Diagnostic challenges in patients with reninomas and extrarenal renin-producing tumours.

Renin-secreting tumours are rare causes of secondary hypertension and hypokalaemia. They are usually surgically curable, hence proper diagnostic work-up and tumour localisation is essential. In this paper, we present three Swedish patients recently diagnosed with renin secreting tumours, two with reninomas and one with an extrarenal renin-producing tumour, to illustrate diagnostic challenges. We also discuss the biochemical work-up, the pros and cons of different imaging techniques (computer tomography [CT], magnetic resonance imaging and [18F]fluorodeoxyglucose-positron emission tomography-CT), as well as how renal vein sampling (RVC) may contribute to localisation of the tumour.

Ambulatory fludrocortisone suppression test in the diagnosis of primary aldosteronism: Safety, accuracy and cost-effectiveness.

OBJECTIVE: The aims of this study were to explore if the ambulatory fludrocortisone suppression test (FST) was safe, accurate and cost-effective. CONTEXT: The diagnosis of primary aldosteronism (PA) remains time-consuming and complex. The FST is used to confirm PA, but it is an in-patient test due to potentially serious complications such as hypokalemia. In Stockholm, FST has been performed since 2005 as an ambulatory procedure. DESIGN: This is a retrospective study including all patients investigated with FST in four hospitals in Stockholm, Sweden, during 2005-2019. PATIENTS/MEASUREMENTS: In total, 156 cases of ambulatory FST (FSTamb) and 15 cases of in-patient FST (FSTin) were included. FSTamb and FSTin were compared regarding health costs, clinical characteristics and laboratory results. RESULTS: No difference was found in the outcomes of FSTamb and FSTin. No severe complications were reported in FSTamb patients. No difference was found in the median value for plasma potassium on Day 5 between the two groups. Only three patients (1.9%) in the FSTamb had to repeat the test due to incomplete intake of medications. FSTamb and FSTin were equally accurate. The cost of performing FSTamb was at least 50% lower compared with FSTin ($2400 vs. $5200 per patient). The time needed for FSTamb was 60 min of physician's time and 150 min of nurse's time which were lower than the 5 days in FSTin. CONCLUSIONS: Ambulatory FST is safe and accurate and can be performed with significantly less healthcare costs compared to FSTin.

Novel somatic mutations and distinct molecular signature in aldosterone-producing adenomas.

Aldosterone-producing adenomas (APAs) are found in 1.5-3.0% of hypertensive patients in primary care and can be cured by surgery. Elucidation of genetic events may improve our understanding of these tumors and ultimately improve patient care. Approximately 40% of APAs harbor a missense mutation in the KCNJ5 gene. More recently, somatic mutations in CACNA1D, ATP1A1 and ATP2B3, also important for membrane potential/intracellular Ca(2) (+) regulation, were observed in APAs. In this study, we analyzed 165 APAs for mutations in selected regions of these genes. We then correlated mutational findings with clinical and molecular phenotype using transcriptome analysis, immunohistochemistry and semiquantitative PCR. Somatic mutations in CACNA1D in 3.0% (one novel mutation), ATP1A1 in 6.1% (six novel mutations) and ATP2B3 in 3.0% (two novel mutations) were detected. All observed mutations were located in previously described hotspot regions. Patients with tumors harboring mutations in CACNA1D, ATP1A1 and ATP2B3 were operated at an older age, were more often male and had tumors that were smaller than those in patients with KCNJ5 mutated tumors. Microarray transcriptome analysis segregated KCNJ5 mutated tumors from ATP1A1/ATP2B3 mutated tumors and those without mutation. We observed significant transcription upregulation of CYP11B2, as well as the previously described glomerulosa-specific gene NPNT, in ATP1A1/ATP2B3 mutated tumors compared to KCNJ5 mutated tumors. In summary, we describe novel somatic mutations in proteins regulating the membrane potential/intracellular Ca(2) (+) levels, and also a distinct mRNA and clinical signature, dependent on genetic alteration.

Limited value of long-term biochemical follow-up in patients with adrenal incidentalomas-a retrospective cohort study.

BACKGROUND: The prevailing view that advocates long-term hormonal follow-up of adrenal incidentalomas is currently under debate. The purpose of the present study was to examine all adrenal incidentalomas presented during five years to a single centre. We hypothesized that 24-month biochemical follow-up in patients with an initial normal screening would fail to increase the sensitivity in finding hormone producing tumours. METHODS: The present study is a retrospective register based cohort study of 194 patients referred to the Department of Endocrinology at Södersjukhuset between the years 2006-2010. Computerized medical records were used to find and extract information on patients with newly discovered adrenal incidentalomas. The sensitivity, specificity, positive predictive value and negative predictive value were calculated to evaluate the validity of an initial normal screening when used to identify individuals with hormone producing tumours. RESULTS: Of the incidentalomas 94% consisted of benign, non-functioning tumours. Three patients were diagnosed with cortisol hypersecretion and one with pheochromocytoma. The sensitivity, specificity, positive predictive value and negative predictive value of an initial complete negative screening to predict a hormone producing tumour were 100%, 63%, 12% and 100%, respectively. CONCLUSION: Patients with an initially normal hormonal screening may not need further biochemical follow-up.

Primary aldosteronism: functional histopathology and long-term follow-up after unilateral adrenalectomy.

OBJECTIVES: To investigate the long-term outcome after unilateral adrenalectomy in patients with primary aldosteronism (PA) and to establish the role of functional pathology for the final diagnosis of aldosterone-producing adenoma (APA) or hyperplasia. DESIGN: A single-centre, retrospective cohort study in a hospital setting. PATIENTS: Consecutive patients with PA, n = 120, who underwent unilateral adrenalectomy between 1985 and 2010. Preoperative and postoperative data were analysed. To indicate the site of aldosterone secretion in the resected adrenal, we added functional methods to routine histopathology, using in situ hybridization and immunohistochemistry to detect the presence of enzymes needed for aldosterone (CYP11B2) and cortisol (CYP11B1, CYP17A1) synthesis. RESULTS: The median follow-up was 5 years and the cure rate of PA 91%. Hypertension was improved in 97% and normalized in 38%. Functional histopathology changed the final diagnosis from APA to hyperplasia in 6 cases (7%). Five of these had no expression of or staining for aldosterone synthase in the adenoma, but only in nodules in the adjacent cortex. All except one APA patient were cured of PA. They had lower preoperative serum potassium and higher 24-h urinary aldosterone than patients with hyperplasia. Among patients with hyperplasia 16 of 26 were cured. CONCLUSIONS: Most patients were cured of PA by unilateral adrenalectomy. Almost all noncured benefitted from the operation as the blood pressure improved. Functional histopathology proved helpful in the distinction between APA and hyperplasia, and we recommend that functional histopathology should be added to routine histopathology to improve the diagnostic evaluation and aid in tailoring the follow-up.

Immunohistochemistry improves histopathologic diagnosis in primary aldosteronism.

BACKGROUND: In primary aldosteronism (PA) the main source of aldosterone hypersecretion is an aldosterone-producing adenoma (APA) or a bilateral hyperplasia. Histopathology of the adrenal gland from patients with PA has been difficult, as there are no morphological criteria to ascertain which are the cells that produce aldosterone. We therefore applied new specific antibodies to explore which cells in the adrenal contain the enzymes for aldosterone and cortisol production, respectively. METHODS: Adrenals from 24 patients with PA were studied. After routine preparation, consecutive sections were stained with antibodies for CYP11B1 (cortisol) and CYP11B2 (aldosterone) enzymes. RESULTS: APA had a strong immunoreactivity for CYB11B2. In adrenals from seven patients, we found no APA, but several nodules with strong CYB11B2 immunoreactivity, indicating aldosterone-producing nodular hyperplasia. CONCLUSIONS: Immunohistochemistry of adrenal steroidogenic enzymes provides novel diagnostic information. This may become an important part of routine histopathology, and contribute to improved clinical management in PA.

Screening for primary aldosteronism in a primary care unit.

OBJECTIVE: Primary aldosteronism (PA) is a common cause of secondary hypertension but the reported prevalence varies. Few studies have been carried out in primary care. We investigated the prevalence of PA by screening with the aldosterone to renin ratio (ARR). DESIGN AND METHODS: Patients with hypertension were recruited from a primary care unit and investigated in a university hospital setting. Of 235 patients asked to participate 77% accepted. Antihypertensive medication apart from amiloride and spironolactone was maintained. The cut-off level for a positive ARR was lower than in clinical practice (> 50 pmol/ng with aldosterone > 350 pmol/l) to adjust for any suppressive effects of medication. A positive ARR was followed by a confirmatory evaluation. RESULTS: The frequency of confirmed PA was 1.6% and including cases with a positive ARR who refused further investigation it would be 3.3% at most. In primary hypertension angiotensin receptor blockers, angiotensin-converting enzyme inhibitors and thiazide diuretics markedly suppressed the ARR by increasing renin levels. CONCLUSION: The detection rate of PA in our study is in the lower part of the wide range shown in previous studies. Larger population studies are needed to establish the true prevalence in primary care. Future studies may clarify if the present cut-off levels allow detection of very mild PA.

Dynamical collective calculation of supernova neutrino signals.

We present the first calculations with three flavors of collective and shock wave effects for neutrino propagation in core-collapse supernovae using hydrodynamical density profiles and the S matrix formalism. We explore the interplay between the neutrino-neutrino interaction and the effects of multiple resonances upon the time signal of positrons in supernova observatories. A specific signature is found for the inverted hierarchy and a large third neutrino mixing angle and we predict, in this case, a dearth of lower energy positrons in Cherenkov detectors midway through the neutrino signal and the simultaneous revelation of valuable information about the original fluxes. We show that this feature is also observable with current generation neutrino detectors at the level of several sigmas.

Postoperative differentiation between unilateral adrenal adenoma and bilateral adrenal hyperplasia in primary aldosteronism by mRNA expression of the gene CYP11B2.

OBJECTIVE: Primary aldosteronism (PA) is characterized by hypertension, hypokalemia and suppressed renin-angiotensin system caused by autonomous aldosterone production. The aim of this study was to localize mRNA expression of the genes coding for steroidogenic enzymes in adrenals from a group of patients with PA and relate this to clinical work-up, histopathology and outcome of adrenalectomy. DESIGN: This was a retrospective study of 27 patients subjected to adrenalectomy for PA. METHODS: Clinical data were collected and follow-up of all patients was performed. Paraffin-embedded specimens were analyzed by the in situ hybridization technique, with oligonucleotide probes coding for the steroidogenic enzyme genes. RESULTS: The resected adrenals had the histopathologic diagnosis of adenoma (11), adenoma and/or hyperplasia (15) or hyperplasia (1). CYP11B2 expression (indicating aldosterone production) was found in a dominant adrenal nodule from 22 patients. Fourteen of these had additional CYP11B2 expression in the zona glomerulosa. All 22 patients were cured of PA by adrenalectomy. One of these patients, who had additional high expression of CYP11B2 in the zona glomerulosa, was initially cured, but the condition had recurred at follow-up. Two patients had a mass shown on computed tomography without CYP11B2 but with CYP11B1 and CYP17 expression (indicating cortisol production). Instead their adrenals contained small nodules with CYP11B2 expression. These patients were not cured. CONCLUSIONS: Clinical data, endocrinologic evaluation and histopathology in combination with mRNA in situ hybridization of steroidogenic enzyme genes provide improved opportunities for correct subclassification postoperatively of patients with primary aldosteronism. At present, the in situ hybridization method is of special value for analysis of cases not cured by adrenalectomy.

New aspects on primary aldosteronism.

The adrenal cortex synthesizes and releases steroid hormones, mainly mineralocorticoids and glucocorticoids. There is a functional zonation of the adrenal cortex and steroid synthesis is thoroughly regulated. Overproduction of aldosterone, primary aldosteronism, may be much more common than previously known and may be responsible for 10% of essential hypertension. Primary aldosteronism is characterized by autonomous production of aldosterone, suppressed renin activity, hypokalemia, and hypertension. The two most common forms are unilateral adenoma and bilateral hyperplasia. In spite of thorough clinical workup and careful histopathology it is often difficult to differentiate between adenoma and hyperplasia. The gene CYP11B2 encodes the steroid synthesizing enzymes for aldosterone production, while the genes CYP17 and CYP11B1 are needed for cortisol production. Most normal controls show expression of CYP11B2 in zona glomerulosa. Expression of CYP11B1 and CYP17 is seen in zona fasciculata and reticularis, whereas the expression of CYP21 is present in all three cortical layers. Adenomas from patients with primary aldosteronism show considerable variation in the expression of CYP11B2. Adenomas from patients with Cushing's syndrome have a strong expression of CYP11B1 and CYP17. In a patient material of 29 cases of primary aldosteronism, 4 patients had small nodules detected with expression of CYP11B2 gene. These nodules were not visualized on CT, whereas adrenal masses seen on CT in these patients showed CYP11B1 and CYP17 gene expression. This suggests that these small nodules are responsible for the aldosterone production and this is characteristic of nodular hyperplasia in patients with primary aldosteronism. In conclusion, this method to visualize mRNA gene expression of steroidogenic enzymes, and especially expression of CYP11B2, has increased the knowledge of adrenal pathophysiology. The results emphasize the value to include functional studies (venous sampling and/or scintigraphy) in the preoperative work up of patients with primary aldosteronism.