger's sequencing method.

RESULTS

Genetic screening of the study population revealed nine different mutations of the RET gene in 42 carriers. The most common mutation was C634F, and it has been detected in 31 % (13/42) of individuals, while C618R, L790F, and S904S were present in only 2 % (1/42) each in the study group. Detected mutations were unequally distributed in different RET gene exons. Among MTC patients, 67 % (28/42) had mutation harbored in exon 11, while the rarest mutation was located in exons 10 and 15, each present in only 2 % (1/42) of patients.

CONCLUSIONS

The RET gene mutation profile has a unique distribution in this study population when compared with the other European populations. The mutations in codon 634 are most common; therefore the cost-reducing genetic screening should primarily target this codon, and if the negative outcome appears, then other codons should be examined in the order that depends on their occurrence. Hippokratia 2016, 20(3): 187-191.

Are patients with hormonally functional phaeochromocytoma and paraganglioma initially receiving a proper adrenoceptor blockade? A retrospective cohort study

OBJECTIVE

Pharmacological treatment is mandatory in patients with hormonally functional phaeochromocytoma and paraganglioma (PHAEO/PGL). We evaluated if patients initially diagnosed with hormonally functional PHAEO/PGL by various medical subspecialties received proper adrenoceptor blockade, and analysed factors predicting the prescription of adequate treatment.

METHODS

In a retrospective cohort study, we reviewed data from patients initially diagnosed with hormonally functional PHAEO/PGL outside the National Institutes of Health and Cedars-Sinai Medical Center, who were referred to these institutions between January 2001 and April 2015. Logistic regression was used to assess factors associated with proper adrenoceptor blockade.

RESULTS

A total of 381 patients were included. Adequate pharmacological treatment was prescribed to 69·3%, of which 93·1% received α-adrenoceptor blockers. Regarding patients who were inappropriately treated, 53% did not receive any medication. Independent predictors of the prescription of a proper blockade were the diagnosis by endocrinologists [odds ratio (OR) 4·14; 95% confidence interval (CI), 2·51-6·85; P < 0·001], the presence of high blood pressure (OR 5·94; 95% CI, 3·11-11·33; P < 0·001) and the evidence of metastasis (OR 5·96; 95% CI, 1·93-18·46; P = 0·002).

CONCLUSIONS

Although most patients received adequate pharmacological treatment, almost one-third were either not treated or received inappropriate medications. The diagnosis by endocrinologists, the presence of high blood pressure and the evidence of metastatic disease were identified as independent predictors of a proper blockade. These results highlight the need to educate physicians about the importance of starting adequate adrenoceptor blockade in all patients with hormonally functional PHAEO/PGL.

Clinical significance of RET mutation screening in a pedigree of multiple endocrine neoplasia type 2A

The clinical characteristics and RET proto-oncogene (RET‑PO) mutation status of a patient with multiple endocrine neoplasia type 2A pedigree (MEN2A) was analyzed with the aim of preliminarily exploring the molecular mechanisms and clinical significance of the disease. Clinical characteristics of a single MEN2A patient were analyzed. Genomic DNA was extracted from the peripheral blood of the proband and 10 family members. The 21 exons of RET‑PO were PCR amplified and the amplified products were sequenced. Of the family members, 5 exhibited a C634Y (TGC→TAC) missense mutation in exon 11 of RET‑PO, among which 2 family members were screened as mutation carriers, while the others did not exhibit clinical symptoms of the mutation. The screening and analysis of RET‑PO mutations for the MEN2A proband and the family members suggests potential clinical phenotypes and enables assessment of the risk of disease development, thus providing useful information for determining the surgical timing of preventive thyroid gland removal.

GEP- NETS UPDATE: Genetics of neuroendocrine tumors

Neuroendocrine tumors (NETs) are a heterogeneous group of neoplasms, arising from neuroendocrine cells that are dispersed throughout the body. Around 20% of NETs occur in the context of a genetic syndrome. Today there are at least ten recognized NET syndromes. This includes the classical syndromes: multiple endocrine neoplasias types 1 and 2, and von Hippel-Lindau and neurofibromatosis type 1. Additional susceptibility genes associated with a smaller fraction of NETs have also been identified. Recognizing genetic susceptibility has proved essential both to provide genetic counseling and to give the best preventive care. In this review we will also discuss the knowledge of somatic genetic alterations in NETs. At least 24 genes have been implicated as drivers of neuroendocrine tumorigenesis, and the overall rates of genomic instability are relatively low. Genetic intra-tumoral, as well as inter-tumoral heterogeneity in the same patient, have also been identified. Together these data point towards the common pathways in NET evolution, separating early from late disease drivers. Although knowledge of specific mutations in NETs has limited impact on actual patient management, we predict that in the near future genomic profiling of tumors will be included in the clinical arsenal for diagnostics, prognostics and therapeutic decisions.

A simple and rapid analytical method based on solid-phase extraction and liquid chromatography-tandem mass spectrometry for the simultaneous determination of free catecholamines and metanephrines in urine and its application to routine clinical analysis

OBJECTIVES

Urinary catecholamines and metanephrines are biochemical indicators of pheochromocytoma. We developed and validated a rapid and precise analytical method based on solid-phase extraction (SPE) and liquid chromatography separation coupled to tandem mass spectrometry (LC-MS/MS) for measuring urinary free catecholamines and metanephrines in a clinical setting.

METHODS

Following SPE purification of catecholamines and metanephrines from urine specimens, chromatographic separation and quantitative detection were performed using LC-MS/MS. The developed method for simultaneous measurement of urinary free catecholamines and metanephrines was validated with clinical urine specimens and was compared with other clinical and biochemical results, including urinary total metanephrines, vanillylmandelic acid (VMA), and plasma free metanephrines.

RESULTS

The performance of our newly developed method for measuring urinary free epinephrine (EPI), norepinephrine (NE), dopamine (DA), metanephrine (MN), and normetanephrine (NMN), was acceptable. The recoveries and matrix effects of analytes were 61-107% and 84.5-130.7%. The linear ranges of each analyte were 3.8-2163μg/L, 7.4-2,359μg/L, 5.4-2,825μg/L, 3.5-2,466μg/L, and 3.7-2,569μg/L, and the coefficients of variation (CV) were less than 10% with respect to imprecision. Carryover and sample stability were also validated. Validation using clinical urine specimens by comparison with various biochemical results showed that urinary free metanephrines had comparable sensitivity (100%) and superior specificity (97.1%) to urinary total and plasma free metanephrines.

CONCLUSIONS

The facile and reliable simultaneous measurement method for urinary free catecholamines and metanephrines using LC-MS/MS developed in this study is helpful in obtaining information about multiple metabolites and is applicable to routine clinical settings for the screening of pheochromocytoma.

European Society of Endocrinology Clinical Practice Guideline for long-term follow-up of patients operated on for a phaeochromocytoma or a paraganglioma

Phaeochromocytomas and paragangliomas (PPGLs) are rare neuroendocrine tumours. Standard treatment is surgical resection. Following complete resection of the primary tumour, patients with PPGL are at risk of developing new tumoural events. The present guideline aims to propose standardised clinical care of long-term follow-up in patients operated on for a PPGL. The guideline has been developed by The European Society of Endocrinology and based on the Grading of Recommendations Assessment, Development and Evaluation (GRADE) principles. We performed a systematic review of the literature and analysed the European Network for the Study of Adrenal Tumours (ENS@T) database. The risk of new events persisted in the long term and was higher for patients with genetic or syndromic diseases. Follow-up in the published cohorts and in the ENS@T database was neither standardised nor exhaustive, resulting in a risk of follow-up bias and in low statistical power beyond 10 years after complete surgery. To inform patients and care providers in this context of low-quality evidence, the Guideline Working Group therefore prepared recommendations on the basis of expert consensus. Key recommendations are the following: we recommend that all patients with PPGL be considered for genetic testing; we recommend assaying plasma or urinary metanephrines every year to screen for local or metastatic recurrences or new tumours; and we suggest follow-up for at least 10 years in all patients operated on for a PPGL. High-risk patients (young patients and those with a genetic disease, a large tumour and/or a paraganglioma) should be offered lifelong annual follow-up.

Efficacy and Safety of Everolimus in Extrapancreatic Neuroendocrine Tumor: A Comprehensive Review of Literature

BACKGROUND

Everolimus, an oral mTOR (mammalian target of rapamycin) inhibitor, is currently approved for the treatment of progressive pancreatic neuroendocrine tumors (NETs). Although promising, only scattered data, often from nondedicated studies, are available for extrapancreatic NETs.

PATIENTS AND METHODS

A systematic review of the published data was performed concerning the use of everolimus in extrapancreatic NET, with the aim of summarizing the current knowledge on its efficacy and tolerability. Moreover, the usefulness of everolimus was evaluated according to the different sites of the primary.

RESULTS

The present study included 22 different publications, including 874 patients and 456 extrapancreatic NETs treated with everolimus. Nine different primary sites of extrapancreatic NETs were found. The median progression-free survival ranged from 12.0 to 29.9 months. The median time to progression was not reached in a phase II prospective study, and the interval to progression ranged from 12 to 36 months in 5 clinical cases. Objective responses were observed in 7 prospective studies, 2 retrospective studies, and 2 case reports. Stabilization of the disease was obtained in a high rate of patients, ranging from 67.4% to 100%. The toxicity of everolimus in extrapancreatic NETs is consistent with the known safety profile of the drug. Most adverse events were either grade 1 or 2 and easy manageable with a dose reduction or temporary interruption and only rarely requiring discontinuation.

CONCLUSION

Treatment with everolimus in patients with extrapancreatic NETs appears to be a promising strategy that is safe and well tolerated. The use of this emerging opportunity needs to be validated with clinical trials specifically designed on this topic.

IMPLICATIONS FOR PRACTICE

The present study reviewed all the available published data concerning the use of everolimus in 456 extrapancreatic neuroendocrine tumors (NETs) and summarized the current knowledge on the efficacy and safety of this drug, not yet approved except for pancreatic NETs. The progression-free survival rates and some objective responses seem promising and support the extension of the use of this drug. The site-by-site analysis seems to suggest that some subtypes of NETs, such as colorectal, could be more sensitive to everolimus than other primary NETs. No severe adverse events were usually reported and discontinuation was rarely required; thus, everolimus should be considered a valid therapeutic option for extrapancreatic NETs.

Differential expression of cell cycle regulators in CDK5-dependent medullary thyroid carcinoma tumorigenesis

Medullary thyroid carcinoma (MTC) is a neuroendocrine cancer of thyroid C-cells, for which few treatment options are available. We have recently reported a role for cyclin-dependent kinase 5 (CDK5) in MTC pathogenesis. We have generated a mouse model, in which MTC proliferation is induced upon conditional overexpression of the CDK5 activator, p25, in C-cells, and arrested by interrupting p25 overexpression. Here, we identify genes and proteins that are differentially expressed in proliferating versus arrested benign mouse MTC. We find that downstream target genes of the tumor suppressor, retinoblastoma protein, including genes encoding cell cycle regulators such as CDKs, cyclins and CDK inhibitors, are significantly upregulated in malignant mouse tumors in a CDK5-dependent manner. Reducing CDK5 activity in human MTC cells down-regulated these cell cycle regulators suggesting that CDK5 activity is critical for cell cycle progression and MTC proliferation. Finally, the same set of cell cycle proteins was consistently overexpressed in human sporadic MTC but not in hereditary MTC. Together these findings suggest that aberrant CDK5 activity precedes cell cycle initiation and thus may function as a tumor-promoting factor facilitating cell cycle protein expression in MTC. Targeting aberrant CDK5 or its downstream effectors may be a strategy to halt MTC tumorigenesis.

Risk-reduction surgery in pediatric surgical oncology: A perspective

OBJECTIVE

A small percentage of pediatric solid cancers arise as a result of clearly identified inherited predisposition syndromes and nongenetic lesions. Evidence supports preemptive surgery for children with genetic [multiple endocrine neoplasia type 2 (MEN2), familial adenomatous polyposis syndrome (FAP), hereditary nonpolyposis colorectal cancer (HNPCC), and hereditary diffuse gastric cancer (HDGC) and nongenetic [thyroglossal duct cysts (TGDC), congenital pulmonary airway malformations (CPAM), alimentary tract duplication cysts (ATDC), and congenital choledochal cysts (CCC)] developmental anomalies. Our aim was to explore the utility of risk reduction surgery to treat and prevent cancer in children.

METHODS

A systematic review of the available peer-reviewed literature on PubMed was performed using a PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) search strategy, where possible. Search items included "risk reduction surgery", "hereditary cancer predisposition syndrome", "multiple endocrine neoplasia type 2", "familial adenomatous polyposis", "hereditary nonpolyposis colorectal cancer", "hereditary diffuse gastric cancer", "thyroglossal duct cysts", congenital pulmonary airway malformations", "alimentary tract duplication cysts", "malignant transformation", and "guidelines".

RESULTS

We identified 67 articles that met the inclusion criteria describing the indications for prophylactic surgery in surgical oncology. For the genetic predisposition syndromes, 7 studies were related to professional endorsed guidelines, 7 were related to surgery for MEN2, 11 were related to colectomy for FAP, 6 were related to colectomy for HNPCC, and 12 related to gastrectomy for HDGC. Articles for the nongenetic lesions included 5 for techniques related to TGDC resection, 9 for surgery for CPAMs, and 10 for resection of ATDCs. Guidelines and strategies varied significantly especially related to the extent and timing of surgical intervention; the exception was for the timing of thyroidectomy in children with MEN2.

CONCLUSION

Current evidence supporting prophylactic surgery in the management of pediatric cancer predisposition syndromes and nongenetic lesions is best delineated for thyroidectomy to prevent medullary thyroid cancer in children with MEN2 (Strength of Recommendation Grade B/C). Despite the lack of pediatric specific evidence-based recommendations regarding the appropriate extent and timing for risk-reduction surgery for FAP, HNPCC, HDGC and nongenetic anomalies, our review represents an opportunity towards understanding the postgenomic development of these lesions and provides current indications and techniques for preemptive cancer prevention surgery in children.

Paraganglioma masquerading as acute myocardial infarction and cardiogenic shock

Paragangliomas, extra-adrenal pheochromocytomas, are rare catecholamine-secreting tumor. A 34-year-old lady admitted with diagnosis of ST elevation acute myocardial infarction with cardiogenic shock. Left ventricular function, severely depressed, returned to normal after initial stabilization. Coronary angiogram was normal. A para-aortic paraganglioma was diagnosed during the patient's work-up with biochemical studies, computed tomography of abdomen and functional radioisotopes imaging and was eventually surgically resected.

This case shows that acute myocardial infarction may be the initial manifestation of these neuroendocrine tumors. Hypertensive emergency, much less elevated blood pressure may not be present at time of presentation.

Pediatric Medullary Thyroid Carcinoma

Medullary thyroid carcinoma (MTC), which originates from thyroid parafollicular C cells, accounts for 3 to 5% of thyroid malignancies. MTC occurs either sporadically or in an inherited autosomal dominant manner. Hereditary MTC occurs as a familial MTC or as a part of multiple endocrine neoplasia (MEN) type 2A and B syndromes. A strong genotype-phenotype correlation has been observed between hereditary MTC and germ-line "gain of function" mutations of the RET proto-oncogene. Most cases of pediatric MTC are hereditary whereas sporadic MTC is rare in children and is usually diagnosed in adults. Therefore, MTC in children is most often diagnosed in the course of a familial genetic investigation. The standard treatment of MTC mainly requires surgery involving total thyroidectomy and central neck node dissection before extrathyroidal extension occurs. To prevent MTC development in hereditary syndromes, prophylactic thyroidectomy is performed in presymptomatic patients. An appropriate age at which the surgery should take place is determined based upon the data from genotyping, serum calcitonin measurements, and ultrasonography. For the treatment of advanced MTC cases, the broad spectrum receptor tyrosine kinase inhibitors vandetanib and cabozantinib, which also inhibit RET, are used although they are not always effective.

Pelvic paraganglioma: a rare and unusual clinical presentation of paraganglioma

Paraganglioma of the urinary bladder is a rare tumour of the urinary bladder causing palpitation, headache, paroxysmal hypertension, tachycardia, blurring of vision and haematuria. Patients may present with these exaggerated symptoms during or just after micturition. We present a case of a 15-year-old girl who presented to us with accelerated hypertension, headache, palpitation and blurring of vision. On the basis of a positive family history, laboratory investigations and imaging studies, she was diagnosed to have an extra-adrenal paraganglioma. Complete enucleation of the tumour with preservation of the bladder was done. This case is reported because of the rarity of the disease in urology.

Somatic and germline mutations in NETs: Implications for their diagnosis and management

It is now understood that specific somatic and germline mutations may lead to the development of the neuroendocrine tumours (NETs). NETs usually occur as sporadic isolated tumours, although they also may present as part of complex familial endocrine cancer syndromes, such as multiple endocrine neoplasia type 1 (MEN1) and type 2 (MEN2), Von Hippel-Lindau (VHL) and neurofibromatosis syndromes, tuberous sclerosis, Carney triad and dyad, Reed syndrome and polycythaemia-paraganglioma syndromes. Only in MEN2 syndrome is there a specific genotype-phenotype correlation, although in both sporadic and syndromic NETs some gene mutations are associated with specific clinico-pathological features and prognosis. There have been several advances in our understanding of the NETs leading to earlier detection and targeted therapeutic treatment, but given the poor prognosis associated with metastatic NETs, it will be necessary to find new biomarkers for the prediction of malignant potential and to find novel therapeutic targets for NETs.

Urinary and plasma catecholamines and metanephrines in dogs with pheochromocytoma, hypercortisolism, nonadrenal disease and in healthy dogs

Background

Diagnosis of pheochromocytoma (PC) is based on a combination of clinical suspicion, finding an adrenal mass, increased plasma, and urine concentrations of catecholamine metabolites and is finally confirmed with histopathology. In human medicine, it is controversial whether biochemically testing plasma is superior to testing urine.

Objectives

To measure urinary and plasma catecholamines and metanephrines in healthy dogs, dogs with PC, hypercortisolism (HC), and nonadrenal diseases (NAD) and to determine the test with the best diagnostic performance for dogs with PC.

Animals

Seven PC dogs, 10 dogs with HC, 14 dogs with NAD, 10 healthy dogs.

Methods

Prospective diagnostic clinical study. Urine and heparin plasma samples were collected and stored at −80°C before analysis using high‐pressure liquid chromatography (HPLC) coupled to electrochemical detection or tandem mass spectrometry were performed. Urinary variables were expressed as ratios to urinary creatinine concentration.

Results

Dogs with PC had significantly higher urinary normetanephrine and metanephrine : creatinine ratios and significantly higher plasma‐total and free normetanephrine and plasma‐free metanephrine concentrations compared to the 3 other groups. There were no overlapping results of urinary normetanephrine concentrations between PC and all other groups, and only one PC dog with a plasma normetanephrine concentration in the range of the dogs with HC and NAD disease. Performances of total and free plasma variables were similar. Overlap of epinephrine and norepinephrine results between the groups was large with both urine and plasma.

Conclusion and clinical importance

Measurement of normetanephrine is the preferred biochemical test for PC and urine was superior to plasma.

Clinical Presentation and Diagnosis of Neuroendocrine Tumors

Neuroendocrine tumors (NETs) are slow-growing neoplasms capable of storing and secreting different peptides and neuroamines. Some of these substances cause specific symptom complexes, whereas others are silent. They usually have episodic expression, and the diagnosis is often made at a late stage. Although considered rare, the incidence of NETs is increasing. For these reasons, a high index of suspicion is needed. In this article, the different clinical syndromes and the pathophysiology of each tumor as well as the new and emerging biochemical markers and imaging techniques that should be used to facilitate an early diagnosis, follow-up, and prognosis are reviewed.

Deconjugated Urinary Metanephrine, Normetanephrine and 3-Methoxytyramine in Laboratory Diagnosis of Pheochromocytoma and Paraganglioma

This work discusses the clinical performance of deconjugated metanephrine (MN), normetanephrine (NMN) and 3-methoxytyramine (3MT) determined in the basal first morning urine using a chromatographic method with electrochemical detection for the clinical diagnosis of pheochromocytoma (PHEO) and paraganglioma (PGL). Urine samples were collected from 44 patients (36 with PHEO, 8 with PGL) aged 54+/-17 (20-78) years (22 females, 22 males). A sampling of biological materials was performed preoperatively and about one week, six months and one year after adrenal gland surgery. The control group consisted of 34 PHEO/PGL patients more than 4 months after adrenal gland surgery. All subjects in the control group were without a diagnosis of PHEO or PGL. Clinical sensitivity was 55 % for MN, 64 % for NMN, 80 % for combination of both MN and NMN, and only 23 % for 3TM. Clinical specificity calculated from the control group was 93 % for MN, 95 % for NMN, 95 % for the combination MN and NMN, and 97 % for 3TM. Cut-off values for deconjugated metanephrines in the basal urine were 310 (MN), 690 (NMN) and 250 μg/l (3MT). Chromatographic determination of deconjugated urinary metanephrines, which is simple without the necessity of special laboratory material, can serve for the screening of PHEO or PGL patients. Urine NMN and 3MT exerts an association to malignity, and all markers are associated with tumor mass. However, the principal laboratory diagnosis of PHEO or PGL must be based on plasma-free metanephrines and plasma chromogranin A with better performance in the laboratory diagnosis of PHEO or PGL.

Pheochromocytomas and Paragangliomas: An Update on Recent Molecular Genetic Advances and Criteria for Malignancy

Pheochromocytomas are uncommon neuroendocrine tumors arising in the adrenal medulla, whereas paragangliomas arise from chromaffin cells in sympathetic and parasympathetic locations outside of the adrenal gland. Molecular genetic studies in the past few years have identified >10 genes involved in the pathogenesis of pheochromocytomas and paragangliomas, including RET oncogene, involved in the pathogenesis of multiple endocrine neoplasia (MEN) 2A and 2B, von Hippel-Lindau tumor-suppressor gene, neurofibromatosis type 1 gene, succinate dehydrogenase, THEM127, and several others. The presence of genetic alterations in some of these genes such as in MEN 2A and 2B can be used to diagnose these disorders clinically, and other mutations such as succinate dehydrogenase can be used in the pathologic prediction of benign and malignant pheochromocytomas and paragangliomas. Although it has been difficult to separate benign and malignant pheochromocytomas and paragangliomas, recent studies that may predict the behavior of these chromaffin-derived neoplasms have been reported. The Pheochromocytoma of the Adrenal Scale Score and the Grading system for Adrenal Pheochromocytoma and Paraganglioma scoring system are also discussed.

Images of pheochromocytoma in adrenal glands

Pheochromocytomas are relatively rare tumors of the adrenal medulla. A wide spectrum of imaging findings has been described. The aim of this article is to describe the multimodality imaging features of pheochromocytomas including diagnostic pearls that can help differentiate them from other adrenal lesions and pitfalls to avoid.

Multifocal Extra-Adrenal Paraganglioma - Case Report

Paraganglioma is a rare neoplasm originating from extra-adrenal pheochromocytes of the sympathetic and parasympathetic nervous system. It is usually benign and the treatment method of choice is a complete resection of the tumour. The authors present a case of 66-year-old female patient with a multifocal benign retroperitoneal paraganglioma, which was completely removed during surgery.

Multidisciplinary management of locally advanced and widely metastatic paraganglioma in a patient with life-threatening compressive symptoms

BACKGROUND

Patients presenting with locally advanced, metastatic paraganglioma with life-threatening compressive symptoms of critical anatomic structure pose a significant management challenge.

METHODS

We present a case of a 15-year-old patient with enlarging right neck mass causing dysphagia and respiratory compromise from near complete obstruction of the oropharynx.

RESULTS

Evaluation of the patient's family history led to the identification of a mutation in the succinate dehydrogenase subunit B (SDSD) gene (G725A). Laboratory and imaging workup revealed an 8.8 × 6.6 × 4.1 cm metabolically and biochemically active right neck mass, a tumor in the left para-aortic region, and multiple bony lesions consistent with widely metastatic disease. Multidisciplinary management included preoperative clinical optimization, coil embolization, and palliative resection of the neck mass.

CONCLUSION

Although the currently available treatment options for patients with advanced metastatic paraganglioma render no survival benefit, a multidisciplinary management approach aimed at relief of tumor-related symptoms and catecholamine excess should be undertaken.

A case of sudden death after ultrasound-guided percutaneous alcohol injection of a paraganglioma mis-diagnosed as a peri-renal cyst

Paragangliomas are cromaffin tumors arising from the neural crest cells of parasympathetic or sympathetic ganglia. They are known to be rare causes of sudden death. Here we present the autopsy findings, as well as microscopical and immunohistochemistry study, of a 48-years-old woman who died suddenly after a percutaneous alcohol injection of a peri-renal cyst previously diagnosed as a common complex cyst. She manifested a multiorgan failure, with acute heart failure, systemic and pulmonary vasoconstriction with hypoxia, metabolic acidosis (pH 6.974). It was therefore enacted resuscitation that was ineffective. The autopsy pointed out, close to the upper right renal pole, a cyst characterized by very friable walls and septa, with a thickness of approximately 0.5cm and containing about 75cm(3) of hemoserous fluid. Microscopically, through immunohistochemical examinations, the cyst showed the presence of chromaffin cells, containing enzymes involved in the synthesis of catecholamines, in particular noradrenalin. So, the cause of the death was ascertained in an multi-organ failure caused by a massive release of catecholamines (noradrenaline) from the cyst, identified post-mortem (on the basis of histologic and immunohistochemical examinations) in a noradrenalin-secreting paraganglioma, that remained silent until the cyst ablation.

Revised American Thyroid Association guidelines for the management of medullary thyroid carcinoma

INTRODUCTION

The American Thyroid Association appointed a Task Force of experts to revise the original Medullary Thyroid Carcinoma: Management Guidelines of the American Thyroid Association.

METHODS

The Task Force identified relevant articles using a systematic PubMed search, supplemented with additional published materials, and then created evidence-based recommendations, which were set in categories using criteria adapted from the United States Preventive Services Task Force Agency for Healthcare Research and Quality. The original guidelines provided abundant source material and an excellent organizational structure that served as the basis for the current revised document.

RESULTS

The revised guidelines are focused primarily on the diagnosis and treatment of patients with sporadic medullary thyroid carcinoma (MTC) and hereditary MTC.

CONCLUSIONS

The Task Force developed 67 evidence-based recommendations to assist clinicians in the care of patients with MTC. The Task Force considers the recommendations to represent current, rational, and optimal medical practice.

Endocrine hypertension: An overview on the current etiopathogenesis and management options

Endocrine causes of secondary hypertension include primary aldosteronism, pheochromocytoma, cushing’s syndrome, hyperparathyroidism and hypo- and hyperthyroidism. They comprise 5%-10% of the causes of secondary hypertension. Primary hyperaldosteronism, the most common of the endocrine cause of hypertension often presents with resistant or difficult to control hypertension associated with either normo-or hypokalemia. Pheochromocytoma, a great mimicker of many conditions, is associated with high morbidity and mortality if left untreated. A complete history including pertinent family history, physical examination along with a high index of suspicion with focused biochemical and radiological evaluation is important to diagnose and effectively treat these conditions. The cost effective targeted genetic screening for current known mutations associated with pheochromocytoma are important for early diagnosis and management in family members. The current review focuses on the most recent evidence regarding causes, clinical features, methods of diagnosis, and management of these conditions. A multidisciplinary approach involving internists, endocrinologists and surgeons is recommended in optimal management of these conditions.

Urinary bladder paraganglioma presenting as micturition-induced palpitations, dyspnea, and angina

BACKGROUND

Sympathetic urinary bladder paragangliomas are rare catecholamine-secreting neuroendocrine tumors arising from neural crest cells. They are uncommon urinary bladder neoplasms. Symptoms classically include micturition-related or unrelated palpitations and syncope with hypertension, headaches, diaphoresis, and hematuria. Other than being attributable to vasovagal reactions, micturition-induced cardiovascular symptoms should prompt a search for catecholamine-secreting tumors such as a urinary bladder paraganglioma, as in this case.

CASE REPORT

A 45-year-old asthmatic African-American female presented with episodic hematuria that began 4 years ago and episodes of micturition-induced palpitations, dyspnea, substernal tightness, sweating, and throbbing headaches. Computed tomography with contrast revealed an enhancing mass along the anterior urinary bladder wall, measuring 2.4×3.5 cm. On Positron emission Tomography with [18F] fluorodeoxyglucose integrated with computed tomography (18F-FDG PET/CT), the urinary bladder mass was 18F-FDG avid. Serum normetanephrine and supine plasma norepinephrine were significantly elevated and there was mild elevation of supine plasma epinephrine. Transurethral resection of the bladder mass revealed a neoplasm with microscopic features and immunohistochemical profile positive for synaptophysin and chromogranin, with negative screening cytokeratin AE1/AE3, suggesting a paraganglioma. Following resection of the paraganglioma, there was complete resolution of micturition-induced cardiovascular symptoms on long-term follow-up.

CONCLUSIONS

Micturition-related cardiovascular symptoms are commonly attributed to vasovagal reactions. However, urinary bladder pathologies must be ruled out as a cause, as in this rare case of a urinary bladder paraganglioma exhibiting catecholaminergic symptoms.

Management of metastatic phaeochromocytoma and paraganglioma: use of iodine-131-meta-iodobenzylguanidine therapy in a tertiary referral centre

BACKGROUND

Phaeochromocytoma (phaeo) and paraganglioma (PGL) are rare conditions, which are malignant in up to 30%. Optimal treatment is controversial, but in patients with metastatic iodine-131-meta-iodobenzylguanidine ((123)I-MIBG) avid tumours, we offer (131)I-MIBG therapy. We summarize response rates, survival and safety in a cohort of such patients treated with (131)I-MIBG in our centre from 1986 to 2012.

DESIGN/METHODS

Retrospective analysis of the case notes of patients with metastatic phaeo/PGL who received (131)I-MIBG was undertaken; patients underwent clinical, biochemical and radiological evaluation within 6 months of each course of (131)I-MIBG therapy.

RESULTS

Twenty-two patients (9 males) were identified, 12 with metastatic PGL and 10 with phaeo. Overall median follow-up time after first dose of (131)I-MIBG was 53 months. In total, 68 doses of (131)I-MIBG were administered; average dose was 9967 MBq (269.4 mCi). After the first dose, >50% of patients demonstrated disease stability or partial response; progressive disease was seen in 9%. A subset of patients underwent repeated treatment with the majority demonstrating partial response or stable disease. No life-threatening adverse events were reported, but three patients developed hypothyroidism and two developed ovarian failure after repeated dosing. Five-year survival after original diagnosis was 68% and median (+inter quartile range) survival from date of diagnosis was 17 years (7.6-26.4) with no difference in survival according to diagnosis (P < 0.1).

CONCLUSIONS

(131)I-MIBG is well tolerated and associates with disease stabilization or improvement in the majority of patients with metastatic phaeo/PGL. However, stronger conclusions on treatment effectiveness are limited by lack of a directly comparable 'control group' as well as an alternative 'gold standard' treatment.

Measurements of plasma metanephrines by immunoassay vs liquid chromatography with tandem mass spectrometry for diagnosis of pheochromocytoma

BACKGROUND

Reports conflict concerning measurements of plasma metanephrines (MNs) for diagnosis of pheochromocytomas/paragangliomas (PPGLs) by immunoassays compared with other methods. We aimed to compare the performance of a commercially available enzyme-linked immunoassay (EIA) kit with liquid chromatography-tandem mass spectrometric (LC-MS/MS) measurements of MNs to diagnose PPGLs.

METHODS

In a substudy of a prospective, multicenter trial to study the biochemical profiles of monoamine-producing tumors, we included 341 patients (174 males and 167 females) with suspected PPGLs (median age 54 years), of whom 54 had confirmed PPGLs. Plasma MNs were measured by EIA and LC-MS/MS, each in a specialized laboratory.

RESULTS

Plasma normetanephrine (NMN) and MN were measured 60 and 39% lower by EIA than by LC-MS/MS. Using upper cut-offs stipulated for the EIA, diagnostic sensitivity was only 74.1% at a specificity of 99.3%. In contrast, use of similar cut-offs for MN and overall lower age-adjusted cut-offs for NMN measured by LC-MS/MS returned a diagnostic sensitivity and specificity of 98.1 and 99.7%. Areas under receiver-operating characteristic curves, nevertheless, indicated comparable diagnostic performance of the EIA (0.993) and LC-MS/MS (0.985). Diagnostic sensitivity for the EIA increased to 96.2% with a minimal loss in specificity (95.1%) following use of cut-offs for the EIA adapted to correct for the negative bias.

CONCLUSIONS

The EIA underestimates plasma MNs and diagnostic sensitivity is poor using commonly stipulated cut-offs, resulting in a high risk for missing patients with PPGLs. Correction of this shortcoming can be achieved by appropriately determined cut-offs resulting in comparable diagnostic performance of EIA and LC-MS/MS assays.

Concurrent Medullary, Papillary, and Follicular Thyroid Carcinomas and Simultaneous Cushing's Syndrome

BACKGROUND

Papillary thyroid carcinoma is the most common thyroid cancer (85%). Follicular thyroid carcinoma is the second most common type of thyroid cancer, accounting for up to 10% of all thyroid cancers. Medullary thyroid carcinoma accounts for only 5-8% of thyroid cancers. Concurrent medullary, follicular, and papillary carcinomas of the thyroid gland are extremely rare and reported scarcely.

CASE REPORT

A 72-year-old male presented with nonspecific neck pain. The workup revealed a nodular thyroid gland with a follicular lesion on fine-needle aspiration. Total thyroidectomy was performed and pathological examination identified a 25-mm follicular carcinoma, two papillary microcarcinomas, and two medullary microcarcinomas. The genetic workup was negative and no other family members were diagnosed with any endocrinopathy. Two months after surgery, the patient was diagnosed with Cushing's syndrome that was treated with laparoscopic left adrenalectomy. On 3-year follow-up, the patient is asymptomatic with no evidence of recurrent disease.

CONCLUSION

We present a rare case of a patient with follicular, papillary, and medullary thyroid carcinoma, and Cushing's syndrome. To date, no known genetic mutation or syndrome can account for this combination of neoplastic thyroid and adrenal pathologies, although future research may prove differently.

Hypertension and hypertensive cardiomyopathy in patients with a relapse-free history of phaeochromocytoma

BACKGROUND

In patients with a relapse-free history of phaeochromocytoma/paraganglioma (PCC/PGL), persistent hypertension has been reported, but has not been well characterized.

METHODS

In 28 patients [mean age 54·5 (26-81) years] with a relapse-free history of PCC/PGLs, we prospectively analysed resting, supine blood pressure (BP), ambulatory BP, echocardiography, exercise testing, metabolic parameters and retrospectively collected data from the time of diagnosis (baseline). Echocardiographic measures were compared to healthy (n = 28) and hypertensive controls (n = 15).

RESULTS

Median follow-up was 6 [1-16] years. Three patients had normal office and ambulatory BP and three patients had only increased office BP. Fifty-four per cent of patients had a blunted circadian rhythm. Comparing normal, hypertensive and PCC/PGL patients, we found significant differences in end-diastolic septal thickness (8·8 ± 0·2, 13·8 ± 0·4, 10·0 ± 0·3 mm, P < 0·05), septal basal thickness (9·0 ± 0·3, 15·9 ± 0·5, 11·2 ± 0·4 mm, P < 0·05) and left ventricular mass (143 ± 8, 255 ± 19, 169 ± 9 g, P < 0·05). In five patients, seven major cardiovascular events were observed. Compared to baseline, no significant difference was found in systolic (140 ± 35 vs 137 ± 18 mmHg) and diastolic (85 ± 18 vs 83 ± 10 mmHg) BP. An increase or a decrease in BP (>10 mmHg) was found in 36% and 39% of patients, respectively. The number of antihypertensive drugs had not changed [1 (0-3) vs 1 (0-4)]. Fewer patients received insulin (1 vs 3) or oral antiglycaemic drugs (2 vs 7).

CONCLUSION

Our data indicate that hypertension persists after removal of PCG/PGL in a substantial proportion of patients. Hypertensive heart disease is common, and cardiovascular events are frequent in patients with a history of PCC/PGL.

Von Hippel-Lindau disease

von Hippel-Lindau (VHL) disease is an inheritable condition with an incidence of 1 in 36000 live births. Individuals with VHL develop benign and malignant tumors including retinal and central nervous system hemangioblastomas, clear cell renal cell carcinomas (RCC), pheochromocytomas, pancreatic neuroendocrine tumors and endolymphatic sac tumors (ELSTs). VHL is caused by germline loss of function of the VHL gene on one allele at chromosome 3p25-26. A somatic "second hit" event leads to the loss of the other allele and tumor formation. Loss of VHL function in cells leads to increased expression and stabilization of hypoxia inducible factor (HIF). VHL protein/HIF pathway has been implicated in tumorigenesis for hemangioblastomas, RCC and other VHL tumors. Clinical examination, imaging, and genetic testing for VHL mutations confirm VHL disease. Management of VHL disease largely consists of surgical resection of symptomatic tumors (hemangioblastomas), tumors prone to metastasize (RCC larger than 3cm), or tumors causing hormonal symptoms (pheochromocytomas). Despite advances in early diagnosis and management of VHL disease, life expectancy for VHL patients remains low at 40-52 years. Secondary effects from VHL manifestations are mitigated by routine surveillance and early detection. In this chapter, we summarize the current state of knowledge in VHL disease.

Tumor-suppressor role of Notch3 in medullary thyroid carcinoma revealed by genetic and pharmacological induction

Notch1-3 are transmembrane receptors that appear to be absent in medullary thyroid cancer (MTC). Previous research has shown that induction of Notch1 has a tumor-suppressor effect in MTC cell lines, but little is known about the biologic consequences of Notch3 activation for the progression of the disease. We elucidate the role of Notch3 in MTC by genetic (doxycycline-inducible Notch3 intracellular domain) and pharmacologic [AB3, novel histone deacetylase (HDAC) inhibitor] approaches. We find that overexpression of Notch3 leads to the dose-dependent reduction of neuroendocrine tumor markers. In addition, Notch3 activity is required to suppress MTC cell proliferation, and the extent of growth repression depends on the amount of Notch3 protein expressed. Moreover, activation of Notch3 induces apoptosis. The translational significance of this finding is highlighted by our observation that MTC tumors lack active Notch3 protein and reinstitution of this isoform could be a therapeutic strategy to treat patients with MTC. We demonstrate, for the first time, that overexpression of Notch3 in MTC cells can alter malignant neuroendocrine phenotype in both in vitro and in vivo models. In addition, our study provides a strong rationale for using Notch3 as a therapeutic target to provide novel pharmacologic treatment options for MTC.