Enhancing clinical care and investigating a novel therapeutic approach for multiple paragangliomas

Paragangliomas (PGLs) are rare tumours of the autonomic nervous system that cause high morbidity and mortality. Diagnosis and management can be challenging and no consensus on pre-operative management exists. PGLs arise in sporadic and familial forms and have the potential for malignant transformation. Despite significant advances in identification of genetic causes there is still a lack of understanding in the pathogenesis of the different clinical phenotypes. Surgical resection is the only cure, but once metastases have occurred treatment options are limited. This thesis aims to address some of these issues with the overall objective of improving clinical care for affected patients and their relatives. The first part of this research focuses on pre-operative management. Using home blood pressure monitoring and personalised titration of medications, the presented data show improved compliance with alpha-blockade medication. Duration of treatment appears to be an important factor in intra- and post-operative haemodynamic instability. Analysis of bioimpedance and serum inflammatory markers demonstrated that medical therapy is potentially able to reverse the inflammatory and catabolic effects of catecholamine excess. Part two focuses on mutations within the Succinate Dehydrogenase (SDH) genes. Mutations in any of these can cause disruption in SDH enzymatic function, but penetrance, clinical presentation and tumour aggressiveness differ between subunits. A model for surveillance monitoring is proposed based on collated data. The final part investigates the immune cell composition of the tumour microenvironment (TME). Emerging evidence suggests that the TME correlates with clinical outcome, however, little is known about the TME of PGLs. Immune cells in the TME were assessed using immunohistochemistry. There was a higher proportion of immune cells in tumour tissue compared to non-pathological medulla, with a predominance of macrophages. Differences in the TME were observed between aggressive and benign tumours. These observations could potentially be exploited as an aid in predicting tumour behaviour

Hepatitis B assessment without hepatitis B virus DNA quantification: a prospective cohort study in Uganda

BACKGROUND: Chronic hepatitis B infection affects 240 million people, with the highest prevalence in Africa and Asia, and results in 700 000 deaths annually. Access to diagnostics, particularly for hepatitis B virus viral load quantification (HBV DNA), is a major barrier to treatment. We aimed to test World Health Organization guidelines for hepatitis B management in resource-limited settings. METHODS: We compared treatment allocation with and without the use of HBV DNA in a cohort in Uganda. Hepatitis B surface antigen test-positive, human immunodeficiency virus-negative, treatment-naïve adults were recruited prospectively. Following liver ultrasound and routine haematological and biochemical tests, preliminary allocations into treatment and observation groups were made. HBV DNA was performed for each participant and final treatment decisions were made and compared with preliminary allocations. RESULTS: Full assessment was completed for 100 participants; treatment was indicated in 20. Assessment without HBV DNA identified patients for treatment with a positive predictive value of 88.2% and a negative predictive value of 94% compared with assessment using HBV DNA. CONCLSUIONS: Where HBV DNA is unavailable, patients with hepatitis B can be assessed by liver ultrasound and routine laboratory tests. These findings will enable physicians in resource-limited settings to initiate treatment more readily and inform policy with regards to viral hepatitis elimination

Diffusion‐weighted imaging (DWI) highlights SDHB ‐related tumours: A pilot study

OBJECTIVE: There is consensus that asymptomatic carriers of SDHB mutations should undergo periodic surveillance imaging. MRI has the advantage of avoiding radiation exposure but its sensitivity and specificity for detecting phaeochromocytoma and paraganglioma (PPGL) are dependent on sequences performed and expertise of reporting radiologists. We aim to highlight the additional value of diffusion-weighted imaging (DWI) for MR based surveillance, demonstrating DWI's ability to identify small PPGLs at all body sites. DESIGN: We presented DWI sequences taken as part of SDHB surveillance to a radiologist, expert in reporting PPGL screening scans. Areas of high signal on DWI were interrogated using other standard MRI sequences. PATIENTS: We reviewed the MRI scans for 18 SDHB mutation carriers with a total of 18 histologically proven SDHB-related tumours and 12 presumed PGLs/metastatic deposits. RESULTS: The DWI sequences identified all 30 lesions. False-positive lesions were excluded by standard sequences. The tumours detected by DWI ranged in size from 5 to 52 mm. PPGLs were identified on DWI in the abdomen (n = 14), adrenal gland (n = 1), thorax (n = 3), neck (n = 2) and bladder (n = 2). Additionally, other SDHB-related tumours (GIST, RCC) were also highlighted by DWI, as were metastatic deposits in the liver and bone. CONCLUSIONS: These preliminary data suggest that DWI has high sensitivity and can identify even small SDHB-related tumours. If these findings are confirmed in larger series, for all SDH subunits, it will provide reassurance about identifying small SDH-related tumours, without exposing patients to the consequences of radiation-based imaging and will secure the role of MRI for surveillance imaging. © 2019 John Wiley & Sons Ltd

An analysis of surveillance screening for SDHB-related disease in childhood and adolescence.

Objective Phaeochromocytomas (PCC) and paragangliomas (PGL) are rare in children. A large proportion of these are now understood to be due to underlying germline mutations. Here we focus on succinate dehydrogenase subunit B (SDHB) gene mutation carriers as these tumours carry a high risk of malignant transformation. There remains no current consensus with respect to optimal surveillance for asymptomatic carriers and those in whom the presenting tumour has been resected. Method We undertook a retrospective analysis of longitudinal clinical data of all children and adolescents with SDHB mutations followed up in a single UK tertiary referral centre. This included index cases that pre-dated the introduction of surveillance screening and asymptomatic carriers identified through cascade genetic testing. We also conducted a literature review to inform a suggested surveillance protocol for children and adolescents harbouring SDHB mutations. Results Clinical outcomes of a total of 38 children are presented: 8 index cases and 30 mutation-positive asymptomatic carriers with 175 patient years of follow-up data. Three of the eight index cases developed metachronous disease and two developed metastatic disease. Of the 30 asymptomatic carriers, 3 were found to have PGLs on surveillance screening. Conclusions Surveillance screening was well tolerated in our paediatric cohort and asymptomatic paediatric subjects. Screening can identify tumours before they become secretory and/or symptomatic, thereby facilitating surgical resection and reducing the chance of distant spread. We propose a regular screening protocol commencing at age 5 years in this at-risk cohort of patients.N T is funded by a grant from The Medical College of St Bartholomew’s Hospital Trust (registered charity number 1115519)

Pregnancy and phaeochromocytoma/paraganglioma: clinical clues affecting diagnosis and outcome - a systematic review

BACKGROUND: Phaeochromocytoma and paraganglioma (PPGL) in pregnancy, if not diagnosed antepartum, pose a high risk for mother and child. OBJECTIVE: To examine the clinical clues of antepartum and postpartum/postmortem diagnosis of PPGL. SEARCH STRATEGY: Case reports on PPGL in pregnancy published between 1 January 1988 and 30 June 2019 in English, German, Dutch or French. SELECTION CRITERIA: Case reports containing a predefined minimum of clinical data on PPGL and pregnancy. DATA COLLECTION AND ANALYSIS: Two authors independently performed data extraction and assessed data quality. We calculated odds ratios (OR) (with 95% confidence intervals) and used uni- and multivariable logistic regression analysis. MAIN RESULTS: Maternal and fetal/neonatal mortalities were 9.0% (18/200) and 14.2% (29/204), respectively. Maternal mortality was 42-fold higher with PPGL diagnosed postpartum/postmortem (17/58; 29.3%) than antepartum (1/142; 0.7%) (adjusted OR 45.9, 95% CI 5.67-370, P = 0.0003). Offspring mortality was 2.6-fold higher with PPGL diagnosed postpartum/postmortem than antepartum (OR 3.1, 95% CI 1.38-6.91, P = 0.0044). Hypertension at admission (OR 2.29, 95% CI 1.12-4.68, P = 0.022), sweating (OR 3.14, 95% CI 1.29-7.63, P = 0.014) and a history of PPGL, a known PPGL-associated gene mutation or adrenal mass (OR 8.87, 95% CI 1.89-41.64, P = 0.0056) were independent factors of antepartum diagnosis. Acute onset of symptoms (OR 8.49, 95% CI 3.52-20.5, P < 0.0001), initial diagnosis of pre-eclampsia (OR 6.34, 95% CI 2.60-15.5, P < 0.0001), admission for obstetric care (OR 10.71, 95% CI 2.70-42.45, P = 0.0007) and maternal tachycardia (OR 2.72, 95% CI 1.26-5.85, P = 0.011) were independent factors of postpartum diagnosis. CONCLUSION: Several clinical clues can assist clinicians in considering an antenatal diagnosis of PPGL in pregnancy, thus potentially improving outcome. TWEETABLE ABSTRACT: Systematic review of 204 pregnant patients with phaeochromocytoma identified clinical clues for a timely antepartum diagnosis

Pituitary carcinoma in a patient with germline Succinate Dehydrogenase B mutation

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Pregnancy and phaeochromocytoma/paraganglioma: clinical clues affecting diagnosis and outcome – a systematic review

BACKGROUND: Phaeochromocytoma and paraganglioma (PPGL) in pregnancy, if not diagnosed antepartum, pose a high risk for mother and child. OBJECTIVE: To examine the clinical clues of antepartum and postpartum/postmortem diagnosis of PPGL. SEARCH STRATEGY: Case reports on PPGL in pregnancy published between 1 January 1988 and 30 June 2019 in English, German, Dutch or French. SELECTION CRITERIA: Case reports containing a predefined minimum of clinical data on PPGL and pregnancy. DATA COLLECTION AND ANALYSIS: Two authors independently performed data extraction and assessed data quality. We calculated odds ratios (OR) (with 95% confidence intervals) and used uni- and multivariable logistic regression analysis. MAIN RESULTS: Maternal and fetal/neonatal mortalities were 9.0% (18/200) and 14.2% (29/204), respectively. Maternal mortality was 42-fold higher with PPGL diagnosed postpartum/postmortem (17/58; 29.3%) than antepartum (1/142; 0.7%) (adjusted OR 45.9, 95% CI 5.67-370, P = 0.0003). Offspring mortality was 2.6-fold higher with PPGL diagnosed postpartum/postmortem than antepartum (OR 3.1, 95% CI 1.38-6.91, P = 0.0044). Hypertension at admission (OR 2.29, 95% CI 1.12-4.68, P = 0.022), sweating (OR 3.14, 95% CI 1.29-7.63, P = 0.014) and a history of PPGL, a known PPGL-associated gene mutation or adrenal mass (OR 8.87, 95% CI 1.89-41.64, P = 0.0056) were independent factors of antepartum diagnosis. Acute onset of symptoms (OR 8.49, 95% CI 3.52-20.5, P < 0.0001), initial diagnosis of pre-eclampsia (OR 6.34, 95% CI 2.60-15.5, P < 0.0001), admission for obstetric care (OR 10.71, 95% CI 2.70-42.45, P = 0.0007) and maternal tachycardia (OR 2.72, 95% CI 1.26-5.85, P = 0.011) were independent factors of postpartum diagnosis. CONCLUSION: Several clinical clues can assist clinicians in considering an antenatal diagnosis of PPGL in pregnancy, thus potentially improving outcome. TWEETABLE ABSTRACT: Systematic review of 204 pregnant patients with phaeochromocytoma identified clinical clues for a timely antepartum diagnosis

A patient with a germline SDHB mutation presenting with an isolated pituitary macroprolactinoma

Symptomatic pituitary adenomas occur with a prevalence of approximately 0.1% in the general population. It is estimated that 5% of pituitary adenomas occur in a familial setting, either in isolated or syndromic form. Recently, loss-of-function mutations in genes encoding succinate dehydrogenase subunits (SDHx) or MYC-associated factor X (MAX) have been found to predispose to pituitary adenomas in co-existence with paragangliomas or phaeochromocytomas. It is rare, however, for a familial SDHx mutation to manifest as an isolated pituitary adenoma. We present the case of a pituitary lactotroph adenoma in a patient with a heterozygous germline SDHB mutation, in the absence of concomitant neoplasms. Initially, the adenoma showed biochemical response but poor tumour shrinkage in response to cabergoline; therefore, transsphenoidal surgery was performed. Following initial clinical improvement, tumour recurrence was identified 15 months later. Interestingly, re-initiation of cabergoline proved successful and the lesion demonstrated both biochemical response and tumour shrinkage. Our patient's SDHB mutation was identified when we realised that her father had a metastatic paraganglioma, prompting genetic testing. Re-inspection of the histopathological report of the prolactinoma confirmed cells with vacuolated cytoplasm. This histological feature is suggestive of an SDHx mutation and should prompt further screening for mutations by immunohistochemistry and/or genetic testing. Surprisingly, immunohistochemistry of this pituitary adenoma demonstrated normal SDHB expression, despite loss of SDHB expression in the patient's father's paraganglioma. Learning points: Pituitary adenomas may be the presenting and/or sole feature of SDHB mutation-related disease. SDHx mutated pituitary adenomas may display clinically aggressive behaviour and demonstrate variable response to medical treatment.Histological evidence of intracytoplasmic vacuoles in a pituitary adenoma might suggest an SDH-deficient tumour and should prompt further screening for SDHx mutations.Immunohistochemistry may not always predict the presence of SDHx mutations

SDHA mutated paragangliomas may be at high risk of metastasis

NT is funded by The Medical College of Saint Bartholomew’s Hospital Trust (1115519)