Clinical diagnosis of pheochromocytoma and paraganglioma-induced secondary hypertension through UPLC-MS/MS analysis of plasma catecholamines and their metabolites

This study aimed to elucidate the clinical diagnostic value of plasma catecholamines and their metabolites for pheochromocytoma and paraganglioma (PPGL)-induced secondary hypertension using ultraperformance liquid chromatography-mass spectrometry (UPLC-MS/MS). The study population included 155 patients with PPGL that were divided into the PPGL with hypertension (n = 79) and a PPGL without hypertension (n = 76) groups, and 90 healthy volunteers and 90 patients with primary hypertension as the control groups. UPLC-MS/MS was performed to detect plasma levels of catecholamines and their metabolites, including dopamine, vanillylmandelic acid (VMA), norepinephrine, metanephrine, and normetanephrine. Receiver operating characteristic curves were generated to analyze the diagnostic value of the plasma levels of catecholamines and their metabolites in PPGL-induced secondary hypertension. Patients in the primary hypertension and PPGL without hypertension groups had higher levels of dopamine, VMA, norepinephrine, metanephrine, and normetanephrine than patients in the normal group (all p < .05). On the other hand, patients in the PPGL with hypertension group had higher levels of dopamine, VMA, norepinephrine, metanephrine, and normetanephrine than patients in the normal, primary hypertension, and PPGL without hypertension groups (all p < .05). Collectively, our findings showed that dopamine, VMA, norepinephrine, metanephrine, and normetanephrine are all effective biomarkers for the diagnosis of PPGL and PPGL-induced secondary hypertension.

[Personalized treatment of pheochromocytoma]

BACKGROUND

Pheochromocytoma is a rare but severe disease of the adrenal glands. The aim of this study is to present and discuss recent developments in the diagnosis and treatment of pheochromocytoma.

MATERIAL AND METHODS

A narrative review article based on the most recent literature is presented.

RESULTS AND DISCUSSION

The proportion of pheochromocytomas as tumors of adrenal origin is about 5% of incidentally discovered adrenal tumors. The classical symptomatic triad of headaches, sweating, and palpitations occurs in only about 20% of patients, while almost all patients show at least 1 of these symptoms. To diagnose pheochromocytoma, levels of free plasma metanephrines or alternatively, fractionated metanephrines in a 24‑h urine collection is required in a first step. In the second step an imaging procedure, computed tomography (CT) or magnetic resonance imaging (MRI), is performed to localize the adrenal tumor. Functional imaging is also recommended to preoperatively detect potential metastases. Genetic testing should always be offered during the course of treatment as 30-40% of pheochromocytomas are associated with genetic mutations. The dogma of preoperative alpha blockade is increasingly being questioned and has been controversially discussed in recent years. Minimally invasive removal of the adrenal tumor is the standard surgical procedure to cure patients with pheochromocytoma. The transabdominal and retroperitoneal laparoscopic approaches are considered equivalent. The choice of the minimally invasive procedure depends on the expertise and experience of the surgeon and should be tailored accordingly. Individualized and regular follow-up care is important after surgery.

Cardiovascular Complications in Pheochromocytoma and Paraganglioma: Does Phenotype Matter?

BACKGROUND

Adrenaline-producing tumors are mostly characterized by a sudden release of catecholamines with episodic symptoms. Noradrenergic ones are usually less symptomatic and characterized by a continuous overproduction of catecholamines that are released into the bloodstream. Their effects on the cardiovascular system can thus be different. The aim of this study was to determine the prevalence of cardiovascular complications by catecholamine phenotype.

METHODS

We retrospectively analyzed data on the prevalence of cardiovascular events in 341 consecutive patients with pheochromocytoma and paraganglioma treated from 1995 to 2023. Biochemical catecholamine phenotype was determined based on plasma or urinary catecholamines and metanephrines.

RESULTS

According to the phenotype, 153 patients had noradrenergic pheochromocytoma and paraganglioma and 188 had adrenergic pheochromocytoma and paraganglioma. In the whole sample, the incidence of serious cardiovascular complications was 28% (95 patients), with no difference between the phenotypes or sexes. The noradrenergic phenotype had significantly more atherosclerotic complications (composite end point of type 1 myocardial infarction and symptomatic peripheral artery disease; odds ratio, 3.58 [95% CI, 1.59-8.83]; P=0.003), while the adrenergic phenotype more often had type 2 myocardial infarction and takotsubo-like cardiomyopathy (OR, 0.24 [95% CI, 0.09-0.57]; P=0.002). These changes remained even after adjustment for conventional risk factors of atherosclerosis.

CONCLUSIONS

We found a 28% incidence of cardiovascular complications in a consecutive group of patients with pheochromocytoma and paraganglioma. Patients presenting with a noradrenergic phenotype have a higher incidence of atherosclerotic complications, while the adrenergic phenotype is associated with a higher incidence of acute myocardial damage due to takotsubo-like cardiomyopathy.

Plasma Metanephrines Yield Fewer False-Positive Results Than Urine Metanephrines in Patients With Obstructive Sleep Apnea

CONTEXT

Obstructive sleep apnea (OSA) is associated with increased nocturnal sympathetic activity. In OSA patients, elevations in metanephrines may lead to false-positive tests when evaluating for pheochromocytoma or paraganglioma (PPGL).

OBJECTIVE

To evaluate whether morning plasma metanephrines would lead to fewer false-positive results than 24-hour urinary metanephrines in OSA patients.

METHODS

Patients undergoing polysomnography for suspected OSA were recruited. Plasma free and 24-hour urinary metanephrines were measured by HPLC-MS/MS. Patients with elevated levels had repeat measurements, abdominal imaging, and follow-up to diagnose or exclude a PPGL.

RESULTS

Seventy-six patients completed polysomnography and biochemical testing; 68 (89.5%) patients had OSA, of whom 19 (27.9%) had elevated plasma and/or urinary metanephrines. On follow-up, one patient had a bladder paraganglioma, while PPGL was excluded in the remaining patients. OSA patients had more false-positive urinary metanephrines (17 of 67, 25.4%) than plasma metanephrines (2 of 67, 3.0%), P < .01, and this was more common in severe OSA (13 of 34, 38.2%), compared to moderate/mild OSA (4 of 33, 12.1%), P < .01. Both plasma and urinary metanephrines decreased after treatment with continuous positive airway pressure. On multivariable analysis, severe OSA, obesity, and family history of hypertension were positive predictors for false-positive urinary metanephrines in patients with suspected OSA.

CONCLUSION

In OSA patients, plasma metanephrines are less likely to yield false-positive results for the diagnosis of PPGL than 24-hour urinary metanephrines. In patients with suspected OSA, obesity, or a family history of hypertension, plasma metanephrines may be the preferred first-line test to avoid unnecessary anxiety or follow-up.

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.

Association between excess catecholamine synthesis and polymorphic premature ventricular contraction

BACKGROUND

The reasons for the etiology of premature ventricular contractions (PVCs) are not specifically known. Many patients are resistant to medical treatment, and a factor that would predict response to medical treatment cannot be identified. This study aims to investigate if a high catecholamine level results in polymorphic PVC.

METHODS

This study was obtained by prospective data registry analysis. A total of 100 patients, 50 from the PVC group, and 50 from the control group have been evaluated. The participants who were included in the patient group had a polymorphic PVC of 5% or more in their 24-h Holter evaluations. Metanephrine showing the level of adrenaline and normetanephrine, showing the level of noradrenaline levels have been measured from these urine samples.

RESULT

There was no difference between the two groups in terms of biochemical and essential characteristics. Normetanephrine level has been significantly higher in the PVC group compared to the control group (323.9 ± 208.9 μg to 129.25 ± 67.88 μg; p < 0.001). Similarly, metanephrine level has also been higher in the PVC group (124.75 ± 82.43 μg to 52.615 ± 36,54 μg; p < 0.001). A positive and moderate correlation has been identified between the number and ratio of PVC and the metanephrine and normetanephrine levels.

CONCLUSION

In this study, we found that the catecholamine levels were higher in the polymorphic PVC group than in the healthy volunteers. Also, an increase in the number and rate of PVC has been observed as the catecholamine levels increased.

CLINICAL TRIAL REGISTRATION

Urine Levels of Metanephrine and Normetanephrine in Patients With Frequent PVC; ClinicalTrials.gov number NCT03447002.

LC-MS based simultaneous profiling of adrenal hormones of steroids, catecholamines, and metanephrines

Metabolic changes in adrenocortical steroids and medullary catecholamines characterize adrenal tumors, but they are measured using different analytical protocols. To increase bioanalytical validity while maintaining sample homogeneity, LC-MS-based profiling of 29 cortical steroids and 6 medullary amines, including catecholamines and metanephrines, in a single run was developed. Alkyloxycarbonylation with isobutyl chloroformate was employed together with our comprehensive steroid assay, and all adrenal hormones were separated on a reversed-phase C18 column (50 × 2.1 mm, 1.9 μm) at a flow rate of 0.3 ml/min. The lower limits of quantification for all analytes ranged from 0.1 to 2.0 ng/ml, with extraction recoveries of 58.5%-109.5%, while the imprecision and accuracy were 1.6%-14.8% and 89.2%-114.9%, respectively. The validated LC-MS assay was applied to serum samples obtained from 60 patients with adrenal Cushing syndrome, primary aldosteronism, and pheochromocytoma/paraganglioma (PPGL). In addition to the characteristic metabolic changes in glucocorticoids, mineralocorticoids, catecholamines, and metanephrine, the molecular ratios of dehydroepiandrosterone sulfate and 20α-dihydrocortisol indicated Cushing syndrome and primary aldosteronism (P < 0.01 for all compounds), respectively. Moreover, the interactive molecular ratios of 11-deoxycortisol with normetanephrine, metanephrine, norepinephrine, and epinephrine (P < 0.01 all compounds) were proposed to characterize the metabolic features of PPGL. Novel LC-MS-based quantitative profiling of steroids, catecholamines, and metanephrines in human serum was successfully established and characterized metabolic features of individual adrenal tumors that could be used for clinical purposes.

An Unusual Location for a Lymph Node

We report a case of a 67-years old non-smoking female diagnosed with hypertension when 24-years-old and complicated with chronic kidney and hypertensive heart diseases. On CT-Chest an incidental discovery of a lesion (16x14x23mm) adjacent to the abdominal aorta was made. Initially suspected to be paraganglioma, a hypothesis which the subsequent MRI did not exclude. Urine analysis showed normal Metanephrine with slightly elevated Chromogranin-A levels. During VATs-procedure "bulging" below the adventitial layer of the descending aorta at the level of the diaphragmatic gutter was identified. By opening the adventitia, a lipomatous lesion with a nodular, consistent center was identified and excised. Final histopathological report confirmed the diagnosis of lymph node not suggestive of neoplasia. Currently, 12 months after the surgery, the patient's condition is good being under surveillance in the Thoracosurgical Outpatient Clinic. Despite not having identified any neuroendocrine component, the patient had clinical signs of clear improvement of arterial hypertension.

Sulfasalazine as a cause of false-positive elevation of urinary normetanephrine in patients with adrenal mass and suspected phaeochromocytoma: a diagnostic challenge

In patients with suspected phaeochromocytoma, biochemical screening of urine or blood for excess secretion catecholamines and/or their metabolites is performed. Elevated levels of catecholamines and metanephrines help in establishing the diagnosis of phaeochromocytoma. In two patients with adrenal lesions who were subjected to biochemical testing significantly elevated urinary normetanephrines appeared to establish the diagnosis of phaeochromocytoma. However, on subsequent investigations, this was demonstrated to be a 'false positive' finding. Both these patients were on sulfasalazine, an anti-inflammatory drug used in inflammatory bowel disease, rheumatoid arthritis and ankylosing spondylitis. Sulfasalazine can cause analytical interference in some assays for urinary normetanephrine and result in spuriously elevated levels, leading to misdiagnosis of phaeochromocytoma. In this report, one patient underwent adrenalectomy and another had conservative management.Although this has been previously reported, increased awareness of the possibility of false-positive results on urinary metanephrines testing is important to reduce the potential for misdiagnosis and unnecessary treatment.

Plasma-free metanephrines, nerve growth factor, and renalase significance in patients with PCOS

PURPOSE

Polycystic ovarian syndrome (PCOS) is a common heterogeneous condition with probably multifactorial genesis. Animal studies have proven the essential role of the sympathetic nervous system in the syndrome development, while human studies are still contradictory. The present study aims to investigate the possible influence of plasma-free metanephrine (MN), and normetanephrine (NMN), nerve growth factor (NGF), and renalase (RNL) on the hormonal and metabolic parameters in women with PCOS and healthy controls.

METHODS

Fifty patients with PCOS and 30 healthy women participated in the study. The plasma-free MN and NMN, NGF, RNL, anti-Mullerian hormone (AMH), gonadotropin, androgen levels, and metabolic parameters were investigated.

RESULTS

Plasma-free NMN and NGF concentrations were increased in PCOS individuals, while RNL levels were decreased compared to healthy volunteers. Increased plasma-free NMN (OR = 1.0213 [95%CI 1.0064-1.0364], p = 0.005) and NGF (OR = 1.0078 [95%CI 1.0001-1.0155], p = 0.046) but not MN or RNL levels were associated with a higher risk of PCOS after adjustment for age. Plasma-free NMN levels were positively associated with the LH (r = +0.253; p = 0.039). androstenedione (r = +0.265; p = 0.029), 17-OH progesterone (r = +0.285; p = 0.024), NGF (r = +0.320; p = 0.008), and AMH (r = +0.417; p < 0.001) concentrations of the investigated women. RNL levels were inversely related to the BMI (r = -0.245; p = 0.029), HOMA-IR (r = -0.250; p = 0.030), free testosterone (r = -0.303; p = 0.006) levels. systolic (r = -0.294; p = 0.008) and diastolic (r = -0.342; p = 0.002) blood pressure.

CONCLUSIONS

Increased sympathetic noradrenergic activity and NGF synthesis might be related to the increased AMH and delta-4 androgen levels in a subgroup of PCOS patients. RNL levels might influence the metabolic status of PCOS patients. Further studies are needed to explore the significance of adrenal medullar and autonomic dysfunction for developing different PCOS phenotypes and their subsequent cardiovascular complications.

Prevalence of Cortisol Cosecretion in Patients With Primary Aldosteronism: Role of Metanephrine in Adrenal Vein Sampling

CONTEXT

Adrenal venous sampling (AVS) is the gold standard procedure for subtype diagnosis in patients with primary aldosteronism (PA). Cortisol is usually adopted for the normalization of aldosterone levels in peripheral and adrenal samples. However, asymmetrical cortisol secretion can potentially affect the lateralization index, leading to subtype misdiagnosis.

OBJECTIVE

We aimed to assess the prevalence of asymmetrical cortisol secretion in patients undergoing AVS and whether variations in adrenal vein cortisol might influence AVS interpretations. We then evaluated the use of metanephrines for the normalization of aldosterone levels for lateralization index.

METHODS

We retrospectively included 101 patients with PA who underwent AVS: 49 patients underwent unstimulated AVS, while 52 patients underwent both unstimulated and cosyntropin-stimulated AVS. Eighty-eight patients had bilateral successful AVS according to metanephrine ratio. We assessed the prevalence of asymmetrical cortisol secretion through the cortisol to metanephrine (C/M) lateralization index (LI). We then evaluated whether the use of aldosterone to metanephrine (A/M) LI can improve the diagnostic accuracy of AVS compared with aldosterone to cortisol (A/C) LI.

RESULTS

Asymmetrical cortisol secretion is present in 18% of patients with PA. Diagnosis with A/M LI and A/C LI is discordant in 14% of patients: 9% had a diagnosis of unilateral PA with A/M LI instead of bilateral PA with A/C LI and 5% had a diagnosis of bilateral PA with A/M LI instead of unilateral PA.

CONCLUSION

The assessment of metanephrine levels in AVS is useful for the determination of selectivity and lateralization, allowing an accurate diagnosis, especially in patients with asymmetrical cortisol secretion.

Diagnosis, treatment and outcome of pheochromocytoma in a cat

Pheochromocytoma in cats is a rare clinical condition characterised by the development of a secretory endocrine tumour that arises from the adrenal medulla. An 8-year-old castrated male, domestic shorthair cat was referred for further investigation of a 4-month history of progressive weight loss with normal appetite, polyuria/polydipsia, generalised weakness, and severe hypertension. Sonography and computed tomography of the abdomen disclosed a mass arising from the left adrenal gland. The contralateral adrenal gland was normal in size and shape. Results from a low dose dexamethasone suppression test and measurements of plasma aldosterone concentration and plasma renin activity ruled out a cortisol-secreting tumour and aldosteronoma. The clinical presentation made a sex-steroid secreting tumour unlikely. Increased plasma metanephrine and normetanephrine concentrations prioritised the differential diagnosis of pheochromocytoma. The cat underwent adrenalectomy of the left gland and histopathological diagnosis with immunohistochemical markers confirmed the diagnosis.

Biomarker response to high-specific-activity I-131 meta-iodobenzylguanidine in pheochromocytoma/paraganglioma

The objective of this study is to present the complete biomarker response dataset from a pivotal trial evaluating the efficacy and safety of high-specific-activity I-131 meta-iodobenzylguanidine in patients with advanced pheochromocytoma or paraganglioma. Biomarker status was assessed and post-treatment responses were analyzed for catecholamines, metanephrines, and serum chromogranin A. Complete biomarker response (normalization) or partial response, defined as at least 50% reduction from baseline if above the normal range, was evaluated at specified time points over a 12-month period. These results were correlated with two other study objectives: blood pressure control and objective tumor response as per RECIST 1.0. In this open-label, single-arm study, 68 patients received at least one therapeutic dose (~18.5 GBq (~500 mCi)) of high-specific-activity I-131 meta-iodobenzylguanidine. Of the patients, 79% and 72% had tumors associated with elevated total plasma free metanephrines and serum chromogranin A levels, respectively. Best overall biomarker responses (complete or partial response) for total plasma free metanephrines and chromogranin A were observed in 69% (37/54) and 80% (39/49) of patients, respectively. The best response for individual biomarkers was observed 6-12 months following the first administration of high-specific-activity I-131 meta-iodobenzylguanidine. Biochemical tumor marker response was significantly associated with both reduction in antihypertensive medication use (correlation coefficient 0.35; P = 0.006) as well as objective tumor response (correlation coefficient 0.36; P = 0.007). Treatment with high-specific-activity I-131 meta-iodobenzylguanidine resulted in long-lasting biomarker responses in patients with advanced pheochromocytoma or paraganglioma that correlated with blood pressure control and objective response rate. ClinicalTrials.gov number: NCT00874614.

Correlation between the size of pheochromocytoma and the level of metanephrines

Objective. Pheochromocytomas (PHEO) and paraganglioma (PGLs) are rare neuroendocrine catecholamine-producing tumors that arise from the chromaffin cells of either the adrenal medulla or extra-adrenal paraganglionic tissues. Despite the recent advances in imaging technologies, biochemical evidence of excessive catecholamine production by the tumor is considered the most important test for the diagnosis of these tumors. The aim of the present study is to investigate the role of the catecholamine metabolites (normetanephrine and metanephrine) levels in the diagnosis of PHEO/PGLs and to evaluate if their levels correlate with the size of these tumors. Patients and Methods. Twenty-five patients were included in the study during the time period of 10 years. Their data were compared with another set of 25 patients to obtain the sensitivity and specificity of metanephrine and normetanephrine in the diagnosis of PHEO/PGLs. The tumor size was reviewed in every patient to obtain the correlation coefficient between the tumor sizes and the plasma/24-hour urinary metanephrine levels. Results. The sensitivity and specificity rates for plasma metanephrine were 80-92% and 92-96%, respectively; while for 24-hour urinary metanephrine were 80-90% and 95-100%, respectively. We found a strong positive relationship between the tumor size and the plasma levels of normetanephrine (r=0.518, p<0.01), and metanephrine (r=0.577, p<0.01). While the relation with the 24-hour urinary concentrations of normetanephrine (r=0.384, p=0.01) and 24-h urinary meta-nephrine (r=0.138, p<0.01) was low. Conclusion. The determination of plasma and 24-hour urinary levels of metanephrines is a reliable test for the diagnosis of PHEO, as they are continuously produced by the tumor cells in contrast to catecholamines.

Comparison of plasma metanephrines in patients with cyanotic and acyanotic congenital heart disease

PURPOSE

The co-occurrence of cyanotic congenital heart disease (CCHD) and PHEO/PGL has been reported, but the role of the hypoxic environment in the pathogenesis of PHEO/PGL remains unclear. Our aim was to compare plasma metanephrine and normetanephrine levels between patients with CCHD and patients with acyanotic congenital heart disease (ACCHD).

METHODS

We performed a cross-sectional study in a prospective cohort of 44 patients with congenital heart disease (CHD) (31 (70.5%) females) with a median age of 37.5 (31.0-55.6) years at the time of evaluation. Thirty-two (73%) patients had CCHD and 12 (27%) patients had ACCHD. Morning blood samples for plasma determination of metanephrine and normetanephrine were collected.

RESULTS

Plasma normetanephrine levels were significantly higher in patients with CCHD compared to ACCHD (p = 0.002). Ten (31.3%) patients with CCHD had plasma normetanephrine levels elevated above the reference range, while all ACCHD patients had normal levels. Patients with lower oxygen saturation and higher proBNP had significantly higher normetanephrine levels (ρ = -0.444, p = 0.003 and ρ = 0.449, p = 0.002, respectively). No chromaffin cell tumors were detected.

CONCLUSION

Increased plasma normetanephrine levels in patients with CCHD can be explained by the effect of hypoxia. Future research is needed to better understand the impact of chronic hypoxia in CCHD on increased sympathetic outflow, hyperplastic response of chromaffin tissue, and the role of somatic mutations in CCHD-PHEO/PGL pathogenesis related to hypoxia.

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.

Computerized tomography texture analysis of pheochromocytoma: relationship with hormonal and histopathological data

OBJECTIVES

Pheochromocytomas are rare tumors which can present with heterogeneous secretion profiles, clinical manifestations, and radiologic appearance. Under a histopathological point of view, they can be characterized as more or less aggressive with the Pheochromocytoma of the Adrenal gland Scaled Score (PASS) and the Grading system for Adrenal Pheochromocytoma and Paraganglioma (GAPP) score. The aim of this study is to analyze the texture analysis characteristics of pheochromocytoma and identify whether the texture analysis can yield information aiding in the diagnosis and the characterization of those tumors.

METHODS

Radiological, biochemical, and histopathological data regarding 30 consecutive patients with histologically confirmed pheochromocytoma were analyzed. Images obtained in the unenhanced, late arterial, venous, and delayed phases were used for the texture analysis.

RESULTS

Urinary epinephrine and metanephrine levels showed a significant correlation (R² = 0.946; R² = 699) in the multivariate linear model with texture features, as well as Ki-67 (R² = 0.397), PASS score (R² = 0.182), GAPP score (R² = 0.705), and cellularity showed a significant correlation (R² = 0.389). The cluster analysis based on radiomic features resulted in 2 clusters, with significative differences in terms of systolic and diastolic blood pressure values at the time of diagnosis (p = 0.025), GAPP score (4 vs 6, p = 0.05), histological pattern (1-2, p = 0.039), and comedonecrosis (0% vs 50%, p = 0.013).

CONCLUSION

In conclusion, our study provides the proof of concept for the use of texture analysis on contrast-enhanced CT images as a noninvasive, quantitative tool for helping in the characterization of the clinical, biochemical, and histopathological features of pheochromocytoma.

A retrospective study on the association between urine metanephrines and cardiometabolic risk in patients with nonfunctioning adrenal incidentaloma

Several studies argued that cardiovascular evaluation of patients with nonfunctioning adrenal incidentaloma is of particular importance. Therefore, we aimed to evaluate the possibility of stratifying the cardiometabolic risk using metanephrine levels in this setting of patients. A retrospective cross-sectional study was designed, collecting data of metanephrine values in 828 patients with nonfunctioning adrenal incidentaloma, referred to our Division within the University of Turin between 2007 and 2021. The univariate analysis showed associations between urine metanephrines and cardiometabolic variables/parameters, particularly considering the noradrenaline metabolite. At the univariate regression, normetanephrine was associated with metabolic syndrome (OR = 1.13, p = 0.002), hypertensive cardiomyopathy (OR = 1.09, p = 0.026), microalbuminuria (OR = 1.14, p = 0.024), and eGFR < 60 mL/min/1.73 m2 (OR = 1.11, p = 0.013), while metanephrine was associated with microalbuminuria (OR = 1.50, p = 0.008). At multivariate regression, considering all major cardiovascular risk factors as possible confounders, normetanephrine retained a significant association with metabolic syndrome (OR = 1.10, p = 0.037). Moreover, metanephrine retained a significant association with the presence of microalbuminuria (OR = 1.66, p = 0.003). The present study showed a further role for metanephrines in the cardiovascular risk stratification of patients with nonfunctioning adrenal incidentaloma. Individuals with high levels of these indirect markers of sympathetic activity should be carefully monitored and may benefit from an aggressive treatment to reduce their additional cardiometabolic burden.

Preanalytical Considerations and Outpatient Versus Inpatient Tests of Plasma Metanephrines to Diagnose Pheochromocytoma

CONTEXT

Sampling of blood in the supine position for diagnosis of pheochromocytoma and paraganglioma (PPGL) results in lower rates of false positives for plasma normetanephrine than seated sampling. It is unclear how inpatient vs outpatient testing and other preanalytical factors impact false positives.

OBJECTIVE

We aimed to identify preanalytical precautions to minimize false-positive results for plasma metanephrines.

METHODS

Impacts of different blood sampling conditions on plasma metanephrines were evaluated, including outpatient vs inpatient testing, sampling of blood in semi- vs fully recumbent positions, use of cannulae vs direct venipuncture, and differences in outside temperature. A total of 3147 patients at 10 tertiary referral centers were tested for PPGL, including 278 with and 2869 without tumors. Rates of false-positive results were analyzed.

RESULTS

Outpatient rather than inpatient sampling resulted in 44% higher plasma concentrations and a 3.4-fold increase in false-positive results for normetanephrine. Low temperature, a semi-recumbent position, and direct venipuncture also resulted in significantly higher plasma concentrations and rates of false-positive results for plasma normetanephrine than alternative sampling conditions, although with less impact than outpatient sampling. Higher concentrations and rates of false-positive results for plasma normetanephrine with low compared with warm temperatures were only apparent for outpatient sampling. Preanalytical factors were without impact on plasma metanephrines in patients with PPGL.

CONCLUSION

Although inpatient blood sampling is largely impractical for screening patients with suspected PPGL, other preanalytical precautions (eg, cannulae, warm testing conditions) may be useful. Inpatient sampling may be reserved for follow-up of patients with difficult to distinguish true- from false-positive results.

Application of Metanephrine and Normetanephrine in Evaluating the Selectivity of Adrenal Vein Sampling

The aim of the study was to investigate the usefulness of metanephrine (MN) and normetanephrine (NMN) in bilateral simultaneous adrenal vein sampling (AVS) with and without ACTH stimulation. The study was conducted in a single referral center. Prospective recruited patients with PA were treated with AVS. The effects of cortisol, MN and NMN on selectivity catheterization were assessed and determined by lateralization. We enrolled 54 patients with PA who were treated with simultaneous bilateral AVS with ACTH. The Selectivity Index (SI) calculated by MN was higher than that calculated by other indicators (p<0.001), the catheterization success rate of MN at baseline was the same as that of cortisol after ACTH stimulation, and in lateralization diagnosis, MN was not inferior to cortisol. In conclusion, among the studied indicators, MN is the best index for determining the catheterization selectivity in AVS, especially in the absence of ACTH stimulation.

Addition of 3-methoxytyramine or chromogranin A to plasma free metanephrines as the initial test for pheochromocytoma and paraganglioma: Which is the best diagnostic strategy

OBJECTIVE

Measurements of plasma free metanephrines (MNs), including MN and normetanephrine, provide high sensitivity and specificity for the diagnosis of pheochromocytoma and paraganglioma (PPGL). 3-Methoxytyramine (3-MT) and chromogranin A (CgA) may allow the detection of dopamine-producing or biochemically silent PPGL. The aim of this study was to evaluate whether measurements of plasma 3-MT or CgA as a supplement of plasma MNs offer a better diagnostic strategy for initial testing of PPGL.

PATIENTS AND DESIGN

We enroled 125 patients who underwent surgery from 2015 to 2016 for our study and identified 33 patients with PPGL and 92 patients with non-PPGL masses.

MEASUREMENT

The levels of plasma free MNs and 3-MT were measured for all 125 patients using liquid chromatography-tandem mass spectrometry. Plasma CgA concentrations were determined using a radioimmunoassay. To evaluate the diagnostic performance of plasma free MNs, 3-MT and CgA, sensitivity and specificity were determined, and receiver operating characteristic curves were constructed.

RESULTS

We found that combining 3-MT and MNs increased the diagnostic sensitivity from 93.9% (95% confidence interval [CI]: 78.4%-98.9%) to 97.0% (95% CI: 82.5%-99.8%). In contrast, addition of plasma CgA test reduced the diagnostic specificity significantly from 91.3% (95% CI: 83.1%-95.9%) to 75.0% (95% CI: 64.7%-83.2%).

CONCLUSION

Here, we demonstrated that 3-MT represents a valuable supplementary test to plasma MNs, which can further enhance the sensitivity of the assay, while plasma CgA added no additional diagnostic value to MNs due to the lowered diagnostic specificity.

Accurate Location of Catheter Tip With the Free-to-Total Metanephrine Ratio During Adrenal Vein Sampling

BACKGROUND

The selectivity index (SI) of cortisol is used to document correct catheter placement during adrenal vein sampling (AVS) in patients with primary aldosteronism (PA). We aimed to determine the cutoff values of the SIs based on cortisol, free metanephrine, and the free-to-total metanephrine ratio (FTMR) using an adapted AVS protocol in combination with CT.

METHODS

Adults with PA and referred for AVS were recruited in two hypertension centers. The cortisol and free metanephrine-derived SIs were calculated as the concentration of the analyte in adrenal veins divided by the concentration of the analyte in the distal vena cava. The FTMR-derived SI was calculated as the concentration of free metanephrine in the adrenal vein divided by that of total metanephrine in the ipsilateral adrenal vein. The AVS was classified as an unequivocal radiological success (uAVS) if the tip of the catheter was seen in the adrenal vein. The SI cutoffs of each index marker were established using receiver operating characteristic curve analysis.

RESULTS

Out of 125 enrolled patients, 65 patients had an uAVS. The SI cutoffs were 2.6 for cortisol, 10.0 for free metanephrine, 0.31 for the FTMR on the left side, and 2.5, 9.9, and 0.25 on the right side. Compared to free metanephrine and the FTMR, cortisol misclassified AVS as unsuccessful in 36.6% and 39.0% of the cases, respectively.

CONCLUSION

This study is the first to calculate the SIs of cortisol, free metanephrine, and the FTMR indices for the AVS procedure. It confirms that free metanephrine-based SIs are better than those based on cortisol.

Case report: Incidentally discovered case of pheochromocytoma as a cause of long COVID-19 syndrome

Pheochromocytomas (PCCs) are rare but potentially lethal tumors that arise from the adrenal medulla. The clinical suspicion and diagnosis of PCC can be challenging due to the non-specific nature of signs and symptoms. In many patients, infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) could lead to long-term symptoms including fatigue, headaches, and cognitive dysfunction. Here, we present the case of a patient incidentally diagnosed with an adrenal mass that proved to be a PCC after imaging was performed due to persisting complaints after coronavirus disease 2019 (COVID-19) infection. A 37-year-old male patient was referred to our center because of a right-sided inhomogeneous adrenal mass, incidentally found during a computed tomographic scan of the thorax performed due to cough and dyspnea that persisted after COVID-19 infection. Other complaints that were present prior to COVID-19 infection included profuse sweating, dizziness, exhaustion with chronic fatigue, and concentration difficulties. The patient had no history of hypertension, his blood pressure was normal, and the 24-h ambulatory blood pressure monitoring confirmed normotension but with the absence of nocturnal dipping. Plasma normetanephrine was 5.7-fold above the upper limit (UL) of reference intervals (738 pg/ml, UL = 129 pg/ml), whereas plasma metanephrine and methoxytyramine were normal at 30 pg/ml (UL = 84 pg/ml) and <4 pg/ml (UL = 16 pg/ml), respectively. Preoperative preparation with phenoxybenzamine was initiated, and a 4-cm tumor was surgically resected. Profuse sweating as well as dizziness was resolved after adrenalectomy pointing toward PCC and not COVID-19-associated patient concerns. Altogether, this case illustrates the difficulties in recognizing the possibility of PCC due to the non-specific nature of signs and symptoms of the tumor, which in this case did not include hypertension and coincided with some of the symptoms of long COVID-19.

Biochemical Diagnosis of Catecholamine-Producing Tumors of Childhood: Neuroblastoma, Pheochromocytoma and Paraganglioma

Catecholamine-producing tumors of childhood include most notably neuroblastoma, but also pheochromocytoma and paraganglioma (PPGL). Diagnosis of the former depends largely on biopsy-dependent histopathology, but this is contraindicated in PPGL where diagnosis depends crucially on biochemical tests of catecholamine excess. Such tests retain some importance in neuroblastoma though continue to largely rely on measurements of homovanillic acid (HVA) and vanillylmandelic acid (VMA), which are no longer recommended for PPGL. For PPGL, urinary or plasma metanephrines are the recommended most accurate tests. Addition of methoxytyramine to the plasma panel is particularly useful to identify dopamine-producing tumors and combined with normetanephrine also shows superior diagnostic performance over HVA and VMA for neuroblastoma. While use of metanephrines and methoxytyramine for diagnosis of PPGL in adults is established, there are numerous pitfalls for use of these tests in children. The establishment of pediatric reference intervals is particularly difficult and complicated by dynamic changes in metabolites during childhood, especially in infants for both plasma and urinary measurements, and extending to adolescence for urinary measurements. Interpretation of test results is further complicated in children by difficulties in following recommended preanalytical precautions. Due to this, the slow growing nature of PPGL and neglected consideration of the tumors in childhood the true pediatric prevalence of PPGL is likely underappreciated. Earlier identification of disease, as facilitated by surveillance programs, may uncover the true prevalence and improve therapeutic outcomes of childhood PPGL. For neuroblastoma there remain considerable obstacles in moving from entrenched to more accurate tests of catecholamine excess.

Biochemically normal adrenal pheochromocytoma following extensive central necrosis in a child with von Hippel-Lindau (VHL) gene mutation

Pheochromocytomas are rare in children. The diagnosis is usually established from a raised urinary or plasma catecholamine or their metabolites. We present a girl aged 11 years who manifested with a hypertensive crisis secondary to an adrenal tumour but with unexpectedly normal urinary metanephrine and catecholamine results. She improved spontaneously following the crisis and underwent surgery later. The histopathological study confirmed a pheochromocytoma with large central necrosis. Her genetic screening reported a pathogenic von Hippel-Lindau gene mutation. Surveillance scan postsurgery detected no other tumours. Following the catecholamine crisis, an acute infarct occurred, resulting in extensive tumour necrosis and subsequent rapid remission of symptoms and paradoxically normal biochemical markers. Although not unheard of in adults, we believe this is the first reported case of an extensive spontaneous necrosis resulting in a biochemically normal pheochromocytoma in a child.

Pheochromocytoma and paraganglioma with negative results for urinary metanephrines show higher risks for metastatic diseases

PURPOSE

Few studies have assessed the clinical features of pheochromocytoma and paraganglioma (PPGL) not producing excessive catecholamine. We aimed to clarify the clinical characteristics of PPGL patients with negative results for urinary metanephrines.

METHODS

This is a retrospective cross-sectional study. We established a database by combining datasets from the Nationwide Cohort Study on the Development of Diagnosis and Treatment of Pheochromocytoma in Japan (PHEO-J) and the Advancing Care and Pathogenesis of Intractable Adrenal diseases in Japan (ACPA-J). We compared the clinical differences between PPGL patients with negative results for urinary metanephrines and those with catecholamine-producing PPGL.

RESULTS

Five hundred PPGL patients in the combined database were analyzed. Among them, 31 were negative for metanephrines. PPGL with negative results for urinary metanephrines was significantly associated with extra-adrenal disease (Odds ratio (OR) 6.58, 95% CI (confidence interval) 3.03-14.3, p < 0.001), the presence of metastatic disease (OR 4.22, 95% CI 1.58-11.3, p = 0.004), and negativity on meta-iodobenzylguanidine (MIBG) scintigraphy (OR 0.15, 95% CI 0.03-0.77, p = 0.023).

CONCLUSIONS

Our findings demonstrate that PPGL patients with negative results for urinary metanephrines are associated with extra-adrenal lesions, metastatic disease, and negative MIBG findings. This suggests that PPGL patients with negative results for urinary metanephrines have a greater need for systemic whole-body imaging other than MIBG scintigraphy and close follow-up to monitor for metastasis than do patients with PPGL overtly producing excessive catecholamine.

Biochemically silent phaeochromocytoma presenting with non-specific loin pain

A 55-year-old woman presented with a 4-month history of right-sided non-specific loin pain and 6 kg weight loss. A CT scan of the abdomen and pelvis showed an incidental 4.5 cm right-sided adrenal lesion which was not typical of an adrenal adenoma. This was further confirmed on MRI of the adrenals. Biochemical investigations to investigate for a functional adrenal lesion included serum catecholamines and metanephrines, an aldosterone to renin ratio and an overnight dexamethasone suppression test. These were all negative. A laparoscopic adrenalectomy was performed in view of the large size of the lesion. Histology was consistent with a phaeochromocytoma, which confirmed the diagnosis of a non-secreting phaeochromocytoma. Non-secreting phaeochromocytomas are rare and usually found in patients with known genetic mutations. Adrenal lesions not related to any mutations similar to our case are even rarer and reported even less in the literature.

Stability and reference intervals of spot urinary fractionated metanephrines and methoxytyramine by tandem mass spectrometry as a screening method for pheochromocytoma and paraganglioma

PURPOSE

The 24 h urinary-fractionated metanephrine (MN) and normetanephrine (NMN) are recommended as the preferred indicators for laboratory diagnosis of pheochromocytoma and paraganglioma (PPGL). However, it might cause missed diagnosis for some type of PPGL, in addition, 24-h urine collection is inconvenient and prone to error, so we aimed to develop a better screening method.

METHODS

Urine samples from patients of primary hypertension (n = 317) or PPGL (n = 64) were collected randomly and in a 24-h cycle. Samples were prepared by solid phase extraction (SPE) and analyzed with LC-MS/MS. Sample stability under different storage conditions was investigated. The gender-specific reference intervals of spot urinary catecholamine metabolites adjusted by creatinine were established and the diagnostic performance was evaluated.

RESULTS

Urinary MN, NMN (MNs), and 3-methoxytyramine (3-MT) were stable at room temperature or 4 °C for at least 4 days without adding any preservatives and at -20 °C for at least 11 weeks. Reference intervals of spot urinary MN, NMN and 3-MT adjusted by creatinine were 20.2-174.0, 47.6-452.0, and 20.6-398.5 µg/g for male and were 15.3-202.0, 34.4-461.0, and 38.0-392.6 µg/g for female. The sensitivity and specificity of spot urinary MN, NMN, and 3-MT were similar with that of 24-h urine (P > 0.05). Regardless of urine sample type, combined application of MNs or MNs and 3-MT can improve the diagnosis efficiency of MN and 3-MT alone.

CONCLUSIONS

Adding 3-MT to diagnosis model can improve diagnostic sensitivity to some extent, and the analysis of spot urinary MNs and 3-MT can provide reliable diagnostic information in a much shorter diagnostic time, it may reduce the medical expenses indirectly.

Moderate renal impairment does not preclude the accuracy of 24-hour urine normetanephrine measurements for suspected pheochromoctyoma

OBJECTIVE

A 24-hour urine nor/metanephrine (urine NM-MN) measurements are a recommended first step in pheochromocytoma diagnosis. We hypothesized the presence of renal impairment (CKD) significantly confounds the results obtained in a urine NM-MN collection, giving artificially lower measurements.

DESIGN

Retrospective review of a comprehensive laboratory database with all urine NM-MN results from Southern Alberta from 2010 to 2018 (n = 15 505). After excluding high probability pheochromocytoma cases, results from patients with three levels of CKD (n = 796) were compared to those without CKD to determine the potential CKD effect.

PATIENTS

All patients having urine NM-MN collection during the time period, irrespective of ordering physician or test indication.

MEASUREMENTS

Urine NM-MN was measured by liquid chromatography-tandem mass spectrometry and glomerular filtration rate determined within a median of 1.9 days, as estimated by CKD-EPI equation.

RESULTS

In subjects with mild-to-moderate renal impairment, there was no continuous gradient between subnormal renal function and urine NM-MN measures. When the estimated GFR was < 15 mL/min/m² , the hypothesized effect on lowered urine NM-MN became apparent.

CONCLUSIONS

A 24-hour urine NM-MN measurement is unlikely to be affected by mild-to-moderate renal impairment and may be used as a reliable diagnostic test. With more advanced renal impairment, CKD-specific reference ranges or an alternative test may be needed.

Clinical profiles of patients with surgically resected pheochromocytoma and paraganglioma

BACKGROUND/AIMS

Pheochromocytoma and paraganglioma (PPGL) are catecholamine-producing tumors that can cause blood pressure (BP) elevation and cardiovascular complications. Clinical presentation of these tumors may be changed through widespread use of imaging studies, which enables detection of PPGLs before onset of symptoms. We investigated clinical profiles of patients with surgically resected PPGLs.

METHODS

From 2005 to 2017, 111 consecutive patients with surgically resected PPGLs in two tertiary hospitals in Korea were studied.

RESULTS

Mean age was 52 ± 16 years, 57 patients (51.4%) were male and 54 (48.6%) were hypertensive. Twenty-nine PPGLs (26.1%) were extra-adrenal paragangliomas. Sixteen (14.4%) and seven patients (6.3%) (Group 1, n = 23) were diagnosed during work-up of hypertension and transient cardiomyopathy respectively, and the remainder (Group 2, n = 88) were incidentalomas detected during routine abdominal imaging. Patients in the Group 1 were younger and more frequently symptomatic, and had higher BPs, heart rates and levels of urinary catecholamines than those in the Group 2. Paragangliomas were less frequent and secretion of epinephrine and metanephrine was more predominant in the Group 1 than in Group 2. After the surgical resections, 18.2% of patients still needed antihypertensive medications.

CONCLUSION

Out of 111 patients with surgically resected PPGLs, 88 (79.3%) were diagnosed as incidentalomas. Seven patients presented with transient cardiomyopathy and 16 with hypertension. Tumor location and secretion of catecholamine may vary depending on the presence of symptoms.

Circulating EM66 is a highly sensitive marker for the diagnosis and follow-up of pheochromocytoma

We have previously demonstrated that measurement of tissue concentration of the novel secretogranin II-derived peptide EM66 may help to discriminate between benign and malignant pheochromocytomas. The aim of the present study was to characterize EM66 in plasma and urine of healthy volunteers and pheochromocytoma patients, in order to further evaluate the usefulness of this peptide as a circulating marker for the management of the tumors. HPLC analysis of plasma and urine samples demonstrated that the EM66-immunoreactive material coeluted with the recombinant peptide. In healthy volunteers, plasma and urinary EM66 levels were, respectively, 2.6 (1.9-3.7) ng/ml and 2.9 (1.9-4.6) ng/ml. In patients with pheochromocytoma, plasma EM66 levels were 10-fold higher than those of healthy volunteers (26.9 (7.3-44) ng/ml), and returned to normal values after removal of the tumor. In contrast, urinary EM66 levels were not significantly different from those of healthy volunteers (3.2 (2.2-3.9) ng/ml). Measurement of total or free plasma metanephrines and 24 hr urinary metanephrines in our series of patients revealed that these tests, taken separately, are less sensitive than the EM66 determination. Pheochromocytes in primary culture secreted high levels of EM66, suggesting that the chromaffin tumor was actually responsible for the increased plasma peptide concentrations in the patients. These data indicate that EM66 is secreted in the general circulation and that elevated plasma EM66 levels are correlated with the occurrence of pheochromocytoma. Thus, EM66 is a sensitive plasma marker that should be considered as a complementary tool in the management of pheochromocytoma.