Diagnosis and management of urinary bladder paragangliomas: A Sino-American-European retrospective observational study.

OBJECTIVE: Paragangliomas of the urinary bladder (UBPGLs) are rare neuroendocrine tumours and pose a diagnostic and surgical challenge. It remains unclear what factors contribute to a timely presurgical diagnosis. The purpose of this study is to identify factors contributing to missing the diagnosis of UBPGLs before surgery. DESIGN, PATIENTS AND MEASUREMENTS: A total of 73 patients from 11 centres in China, and 51 patients from 6 centres in Europe and 1 center in the United States were included. Clinical, surgical and genetic data were collected and compared in patients diagnosed before versus after surgery. Logistic regression analysis was used to identify clinical factors associated with initiation of presurgical biochemical testing. RESULTS: Among all patients, only 47.6% were diagnosed before surgery. These patients were younger (34.0 vs. 54.0 years, p < .001), had larger tumours (2.9 vs. 1.8 cm, p < .001), and more had a SDHB pathogenic variant (54.7% vs. 11.9%, p < .001) than those diagnosed after surgery. Patients with presurgical diagnosis presented with more micturition spells (39.7% vs. 15.9%, p = .003), hypertension (50.0% vs. 31.7%, p = .041) and catecholamine-related symptoms (37.9% vs. 17.5%, p = .012). Multivariable logistic analysis revealed that presence of younger age (<35 years, odds ratio [OR] = 6.47, p = .013), micturition spells (OR = 6.79, p = .007), hypertension (OR = 3.98, p = .011), and sweating (OR = 41.72, p = .013) increased the probability of initiating presurgical biochemical testing. CONCLUSIONS: Most patients with UBPGL are diagnosed after surgery. Young age, hypertension, micturition spells and sweating are clues in assisting to initiate early biochemical testing and thus may establish a timely presurgical diagnosis.

Morbidity in Patients with Chronic Adrenal Insufficiency - Cardiovascular Risk Factors and Hospitalization Rate Compared to Population Based Controls.

Patients with adrenal insufficiency (AI) have been found to have increased cardiovascular morbidity, partly associated with nonphysiologic glucocorticoid replacement. We included two separate cohorts (cohort 1 n=384 patients, cohort 2 n=180 patients) of patients with chronic primary and secondary AI under standard replacement therapy and compared them to two age- and sex-matched population-based studies (SHIP-TREND/DEGS). Odds ratios with 95% CI for hypertension, hyperlipidemia/HLP, type 2 diabetes/T2DM, obesity, and hospitalization with adjustment for confounders were evaluated by logistic regression. Patient cohort 1 had significantly lower ORs for obesity [0.4 (0.3-0.6), p<0.001] and hypertension [0.5 (0.3-0.6), p<0.001] compared to SHIP-TREND and for obesity [0.7 (0.5-0.9), p=0.01], hypertension [0.4 (0.3-0.5), p<0.001] and HLP [0.4 (0.3-0.6), p<0.001] compared to DEGS. In cohort 2, ORs were significantly lower for HLP compared to both SHIP-TREND [0.4 (0.2-0.7), p=0.001] and DEGS [0.3 (0.2-0.5), p<0.001] and for hypertension [0.7 (0.4-0.9), p=0.04] compared to SHIP-TREND. In patients with SAI from cohort 2, ORs for DM2 [2.5 (1.3-4.9) p=0.009], hypertension [2.5 (1.4-4.5), p=0.002] and obesity [1.9 (1.1-3.1), p=0.02] were significantly higher compared to DEGS, whereas ORs for HLP were significantly lower compared to both SHIP [0.3 (0.1-0.6), p=0.002] and DEGS [0.3 (0.1-0.6), p<0.001]. In most of our AI patients treated with conventional glucocorticoid doses, the risk for T2DM, obesity, hypertension, and HLP was not increased. The number of hospitalizations was significantly higher in AI patients compared to controls, which might reflect increased susceptibility but also a more proactive management of concomitant diseases by physicians and patients.

A novel LC-MS/MS-based assay for the simultaneous quantification of aldosterone-related steroids in human urine.

OBJECTIVES: Primary aldosteronism is the most common cause of endocrine hypertension and is associated with significant cardiovascular morbidities. The diagnostic workup depends on determinations of plasma aldosterone and renin which are highly variable and associated with false-positive and false-negative results. Quantification of aldosterone in 24 h urine may provide more reliable results, but the methodology is not well established. We aimed to establish an assay for urinary aldosterone and related steroids with suitability for clinical routine implementation. METHODS: Here, we report on the development and validation of a quantitative LC-MS/MS method for six urinary steroids: aldosterone, cortisol, 18-hydroxycorticosterone, 18-hydroxycortisol, 18-oxocortisol, tetrahydroaldosterone. After enzymatic deconjugation, total steroids were extracted using SepPak tC18 plates and quantified in positive electrospray ionization mode on a QTRAP 6500+ mass spectrometer. RESULTS: Excellent linearity was demonstrated with R2>0.998 for all analytes. Extraction recoveries were 89.8-98.4 % and intra- and inter-day coefficients of variations were <6.4 and <9.0 %, establishing superb precision. Patients with primary aldosteronism (n=10) had higher mean 24 h excretions of aldosterone-related metabolites than normotensive volunteers (n=20): 3.91 (95 % CI 2.27-5.55) vs. 1.92 (1.16-2.68) µmol/mol for aldosterone/creatinine, 2.57 (1.49-3.66) vs. 0.79 (0.48-1.10) µmol/mol for 18-hydroxycorticosterone/creatinine, 37.4 (13.59-61.2) vs. 11.61 (10.24-12.98) µmol/mol for 18-hydroxycortisol/creatinine, 1.56 (0.34-2.78) vs. 0.13 (0.09-0.17) µmol/mol for 18-oxocortisol/creatinine, and 21.5 (13.4-29.6) vs. 7.21 (4.88-9.54) µmol/mol for tetrahydroaldosterone/creatinine. CONCLUSIONS: The reported assay is robust and suitable for routine clinical use. First results in patient samples, though promising, require clinical validation in a larger sample set.

Clonidine suppression test for a reliable diagnosis of pheochromocytoma: When to use.

OBJECTIVE: In clinical practice, false-positive results in biochemical testing for suspected pheochromocytoma/paraganglioma (PPGL) are not infrequent and may lead to unnecessary examinations. We aimed to evaluate the role of the clonidine suppression test (CST) in the era of analyses of plasma-free metanephrines for the diagnosis or exclusion of PPGL in patients with adrenal tumours and/or arterial hypertension. DESIGN AND METHODS: This single-centre, prospective trial investigated the use of CST in 60 patients with suspected PPGL associated with out-patient elevations of plasma normetanephrine (NMN) and/or metanephrine (MN), in most cases accompanied with hypertension or an adrenal mass. Measurements of plasma catecholamines and free metanephrines were performed by liquid chromatography with electrochemical detection and tandem mass spectrometry, respectively. RESULTS: Forty-six patients entered final analysis (n = 20 with PPGL and n = 26 with a nonfunctional adrenal mass and/or hypertension). CST reliably excluded false-positive baseline NMN results with a specificity of 100%. The sensitivity of CST improved from 85% to 94% when tumours with isolated MN increase (n = 3) were not considered. In patients with elevated baseline NMN (n = 24), CST correctly identified all patients without PPGL. Patients with falsely elevated baseline NMN results (n = 7, 26.9%) exhibited increases of baseline NMN up to 1.7-fold above the upper reference limit. CONCLUSION: CST qualifies as a useful diagnostic tool for differential diagnosis of borderline elevated plasma-free NMN in patients with suspected PPGL. In this context, CST helps to correctly identify all false-positive NMN screening results.

Differences in clinical presentation and management between pre- and postsurgical diagnoses of urinary bladder paraganglioma: is there clinical relevance? A systematic review.

PURPOSE: Paraganglioma of the urinary bladder (UBPGL) is a rare neuroendocrine tumor diagnosed in many patients only after surgery. We, therefore, assessed clinical clues relevant to presurgical diagnosis and clinical consequences in patients with a missed presurgical diagnosis of UBPGL. MATERIALS AND METHODS: Case reports describing a UBPGL (published from 1-1-2001 and 31-12-2020) were identified in Pubmed. Two authors independently performed data extraction and assessed data quality according to the PRISMA guideline. Patients were divided into two groups: UBPGL diagnosis before and after surgery. RESULTS: We included 177 articles reporting 194 cases. In 90 (46.4%) patients, the UBPGL was diagnosed before and in 104 (53.6%) after surgery. In presurgically diagnosed UBPGL, hypertension and catecholamine-associated symptoms were 2- to 3-fold (p < 0.001) more frequent than in postsurgically diagnosed patients whereas hematuria was twofold (p = 0.003) more prevalent in those with postsurgical diagnosis. Hypertension was an independent factor for presurgical biochemical testing (OR 4.45, 95% CI 1.66-11.94) while hematuria (OR 0.23, 95% CI 0.09-0.60) was an independent factor for not performing presurgical biochemical testing. Most patients diagnosed after surgery were not pretreated with alpha-adrenoceptor blockade (95.2%), underwent more frequently transurethral resection instead of cystectomy (70.2% vs. 23.1%) and had more frequent peroperative complications and residual tumor mass. CONCLUSIONS: In nearly half of all patients with a UBPGL, the diagnosis was not established before surgery. Hypertension and hematuria contributed independently to a presurgical diagnosis. Postsurgical diagnosis, which was associated with suboptimal presurgical and surgical management, resulted in more peroperative complications and incomplete tumor resections.

Pseudohypoxic pheochromocytomas and paragangliomas dominate in children.

OBJECTIVE: Pheochromocytomas and paragangliomas (PPGLs) are rare neuroendocrine tumors that are associated with cancer predisposition syndromes in up to 80% of affected children. PPGLs can be divided into molecularly defined groups with comparable pathogenesis and biology: (1) pseudohypoxic, (2) kinase signaling, and (3) Wnt-altered. METHODS: We report the data of children and adolescents diagnosed with PPGL who have been registered with the German GPOH-MET registry since 1997. RESULTS: By December 2019, a total of 88 patients with PPGL were reported. Pheochromocytoma occurred in 56%, paraganglioma in 35%, and synchronous PPGLs in 9.1%. A total of 16% of patients presented with lymph node (5.7%) and distant metastases (10%). Median follow-up was 4.2 years (range 0-17.1). Overall and disease-free survival (DFS) were 98.6% and 54.0%, respectively. Local relapses, metastases, and subsequent PPGLs occurred in 11%, 4.5%, and 15% of patients. Germline mutations were detected in 83% of patients (51% in VHL, 21% in SDHB, 7.8% in SDHD, and one patient each in RET and NF1). One patient was diagnosed with Pacak-Zhuang syndrome. A total of 96% of patients presented with PPGL of the pseudohypoxic subgroup (34% TCA cycle-related, 66% VHL/EPAS1-related). In multivariate analyses, extent of tumor resection was a significant prognostic factor for DFS. CONCLUSIONS: Most pediatric PPGLs belong to the pseudohypoxia subgroup, which is associated with a high risk of subsequent PPGL events and metastatic disease. Comprehensive molecular profiling of children and adolescents with newly diagnosed PPGLs will open new avenues for personalized diagnosis, treatment, and surveillance.

Plasma metanephrines and prospective prediction of tumor location, size and mutation type in patients with pheochromocytoma and paraganglioma.

Objectives: Plasma free metanephrines are commonly used for diagnosis of pheochromocytoma and paraganglioma (PPGLs), but can also provide other information. This multicenter study prospectively examined whether tumor size, location, and mutations could be predicted by these metabolites. Methods: Predictions of tumor location, size, and mutation type, based on measurements of plasma normetanephrine, metanephrine, and methoxytyramine were made without knowledge of disease in 267 patients subsequently determined to have PPGLs. Results: Predictions of adrenal vs. extra-adrenal locations according to increased plasma concentrations of metanephrine and methoxytyramine were correct in 93 and 97% of the respective 136 and 33 patients in who these predictions were possible. Predicted mean tumor diameters correlated positively (p<0.0001) with measured diameters; predictions agreed well for pheochromocytomas but were overestimated for paragangliomas. Considering only patients with mutations, 51 of the 54 (94%) patients with NF1 or RET mutations were correctly predicted with those mutations according to increased plasma metanephrine, whereas no or minimal increase in metanephrine correctly predicted all 71 patients with either VHL or SDHx mutations; furthermore, among the latter group increases in methoxytyramine correctly predicted SDHx mutations in 93% of the 29 cases for this specific prediction. Conclusions: Extents and patterns of increased plasma O-methylated catecholamine metabolites among patients with PPGLs allow predictions of tumor size, adrenal vs. extra-adrenal locations and general types of mutations. Predictions of tumor location are, however, only possible for patients with clearly increased plasma methoxytyramine or metanephrine. Where possible or clinically relevant the predictions are potentially useful for subsequent clinical decision-making.

Intrathyroidal parathyroid adenoma mimicking thyroid cancer.

Primary hyperparathyroidism (PHPT) is the most common cause of hypercalcemia; patients are usually asymptomatic and the cause in 80-85% of cases is a single parathyroid adenoma (PA). Parathyroid adenomas arise from clonal expansion of tumor cells and may be located either posteriorly to the thyroid lobes or in ectopic sites. The incidence of intrathyroidal PAs varies from 1% to 6% and although uncommon, they pose certain diagnostic difficulties which may complicate treatment. The identification of the adenoma requires a combination of clinical evidence, imaging information and cytological findings due to the challenging distinction between thyroid and parathyroid lesions. We present the case of a patient with a large, partially cystic intrathyroidal parathyroid adenoma which was initially identified as a malignant thyroid nodule. We discuss the caveats that present in these rare cases and the important clinical and histological features that aid in the final diagnosis. In the case of our patient the cytological similarities between thyroid malignant cells and parathyroid cells, in combination with the negative sestamibi scan, resulted in a more invasive surgery than that a single parathyroid adenoma would require. Clinicians need to be vigilant in terms of the similarities between parathyroid and thyroid cytology in order to provide optimal patient care in these rare cases.

Development of a Function-Integrative Sleeve for Medical Applications.

Function-integrative textiles bear the potential for a variety of applications in the medical field. Recent clinical investigations suggest that the application of a function-integrative fabric could have a positive impact on currently applied diagnostic procedures of a specific type of tumour. In this context, the fabric should enable local warming of a patient's upper extremity as well as blood flow measurement. Existing solutions comprise a warming a warming system but lack a measuring apparatus for blood flow determination. With regard to the quality of results of current diagnostic procedures, the local warming of the patients' upper extremity and the simultaneous determination of the blood flow plateau are crucial. In the present paper, the development process of a function-integrative sleeve is introduced. Besides the development of an adaptable sleeve-design, the manufacturing process of an integrated warming system was also addressed. Furthermore, the identification of crucial physiological effects, using a Laser Doppler Perfusion Monitor, is introduced. During testing of the function-integrative sleeve, modulation of the desired physiological effects was observed. The results support the initial assumptions and dictate further investigations on increasing user-friendliness and cost-efficiency during adjusting and determining the physiological effects in the course of tumour diagnosis.

Biochemical Diagnosis of Chromaffin Cell Tumors in Patients at High and Low Risk of Disease: Plasma versus Urinary Free or Deconjugated O-Methylated Catecholamine Metabolites.

BACKGROUND: Measurements of plasma or urinary metanephrines are recommended for diagnosis of pheochromocytoma and paraganglioma (PPGL). What test offers optimal diagnostic accuracy for patients at high and low risk of disease, whether urinary free metanephrines offer advantages over deconjugated metanephrines, and what advantages are offered by including methoxytyramine in panels all remain unclear. METHODS: A population of 2056 patients with suspected PPGLs underwent prospective screening for disease using mass spectrometric-based measurements of plasma free, urinary deconjugated, and urinary free metanephrines and methoxytyramine. PPGLs were confirmed in 236 patients and were excluded in others on follow-up evaluation. RESULTS: Measurements of plasma free metabolites offered higher (P < 0.01) diagnostic sensitivity (97.9%) than urinary free (93.4%) and deconjugated (92.9%) metabolites at identical specificities for plasma and urinary free metabolites (94.2%) but at a lower (P < 0.005) specificity for deconjugated metabolites (92.1%). The addition of methoxytyramine offered little value for urinary panels but provided higher (P < 0.005) diagnostic performance for plasma measurements than either urinary panel according to areas under ROC curves (0.991 vs 0.972 and 0.964). Diagnostic performance of urinary and plasma tests was similar for patients at low risk of disease, whereas plasma measurements were superior to both urinary panels for high-risk patients. CONCLUSIONS: Diagnosis of PPGLs using plasma or urinary free metabolites provides advantages of fewer false-positive results compared with commonly measured deconjugated metabolites. The plasma panel offers better diagnostic performance than either urinary panel for patients at high risk of disease and, with appropriate preanalytics, provides the test of choice. Measurements of methoxytyramine in urine show limited diagnostic utility compared with plasma.

The ovarian response to standard gonadotropin stimulation is influenced by AMHRII genotypes.

The aim of the current study was to explore whether anti-Müllerian hormone receptor II (AMHRII) genetic variants influence the hormonal profile and the ovarian response to standard gonadotropin stimulation of women undergoing medically assisted reproduction. Three hundred in vitro fertilization or intracytoplasmic sperm injection patients constituted the study population, while 300 women with at least one spontaneous pregnancy participated as controls. The follicle-stimulating hormone (FSH), luteinizing hormone (LH), estradiol (E2) and AMH levels were determined at the third day of the menstrual cycle. AMHRII 10A > G (rs11170555), 1749C > T (rs2071558) and -482A > G (rs2002555) polymorphisms were genotyped. The follicle and oocyte numbers, the follicle size and the clinical pregnancies were recorded. Regarding the AMHRII 1749C > T polymorphism, 1749CT women presented with higher total follicle and small follicle numbers compared to 1749CC women (p = 0.04 and p = 0.01, respectively). Whereas, as concerns the -482A > G polymorphism, -482AG women were characterized by higher total follicle and small follicle numbers comparing with -482AA women (p = 0.07 and p = 0.004, respectively). Finally, -482AG women presented with increased FSH levels compared to -482AA women (p < 0.05). However, no associations of AMHRII gene polymorphisms with serum AMH levels or clinical pregnancy rates were observed. AMHRII 1749C > T and -482A > G genetic variants were associated with the ovarian response to standard gonadotropin stimulation, affecting mainly the follicular growth.

Biochemical diagnosis of phaeochromocytoma using plasma-free normetanephrine, metanephrine and methoxytyramine: importance of supine sampling under fasting conditions.

OBJECTIVE: To document the influences of blood sampling under supine fasting versus seated nonfasting conditions on diagnosis of phaeochromocytomas and paragangliomas (PPGL) using plasma concentrations of normetanephrine, metanephrine and methoxytyramine. DESIGN AND METHODS: Biochemical testing for PPGL was performed on 762 patients at six centres, two of which complied with requirements for supine sampling after an overnight fast and four of which did not. Phaeochromocytomas and paragangliomas were found in 129 patients (67 noncompliant, 62 compliant) and not in 633 patients (195 noncompliant, 438 compliant). RESULTS: Plasma concentrations of normetanephrine and methoxytyramine did not differ between compliant and noncompliant sampling conditions in patients with PPGL but were 49-51% higher in patients without PPGL sampled under noncompliant compared with compliant conditions. The 97·5 percentiles of distributions were also higher under noncompliant compared with compliant conditions for normetanephrine (1·29 vs 0·79 nmol/l), metanephrine (0·49 vs 0·41 nmol/l) and methoxytyramine (0·42 vs 0·18 nmol/l). Use of upper cut-offs established from seated nonfasting sampling conditions resulted in substantially decreased diagnostic sensitivity (98% vs 85%). In contrast, use of upper cut-offs established from supine fasting conditions resulted in decreased diagnostic specificity for testing under noncompliant compared with compliant conditions (71% vs 95%). CONCLUSIONS: High diagnostic sensitivity of plasma normetanephrine, metanephrine and methoxytyramine for the detection of PPGL can only be guaranteed using upper cut-offs of reference intervals established with blood sampling under supine fasting conditions. With such cut-offs, sampling under seated nonfasting conditions can lead to a 5·7-fold increase in false-positive results necessitating repeat sampling under supine fasting conditions.

Management and follow-up strategies for patients with head and neck paraganglioma.

OBJECTIVE: Head-neck paragangliomas (HNPGLs) are rare tumors with approximately half arising due to germline pathogenic variants (PVs) in succinate dehydrogenase genes (SDHx). Patients with HNPGL have heterogeneous propensity to recur and metastasize. Thus, we aim to assess prevalence and predictors of recurrent (RD) and/or metastatic disease in patients with and without SDHx-related HNPGLs. DESIGN AND METHODS: This cross-sectional study used retrospective data of 214 patients enrolled in six referral centers. Data included sex, age, primary tumor treatment, location, and size, biochemical phenotype, germline PVs, presence of RD (locoregional or new tumor), and/or metastasis. RESULTS: Patients with and without SDHx-related HNPGLs showed 74% and 40% prevalence of RD, respectively. Patients without SDHx-related HNPGLs presented with recurrent tumors only in head-neck regions. The only independent predictor for RD in the entire cohort was presence of SDHx PVs. Metastatic prevalence reached 9%-13%. For patients with SDHx-related HNPGLs, large tumor size (>2.3 cm, OR:50.0, CI:2.6-977.6), young age at initial diagnosis (<42years, OR:27.3, CI:1.8-407.2), and presence of SDHB PV (OR:15.6; CI:1.5-164.8) were independent predictors of metastasis. For patients without SDHx-related HNPGLs, only carotid-body location was an independent predictor of metastasis (OR:18.9, CI:2.0-182.5). CONCLUSIONS: Patients without SDHx-related HNPGLs require long-term follow-up due to high prevalence of RD with imaging largely restricted to head-neck regions. As carotid-body HNPGLs have the highest metastatic risk among sporadic tumors, radical treatment with frequent follow-up is suggested until population-based data are available. Importantly, patients with SDHx-related HNPGLs might benefit from early radical treatment when tumors are still small to reduce metastatic risk.

Approach to the paediatric patient with suspected pheochromocytoma or paraganglioma versus neuroblastoma.

Catecholamine producing tumours of childhood include neuroblastic tumours, phaeochromocytoma and paraganglioma (PPGL). PPGL and neuroblastic tumours can arise in similar anatomical locations and clinical presentations can overlap resulting in diagnostic challenges. Distinguishing between these tumour types is critical as management and long-term surveillance strategies differ depending on the diagnosis. Herein we describe two clinical cases and illustrate key considerations in the diagnostic work up of a neuroblastoma versus PPGL for patients presenting with adrenal, pelvic, and retroperitoneal masses in childhood.

False-positive results for pheochromocytoma associated with norepinephrine reuptake blockade.

Measurements of plasma metanephrines and methoxytyramine provide a sensitive test for diagnosis of pheochromocytoma/paraganglioma. False-positive results remain a problem, particularly in patients taking norepinephrine reuptake-blocking drugs. Therefore, in this retrospective observational study, we measured plasma metanephrines and methoxytyramine in 61 patients taking norepinephrine reuptake blockers (tricyclic antidepressants or serotonin-norepinephrine reuptake inhibitors) and 17 others taking selective serotonin reuptake inhibitors, all without pheochromocytoma/paraganglioma. We highlight a singular case with strongly elevated plasma normetanephrine and methoxytyramine concentrations associated with norepinephrine reuptake blockade. Data were compared to results from 252 and 1804 respective patients with and without tumors. Plasma normetanephrine was 40% higher (P < 0.0001) in patients on norepinephrine reuptake blockers and methoxytyramine was 127% higher (P = 0.0062) in patients taking tricyclic antidepressants compared to patients not taking uptake blockers and without tumors. The corresponding false-positive rates rose (P < 0.0001) from 4.8% to 23.0% for normetanephrine and from 0.9% to 28.6% for methoxytyramine. Selective serotonin reuptake inhibitors did not increase plasma concentrations of metabolites. In the highlighted case, plasma normetanephrine and methoxytyramine were elevated more than six times above upper reference limits. A pheochromocytoma/paraganglioma, however, was excluded by functional imaging. All biochemical test results normalized after discontinuation of norepinephrine reuptake blockers. These findings clarify that norepinephrine reuptake blockers usually result in mild elevations of normetanephrine and methoxytyramine that, nevertheless, significantly increase the number of false-positive results. There can, however, be exceptions where increases in normetanephrine and methoxytyramine reach pathological levels. Such exceptions may reflect failure of centrally mediated sympathoinhibition that normally occurs with the norepinephrine reuptake blockade.

Screening for Primary Aldosteronism by Mass Spectrometry Versus Immunoassay Measurements of Aldosterone: A Prospective Within-Patient Study.

BACKGROUND: Measurements of aldosterone by mass spectrometry are more accurate and less prone to interferences than immunoassay measurements, and may produce a more accurate aldosterone:renin ratio (ARR) when screening for primary aldosteronism (PA). METHODS: Differences in diagnostic performance of the ARR using mass spectrometry vs immunoassay measurements of aldosterone were examined in 710 patients screened for PA. PA was confirmed in 153 patients and excluded in 451 others. Disease classifications were not achieved in 106 patients. Areas under receiver-operating characteristic curves (AUROC) and other measures were used to compare diagnostic performance. RESULTS: Mass spectrometry-based measurements yielded lower plasma aldosterone concentrations than immunoassay measurements. For the ARR based on immunoassay measurements of aldosterone, AUROCs were slightly lower (P = 0.018) than those using mass spectrometry measurements (0.895 vs 0.906). The cutoff for the ARR to reach a sensitivity of 95% was 30 and 21.5 pmol/mU by respective immunoassay and mass spectrometry-based measurements, which corresponded to specificities of 57% for both. With data restricted to patients with unilateral PA, diagnostic sensitivities of 94% with specificities >81% could be achieved at cutoffs of 68 and 52 pmol/mU for respective immunoassay and mass spectrometry measurements. CONCLUSIONS: Mass spectrometry-based measurements of aldosterone for the ARR provide no clear diagnostic advantage over immunoassay-based measurements. Both approaches offer limited diagnostic accuracy for the ARR as a screening test. One solution is to employ the higher cutoffs to triage patients likely to have unilateral PA for further tests and possible adrenalectomy, while using the lower cutoffs to identify others for targeted medical therapy.German Clinical Trials Register ID: DRKS00017084.

Steroidomics-Based Screening for Primary Aldosteronism: Impact of antihypertensive Drugs.

BACKGROUND: Diagnosis of primary aldosteronism (PA) is complicated by the need to withdraw antihypertensive medications that interfere with test results, particularly renin. This study examined whether machine learning-based steroid-probability scores offer a renin measurement-independent approach for testing less prone to interference than the aldosterone-to-renin ratio (ARR). METHODS: This prospective multicenter cohort study involved the use of plasma steroidomics and the ARR in 839 patients tested for PA, including 190 with and 578 without PA (71 indeterminate). Receiver operating characteristic curves for steroid-probability scores and the ARR were examined with and without interfering medications. Impacts of individual medications on plasma aldosterone, 18-oxocortisol, 18-hydroxycortisol, steroid-probability scores, renin, and ARRs were examined by multivariable and paired analyses in patients with and without PA. RESULTS: Receiver operating characteristic curves indicated a significant impact of interfering antihypertensive medications on the diagnostic performance of the ARR and minimal impact on steroid-probability scores. Mineralocorticoid receptor antagonists increased plasma aldosterone, 18-oxocortisol, and 18-hydroxycortisol in patients without PA and resulted in false-positive test results for steroid-probability scores and false-negative results for the ARR. Diuretics increased aldosterone, 18-oxocortisol, and steroid-probability scores in patients without PA, whereas angiotensin-converting enzyme inhibitors decreased aldosterone, steroid-probability scores, and ARRs. Beta-adrenoceptor blockers, dihydropyridine calcium channel blockers, and angiotensin receptor blockers had negligible impact on mineralocorticoids and steroid-probability scores. CONCLUSIONS: Among antihypertensive drugs that impact plasma aldosterone, 18-oxocortisol, and 18-hydroxycortisol, mineralocorticoid receptor antagonists stood out as a cause of false-positive results for derived steroid-probability scores. Other antihypertensives have minimal or no impact, an advantage for use of steroid-probability scores over the ARR when those medications cannot be withdrawn. REGISTRATION: URL: https://drks.de/search/en/trial/DRKS00017084; Unique identifier: DRKS00017084.

Identification of Succinate Dehydrogenase Gene Variant Carriers by Blood Biomarkers.

Background: Carriers of germline pathogenic variants (PVs) in succinate dehydrogenase genes (SDHx) are at risk of developing tumors, including paragangliomas, gastrointestinal stromal tumors, and renal cell carcinomas. Early tumor detection is paramount for improved clinical outcome. Blood-based biomarkers could aid in identifying individuals with PVs early and provide functional evidence in patients with variants of unknown significance. Methods: Blood plasma, urine, peripheral blood mononuclear cells, and erythrocytes from patients with and without SDHx PVs were investigated for central carbon metabolites. These were measured by liquid chromatography-tandem mass spectrometry and nuclear magnetic resonance spectroscopy and included among others, succinate, fumarate, α-ketoglutarate, and lactate. Results: Plasma succinate to fumarate ratios effectively distinguished tumor-bearing and asymptomatic patients with and without SDHx PV with promising diagnostic performance (areas under the receiver operating characteristic curve 0.86-0.95), although higher levels were noted in individuals with SDHB PV. Metabolites in urine and in peripheral blood mononuclear cell extracts were largely similar between groups. Erythrocytes showed strong metabolic alterations in patients with SDHx PV compared to controls, with 8 of 13 low-molecular organic acids being significantly different (P < .05). The lactate-α-ketoglutarate-ratio of erythrocytes identified individuals with SDHx PV equally well as plasma, with a sensitivity and specificity of 92% (AUC 0.97). Conclusion: Blood biomarkers have been underutilized for identifying carriers of SDHx PV or to validate variants of unknown significance. Our findings advocate for further investigation into a combined approach involving plasma and erythrocytes for future diagnostic strategies.