Properly Collected Plasma Metanephrines Excludes PPGL After False-Positive Screening Tests

CONTEXT

False-positive results are common for pheochromocytoma/paraganglioma (PPGL) real-world screening.

OBJECTIVE

Determine the correlation between screening urine and seated plasma metanephrines in outpatients where PPGL was absent, compared to meticulously prepared and supine-collected plasma metanephrines with age-adjusted references.

DESIGN

Retrospective cohort study.

SETTING

Databases from a single-provider provincial laboratory (2012-2018), a validated PPGL registry, and a manual chart review from a specialized endocrine testing unit.

PATIENTS

PPGL registry data excluded known PPGL cases from the laboratory database. Outpatients having both urine and plasma metanephrines <90 days apart.

METHODS

The correlation between urine and seated plasma measures along with the total positivity rate. All cases of plasma metanephrines drawn in the endocrine unit were reviewed for test indication and test positivity rate.

RESULTS

There were 810 non-PPGL pairs of urine and plasma metanephrines in the laboratory database; 46.1% of urine metanephrines were reported high. Of seated outpatient plasma metanephrines drawn a median of 5.9 days later, 19.2% were also high (r = 0.33 and 0.50 for normetanephrine and metanephrine, respectively). In contrast, the meticulously prepared and supine collected patients (n = 139, 51% prior high urine metanephrines) had <3% rate of abnormal high results in patients without known PPGL/adrenal mass.

CONCLUSIONS

There was a poor-to-moderate correlation between urine and seated plasma metanephrines. Up to 20% of those with high urine measures also had high seated plasma metanephrines in the absence of PPGL. Properly prepared and collected supine plasma metanephrines had a false-positive rate of <3% in the absence of known PPGL/adrenal mass.

Urinary vanillylmandelic acid:creatinine ratio in dogs with pheochromocytoma

Pheochromocytoma diagnosis in dogs is challenging because biochemical tests are not always available. In humans, urinary vanillylmandelic acid (VMA) is part of a pheochromocytoma biochemical diagnostic profile, whereas its diagnostic accuracy is currently unknown in dogs with pheochromocytoma. Prospectively, VMA was determined by HPLC and expressed as the ratio with respect to urinary creatinine (VMA:C). The diagnostic accuracy of the VMA:C ratio was evaluated by analyzing the receiver operating characteristic (ROC) curve in 10 healthy dogs, 8 dogs with pituitary-dependent hypercortisolism, 8 dogs with adrenal-dependent hypercortisolism, and 7 dogs with pheochromocytoma. The pheochromocytoma diagnosis was confirmed by histology and immunohistochemistry in all tumors. The VMA:C ratio was significantly higher in dogs with pheochromocytoma (158 [53.4 to 230.8] × 10^-3) than in dogs with adrenal-dependent hypercortisolism (48.1 [24.3 to 144.9] × 10^-3; P < 0.05), dogs with pituitary-dependent hypercortisolism (37.5 [32 to 47.1] × 10^-3; P < 0.001), and healthy dogs (33.8 [13.3 to 87.9] × 10^-3; P < 0.001). When using a VMA:C ratio >58.2 × 10^-3 for pheochromocytoma diagnosis, a sensitivity of 85.7% and a specificity of 88.4% were obtained. Nevertheless, when using a cut-off ratio of 4 times the median VMA:C ratio determined in healthy dogs, there was no overlap (100% specificity). The area under the ROC curve indicated that the VMA:C ratio test could be used to discriminate between dogs with and without pheochromocytoma, what leads to the conclusion that it is useful for pheochromocytoma diagnosis in dogs.

Random 'spot' urinary metanephrines compared with 24-h-urinary and plasma results in phaeochromocytomas and paragangliomas

BACKGROUND

In patients with phaeochromocytomas or paragangliomas (PPGLs), 24-h urine collections for metanephrines (uMNs) are cumbersome.

OBJECTIVE

To evaluate the diagnostic utility of ratios to creatinine of 'spot' uMNs.

METHODS

Concentrations of uMNs and plasma metanephrines (pMNs) were measured by HPLC-mass-spectrometry. We retrospectively compared correlations of 24-h-urine output and ratio to creatinine in historical specimens and prospectively assessed 24-h and contemporaneous spot urines and, where possible, pMNs. Using trimmed log-transformed values, we derived reference intervals based on age and sex for spot urines. We used multiples of upper limit of normal (ULNs) to compare areas under curves (AUCs) for receiver-operator characteristic curves of individual, and sum and product of, components.

RESULTS

In 3143 24-h-urine specimens on 2416 patients, the correlation coefficients between the ratios and outputs of metanephrine, normetanephrine and 3-methoxytyramine in 24-h urines were 0.983, 0.905 and 0.875, respectively. In 96 patients, the correlations between plasma concentrations, urine output and ratios in spot specimens were similar to those for raw output or ratios in 24-h specimens. Of the 160 patients with PPGLs, the CIs for AUCs for individual metabolites overlapped for all four types of measurement, as did those for the sum of the multiple ULNs although these were slightly higher (AUC for spot urine: 0.838 (0.529-1), plasma: 0.929 (0.874-0.984) and output: 0.858 (0.764-0.952)).

CONCLUSIONS

Ratios of fractionated metanephrines to creatinine in spot urine samples appear to have a similar diagnostic power to other measurements. The ease of spot urine collection may facilitate diagnosis and follow-up of PPGLs through improved patient compliance.

Structure Engineering of a Lanthanide-Based Metal-Organic Framework for the Regulation of Dynamic Ranges and Sensitivities for Pheochromocytoma Diagnosis

Exploring innovative technologies to precisely quantify biomolecules is crucial but remains a great challenge for disease diagnosis. Unfortunately, the humoral concentrations of most biotargets generally vary within rather limited scopes between normal and pathological states, while most literature-reported biosensors can detect large spans of targets concentrations, but are less sensitive to small concentration changes, which consequently make them mostly unsatisfactory or even unreliable in distinguishing positives from negatives. Herein, a novel strategy of precisely quantifying the small concentration changes of a certain biotarget by editing the dynamic ranges and sensitivities of a lanthanide-based metal-organic framework (Eu-ZnMOF) biosensor is reported. By elaborately tailoring the biosensor's structure and surface areas, the tunable Eu-ZnMOF is developed with remarkably enhanced response slope within the "optimized useful detection window," enabling it to serve as a powerful signal amplifier (87.2-fold increase) for discriminating the small concentration variation of urinary vanillylmandelic acid (an early pathological signature of pheochromocytoma) within only three times between healthy and diseased subjects. This study provides a facile approach to edit the biosensors' performances through structure engineering, and exhibits promising perspectives for future clinical application in the non-invasive and accurate diagnosis of severe diseases.

Overnight/first-morning urine free metanephrines and methoxytyramine for diagnosis of pheochromocytoma and paraganglioma: is this an option?

OBJECTIVE

Sympathoadrenal activity is decreased during overnight rest. This study assessed whether urinary-free normetanephrine, metanephrine and methoxytyramine in overnight/first-morning urine collections might offer an alternative to measurements in 24-h collections or plasma for diagnosis of pheochromocytoma and paraganglioma (PPGL).

DESIGN AND METHODS

Prospective multicenter cross-sectional diagnostic study involving 706 patients tested for PPGL, in whom tumors were confirmed in 79 and excluded in 627 after follow-up. Another 335 age- and sex-matched volunteers were included for reference purposes. Catecholamines and their free O-methylated metabolites were measured in 24-h collections divided according to waking and sleeping hours and normalized to creatinine. Plasma metabolites from blood sampled after supine rest were measured for comparison.

RESULTS

Urinary outputs of norepinephrine, normetanephrine, epinephrine and metanephrine in the reference population were respectively 50 (48-52)%, 35 (32-37)%, 76 (74-78)% and 15 (12-17)% lower following overnight than daytime collections. Patients in whom PPGLs were excluded showed 28 (26-30)% and 6 (3-9)% day-to-night falls in normetanephrine and metanephrine, while patients with PPGLs showed no significant day-to-night falls in metabolites. Urinary methoxytyramine was consistently unchanged from day to night. According to receiver-operating characteristic curves, diagnostic accuracy of metabolite measurements in overnight/first-morning urine samples did not differ from measurements in 24-h urine collections, but was lower for both than for plasma. Using optimized reference intervals, diagnostic specificity was higher for overnight than daytime collections at similar sensitivities.

CONCLUSIONS

Measurements of urinary-free catecholamine metabolites in first-morning/overnight urine collections offer an alternative for diagnosis of PPGL to 24-h collections but remain less accurate than plasma measurements.

Pheochromocytoma: An approach to diagnosis

Pheochromocytomas are rare neuroendocrine chromaffin-derived tumors that arise within the adrenal medulla. They are usually benign, but if not diagnosed or if left untreated, they can have devastating consequences. Clinical consideration of the diagnosis is paramount, as they may have protean manifestations, and a high index of suspicion is essential if serious consequences are to be avoided. An accurate biochemical diagnosis is crucial for the management of these patients: either plasma or urinary metanephrines are both highly sensitive and specific if correctly employed, but knowledge of pre- and post-analytic interference is essential. Diagnostic imaging with cross-sectional CT and/or MRI offers high sensitivity in their detection, but lack specificity. The introduction of PET/CT/MR has led to a dramatic improvement in the localization of both pheochromocytomas and paragangliomas, together with the increasing availability of new functional imaging radionuclides. Optimal investigation and accurate diagnosis is best achieved at 'centers of excellence' with expert multidisciplinary teams.

Preoperative Management of Pheochromocytoma and Paraganglioma

Pheochromocytoma and paraganglioma (PPGL) are rare neuroendocrine tumors, characterized by excessive release of catecholamines (CAs), and manifested as the classic triad of headaches, palpitations, profuse sweating, and a variety of other signs and symptoms. The diagnosis of PPGL requires both evidence of excessive release of CAs and anatomical localization of CA-secreting tumor. Surgery is the mainstay of treatment for all patients with PPGL unless contraindicated. However, without proper preparation, the release of excessive CAs, especially during surgery, can result in lethal cardiovascular complications. Herein, we briefly reviewed the pathogenesis of this disease, discussed the current approaches and evidence available for preoperative management, summarizing the results of the latest studies which compared the efficacies of preoperative management with or without α adrenergic-receptor antagonists, aiming to facilitate better understanding of the preoperative management of PPGL for the physicians.

Correlation between urinary fractionated metanephrines in 24-hour and spot urine samples for evaluating the therapeutic effect of metyrosine: a subanalysis of a multicenter, open-label phase I/II study

We recently conducted an open-label phase I/II study to evaluate the efficacy and safety of preoperative and chronic treatment with metyrosine (an inhibitor of catecholamine synthesis) in pheochromocytoma/paraganglioma (PPGL) in Japan. We compared creatinine-corrected metanephrine fractions in spot urine and 24-hour urine samples (the current standard for the screening and diagnosis of PPGLs) from 16 patients to assess the therapeutic effect of metyrosine. Percent changes from baseline in urinary metanephrine (uMN) or normetanephrine (uNMN) were compared between spot and 24-hour urine samples. Mean percent changes in uMN or uNMN in spot and 24-hour urine were -26.36% and -29.27%, respectively. The difference in the percent change from baseline between uMN or uNMN in spot and 24-hour urine was small (-2.90%). The correlation coefficient was 0.87 for percent changes from baseline between uMN or uNMN measured in spot and 24-hour urine. The area under the receiver operator characteristic (ROC) curve of uMN or uNMN measured in spot urine vs. 24-hour urine (reference standard) to assess the efficacy of metyrosine treatment was 0.93. Correlations and ROCs between 24-hour urinary vanillylmandelic acid, adrenaline, and noradrenaline and 24-hour uMN or uNMN were similar to those between spot uMN or uNMN and 24-hour uMN or uNMN. No large difference was observed between spot and 24-hour urine for the assessment of metyrosine treatment by quantifying uMN or uNMN in Japanese patients with PPGLs. These results suggest that spot urine samples may be useful in assessing the therapeutic effect of metyrosine.

Metabolic impact of pheochromocytoma/paraganglioma: targeted metabolomics in patients before and after tumor removal

OBJECTIVE

Excess catecholamine release by pheochromocytomas and paragangliomas (PPGL) leads to characteristic clinical features and increased morbidity and mortality. The influence of PPGLs on metabolism is ill described but may impact diagnosis and management. The objective of this study was to systematically and quantitatively study PPGL-induced metabolic changes at a systems level.

DESIGN

Targeted metabolomics by liquid chromatography-tandem mass spectrometry of plasma specimens in a clinically well-characterized prospective cohort study.

METHODS

Analyses of metabolic profiles of plasma specimens from 56 prospectively enrolled and clinically well-characterized patients (23 males, 33 females) with catecholamine-producing PPGL before and after surgery, as well as measurement of 24-h urinary catecholamine using LC-MS/MS.

RESULTS

From 127 analyzed metabolites, 15 were identified with significant changes before and after surgery: five amino acids/biogenic amines (creatinine, histidine, ornithine, sarcosine, tyrosine) and one glycerophospholipid (PCaeC34:2) with increased concentrations and six glycerophospholipids (PCaaC38:1, PCaaC42:0, PCaeC40:2, PCaeC42:5, PCaeC44:5, PCaeC44:6), two sphingomyelins (SMC24:1, SMC26:1) and hexose with decreased levels after surgery. Patients with a noradrenergic tumor phenotype had more pronounced alterations compared to those with an adrenergic tumor phenotype. Weak, but significant correlations for 8 of these 15 metabolites with total urine catecholamine levels were identified.

CONCLUSIONS

This first large prospective metabolomics analysis of PPGL patients demonstrates broad metabolic consequences of catecholamine excess. Robust impact on lipid and amino acid metabolism may contribute to increased morbidity of PPGL patients.

Metabolomic Urine Profile: Searching for New Biomarkers of SDHx-Associated Pheochromocytomas and Paragangliomas

CONTEXT

Metabolomic studies of pheochromocytoma and paraganglioma tissue showed a correlation between metabolomic profile and presence of SDHx mutations, especially a pronounced increase of succinate.

OBJECTIVE

To compare the metabolomic profile of 24-hour urine samples of SDHx mutation carriers with tumors (affected mutation carriers), without tumors (asymptomatic mutation carriers), and patients with sporadic pheochromocytomas and paragangliomas.

METHODS

Proton nuclear magnetic resonance spectroscopic profiling of urine samples and metabolomic analysis using pairwise comparisons were complemented by metabolite set enrichment analysis to identify meaningful patterns.

RESULTS

The urine of the affected SDHx carriers showed substantially lower levels of seven metabolites than the urine of asymptomatic mutation carriers (including, succinate and N-acetylaspartate). The urine of patients with SDHx-associated tumors presented substantially higher levels of three metabolites compared with the urine of patients without mutation; the metabolite set enrichment analysis identified gluconeogenesis, pyruvate, and aspartate metabolism as the pathways that most probably explained the differences found. N-acetylaspartate was the only metabolite the urinary levels of which were significantly different between the three groups.

CONCLUSIONS

The metabolomic urine profile of the SDHx mutation carriers with tumors is different from that of asymptomatic carriers and from that of patients with sporadic neoplasms. Differences are likely to reflect the altered mitochondria energy production and pseudohypoxia signature of these tumors. The urinary levels of N-acetylaspartate and succinate contrast with those reported in tumor tissue, suggesting a defective washout process of oncometabolites in association with tumorigenesis. The role of N-acetylaspartate as a tumor marker for these tumors merits further investigation.

Association Between Urinary Catecholamine Excretion and Urine Volume

Several confounders must be considered in the evaluation of urinary catecholamine excretion. However, literature is contradictory about potential confounders. The aim of the present study was to assess correlations between catecholamine excretion and anthropometric or clinical parameters with special attention to urine volume. A total of 967 24-h urinary catecholamine measurements were performed in 593 patients for diagnostic purposes. The indication for urine examination was suspicion of secondary hypertension, phaeochromocytoma, or paraganglioma. From the patients examined, 57% were females and 43% were males. The patients' age ranged between 15 and 87 years with a median [Q1; Q3] of 51 [39; 62] years. Seventy-eight percent of the patients suffered from hypertension. Seventy percent of patients took one or more antihypertensive drugs. The most commonly used drugs were ACE inhibitors (43%), while α-blockers (15%) were the least used drugs. Urinary excretion was between 500 and 11 950 ml/24 h with a median of 2200 [1600; 2685] ml/24 h. The median body mass index (BMI) was 26.7 [24.0; 30.4] kg/m². The excretion of all catecholamines was greater in men than in women (all p<0.0001). Epinephrine (p=0.0026), dopamine (p<0.0001), and metanephrine (p=0.0106) excretion decreased with age. BMI was associated with urinary excretion of dopamine (p<0.0001), norepinephrine (p=0.0026), normetanephrine (p<0.0001), and homovanillylmandelic acid (HVMA; p=0.0251). Urine volume correlated with urinary dopamine (p=0.0127), metanephrine (p<0.0001), normetanephrine (p=0.0070), and HVMA (p<0.0028) excretion. In addition to the established associations between urinary catecholamine excretion and age, gender, and BMI in the present study, urinary catecholamine excretion correlated also with urine volume.

Change of skeletal muscle mass in patients with pheochromocytoma

The effects of catecholamine excess due to pheochromocytoma on body composition, including skeletal muscle mass, are unknown. Here, we investigated the effects of catecholamine metabolites on body composition in subjects with pheochromocytoma. After body compositions using bioelectrical impedance analysis, urinary metanephrine (UM), and urinary normetanephrine (UNM) were measured in 16 patients with pheochromocytoma and 224 patients with nonfunctioning adrenal incidentaloma (NFAI), we compared skeletal muscle mass and fat mass (FM) between the two groups. After adjustments for confounders, UM (β = - 0.171, P = 0.006) and UNM (β = - 0.249, P < 0.001) levels were correlated inversely with skeletal muscle mass index (SMI), but not FM or percentage FM (pFM), in all subjects. Patients with pheochromocytoma had lower ASM by 7.7% (P = 0.022) and SMI by 6.6% (P = 0.001) than patients with NFAI. Conversely, FM and pFM were not statistically different between the two groups. The odds ratio for low skeletal muscle mass in the presence of pheochromocytoma was 10.33 (95% confidence interval, 2.65-40.22). Our results indicate that patients with pheochromocytoma have a reduced skeletal muscle mass and suggest that catecholamine excess has adverse effects on skeletal muscle metabolism.

Multiple endocrine neoplasia type 2A syndrome (MEN2A) and usefulness of 68Ga-DOTATATE PET/CT in this syndrome

AIM

The aim of this study was to evaluate a new imaging method 68Ga-DOTATATE PET/CT as an alternative method to diagnose evidence of neuroendocrine tumors or their metastasis (if any) in patient with MEN 2A.

METHODS

Three patients( 2F, 1M; age 28,46 and 50 years) with MEN 2A syndrome who underwent 68Ga-DOTATATE PET/CT scan were prospectively evaluated. PET/CT images were analyzed with measurement of maximum standardized uptake value (SUVmax).

RESULTS

All patients had adrenal masses with increased uptake of 68Ga-DOTATATE (first case adrenal mass SUVmax: 9,1, second case adrenal mass SUVmax: 32,4(right), 30,3(left) and third case SUVmax:12,4). All of the patients had medullary thyroid carcinoma with increased uptake of 68Ga-DOTATATE (first case SUVmax: 3,3 second case SUVmax:7,7 and third case SUVmax: left thyroid nodule: 19,4, right thyroid nodule: 21,2). Third case has a parathyroid adenoma with SUVmax: 2,8.

CONCLUSIONS

New imaging method 68Ga-DOTATATE PET/CT may be an alternative method to diagnose MEN 2A patients. 68Ga-DOTATATE PET/CT can give a great opportunity to detecting the multiple neoplasia like MEN 2A with only one session.

KEY WORDS

MEN 2A syndrome, 68Ga-DOTATATE PET/CT, Neuroendocrine tumors.

Vanishing of ruptured adrenal mass with takotsubo cardiomyopathy

A 45-year-old male suddenly experienced left-flank abdominal pain. Echocardiography revealed akinesis of the 'takotsubo cardiomyopathy' type. He experienced a sudden haemodynamic collapse (blood pressure, 324/154 mmHg; pulse rate, 180 beats/min) during emergency cardiac catheterisation. An abdominal computed tomography (CT) revealed expansion of a soft tissue mass 64 × 33 mm in dimension in the left adrenal region, with accumulation of fluid surrounding the left pararenal space. Three days after the attack, his urinary catecholamine concentrations were slightly elevated. We suspected the patient as having a pheochromocytoma followed by acute haemorrhagic rupture, based on signatures of adrenal mass, 'takotsubo cardiomyopathy', and the hypertensive crisis. Over the next few weeks, he recovered well as an outpatient, and his blood pressure remained around 110/60 mmHg without medication. Three weeks after the attack, an abdominal CT showed shrinkage of the ruptured adrenal mass (to a diameter of 30 mm) and absorption of the retroperitoneal hematoma. On day 190 after the attack, abdominal CT did not detect any left adrenal mass. This is the first report of the case showing a complete vanishing of ruptured adrenal mass with takotsubo cardiomyopathy. Although surgical approaches for ruptured adrenal mass involve either emergency or elective surgery, the patients did not need even the elective surgery. Accumulation of the similar cases may unravel clinical factors predicting self-limiting of the ruptured adrenal mass to avoid unnecessary risky surgery.

Higher sympathetic activity as a risk factor for skeletal deterioration in pheochromocytoma

Despite the potential biological importance of sympathetic activity in human bone metabolism, its effects on bone microarchitecture, a key determinant of bone quality, has not been thoroughly studied. In the present study, we investigated the lumbar spine trabecular bone score (TBS) as an indicator of skeletal deterioration in pheochromocytoma. Among 620 consecutive patients with newly diagnosed adrenal incidentaloma, 29 with histologically confirmed pheochromocytoma (a catecholamine-secreting neuroendocrine tumor) and 266 with nonfunctional adrenal incidentaloma were defined as cases and controls, respectively. After adjustment for confounders, subjects with pheochromocytoma had 2.9% lower lumbar spine TBS than those without pheochromocytoma (P = 0.038). Moreover, urinary normetanephrine level, but not urinary metanephrine level, was inversely correlated with lumbar spine TBS (P = 0.009). Subjects in the highest urinary normetanephrine quartile showed markedly lower lumbar spine TBS than those in the lowest quartile (P = 0.018), in a dose-response manner across increasing urinary normetanephrine quartile categories (P for trend = 0.021). Consistent with the results of previous studies, subjects with pheochromocytoma had significantly lower bone mass at the lumbar spine and higher serum level of C-terminal telopeptide of type I collagen than controls (P = 0.013 and 0.002, respectively). These findings provide clinical evidence that catecholamine excess and the resultant sympathetic overstimulation in pheochromocytoma may contribute to bone fragility, especially in the trabecular bone, through a weak microarchitecture in addition to a lower bone mass and increased bone resorption, and support the possibility of pheochromocytoma as a secondary cause of osteoporosis.

[Biological diagnosis of pheochromocytoma: is there an interest in urinary metanephrines measurement over 3 consecutive days?]

Pheochromocytoma and paraganglioma are neuroendocrine tumors characterized by a catecholamine production potential. The biochemical diagnosis for this type of tumor is carried out through the metanephrine titration on 24-hours urines. Some authors have suggested that the sensitivity of the test could be improved by sampling and analyzing urines 3 days in a row (cycle) versus a unique measurement but this method has never been fully evaluated. The goal of this study was to establish a comparison of diagnosis performances between urinary metanephrines measurement for 3 consecutive days, and metanephrines measurement on a unique 24-hour sample. Patients of Brest Regional University Hospital whose 3-consecutive day 24-hour urine samples had been analyzed from January 2011 to May 2017 were included in this study. The primary endpoint was the comparison of diagnostic performances of urinary metanephrine titration over a single day versus 3 consecutive days. Eighty-two patients for a total of 103 cycles among which 7 revealed a pheochromocytoma were analyzed. ROC curve analysis shows that the metanephrine cycle titration method is more efficient than the metanephrine single titration method (metanephrine: AUC=0.881 against 0.826 respectively; normetanephrine: AUC=0.946 against 0.901 respectively). Urinary titration over 3 days allows the diagnosis of 100% (7/7) of pheochromocytomas against 85.7% (6/7) for the the single urinary titration. In conclusion, metanephrine titration over 3 consecutive days of 24-hours urine samples shows a better sensitivity and better diagnosis performances for detecting pheochromocytoma and paraganglioma than the single titration method.

Malignant Pheochromocytoma in Multiple Endocrine Neoplasia Type 2B Syndrome. Case Report and Review of the Literature

A malignant behavior (i.e., distant metastatic spread) has been recorded in 3-4% of pheochromocytomas occurring in the context of multiple endocrine neoplasia type 2A syndrome, but has never been documented in patients with the type 2B form. In this report we describe a case of malignant pheochromocytoma arising in the latter syndrome setting. The patient, a white young male, had the full-blown syndrome, including multicentric, bilateral medullary thyroid carcinoma metastatic to regional lymph nodes, mucosal neuromas, digestive ganglioneuromatosis, marfanoid habitus, and bumpy lips. Three and a half years after surgical resection of an apparently benign adrenal pheochromocytoma he developed widespread osseous metastases. The presence of hypertensive crises and high urinary catecholamine excretion rates, coupled to moderate hypercalcitoninemia, normal circulating carcinoembryonic antigen levels, negative whole-body 99mTc-(V) dimercaptosuccinic acid scan, and absence of neck or mediastinal disease by magnetic resonance imaging, proved that the metastases were from his previous adrenal and not thyroid tumor. Furthermore, since the bone metastases strongly accumulated 131I-metaiodobenzylguanidine, several courses of the radiocompound were given, which resulted in an objective, though partial, tumor regression.

Changes in Body Mass Index in Pheochromocytoma Patients Following Adrenalectomy

Catecholamine excess from pheochromocytoma results in cardiovascular symptoms such as arterial hypertension and tachycardia and induces metabolic alterations including glucose intolerance and increase in resting metabolic rate. The objective of our study was to investigate the effect of surgical cure of pheochromocytoma on body-mass-index and the correlation of body-mass-index changes to preoperative endocrine parameters. Pheochromocytoma patients from the Munich ENSAT Registry were matched (1:2) for age and gender to patients from the German Conn's Registry, who had undergone surgery for aldosterone-producing-adenomas. Thereby, 43 pheochromocytoma patients (17 males/26 females) and 86 aldosterone-producing-adenoma patients were analyzed for body-mass-index, blood pressure, and catecholamine levels before and one year after adrenalectomy. Seventy-four percent of pheochromocytoma patients were hypertensive preoperatively and 48% one year postoperatively. Systolic blood pressure did not differ significantly in pre- and postoperative measurements whereas diastolic blood pressure was significantly reduced over time. Moreover, pheochromocytoma patients gained body weight (p<0.001) one year following adrenalectomy accompanied by significant increases in body-mass-index, whereas aldosterone-producing adenoma patients displayed a slight weight loss. Despite weight gain, diagnosis of diabetes mellitus dropped from 9 of 43 investigated pheochromocytoma patients at baseline to 4 at follow-up. A significant correlation between body-mass-index changes to the preoperative catecholamine levels was found only for urinary normetanephrines. These data suggest that normalization of chronic catecholamine excess by adrenalectomy is associated with an increase in body-mass-index, which is more pronounced in patients with high preoperative levels of urinary normetanephrines.

Symptom-dependent cut-offs of urine metanephrines improve diagnostic accuracy for detecting pheochromocytomas in two separate cohorts, compared to symptom-independent cut-offs

The development of advanced imaging techniques has increased the detection of subclinical pheochromocytomas. Because of the substantial proportions of subclinical pheochromocytomas, measurement of urine metanephrine concentrations is crucial due to detect or exclude pheochromocytoma. Although urine metanephrines are elevated in symptomatic subjects, diagnostic cut-offs according to the presence of adrenergic symptoms have not been studied. Pheochromocytomas patients who underwent adrenalectomy at Samsung Medical Center and a control group were compared to determine cut-off concentrations of urine metanephrines. An independent population was analyzed for urine metanephrines with different kits to validate the improvement in diagnostic accuracy using adjusted cut-offs. Symptom-dependent cut-offs of urine metanephrines were higher for symptomatic patients (307 μg/day in males, 235 μg/day in females for urine metanephrine, and 1,045 μg/day in males and 457 μg/day in females for urine normetanephrine) than for asymptomatic patients (206 μg/day in males, 199 μg/day in females for urine metanephrine, and 489 μg/day in males and 442 μg/day in females for urine normetanephrine). Symptom-dependent cut-offs of urine metanephrines improved a specificity from 92.7 % to 96.3 % and a high sensitivity of 97.8 % was maintained. Using the Symptom-dependent cut-offs raised diagnostic accuracy by 5.5 % (p <0.001). Similar trend was also observed in an independent population using different hormone kits. Using symptom-dependent cut-offs of urine metanephrines in symptomatic patients for pheochromocytomas resulted in a significant improvement in diagnostic accuracy in two separate cohorts.

Parkinson's disease: the effect of L-dopa therapy on urinary free catecholamines and metabolites

Background: L-dopa is an important antiparkinsonian drug. It is a precursor of dopamine and the other catecholamines. Potentially, administration of L-dopa could lead to increased urinary excretion of catecholamines and their metabolites to abnormal amounts. The current study aimed to determine these excretions in patients with Parkinson's disease (PD) receiving L-dopa compared with suitable controls. This is the first assessment of the effect of exogenous administration of L-dopa on urinary free metadrenalines.

Methods: Using one-way analysis of variance (ANOVA), urine catecholamines and metabolites, expressed as mmol per mole creatinine, were compared in: patients with PD who were receiving L-dopa; patients with PD but not receiving L-dopa; and patients without PD who were being investigated for the presence of phaechromocytoma but were found not to have the disease.

Results: Significantly higher values for urinary dopamine, homovanillic acid, free normetadrenaline and free metadrenaline were found in patients with PD receiving L-dopa compared with the other two control groups. In all the patients with PD, these four analytes were significantly correlated with daily dose of L-dopa.

Conclusion: L-dopa therapy can result in production of false positives for urinary excretion of dopamine, homovanillic acid, free normetadrenaline or free metadrenaline and thereby decrease the diagnostic value of these measurements in identifying phaeochromocytoma and related tumours.

Elevated urinary dopamine in adults and children

Background: Information on the significance of an elevated urinary dopamine is limited and can lead to misinterpretation of the cause of such a finding. This laboratory-based study examines the associations with elevated dopamine gathered from a significant number of patients.

Methods: The urine catecholamine and metabolite results of specimens (analysed by HPLC-ECD) from 5933 adults and 467 children were examined retrospectively over a 57-month period. Those with elevated dopamine were identified and the explanation for this finding was sought.

Results: In adults, the conditions associated with an elevated dopamine were: urine over-collection; drug effects (including those due to intravenous dopamine, L-dopa, methyldopa, clozapine, antidepressants and metoclopramide); clinical effects (including those due to phaeochromocytoma, carcinoid tumour and pregnancy). In children, high urine dopamine was found in cases of neuroblastoma, Costello syndrome, leukaemia, phaeochromocytoma, Menkes disease and rhabdomyosarcoma of the bladder.

Conclusions: A high urine dopamine was found in <3% of adult urine specimens. It was most commonly associated with: over-collection, probable drug effects and neural crest tumours. Neuroblastoma was the most common cause of elevated dopamine in children's specimens, although other associations are described. Some await explanation.

A simple and rapid analytical method based on solid-phase extraction and liquid chromatography-tandem mass spectrometry for the simultaneous determination of free catecholamines and metanephrines in urine and its application to routine clinical analysis

OBJECTIVES

Urinary catecholamines and metanephrines are biochemical indicators of pheochromocytoma. We developed and validated a rapid and precise analytical method based on solid-phase extraction (SPE) and liquid chromatography separation coupled to tandem mass spectrometry (LC-MS/MS) for measuring urinary free catecholamines and metanephrines in a clinical setting.

METHODS

Following SPE purification of catecholamines and metanephrines from urine specimens, chromatographic separation and quantitative detection were performed using LC-MS/MS. The developed method for simultaneous measurement of urinary free catecholamines and metanephrines was validated with clinical urine specimens and was compared with other clinical and biochemical results, including urinary total metanephrines, vanillylmandelic acid (VMA), and plasma free metanephrines.

RESULTS

The performance of our newly developed method for measuring urinary free epinephrine (EPI), norepinephrine (NE), dopamine (DA), metanephrine (MN), and normetanephrine (NMN), was acceptable. The recoveries and matrix effects of analytes were 61-107% and 84.5-130.7%. The linear ranges of each analyte were 3.8-2163μg/L, 7.4-2,359μg/L, 5.4-2,825μg/L, 3.5-2,466μg/L, and 3.7-2,569μg/L, and the coefficients of variation (CV) were less than 10% with respect to imprecision. Carryover and sample stability were also validated. Validation using clinical urine specimens by comparison with various biochemical results showed that urinary free metanephrines had comparable sensitivity (100%) and superior specificity (97.1%) to urinary total and plasma free metanephrines.

CONCLUSIONS

The facile and reliable simultaneous measurement method for urinary free catecholamines and metanephrines using LC-MS/MS developed in this study is helpful in obtaining information about multiple metabolites and is applicable to routine clinical settings for the screening of pheochromocytoma.

Incidental pheochromocytoma in a patient with nasopharyngeal carcinoma

Because the adrenal glands are common locations for metastases, pheochromocytoma is frequently misdiagnosed as adrenal metastasis in patients with a history of cancer. An incidental adrenal mass was detected during an abdominal computed tomography (CT) scan performed to stage the nasopharyngeal carcinoma in a 35-year-old male patient. The features of an adrenal mass on the CT, magnetic resonance imaging (MRI), and fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) were thought to show adrenal metastasis. However, the patient did not complain about flushing, palpitation, headache or excessive sweating. His blood pressure was 132/74 mmHg, and his pulse rate was 82 bpm. A pheochromocytoma was found during a biochemical diagnosis that evaluated the catecholamine in urine collected over a 24-hour period. The urine had elevated urinary adrenaline, metanephrine, and vanillylmandelic. An I123 MIBG scan showed avid tracer uptake in the right adrenal mass with no evidence of abnormal uptake elsewhere. A right adrenalectomy operation was performed and a diagnosis of pheochromocytoma was confirmed histopathologically. Incidental adrenal masses detected in the presence history of cancer should always be subjected to hormonal evaluation. Although patients may be asymptomatic, the probability of incidental pheochromocytoma should not be ignored.

Diagnosing phaeochromocytoma/paraganglioma in a patient presenting with critical illness: biochemistry versus imaging

Phaeochromocytomas and paragangliomas (PPGLs) are revealed by acute cardiovascular complications involving end-organ damage in up to 20% of cases, a presentation associated with particularly high risk for mortality. Among such cases, PPGLs should be considered in patients with unexplained left ventricular failure, multi-organ failure, hypertensive crises or shock. The diagnosis of PPGL commonly relies on measurements of metanephrines in plasma or urine. However, acute critical illness is usually associated with sympathoadrenal activation. Thus, levels of metanephrines in patients in an acute emergency or intensive care setting, whether treated or not with vasoactive drugs, usually cannot be used to reliably diagnose PPGL. Delays in provision of diagnostic test results, particularly when these require 24-h urine collections, may also be incompatible for any need for rapid decisions on patient management or therapeutic interventions. The acute emergency situation therefore represents one exception to the rule where imaging studies to search for a PPGL may be undertaken without biochemical evidence of a catecholamine-producing tumour.

Development of pheochromocytoma in ceramide synthase 2 null mice

Pheochromocytoma (PCC) and paraganglioma are rare neuroendocrine tumors of the adrenal medulla and sympathetic and parasympathetic paraganglia, for which mutations in ∼15 disease-associated genes have been identified. We now document the role of an additional gene in mice, the ceramide synthase 2 (CerS2) gene. CerS2, one of six mammalian CerS, synthesizes ceramides with very-long (C22-C24) chains. The CerS2 null mouse has been well characterized and displays lesions in several organs including the liver, lung and the brain. We now demonstrate that changes in the sphingolipid acyl chain profile of the adrenal gland lead to the generation of adrenal medullary tumors. Histological analyses revealed that about half of the CerS2 null mice developed PCC by ∼13 months, and the rest showed signs of medullary hyperplasia. Norepinephrine and normetanephrine levels in the urine were elevated at 7 months of age consistent with the morphological abnormalities found at later ages. Accumulation of ceroid in the X-zone was observed as early as 2 months of age and as a consequence, older mice displayed elevated levels of lysosomal cathepsins, reduced proteasome activity and reduced activity of mitochondrial complex IV by 6 months of age. Together, these findings implicate an additional pathway that can lead to PCC formation, which involves alterations in the sphingolipid acyl chain length. Analysis of the role of sphingolipids in PCC may lead to further understanding of the mechanism by which PCC develops, and might implicate the sphingolipid pathway as a possible novel therapeutic target for this rare tumor.

Diagnostic accuracy of plasma free metanephrines in a seated position compared with 24-hour urinary metanephrines in the investigation of pheochromocytoma

The aim of this study was to determine the diagnostic efficacy of free metanephrines in plasma samples drawn in the seated position compared with 24-h urinary metanephrines in detecting pheochromocytomas in Asian patients. This prospective study was conducted at Samsung Medical Center between May 2010 and July 2011. The study contained 245 subjects, including 28 patients with histologically-proven pheochromocytoma, 44 with histologically-proven non-pheochromocytoma, 112 controls suspected of having tumors but with negative investigations during two or more years of follow-up, and 45 healthy normotensive volunteers. Plasma-free metanephrines were measured by LC-MS/MS. The cut-off values with optimal sensitivity and specificity for plasma metanephrine and plasma normetanephrine were 0.33 nmol/L and 0.61 nmol/L, respectively. Both the plasma metanephrines measurement and urinary metanephrines measurement had a sensitivity of 96.4% (p = 1.00). However, the urinary metanephrines measurement was significantly more specific than the plasma metanephrines measurement (94.2% vs. 75.6%; p < 0.001). When we applied cut-off values based on BMI, specificity improved from 75.6% to 87.2%, with a comparable gain in sensitivity. From a diagnostic perspective, measurement of free metanephrines in plasma drawn in the seated position is highly sensitive but insufficiently specific when compared with measurement of 24-h urinary fractionated metanephrines. The specificity may be improved by applying cut-off values based on BMI. We suggest that free metanephrines in plasma drawn from seated position can also be used as an initial screening test to ensure that pheochromocytomas are not missed in Asian patients.

Catecholamine-Synthesizing Enzymes Are Expressed in Parasympathetic Head and Neck Paraganglioma Tissue

BACKGROUND/AIM

Increased dopamine production may be a feature of head and neck paraganglioma (HNPGL). 18F-fluorodihydroxyphenylalanine positron emission tomography scintigraphy has a high sensitivity for detecting HNPGLs. These observations strongly suggest that HNPGLs have the capacity for L-3,4-dihydroxyphenylalanine uptake and conversion towards dopamine. Therefore, our aim was to demonstrate the presence of catecholamine-synthesizing enzymes, i.e. tyrosine hydroxylase (TH), aromatic L-amino acid decarboxylase (AADC) and dopamine β-hydroxylase (DBH) in HNPGL tissue.

METHODS

A single-center study was performed among patients who underwent surgery for HNPGL at a single university referral center between 1994 and 2012. HNPGL tissue was immunohistochemically stained for TH, AADC and DBH. Data on paraganglioma-associated germline mutations, preoperative biochemical phenotype and imaging studies were retrieved. Catecholamine excess was defined as preoperative plasma and/or urinary levels of metanephrine, normetanephrine or 3-methoxytyramine above the upper reference limit.

RESULTS

Nineteen HNPGLs from 18 patients were evaluated. All tumor tissues (100%) stained positive for AADC, 6 (32%) for TH and 2 (11%) for DBH. Of 3 HNPGLs staining positive for DBH, 2 were also positive for AADC and TH. Catecholamine excess was only present in 1 patient (5%). The HNPGLs of this single patient only showed positive staining for AADC.

CONCLUSIONS

Catecholamine-synthesizing enzymes, in particular AADC, are expressed in the majority of HNPGL tissues.

In vivo fluorescence imaging and urinary monoamines as surrogate biomarkers of disease progression in a mouse model of pheochromocytoma

Pheochromocytoma (PHEO) is a rare but potentially lethal neuroendocrine tumor arising from catecholamine-producing chromaffin cells. Especially for metastatic PHEO, the availability of animal models is essential for developing novel therapies. For evaluating therapeutic outcome in rodent PHEO models, reliable quantification of multiple organ lesions depends on dedicated small-animal in vivo imaging, which is still challenging and only available at specialized research facilities. Here, we investigated whether whole-body fluorescence imaging and monitoring of urinary free monoamines provide suitable parameters for measuring tumor progression in a murine allograft model of PHEO. We generated an mCherry-expressing mouse PHEO cell line by lentiviral gene transfer. These cells were injected subcutaneously into nude mice to perform whole-body fluorescence imaging of tumor development. Urinary free monoamines were measured by liquid chromatography with tandem mass spectrometry. Tumor fluorescence intensity and urinary outputs of monoamines showed tumor growth-dependent increases (P < .001) over the 30 days of monitoring post-tumor engraftment. Concomitantly, systolic blood pressure was increased significantly during tumor growth. Tumor volume correlated significantly (P < .001) and strongly with tumor fluorescence intensity (rs = 0.946), and urinary outputs of dopamine (rs = 0.952), methoxytyramine (rs = 0.947), norepinephrine (rs = 0.756), and normetanephrine (rs = 0.949). Dopamine and methoxytyramine outputs allowed for detection of lesions at diameters below 2.3 mm. Our results demonstrate that mouse pheochromocytoma (MPC)-mCherry cell tumors are functionally similar to human PHEO. Both tumor fluorescence intensity and urinary outputs of free monoamines provide precise parameters of tumor progression in this sc mouse model of PHEO. This animal model will allow for testing new treatment strategies for chromaffin cell tumors.

Streamlining the imaging of clinically suspected pheochromocytoma: using urine metanephrines to decrease imaging costs

PURPOSE

To improve the cost efficiency of the imaging evaluation of clinically suspected pheochromocytoma by using 24-hour fractionated urine metanephrine (FUM) results.

METHODS

A retrospective review of I-123 meta-iodo-benzyl-guanidine single photon emission tomography (SPECT) computed tomography (CT) studies performed at our institution between January 2007 and February 2011 for clinically suspected pheochromocytoma was performed. SPECT-CT results from 70 patients were compared with results from 24-hour FUM analysis (within 2 months of SPECT-CT) and with relevant CT or magnetic resonance imaging studies (within 6 months of SPECT-CT). An imaging algorithm was developed to maximize cost efficiency without altering the final imaging interpretation. Actual imaging costs for the studied cohort were compared with the expected costs if this algorithm had been applied.

RESULTS

If the 24-hour FUMs were normal, then all the SPECT-CT studies were negative (16/70). Eighty-seven percent of patients with abnormal total metanephrine had a positive SPECT-CT. If the total metanephrine was normal but 1 or more of the metanephrine fractions were abnormal, then 39%-58% of the SPECT-CT studies were positive. Within this subgroup, none had a positive SPECT-CT if a CT or magnetic resonance image was negative or benign. The actual imaging costs averaged CAD$2833.19 per patient for this cohort. Applying a streamlined imaging algorithm guided by 24-hour FUM analysis would result in an average imaging cost of CAD$1225.97 per patient without an expected change in the final imaging impression.

CONCLUSION

By using 24-hour FUM results to streamline imaging, considerable cost savings per patient (56.7%) can be attained without a change in the final overall imaging interpretation.

Biochemical and radiological relationships in patients with pheochromocytoma: lessons from a case control study

BACKGROUND

An elevation of fractionated plasma or urinary metanephrine (MN) or nor-metanephrine (NMN), collectively called metanephrines (MN and NMN), >4-fold above the upper limit of normal (ULN) is usually considered to be diagnostic for pheochromocytoma (PHEO). There are a greater number of false positive results when the elevations are more modest.

AIM

To identify biochemical and radiological features in PHEOs with modest elevations (<4-fold above ULN) of metanephrines.

METHODOLOGY

We retrospectively reviewed the charts of 112 patients with PHEO (10% extra-adrenal) and 208 patients with a non-PHEO adrenal mass operated from 1997-2011, who had metanephrines measured pre-operatively. We divided PHEO into group 1 (n = 90) with metanephrines ≥4-fold ULN and group 2 (n = 22) with metanephrines <4-fold ULN. The non-PHEO group was designated as group 3.

RESULTS

The median (range) tumour size in group 1 and group 2 was 4·8 cm (1·7-22) and 3·0 cm (1·7-5) respectively (P < 0·001). All patients with PHEO in group 2 had a tumour <5 cm in size. The MN fraction was elevated in about 65% of groups 1 and 2; only 2 (1%) patients in group 3 had an elevated urinary MN fraction, and none were associated with an elevated plasma MN fraction. All PHEOs had a pre-contrast attenuation ≥17 Hounsfield Units (HU).

CONCLUSIONS

Modest elevations (<4-fold ULN) of the NMN fraction in an adrenal mass >5 cm are almost always falsely positive. Elevations in plasma and urinary MN fraction are less likely to be false positive. The CT pre-contrast attenuation of PHEOs is >10 HU.

A single pathophysiological pathway in Takotsubo cardiomyopathy: Catecholaminergic stress

BACKGROUND

Takotsubo cardiomyopathy (TTC) continues to be under-diagnosed, due to its varying presentation, with potentially serious consequences if treatment is delayed.

AIMS

To demonstrate the consistent involvement of catecholaminergic stress in TTC, regardless of the trigger.

METHODS

Between 01 July 2009 and 31 August 2013, patients managed in our centre for thoracic pain syndrome, with or without troponin release, were followed up prospectively. TTC was diagnosed from the apical ballooning seen on left ventricular imaging (angiography or transthoracic echocardiography) in the absence of a significant coronary artery lesion. Triggers (emotional trauma, surgical stress and β2-mimetic intoxication) were recorded; catecholamine-secreting tumours were screened for with a urinary methoxylate-derivative assay.

RESULTS

TTC was diagnosed in 40 out of 2754 (1.5%) patients with thoracic pain syndrome, with or without troponin release. Triggers were emotional trauma (n=29, 72.5%), surgical stress (n=5, 12.5%), adrenergic intoxication (n=3, 7.5%) and catecholaminergic tumour (n=3, 7.5%). Mean left ventricular ejection fraction at admission was 38.0 ± 15.7%. Eight (20%) patients initially showed cardiogenic shock. In-hospital mortality was 7.5%, with no deaths from cardiogenic causes. Thirty-five (94.6%) of the survivors had recovered a normal left ventricular ejection fraction (> 55%) by discharge.

CONCLUSION

Whatever the trigger, the common denominator in TTC is catecholaminergic stress. Classically suggested after emotional trauma, TTC may also be induced by surgical stress or endogenous or iatrogenic β2-mimetic intoxication. The various contexts all have a similarly excellent cardiovascular prognosis if treated early.

Plasma free metanephrines in the diagnosis of pheochromocytoma: diagnostic accuracy and strategies for Japanese patients

Measuring the levels of the plasma free metanephrines (PFMs) represents a recently developed and promising test for the diagnosis of pheochromocytoma in the United States and Europe. As this test has not yet been evaluated in Japan, it is necessary to evaluate the diagnostic efficacy of measuring the levels of PFMs compared with the standard measurement of the urinary excretion of metanephrines (uMNs) whose reliability is well established to detect of pheochromocytoma. A total of 101 Japanese subjects clinically suspected of having pheochromocytoma in were included in this study. Subsequently, we prospectively measured the PFMs levels in all patients, compared with those of biochemical markers of the catecholamine secretion and metabolisms in the plasma and urine. All subjects with adrenal tumors underwent tumor excision. Data were available for 84 of the 101 patients, 47 of whom had histopathologically proven pheochromocytoma and 37 were finally diagnosed with non-pheochromocytoma. The results of comparisons in the accuracy of measurement for diagnosis of pheochromocytoma between PFMs and the urinary excretion of metanephrines (uMNs) were 0.980 VS 0.951 for AUC of receiver operatorating characteristic (ROC) curve, 0.957 VS 0.894 for sensitivity, and 0.973 VS 0.946 for specificity, respectively. Although the differences were small, the results of our study definitely demonstrated that measurement of PFMs was not inferior to standard urinary metanephrines (uMNs) measurement, which is established to be the most reliable biochemical method to detect pheochromocytoma. This study clearly shows measuring the PFMs levels to be a reliable and efficient method for diagnosing pheochromocytoma in Japanese patients, as demonstrated in previous reports.

[Evaluation of urinary metanephrines for the diagnosis of pheochromocytoma]

OBJECTIVE

evaluate the assay of urinary metanephrines in diagnosis of pheochromocytoma (PH) and determine diagnostic cut-off values.

METHODS

this is a retrospective study about 87 patients suspected of pheochromocytoma,whose of 24-h urinary fractionated metanephrine was measured. These cases were collected from Internal Medecine Departments (A and B) at Charles Nicolle's Hospital. Two groups of patients were studied: a pheochromocytoma group (n=33) with a histologically-proven pheochromocytoma and a control group of 54 patients. Receiver Operating Characteristic (ROC) curves were used to determine the best sensitivities and specificities.

RESULTS

The analysis of biological parameters showed that means and standard deviation of urinary fractionated metanephrines in pheochromocytoma group were significantly higher than those of control group. Sensitivity and specificity of urinary normetanephrine test (95% and 98.1% respectively) were higher than those of urinary metanephrine and 3-methoxytyramine. A correlation between urinary normetanephrine and tumor size of pheochromocytoma was found.

CONCLUSION

Urinary fractionated metanephrines is an efficient biochemical test for the diagnosis of pheochromocytoma.

Levodopa therapy in Parkinson's disease: influence on liquid chromatographic tandem mass spectrometric-based measurements of plasma and urinary normetanephrine, metanephrine and methoxytyramine

BACKGROUND

Medication-related interferences with measurements of catecholamines and their metabolites represent important causes of false-positive results during diagnosis of phaeochromocytomas and paragangliomas (PPGLs). Such interferences are less troublesome with measurements by liquid chromatography with tandem mass-spectrometry (LC-MS/MS) than by other methods, but can still present problems for some drugs. Levodopa, the precursor for dopamine used in the treatment of Parkinson's disease, represents one potentially interfering medication.

METHODS

Plasma and urine samples, obtained from 20 Parkinsonian patients receiving levodopa, were analysed for concentrations of catecholamines and their O-methylated metabolites by LC-MS/MS. Results were compared with those from a group of 120 age-matched subjects and 18 patients with PPGLs.

RESULTS

Plasma and urinary free and deconjugated (free + conjugated) methoxytyramine, as well as urinary dopamine, showed 22- to 148-fold higher (P < 0.0001) concentrations in patients receiving levodopa than in the reference group. In contrast, plasma normetanephrine, urinary noradrenaline and urinary free and deconjugated normetanephrine concentrations were unaffected. Plasma free metanephrine, urinary adrenaline and urinary free and deconjugated metanephrine all showed higher (P < 0.05) concentrations in Parkinsonian patients than the reference group, but this was only a problem for adrenaline. Similar to normetanephrine, plasma and urinary metanephrine remained below the 97.5 percentiles of the reference group in almost all Parkinsonian patients.

CONCLUSIONS

These data establish that although levodopa treatment confounds identification of PPGLs that produce dopamine, the therapy is not a problem for use of LC-MS/MS measurements of plasma and urinary normetanephrine and metanephrine to diagnose more commonly encountered PPGLs that produce noradrenaline or adrenaline.

[Familial paraganglioma syndrome: phenotype and relevance of a new SDHB mutation]

BACKGROUND AND OBJECTIVE

Advances in molecular biology have discovered new genes involved in the development of familial paraganglioma syndrome (PGL) including those encoding mitochondrial succinate dehydrogenase complex (SDH). We describe the diagnosis, clinical expression and genetic counselling in a family diagnosed of PGL due to a new SDHB mutation.

PATIENTS AND METHOD

Genetic study by PCR-direct sequencing SDHB gene and biochemical determination in blood/urine fractionated catecholamine 24h, metanephrines and conventional (computed tomography/magnetic resonance imaging) and functional imaging ((123)I-MIBG) in all members of a family diagnosed of PGL.

RESULT

DNA sequencing showed a non-described SDHB heterozygous mutation (c.287-3C>G intron3/exon4) in 5 of the subjects (71%). The estimated penetrance of the mutation's carriers was 40%, with a mean age of 35 years at diagnosis. All patients with active illness required surgical treatment after imaging and laboratory confirmation.

CONCLUSIONS

We describe the pathogenicity, diagnostic algorithm, genetic counselling and clinical expression of a new SDHB mutation (c.287-3C>G) in a family diagnosed of PGL.

Unilateral and bilateral adrenalectomy for pheochromocytoma requires adjustment of urinary and plasma metanephrine reference ranges

CONTEXT

Follow-up after adrenalectomy for pheochromocytoma is recommended because of a recurrence risk. During follow-up, plasma and/or urinary metanephrine (MN) and normetanephrine (NMN) are interpreted using reference ranges obtained in healthy subjects.

OBJECTIVE

Because adrenalectomy may decrease epinephrine production, we compared MN and NMN concentrations in patients after adrenalectomy to concentrations in a healthy reference population.

DESIGN

A single-center cohort study was performed in pheochromocytoma patients after adrenalectomy between 1980 and 2011.

SUBJECTS

Seventy patients after unilateral and 24 after bilateral adrenalectomy were included.

MAIN OUTCOME MEASURES

Plasma-free and urinary-deconjugated MN and NMN determined at 3 to 6 months and annually until 5 years after adrenalectomy were compared with concentrations in a reference population. Data are presented in median (interquartile range).

RESULTS

Urinary and plasma MN concentrations 3 to 6 months after unilateral adrenalectomy were lower compared with the reference population (39 [31-53] μmol/mol creatinine and 0.14 [0.09-0.18] nmol/L vs 61 [49-74] μmol/mol creatinine and 0.18 [0.13-0.23] nmol/L, respectively, both P < .05). Urinary MN after bilateral adrenalectomy was reduced even further (7 [1-22] μmol/mol creatinine; P < .05). Urinary and plasma NMN were higher after unilateral adrenalectomy (151 [117-189] μmol/mol creatinine and 0.78 [0.59-1.00] nmol/L vs 114 [98-176] μmol/mol creatinine and 0.53 [0.41-0.70] nmol/L; both P < .05). Urinary NMN after bilateral adrenalectomy was higher (177 [106-238] μmol/mol creatinine; P < .05). Changes in urinary and plasma MNs persisted during follow-up.

CONCLUSION

Concentrations of MN are decreased, whereas NMN concentrations are increased after unilateral and bilateral adrenalectomy. Adjusted reference values for MN and NMN are needed in the postsurgical follow-up of pheochromocytoma patients.

Pheochromocytoma--analysis of 15 consecutive cases from one centre

INTRODUCTION

Pheochromocytoma is a rare tumour, but one of great clinical importance as a risk factor of malignancy, cardiovascular diseases and sudden death.

MATERIAL AND METHODS

15 consecutive patients (eight women and seven men) were hospitalised and submitted for adrenalectomy with pheochromocytoma confirmed by histopathologic examination. Adrenalectomies were performed laparoscopically in 14 cases (93.3%): in nine by the retroperitoneal posterior mode and in five by the transperitoneal lateral approach.

RESULTS

Molecular-genetic examination of VHL, RET, SDHB, SDHC and SDHD genes revealed inherited predisposition for PHEO in three of 15 patients (20%): RET mutations typical for MEN 2a in two patients and VHL mutation in one patient. Disturbances of the carbohydrate metabolism occurred in nine patients (60%). Ten patients (66%) reported paroxysmal symptoms. In all cases, with the exception of a von Hippel-Lindau patient, density of tumours exceeded 20 HU. In all studied patients, urine concentration of normetanephrines exceeded their normal range and greatly prevailed over metanephrines values, which were increased in six of them (40%).

CONCLUSIONS

Urine metoxycatecholamines and increased tissue density are sufficient in pheochromocytoma detection. However, taking into account clinical and supplemental biochemical data may be helpful in the diagnostic process. Laparoscopic adrenalectomy is a fully sufficient and safe method of pheochromocytoma excision.

Different diagnostic cut-off values of urinary fractionated metanephrines according to sex for the diagnosis of pheochromocytoma in Korean subjects

The diagnosis of pheochromocytoma depends on the documentation of catecholamine overproduction. The use of urinary fractionated metanephrines has recently become common for the diagnosis of pheochromocytoma. In order to avoid false positive and false negative results, optimal cut-off levels are necessary; however, there have been few published reports on whether different cut-off levels are needed to diagnose pheochromocytoma according to sex. We reviewed the medical records of 815 subjects (including 103 pheochromocytoma patients) whose of 24-h urinary fractionated metanephrine was measured using high-performance liquid chromatography methods and adrenal imaging at Samsung Medical Center. Receiver operating characteristic (ROC) curves were used to determine cut-off values according to sex. The upper limit values of fractionated metanephrine in healthy volunteers and the control group were significantly higher in male subjects compared with females. When we applied cut-off values according to sex, the diagnostic efficacies (defining a positive test as either metanephrine or normetanephrine levels above the cut-off value) were a sensitivity of 96% in male subjects and 98.1% in female subjects and a specificity of 88.6% in male subjects and 94.1% in female subjects. However, when we applied cut-off values without considering sex, the specificity decreased from 88.6% to 77.8% in male subjects. In this study, urinary fractionated metanephrines had a high level of sensitivity and specificity for the diagnosis of pheochromocytoma. However, diagnostic cut-off values were higher in male subjects than in female subjects. Therefore, different cut-off values may be needed according to sex to diagnose pheochromocytoma in Koreans.

Be wary of a mature adult, who presents with a parent

The importance of interviewing a patient alone cannot be overemphasised, especially when a mature adult patient presents with a parent. We present the case of a 47-year-old man who was seen in the outpatient clinic with his mother, as his general practitioner (GP) was concerned whether he had a pheochromocytoma. The GP had arranged a CT scan of the abdomen, to investigate for an abdominal cause for oedematous legs. This had picked a benign growth in the right adrenal gland. A 24-hour urinary normetanephrine level checked was raised. Further tests and regular monitoring showed persistently raised levels of catecholamines to the point that adrenalectomy was being considered. He was always accompanied by his mother except on the clinic visit, when he admitted to taking amphetamine. Urinary catecholamine levels normalised, after he stopped taking it.

When is a phaeo not a phaeo? Depression in an adolescent leading to a phaeochromocytoma-like biochemical profile

A pheochromocytoma was suspected in a 14 year old boy. Elevated urinary and plasma catecholamines as well as clonidine test were consistent with the diagnosis. However, imaging studies were negative, and biochemical abnormalities normalized with treatment of concomitant depression. It is important to consider an array of confounders, including psychiatric conditions, when testing for pheochromocytoma.

Catecholamine metabolomic and secretory phenotypes in phaeochromocytoma

Phaeochromocytomas and paragangliomas (PPGLs) are highly heterogeneous tumours with variable catecholamine biochemical phenotypes and diverse hereditary backgrounds. This analysis of 18 catecholamine-related plasma and urinary biomarkers in 365 patients with PPGLs and 846 subjects without PPGLs examined how catecholamine metabolomic profiles are impacted by hereditary background and relate to variable hormone secretion. Catecholamine secretion was assessed in a subgroup of 156 patients from whom tumour tissue was available for measurements of catecholamine contents. Among all analytes, the free catecholamine O-methylated metabolites measured in plasma showed the largest tumour-related increases relative to the reference group. Patients with tumours due to multiple endocrine neoplasia type 2 and neurofibromatosis type 1 (NF1) showed similar catecholamine metabolite and secretory profiles to patients with adrenaline-producing tumours and no evident hereditary background. Tumours from these three patient groups contained higher contents of catecholamines, but secreted the hormones at lower rates than tumours that did not contain appreciable adrenaline, the latter including PPGLs due to von Hippel-Lindau (VHL) and succinate dehydrogenase (SDH) gene mutations. Large increases of plasma dopamine and its metabolites additionally characterised patients with PPGLs due to the latter mutations, whereas patients with NF1 were characterised by large increases in plasma dihydroxyphenylglycol and dihydroxyphenylacetic acid, the deaminated metabolites of noradrenaline and dopamine. This analysis establishes the utility of comprehensive catecholamine metabolite profiling for characterising the distinct and highly diverse catecholamine metabolomic and secretory phenotypes among different groups of patients with PPGLs. The data further suggest developmental origins of PPGLs from different populations of chromaffin cell progenitors.

Adrenergic myocarditis in pheochromocytoma

The clinical presentation of pheochromocytoma is variable and many biochemical and imaging methods have been suggested to improve the diagnostic accuracy of what has been termed "the great masquerader". This case-report is of a middle-aged woman with a non-specific clinical presentation suggesting acute coronary syndrome or subacute myocarditis. Cardiovascular magnetic resonance (CMR) at presentation showed myocardial edema and intramyocardial late gadolinium enhancement (LGE). An adrenal mass was seen, which was confirmed as pheochromocytoma and surgically removed. Our case shows evidence for acute adrenergic myocarditis, with resolution of both the edema and the LGE after surgical excision.

[Diagnosis of pheochromocytoma in Yaoundé (Cameroon): a study of nine cases]

The aim of this study was to describe methods used for diagnosis of pheochromocytoma inYaoundé, Cameroon. This retrospective study was based on analysis of the charts of patients treated in the surgical department of the Yaoundé University Teaching Hospital from 1985 to 2009. Nine patients with histologically confirmed pheochromocytoma were identified. There were 8 women and 1 man with a mean age of 39.5 years (range, 12 and 66). Pheochromocytoma was associated with hypertension in 6 cases. In two women with hypertension, diagnosis was based on palpation of an abdominal tumor after caesarean section following pregnancy associated with arterial hypertension. In another woman, diagnosis was made during laparotomy for a left hypochondrial tumor. In 7 patients, diagnosis was based on laboratory findings showing high urinary levels of vanyl mandelic acid (VMA). In six patients, ultrasound examination allowed topographic diagnosis that was confirmed by CT-scan in 3 cases. Two patients presented extra-renal pheochromocytomas in the abdomen. In three patients, i.e., one third of cases, histology showed malignant features. The findings of this study indicated that diagnosis of pheochromocytoma in Yaoundé be improved with the introduction MRI, scintigraphy, and modern techniques for assaying urinary methoxyderivates.

Diagnostic accuracy of free and total metanephrines in plasma and fractionated metanephrines in urine of patients with pheochromocytoma

BACKGROUND

Plasma free and urinary metanephrines are recognized biomarkers for the assessment of pheochromocytoma. Plasma total metanephrines with a long half-life may represent another useful biomarker.

OBJECTIVE

The aim of this study is to evaluate the diagnostic performances of plasma total metanephrines alone or combined with free metanephrines and fractionated 24-h urinary metanephrines.

METHODS

A retrospective, case-control diagnostic test study was conducted between 1999 and 2007 in two university hospitals in Switzerland and two institutions in France. The patients included 46 cases with histologically proven pheochromocytoma, and 181 controls suspected of tumor with negative investigations and 3-year follow-up. None had renal dysfunction. Sensitivity and specificity were compared after expressing each measurement result as a ratio over its upper reference limit, adding the ratios of normetanephrine and metanephrine, and defining cut-off values of 1 or 2 for this sum.

RESULTS

Applying a cut-off value of 1, plasma free and total metanephrines and urinary fractionated metanephrines had similar sensitivities of 96% (95% confidence interval, 86-99%), 95% (85-99%), and 95% (84-99%) along with similar specificities of 89% (83-94%), 91% (84-95%), and 86% (80-91%). A cut-off of 2 for the sum of ratios over reference limit improves the specificity, and it can be used for a confirmation test based on another biomarker taken among the three biomarkers.

CONCLUSION

All three metanephrine-based tests perform equivalently for diagnosing pheochromocytoma in the absence of renal insufficiency, and can be conveniently associated two by two for confirming/excluding tumor.

Obstructive sleep apnea presenting as pseudopheochromocytoma

A 39-year-old man with a history of poorly controlled hypertension presented with a 2-year history of fatigue, daytime somnolence, and intermittent episodes of diaphoresis and palpitations. Episodes were self-limiting, lasting approximately 5-10 minutes and occurred several times per month, most notably at night. Laboratory evaluation was significant for elevated 24-h urinary catecholamine levels, suggestive of pheochromocytoma. However, thorough imaging failed to identify a catecholamine-secreting tumor. Subsequent polysomnography revealed severe obstructive sleep apnea, with an apnea-hypopnea index of 112 events/h. After one month of continuous positive airway pressure therapy, the patient experienced resolution of his presenting symptoms, improved blood pressure control and normalization of his urinary catecholamine levels. This case highlights sleep disordered breathing as a potentially reversible cause of pseudopheochromocytoma.

[Diagnostic difficulties in recognizing of pheochromocytoma]

Pheochromocytoma (PH) is a tumour of chromaffin cells of the sympathetic nervous system and its clinical symptoms are associated with excessive production and release of catecholamines. The main criterion for clinical diagnosis of PH is finding increased concentrations of catecholamines or their metabolites in serum and/or urine. The largest diagnostic and therapeutic problems are patients with slightly elevated levels of methoxycatecholamines in serum and/ or urine. Aim of this study was to determine the cut-off point for elevated methoxycatecholamine in the collection of daily urine, which would give the basis for determining the reasonable recommendations of the biochemical criteria for diagnosis of PH. Retrospectively we analysed the results of 45 patients sent to laparoscopic adrenalectomy to the Department of General Surgery II with the preoperative diagnosis of pheochromocytoma. The diagnosis of pheochromocytoma was based on the finding of elevated 24-hour urine methoxycatecholamines. Based on the results of the histopathological examination patients were divided into two groups. Group 1 included 27 patients (14 women and 13 men) with histopathologically confirmed pheochromocytoma of adrenal gland. Group 2 consisted of 18 patients (11 women and 7 men), in which histopathological examination did not confirm the presence of pheochromocytoma. Mean age of patients in group 1: 46.8 +/- 14.4 years, in group 2: 55.7 +/- 13.7 years. Hypertension was diagnosed in 77.8% of those with group 1 and 94.4% from group 2. Based on the analyzed results of the CT, we found that the average tumor size in group 1 (4.2 +/- 1.9 cm) was statistically higher than in group 2 (2.9 +/- 1.1 cm). The average concentration of normetanephrine (NMN) in 24-hour urine in group 1 was statistically significantly higher than in group 2 (2,686 +/- 870.4 vs. 2375.1 +/- 754 mg/24h), as well as the average concentration of metanephrine (MN) (2533.4 +/- 3269.3 +/- 491.6 vs. 371.5 mg/24 hrs), and the sum of both methoxycatecholamines (NMN + MN) (5219.3 +/- 5190.6 vs. 1241.8 +/- 1202.2). The highest sensitivity in diagnosing pheochromocytoma with the rate of 81.5% was obtained for the sum of normetanephrine and metanephrine in 24-hour urine, while the sensivity for levels of each methoxycatecholamine separately was similar (63%). The highest specificity in the exclusion of PH was shown for 24-hour urine metanephrine (94.4%). The highest positive predictive value was found for the level of metanephrine in 24-hour urine (94.4%). The diagnostic cutoff concentrations of NMN, MN and NMN + MN for the diagnosis of pheochromocytoma were set. For the 24-hour urine NMN- cut-off > 1500 ug/24 h, for MN > 700 ug/24h and for NMN + MN > 1350 ug/24h. Shown above cut-off levels of methoxycatecholamines urine concentration will allow to pose a more accurate preoperative diagnosis of PH.