A comprehensive characterisation of phaeochromocytoma and paraganglioma tumours through histone protein profiling, DNA methylation and transcriptomic analysis genome wide.

BACKGROUND: Phaeochromocytomas and paragangliomas (PPGLs) are rare neuroendocrine tumours. Pathogenic variants have been identified in more than 15 susceptibility genes; associated tumours are grouped into three Clusters, reinforced by their transcriptional profiles. Cluster 1A PPGLs have pathogenic variants affecting enzymes of the tricarboxylic acid cycle, including succinate dehydrogenase. Within inherited PPGLs, these are the most common. PPGL tumours are known to undergo epigenetic reprograming, and here, we report on global histone post-translational modifications and DNA methylation levels, alongside clinical phenotypes. RESULTS: Out of the 25 histone post-translational modifications examined, Cluster 1A PPGLs were distinguished from other tumours by a decrease in hyper-acetylated peptides and an increase in H3K4me2. DNA methylation was compared between tumours from individuals who developed metastatic disease versus those that did not. The majority of differentially methylated sites identified tended to be completely methylated or unmethylated in non-metastatic tumours, with low inter-sample variance. Metastatic tumours by contrast consistently had an intermediate DNA methylation state, including the ephrin receptor EPHA4 and its ligand EFNA3. Gene expression analyses performed to identify genes involved in metastatic tumour behaviour pin-pointed a number of genes previously described as mis-regulated in Cluster 1A tumours, as well as highlighting the tumour suppressor RGS22 and the pituitary tumour-transforming gene PTTG1. CONCLUSIONS: Combined transcriptomic and DNA methylation analyses revealed aberrant pathways, including ones that could be implicated in metastatic phenotypes and, for the first time, we report a decrease in hyper-acetylated histone marks in Cluster 1 PPGLs.

Comparing subtotal parathyroidectomy and total parathyroidectomy with autotransplantation in renal transplant recipients.

Background: Both subtotal parathyroidectomy (SPTX) and total parathyroidectomy with autotransplantation (TPTX + AT) are considered acceptable surgical approaches for renal patients. It is common that parathyroid surgery is performed in patients before they undergo kidney transplantation and there is currently no evidence considering the best surgical approach in this subset of patients. Methods: Two cohorts were identified of consecutive patients who underwent parathyroidectomy for renal hyperparathyroidism by two surgeons at a single institution over equivalent time periods (SPTX and TPTX + AT). A retrospective chart review was performed to assess these techniques, including outcomes following kidney transplantation. Results: There were 125 patients analysed, with 56 patients who underwent SPTX and 69 who underwent TPTX + AT. Both cohorts effectively reduced PTH post operatively. There were 22 patients in the SPTX cohort and 26 in the TPTX + AT cohort that subsequently received kidney transplants. There were no cases of recurrent hyperparathyroidism and one of hypoparathyroidism (4.5%) in the SPTX patients post-transplant. There was one case of recurrent hyperparathyroidism (3.8%) and four of persistent hypoparathyroidism (15.4%) in the TPTX + AT patients post-transplant. Conclusions: Surgery for renal hyperparathyroidism requires a careful balance of the extent of parathyroid resection to prevent persistent/recurrent disease and avoid permanent hypoparathyroidism. SPTX may be a more appropriate option in kidney transplant candidates in order to minimise the risk of long-term hypoparathyroidism.

Tumour detection and outcomes of surveillance screening in SDHB and SDHD pathogenic variant carriers.

OBJECTIVE: Succinate dehydrogenase subunit (SDHx) pathogenic variants predispose to phaeochromocytoma and paraganglioma (PPGL). Lifelong surveillance is recommended for all patients to enable prompt detection and treatment. There is currently limited evidence for optimal surveillance strategies in hereditary PPGL. We aim to detail the clinical presentation of PPGL in our cohort of non-index SDHB and SDHD pathogenic variant carriers. METHODS: Retrospective analysis of medical and genetic records from a single tertiary referral centre identified SDHB or SDHD pathogenic variants in 74 non-index cases (56 SDHB and 18 SDHD). Surveillance screening for asymptomatic relatives consisted of annual plasma metanephrine measurement and whole-body MRI with contrast at 3-5 yearly intervals. RESULTS: Twenty-three out of 74 non-index patients (10 SDHB and 13 SDHD) were diagnosed with PPGL, 17 patients through surveillance screening (24 tumours in total) and 6 diagnosed prior to commencement of cascade screening with symptomatic presentation. MRI with contrast identified PPGL in 22/24 screen-detected tumours and 5/24 tumours had elevated plasma metanephrine levels. Penetrance in non-index family members was 15.2 and 47.2% for SDHB carriers and 71.6 and 78.7% for SDHD carriers at age of 50 and 70 years, respectively. CONCLUSION: Surveillance screening with combined biochemical testing and imaging enables early detection of PPGL in asymptomatic relatives with SDHx pathogenic variants. The presence of disease at first screen was significant in our cohort and hence further multi-centre long-term data are needed to inform counselling of family members undergoing lifelong surveillance.

Treatment outcome with a selective RET tyrosine kinase inhibitor selpercatinib in children with multiple endocrine neoplasia type 2 and advanced medullary thyroid carcinoma.

BACKGROUND: Medullary thyroid carcinoma (MTC) in the context of multiple endocrine neoplasia type 2 (MEN2) is caused by mutations in the RET proto-oncogene. Therefore, in children with MEN2 and advanced MTC, the RET tyrosine kinase (TK) pathway is a target for treatment with selpercatinib, a selective RET TK inhibitor. PATIENTS AND METHODS: A retrospective review of the clinical, genetic, biochemical (calcitonin and carcinoembryonic antigen [CEA]) and imaging data of six medically untreated children with MEN2 and recurrent and or progressive MTC. The main parameters were safety and objective treatment response to selpercatinib. RESULTS: Six children (three males and three females, aged 3-12 years), four with MEN2B and two MEN2A, are reported. All had initial total thyroidectomy and extensive neck dissections but subsequently developed recurrent and progressive disease. All experienced an improvement in clinical symptoms with a concomitant biochemical response evidenced by significant fall in serum calcitonin and CEA concentrations. The fall in serum calcitonin was evident within 2 weeks of the start of selpercatinib, and responses were ongoing at a median follow-up of 13 months (range, 11-22 months). Four children with measurable radiological disease had good volume reduction. The most common adverse effects were transient but reversible grade 1 or 2 increase in alanine aminotransferase, serum bilirubin and constipation. No child required a dose modification or had to discontinue selpercatinib because of a drug-related adverse event. CONCLUSION: Selpercatinib has shown excellent therapeutic efficacy with minimal toxicity in children with MEN2 and progressive metastatic RET-mutated MTC.

Making (mis) sense of asymptomatic marked hypercalcemia in pregnancy.

We describe a rare case of homozygous inactivating calcium-sensing receptor mutation detected during pregnancy and mimicking primary hyperparathyroidism. In pregnancy, the differential diagnosis of hypercalcaemia requires a cautious approach as physiological changes in calcium homeostasis may mask rare genetic conditions.

Role of intraoperative PTH monitoring and surgical approach in primary hyperparathyroidism.

AIMS: The use of intraoperative PTH monitoring (IOPTH) in combination with preoperative imaging has been useful to surgeons performing minimally invasive parathyroidectomy principally for adequacy of excision. However, its role within patients with equivocal imaging remains less clear particularly regarding the reduction of bilateral neck explorations. This study investigated the influence of IOPTH monitoring on the type of surgical approach adopted for patients with primary hyperparathyroidism (PHPT). Specifically, determining its impact amongst patients with equivocal imaging results. METHODS: 165 patients undergoing parathyroidectomy for PHPT at a single institution by a single surgeon, between 2008 and 2012, were included. Patients were divided into 2 groups, IOPTH monitoring and non-IOPTH monitoring. They were sub-classified according to their imaging strengths: strongly positive, equivocal and negative imaging. The percentages of patients undergoing focused, unilateral and bilateral operations were determined. RESULTS: 108 patients had IOPTH monitoring and 57 patients did not based on the availability of IOPTH monitoring. Patients with strongly positive imaging had a higher frequency of focused operation in both groups; IOPTH 73.4% and non-IOPTH 71.4%. Patients with negative imaging results had a higher frequency of bilateral operations; IOPTH 77.8% and non-IOPTH 72.7%. In patients with equivocal imaging results more focused/unilateral operations were performed with IOPTH monitoring 66.6% versus non-IOPTH 25%. The use of intraoperative PTH increased the likelihood of a unilateral procedure with equivocal imaging compared to those with negative imaging p = 0.04. CONCLUSION: IOPTH monitoring is most useful as an adjunct to preoperative imaging when imaging results are equivocal allowing for more focused/unilateral operations to be performed.

Incidence and Significance of Incidental Focal Thyroid Uptake on (18)F-FDG PET Study in a Large Patient Cohort: Retrospective Single-Centre Experience in the United Kingdom.

OBJECTIVE: To assess the prevalence and pathological nature of incidental focal thyroid uptake on (18)F-FDG (2-[(18)F]-fluoro-2-deoxy-D-glucose) PET (positron emission tomography) and examine the role of the maximum standardised uptake value (SUVmax) to differentiate benign from malignant thyroid pathology. MATERIAL AND METHODS: (18)F-FDG PET reports were retrospectively reviewed. Incidental focal tracer uptake in the thyroid was noted in 147 patients (0.5%). Patients with known primary thyroid malignancy were excluded. The final diagnosis was made following ultrasonography of the neck, fine-needle aspiration cytology (FNAC) or histopathology of the surgically resected specimen where surgery was indicated. A Mann-Whitney U test was used to compare the SUVmax of benign and malignant thyroid pathology. Receiver operating characteristic (ROC) analysis was performed to identify an SUVmax cutoff in differentiating benign from malignant pathology. RESULTS: A final diagnosis was achieved in 47/147 (32%) of the patients. The diagnoses included benign lesions in 36 patients and malignancy in 9 patients. In 2 patients, FNAC demonstrated indeterminate follicular lesions; however, surgical excision was not performed. There was a highly significant difference in the mean SUVmax of malignant focal thyroid uptake (15.7 ± 5.9) compared to that of benign lesions (7.1 ± 6.8) with a p value of 0.000123. An SUVmax of 9.1 achieved a sensitivity of 81.6%, specificity of 100% and area under the curve of 0.915 in the ROC analysis differentiating benign from malignant disease. CONCLUSION: The malignancy potential of incidental focal thyroid uptake remains high and warrants prompt and appropriate follow-up by the clinician. The SUVmax may aid in further characterisation of the lesion and its management.

"Parathyroidectomy in pregnancy"-a single centre experience with review of evidence and proposal for treatment algorithim.

BACKGROUND: As many as 25% of women with primary hyperparathyroidism (PHPT) present during their child bearing years. However there is a paucity of data about management of PHPT in pregnancy, despite its association with severe complications including foetal loss. A recent review called for early surgical intervention to optimise maternal and foetal outcomes. We present our experience of parathyroidectomy in five pregnant patients, representing the largest series reported to date, alongside a review of literature to formulate a best evidence approach to management. METHODS: A retrospective case series of five patients managed at a single tertiary referral centre in London, UK. Data analysed include patient demographics, clinical features, pre- and post-operative biochemical markers, pathology findings, surgical procedure, complications, and outcome of pregnancy. RESULTS: Parathyroidectomy was safely carried out in all five patients during their second trimester. Cure was achieved by excision of adenoma in four patients at first operation with no reported complications. One patient with severe preoperative hypercalcaemia of >3 mmol/L suffered persistent severe hypercalcaemia despite three gland excision, with subsequent genetic testing revealing a mutation consistent with familial hypocalciuric hypercalcaemia (FHH). CONCLUSIONS: This case series illustrates the challenges and successes of managing PHPT in pregnancy. Parathyroidectomy can be safely carried out with excellent outcomes for both mother and child. However, a modified approach to diagnosis and localisation studies is required. We propose a model for investigation and approach to management of such patients.

18F-FDG PET rarely provides additional information to 11C-methionine PET imaging in hyperparathyroidism.

AIM: The aim of this study was to assess the utility of combined C-methionine and F-FDG PET/CT imaging in hyperparathyroidism. PATIENTS AND METHODS: We reviewed all scans performed for hyperparathyroidism with both C-methionine and F-FDG PET/CT or PET in our institution since 1993. Forty-three patients (47 pairs of scans) were included (13 men and 30 women) with a mean age of 63 years. C-methionine and F-FDG PET/CT scans were classified as positive or negative for localization of abnormal parathyroid tissue, and the site of uptake was noted in the positive scans. Other concurrent imaging (Tc-MIBI scintigraphy, ultrasonography, CT, or MRI) findings were also noted when performed. Clinical follow-up information was available in 27 patients (30 episodes). RESULTS: Of the 47 PET scan episodes, 23 (49%) were positive. Twenty-two C-methionine scans showed abnormal focal localization of which 10 also showed concordant abnormal F-FDG uptake. One patient was positive with F-FDG and negative with C-methionine.Of the 16 patients who underwent subsequent surgery, 6 had concordant C-methionine, F-FDG, and surgical findings; 6 had concordant C-methionine and surgical findings; 1 had concordant F-FDG and surgical findings; and 3 had both PET scans negative but had adenomas excised during surgery.Of the 3 with both PET scans negative and discordant surgical findings, 1 had mediastinal parathyroid lipoadenoma excised and 2 had normally sited parathyroid adenoma excised. CONCLUSIONS: F-FDG PET/CT rarely provides additional information and could be saved for patients in whom C-methionine PET/CT is negative.

Subtotal parathyroidectomy as an adequate treatment for primary hyperparathyroidism in multiple endocrine neoplasia type 1.

HYPOTHESIS: The most appropriate surgical approach for hyperparathyroidism (HPT) in multiple endocrine neoplasia type 1 remains controversial. It has been advocated that reoperations for recurrent disease are easier to perform after total parathyroidectomy (TP) with autotransplantation than after subtotal parathyroidectomy (SP). In view of our large experience in patients with secondary HPT for whom TP with autotransplantation did not simplify reoperations, SP remains our preferred treatment for patients with HPT and multiple endocrine neoplasia type 1. DESIGN: Retrospective cohort study. SETTING: Tertiary referral medical center. PATIENTS: A total of 29 consecutive patients (22 women, 7 men; mean age, 42.2 years) with multiple endocrine neoplasia type 1 who underwent definitive cervical exploration for HPT. MAIN OUTCOME MEASURES: Temporary and permanent hypocalcemia, pattern of parathyroid disease, and sites and timing of recurrent HPT. Definitive primary surgery included SP in 21 patients, TP with autotransplantation in 4 patients, and less-than-subtotal parathyroidectomy in 4 selected patients. RESULTS: The mean follow-up was 88.5 months (range, 8-285 months). Four patients died during follow-up; 2 of these deaths were related to multiple endocrine neoplasia. No patients had persistent HPT. Temporary hypocalcemia occurred in 12 SP cases (57%), 4 TP with autotransplantation cases (100%), and 0 less-than-subtotal parathyroidectomy cases. Permanent hypocalcemia requiring long-term treatment occurred in 2 SP cases (10%), 1 TP with autotransplantation case (25%), and 0 less-than-subtotal parathyroidectomy cases. Four patients developed recurrent disease, including 1 with SP, 2 with TP with autotransplantation, and 1 with less-than-subtotal parathyroidectomy at 57 months, 197 and 180 months, and 164 months, respectively, representing 14% of all of the patients and 43% of patients with more than 10 years of follow-up. CONCLUSIONS: Recurrent HPT occurs many years after definitive primary surgery (median, 14.3 years). Surgical treatment should therefore aim to minimize the risk of permanent hypocalcemia and facilitate future surgery. When correctly performed, SP fulfills these objectives.

Negative preoperative localization studies are highly predictive of multiglandular disease in sporadic primary hyperparathyroidism.

BACKGROUND: The development of localization studies and quick parathyroid hormone assay (QPTH) has allowed the development of focused surgery in sporadic primary hyperparathyroidism. The aim of this investigation was to determine whether localization studies select a specific population of patients. METHODS: From 1999 to 2001, 213 patients underwent surgery for sporadic primary hyperparathyroidism. All were investigated with sestamibi scanning and ultrasonography. When at least 1 study showed a positive result (n=175), the patient underwent a video-assisted approach with QPTH. When results were negative (n=38), the patient underwent cervicotomy and exploratory procedures of all 4 parathyroid glands. RESULTS: All patients are cured (mean follow-up, 17.8+/-10.3 months [SD]). Patients with negative preoperative study results had a high risk of multiglandular disease (12/38 patients; 31,6%), compared with patients with 1 positive study result (3/83 patients; 3.6%; P<.0001) and those with 2 concordant positive study results (0/92 patients; P<.0001). CONCLUSION: When preoperative localization study results are negative, the patient has a high risk of multiglandular disease, and a conventional cervicotomy with identification of the 4 glands is recommended strongly. When only 1 localization study is positive, the risk of multiglandular disease justifies the use of QPTH during a focused approach. When positive localization study results are concordant, the use of QPTH is questionable during a focused approach.

Primary hyperparathyroidism in MEN 1--how radical should surgery be?

Primary hyperparathyroidism is the most common manifestation of MEN 1 syndrome. The management of these patients is complex due to the underlying disease process, which predisposes patients to persistent and recurrent disease. The surgical treatment of patients with MEN 1 and hyperparathyroidism can therefore be considered to be palliative in nature. The basic principles of surgery include (1) obtaining and maintaining normocalcaemia for the longest time possible, avoiding persistent/recurrent hypercalcaemia, (2) avoiding surgically induced hypocalcaemia, and (3) facilitating future surgery for recurrent disease. Two approaches have been described as the best practice for patients with hyperparathyroidism in MEN 1: subtotal parathyroidectomy, leaving a remnant of no more than 60 mg in the neck, and total parathyroidectomy with immediate autotransplantation of 10-20 1 mm(3) pieces of parathyroid tissue. Both approaches should be combined with efforts to exclude supernumerary glands and ectopic parathyroid tissue by including resection of fatty tissue from the central neck compartment and thymectomy in all patients. Cryopreservation of parathyroid tissue should be performed whenever facilities are available. In patients with persistent or recurrent disease, an attempt to obtain total elimination of cervical parathyroid tissue is justified, combined with cryopreservation of parathyroid tissue. As radical as surgery is for hyperparathyroidism in MEN 1, the surgeon must take steps to avoid permanent hypoparathyroidism, which in young patients may be worse than the disease itself.