Free Metanephrines Research Articles

Simple, rapid, and cost-effective microextraction by the packed sorbent method for quantifying of urinary free catecholamines and metanephrines using liquid chromatography-tandem mass spectrometry and its application in clinical analysis.

Pheochromocytoma and paraganglioma (PPGL) are rare neuroendocrine tumors arising from adrenal and extra-adrenal chromaffin cells. They produce excessive amounts of catecholamines and their metabolites. A newly analytical procedure based on the semi-automated microextraction by packed sorbent (MEPS) technique, using a digitally controlled syringe (eVol) combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS), was developed to quantify free urinary catecholamines and metanephrines. The important parameters affecting MEPS performance, namely the type of sorbent material (porous graphitized carbon (PGC), polar enhanced polymer (PEP), cation-exchange (CX) and C18), number of extraction cycles, and elution solvent system, were evaluated. The optimal experimental conditions involved the loading of sample mixture in seven extraction cycles through a C18 sorbent in a MEPS syringe, followed by using elution solutions (water/acetonitrile/formic acid, 95/4.75/0.25). The entire sample preparation took about 4min. Chromatographic separation was well achieved with an HSS PFP column using the gradient elution. The linearity range of the method was 0.167-33.4ng/mL for epinephrine, 0.650-130ng/mL for norepinephrine, 1.53-306ng/mL for dopamine, 1.34-268ng/mL for metanephrine, 3.43-686ng/mL for normetanephrine, and 1.33-265ng/mL for 3-methoxytyramine. The intra- and interassay precisions were ≤ 12.8%, and the respective accuracies were 88.4-112.0% and 89.0-109.5%. The carryover and sample stability without acidification were also investigated. Validation using clinical urine specimens showed that the proposed method had higher sensitivity compared with other urinary biochemical tests. The developed MEPS-LC-MS/MS method was simple, fast, and cost-effective; it helped to obtain information about multiple metabolites. It is applicable in routine clinical laboratories for the screening of PPGL. Graphical abstract.

Surgical approach to patients with pheochromocytoma.

Pheochromocytomas and paragangliomas (PPGLs) are rare neuroendocrine tumors that secrete excess catecholamines leading to secondary hypertension and cardiovascular morbidity. Once biochemical testing with either 24-hour urinary fractioned metanephrines or plasma free metanephrines confirms the diagnosis, patients are optimized with adequate hydration to maintain their intravascular volume and the appropriate antihypertensive medications are initiated for optimal blood pressure control. Genetic testing and imaging is performed to determine the extent of adrenalectomy and the optimal surgical approach. Surgical approaches include transabdominal or retroperitoneal minimally invasive approaches, and transabdominal open approaches. Factors that influence the surgical approach include germline genetic test results, the size of the tumor, body mass index, surgeon experience, and the likelihood of malignancy. The extent of adrenalectomy is based on germline genetic findings. Patients with syndromes such as von Hippel Lindau (VHL) or multiple endocrine neoplasia 2 (MEN 2) benefit from cortical-sparing adrenalectomy to avoid chronic steroid replacement and the risk of Addisonian crisis. Postoperative management includes hemodynamic monitoring and assessment for signs of hypoglycemia. Outcomes after surgery show improved blood pressure control in most patients and normalization of blood pressure in about a third of patients. Long-term follow-up is required for all patients to assess for recurrence.

Pheochromocytoma and Paraganglioma: From Clinical Findings to Diagnosis.

The majority of pheochromocytoma (PCC) and paraganglioma (PGL) are endocrine active tumors, and they cause clinical symptoms by secreting excess one or more catecholamines (epinephrine, norepinephrine, and dopamine) and their inactive metabolites (metanephrine, normetanephrine, 3-metoxythromine). Although signs and symptoms regarding excess catecholamine often develop in PCC and PGL (PPGL), non-functional PPGLs may present with local compression symptoms. Persistent, sometimes worsening hypertension is the most common finding and occurs in 80-90% of the patients. Classically defined symptom triad; headache, sweating and palpitations are seen in only 25% of the patients with PCC. The difference of clinical symptoms may be related to the tumor secretion, epinephrine or norepinephrine. All patients with signs and symptoms suggestive of catecholamine excess should be screened by biochemical tests regardless of whether they have hypertension or not. Not all patients with newly diagnosed hypertension need to be screened, but only patients with additional tips for catecholamine excess should be screened. Approximately 20% of the PPGLs are diagnosed in childhood, and the male/female ratio is 2/1. 60-90% of pediatric patients present with hypertension. PPGL in pregnancy is rare, and the estimated incidence ranges between 1/15000-1/54000. Although early diagnosis is the most important factor in preventing mortality, diagnosis is not as easy as it is a rare condition. Hypertension is a common complication in pregnancy, occurring in 5-10%. Computed tomography should not be used as the imaging method during pregnancy; the first choice is magnetic resonance imaging with gadolinium or without contrast. Plasma free metanephrine or 24-hour urinary fractionated metanephrine level is recommended as a screening test for the diagnosis of PPGL in the Endocrine Society Clinical Practice Guideline. In suspicious situations, tests should be repeated. Since 40% of these patients have germline mutations, genetic tests are recommended for all patients with PPGL regardless of family history and age. Preoperative knowledge of germline mutations affects the surgical approach and the extent of adrenalectomy. After the biochemical diagnosis is made in PPGL, the tumor is localized with imaging methods to make the operation plan. In this review, we aimed to evaluate the clinical findings, diagnostic tests, and imaging studies for tumor localization in PPGL.

A simple and robust liquid chromatography tandem mass spectrometry assay for determination of plasma free metanephrines and its application to routine clinical testing for diagnosis of pheochromocytoma.

Plasma free metanephrines (PFMs) have high sensitivity for detecting pheochromocytoma (PCC). Herein, we developed a simple and reliable liquid chromatography tandem mass spectrometry assay for PFMs determination in Chinese population. PFMs were enriched by SPE without requiring extract evaporation or the use of buffers containing nonvolatile salts. The analytes were analyzed in multiple reaction monitoring mode. Inter- and intra-assay precisions were ≤4.3% and ≤ 6.3%. The lower limits of quantification were 0.07 nmol/L for metanephrine and 0.06 nmol/L for normetanephrine. Recoveries of PFMs were in the range of 89.3-113%. The method was free from significant matrix effect, carryover and interference. Owing to its fast analysis time, more than 150 samples/day could be easily performed by a single operator. With the established reference intervals of PFMs in the Chinese population, this simple and robust LC-MS/MS method could be valuable for use in routine clinical laboratories. It is noted that the combined tests of PFMs with urinary catecholamines or urinary vanillylmandelic acid could improve specificity.

CAN WE USE FREE METANEPHRINE TO IMPROVE INTERPRETATION OF ADRENAL VENOUS SAMPLING ?

Objective: Adrenal venous sampling (AVS) is the gold standard to assess lateralization of aldosterone secretion in primary aldosteronism (PA). The selectivity index (SIcortisol, adrenal:peripheral cortisol ratio) determines correct catheter positioning. The lateralization index (LIcortisol, aldosterone:cortisol ratios between adrenal veins) distinguishes unilateral aldosterone producing adenoma (APA) from bilateral adrenal hyperplasia (BAH). Cortisol is not always reliable and metanephrine has been alternatively suggested for SI determination. The aim of our study was to assess the performance of SImetanephrine and LImetanephrine. Design and method: This retrospective study conducted at the HEGP ESH excellence center included 245 patients who had 1) AVS with simultaneous adrenal and peripheral vein samplings without cosyntropin stimulation between 07/2013 and 05/2017, 2) adrenal and peripheral vein samples stored at −80°C to measure retrospectively free metanephrine. Receiver operating characteristic (ROC) curves were used to assess the performance of SImetanephrine and LImetanephrine. Results: Based on SIcortisol and LIcortisol, 198/245 patients had successful AVS (SIcortisol above 2) among whom 108 had APA (LIcortisol above 4) and 90 BAH (LIcortisol below 4). 48/245 patients had failed AVS. Among the 245 AVS, 434 adrenal samples had SIcortisol above 2. A SImetanephrine of 16 was the optimal threshold for successful AVS. This cutoff confirms the selectivity of 22 AVS among the 48 considered as non-selective with SIcortisol. 65 patients underwent unilateral adrenalectomy with 6-month follow up confirming PA biochemical cure (PASO criteria). ROC curve analysis of LImetanephrine plotted APA (n = 65) versus BAH (n = 52) (AUC = 0.954). There was a large overlap of LImetanephrine between APA and BAH. A LImetanephrine threshold of 5 had 80% sensitivity and 95% specificity to distinguish between APA from BAH. Conclusions: We confirmed that SImetanephrine is superior to SIcortisol in assessing the selectivity of AVS. A threshold of 16 for SImetanephrine decreased the rate of AVS falsely considered as failed. In contrast, LImetanephrine did not have enough sensitivity/specificity to distinguish between APA and BAH. The lack of a gold standard to confirm BAH may participate in this finding. A prospective study would be needed to confirm these results

Performance of plasma free metanephrines in diagnosis of pheochromocytomas and paragangliomas in the population of Asturias

IntroductionPheochromocytoma and paraganglioma are uncommon tumours whose best known symptoms include high blood pressure, palpitations, headache, and sweating. Clinical identification is not easy, however, and requires biochemical tests that allow for early diagnosis, including measurement of metanephrines levels. The aim of this study was to assess the diagnostic performance of plasma free metanephrines (PMETs) and to verify the transferability of the reference values used. MethodsPMETs levels were measured by liquid chromatography coupled to tandem mass spectrometry. Other biochemical tests evaluated (plasma catecholamine, urine metanephrine, catecholamine and vanilmandelic acid levels) were performed by liquid chromatography with electrochemical detection. Requests of these tests from 01/09/2015 to 31/10/2017 were reviewed, and both the reference values (document EP28-A3c) and the parameters of biological variation (Fraser method) for PMETs were estimated. ResultsThe study sample consisted of 1279 patients (61.3% females) aged 0–90 years, including 19 with pheochromocytoma/paraganglioma. Tests requested included: PMETs (n=662), catecholamines (n=589), metanephrines (n=586), and vanilmandelic acid (n=513) in urine, and plasma catecholamines (n=228). Tests with higher sensitivity were urinary fractionated metanephrines (91.7%) and PMETs (82.4%). When performance was compared in patients with both tests (n=243), they detected the same number of tumours (90.9%), but PMETs showed greater specificity (93.5% vs. 88.8%). Plasma normetanephrine levels showed a significant association with age (rho=0.19, p<0.0001). ConclusionPMETs and urinary fractionated metanephrines are the biochemical tests with better performance in diagnosis of pheochromocytomas/paragangliomas.

Short-term stability of free metanephrines in plasma and whole blood.

Background Analysis of plasma metanephrine (MN) and normetanephrine (NMN) with liquid chromatography tandem mass spectrometry (LC-MS/MS) is the gold standard for the screening of pheochromocytomas and paragangliomas (PPGLs). As scarce information is available on the stability of MNs in diagnostic samples, this study was aimed at analyzing the short-term stability of plasma free MNs in whole blood and plasma, using LC-MS/MS. Methods The stability of plasma MNs was evaluated after sample collection at 1, 2 and 3 h in whole blood, and at 2, 4 and 6 h in centrifuged samples. Both studies were performed while maintaining the samples at room temperature (RT) and at 4 °C. The ClinMass Complete Kit (Recipe, Munchen, Germany) was used for measuring MNs with LC-MS/MS (Nexera X2 UHPLC-4500MD Sciex). Differences from the baseline (T0) were assessed using repeated measures one-way ANOVA, Students' paired t-test and a comparison of the mean percentage changes with the total change limit (TCL). Results Statistically significant differences from T0 were found for both MNs (p < 0.001) in whole blood stored at RT, and for NMN (p = 0.028) but not MN (p = 0.220) at 4 °C. The mean difference exceeded the TCL after 1 h and 3 h at RT for MN, and after 1 h at RT for NMN. Statistically significant differences from T0 were only observed in the plasma samples for NMN at RT (p = 0.012), but the variation was within the TCL. Conclusions MN and NMN displayed different patterns of stability before and after centrifugation. Even short-time storage at RT in whole blood should hence be avoided.

Chromogranin A in the Laboratory Diagnosis of Pheochromocytoma and Paraganglioma.

This work discusses the clinical performance of chromogranin A (CGA), a commonly measured marker in neuroendocrine neoplasms, for the diagnosis of pheochromocytoma/paraganglioma (PPGL). Plasma CGA (cut-off value 150 µg/L) was determined by an immunoradiometric assay. Free metanephrine (cut-off value 100 ng/L) and normetanephrine (cut-off value 170 ng/L) were determined by radioimmunoassay. Blood samples were collected from PPGL patients preoperatively, one week, six months, one year and two years after adrenal gland surgery. The control patients not diagnosed with PPGL suffered from adrenal problems or from MEN2 and thyroid carcinoma. The clinical sensitivity in the PPGL group of patients (n = 71) based on CGA is 90% and is below the clinical sensitivity determined by metanephrines (97%). The clinical specificity based on all plasma CGA values after surgery (n = 98) is 99% and is the same for metanephrines assays. The clinical specificity of CGA in the control group (n = 85) was 92% or 99% using metanephrines tests. We can conclude that plasma CGA can serve as an appropriate complement to metanephrines assays in laboratory diagnosis of PPGL patients. CGA is elevated in PPGLs, as well as in other neuroendocrine or non-neuroendocrine neoplasia and under clinical conditions increasing adrenergic activity.

SUN-LB067 Uncontrolled Diabetes with Severe Ketoacidosis: Blame It on the Pheochromocytoma!

Background: Pheochromocytomas are rare catecholamine secreting tumors that arise from chromaffin cells of the adrenal medulla and sympathetic ganglia. Typical symptoms include paroxysmal hypertension, headache, and palpitations. Hyperglycemia is seen in 35-50% of these patients. There are a few case reports depicting the rare presentation of diabetic ketoacidosis (DKA) precipitated by a catecholamine-secreting tumor. We present a patient with recurrent DKA in the setting of a pheochromocytoma. Clinical Case: A 57-year-old woman with a history of breast cancer, hypertension, adrenal mass, and uncontrolled diabetes mellitus presented with severe DKA after taking oral steroids. Her review of systems noted intermittent pounding headaches, blurred vision, dizziness, unintentional weight loss, palpitations, and fluctuating blood pressure (BP). She had an episode of DKA 6 months prior. She was treated in the ICU with intravenous fluid and insulin with resolution of DKA. Subsequently, she acutely became severely hypertensive. BP was uncontrolled despite aggressive intravenous anti-hypertensive medication. Pertinent labs included hemoglobin A1c (HbA1c) 9.1%, GAD-65 Ab <5 IU/mL, fasting C-peptide 0.81 ng/mL, plasma free total metanephrines 29073 pg/mL(<205) and 24 hour urine total metanephrines 34633 mcg (149-603). A CT scan of the abdomen showed a 7.8 cm right adrenal mass with heterogeneous internal enhancement. Her BP was stabilized with clonidine and doxazosin and she was discharged on these medications and insulin. After appropriate alpha and beta blockade, she underwent right adrenalectomy at another hospital. Postoperatively her BP has been controlled off alpha-blockade and her diabetes has been controlled on metformin alone. Conclusion: This case illustrates the causative role of a pheochromocytoma in a patient with hyperglycemia and severe ketoacidosis. Epinephrine secreted by a pheochromocytoma inhibits insulin secretion by stimulation of alpha-adrenergic receptors and induces glucagon secretion by stimulation of beta and alpha-adrenergic receptors in the pancreas. In addition, stimulation of these receptors promotes glycogenolysis and gluconeogenesis in the liver and activates lipolysis contributing to insulin resistance. In a predisposed patient, these factors may lead to DKA. In a patient who presents with DKA and paroxysmal or uncontrolled hypertension, the diagnosis of pheochromocytoma should be considered. Unless otherwise noted, all abstracts presented at ENDO are embargoed until the date and time of presentation. For oral presentations, the abstracts are embargoed until the session begins. s presented at a news conference are embargoed until the date and time of the news conference. The Endocrine Society reserves the right to lift the embargo on specific abstracts that are selected for promotion prior to or during ENDO.

SUN-347 Measurement of Plasma and Urine Metanephrines in the Setting of Hypertensive Emergency: Is There a Clinical Utility?

Background: Metanephrines (MTN), which include normetanephrine (NMN) and metanephrine (MN), are metabolites of catecholamines formed by o-methylation of norepinephrine and epinephrine respectively, by the enzyme catechol-o-methyl transferase present in its most active form in the chromaffin cell derived tumors, namely pheochromocytoma and paraganglioma (PPGL). The initial biochemical work-up for PPGL aims at measuring MTN in plasma (PMTN) or urine (UMTN), comprising of plasma free metanephrine (PMN), and normetanephrine (PNMN), and/or 24-hour urinary fractionated metanephrine (UMN) and normetanephrine (UNMN). Marked MTN elevations (>3 times the upper limit of normal [ULN]) are highly suggestive of PPGL.1 Rarely, marked MTN elevations have been reported in stress cardiomyopathy, myocardial infarction and with certain medications. Reversible, marked MTN elevations have been reported in two cases of hypertensive emergency (HTNE) in whom imaging did not reveal PPGL.2 This finding questions the validity of measuring MTN in HTNE given the potential of ‘false positive’ MTN elevations, which may subject patients to unnecessary imaging studies, radiation or contrast exposure. Methods: To further investigate the frequency of marked MTN elevations in HTNE, we retrospectively studied the results of PMTN and UMTN measurements in 48 patients (59.7±15.6 years; 48% female; BMI: 31±9.7 kg/m2) hospitalized for HTNE, with end-organ damage manifesting either as encephalopathy (19%), stroke (30%), congestive heart failure (CHF; 54%), myocardial ischemia (MI; 17%), or acute renal injury (AKI; 31%). PMN and PNMN were measured in 47 patients, UMN and UNMN were measured in 16 patients and 15 patients had both PMTN and UMTN measured. Results: Multiple regression analysis did not reveal a significant association between PMTN/UMTN levels and systolic/diastolic blood pressures, type of end-organ damage, or intake of medications known to alter MTN levels. Only 3 (6%) patients had marked MTN elevations, specifically of PNMN (647, 521, and 453 pg/ml; ULN: 148 pg/ml). All 3 patients had CHF and one also had MI and AKI. Imaging in two of the patients did not reveal evidence of PPGL. Imaging for the third patient is in progress. Conclusions: Marked MTN elevations in HTNE are uncommon. When present, they occur mostly due to a non-PPGL condition, where imaging is unlikely to reveal a PPGL. Therefore, we recommend against measuring MTN in the setting of an obvious precipitating cause for HTNE in order to avoid unnecessary testing and imaging. Testing for MTN in HTNE should be pursued only when there is a strong suspicion for PPGL with no clear precipitating cause. However, should testing be performed, marked MTN elevations should not be disregarded as a commonly occurring result of HTNE.

MON-398 Clinical Case Of Retroperitoneal Paraganglioma

Background: Paraganglioma is a rare neuroendocrine tumor from extra-adrenal chromaffin cells of the sympathetic paravertebral ganglia of thorax, abdomen, and pelvis. In most cases paragangliomas produce catecholamines in large concentrations and the lack of treatment can lead to cardiovascular and cerebral catastrophes [1]. That is why early diagnosis of this tumor is so important and, consequently, knowledge of its diagnostic criterion, too. Clinical case: A 59-year-old man was presented to a cardiologist for rapid increasing of blood pressure (up to 220/120 mmHg), which was accompanied by severe headache and epigastric pain in September 2017. From anamnesis it is known: the disease began suddenly and had paroxysmal flow. The first attack lasted for about 3 minutes and finished itself. Then such attacks occured with different frequency (from 1 per month to several times per week) and were connected with physical activity. The cardiologist suspected diagnosis of pheochromocytoma. The result of urinary fractionated metanephrines measurement showed its levels higher than normal rage but did not confirm suspected diagnosis reliably, so antihypertensive therapy was prescribed to minimize the symptoms. Despite this, the attacks persisted and the patient referred to a surgeon in May 2018. On the basis of patient’s complaints on epigastric pain during the attacks and the neck inflection of the gallbladder revealed by the ultrasound examination, it was decided to carry out cholecystectomy. A week after the operation the patient referred to the endocrinologist because of the continuing attacks. The diagnosis of pheochromocytoma was suspected again, the urinary fractionated metanephrines measurement was repeated, which revealed elevated normetanephrine level (1008 µg/day). A CT of retroperitoneal space revealed a spherical mass sized about 17х16х18 mm in paraaortal region under the left renal vein. The retroperitoneal tumor was removed laparoscopically in August 2018. Pathological examination of the removed mass showed a paraganglioma with uncertain potential of biological behaviour. BP was normal and remained within range without the need of any antihypertensive medication until discharge from hospital. The patient is asymptomatic and normotensive during his follow-up visits. Conclusion: This clinical case shows how a tumor with bright and specific symptoms can be revealed only in several years and after referring to several specialists. Also, this case highlights the importance of knowledge of diagnostic process of different diseases. In the present case the paraganglioma would have been revealed earlier if only the CT of retroperitoneal space had been done just after getting the results of free metanephrines, which were higher than normal.

SUN-283 FH Variant in a Child with Family History of Early-Onset Pheochromocytoma

Pheochromocytoma (PCC) and paraganglioma (PGL) are rare neuroendocrine tumors associated with many genes. Recently, the fumarate hydratase gene (FH) has been implicated. We describe a case of a child evaluated for PCC who was found to have a variant in FH. A 7y5mo female was referred to our pediatric endocrinology clinic for evaluation of possible PCC. Family history included 3 relatives with reported early-onset PCC (ages 8-15), including mother (alive), maternal uncle and maternal grandfather (both deceased). There was reported thyroid disease in maternal grandmother, but no other family history of conditions seen with PCC-related syndromes. The patient was healthy aside from obesity until developing headaches 5 mo prior to visit with us. Given her family history, 24-hr urine collection for catecholamines was done which showed marked elevations in urine metanephrines, normetanephrines, norepinephrine, and dopamine compared to lab reference ranges. Contrast-enhanced abdominal CT was normal by report. At the time of her visit, headaches had improved. Exam was notable for high BP at >95th percentile for height (no prior hypertension diagnosis) and obesity; there were no mucosal neuromas and thyroid exam was normal. We arranged for plasma fractionated metanephrine and normetanephrine testing and checked prolactin, gastrin, calcitonin, calcium, phosphorus, and vitamin D levels. All labs were unremarkable. MIBG scan was normal. 24-hr urine free metanephrine testing was repeated and normal. She was seen in our genetics division and tested for PCC-associated genes. A heterozygous variant in FH, c.925C>T (p.Pro309Ser), was found. This variant was classified as of uncertain significance and is present in population databases but has not been described with FH-related disease. FH is associated with autosomal dominant hereditary leiomyomatosis and renal cell cancer (HLRCC), and has early evidence of correlation with hereditary PCC/PGL. We present a case of a child who was initially suspected to have PCC based on family history, headaches, and elevated urine catecholamines but who had normal results on confirmatory testing. She was found to have a FH variant, p.Pro309Ser, classified as uncertain in significance but which we believe may be disease-causing in this family; testing for the variant in her mother is being pursued. To our knowledge, only one case of a FH mutation associated with PCC in a child has been published. On a practical note, the patient’s fluctuating urine catecholamines may have been due to large volume on initial sample, which did not occur on the second sample; it is important to consider urine volume when interpreting urine catecholamine results. This case also highlights the impact on management that targeted genetic testing can have: knowledge of FH’s association with non-PCC conditions prompts consideration of additional screening that might not be performed for PCC alone.

SAT-323 Thoracic Paraganglioma Presenting with Recurrent Cerebrovascular Events

Background: Thoracic spine paraganglioma precipitating acute stroke is extremely rare. We report a case of a patient with thoracic paraganglioma at high risk for spinal cord compression with recurrent cerebrovascular events. Clinical Case: A 59 year old male was admitted for transient right hemiplegia after recent admission for right lacunar CVA. The patient was noted to have episodes of labile hypertension, sinus tachycardia and paroxysmal diaphoresis. Five days after admission, he developed ataxia with right pronator drift and was treated with intravenous thrombolytics for suspected acute CVA. Incidentally, an 8 cm thoracic paraspinal necrotic mass invading T10 and T11 vertebral bodies with impending cord compression was found on imaging. CT-guided needle biopsy of the mass was performed. Pathology showed an oval and spindle cell neoplasm staining positive for synaptophysin and chromogranin, favoring paraganglioma. Chromogranin A was elevated 472 ng/mL (25 - 140 ng/mL). Plasma free metanephrines were 32 g/mL (n < 57 pg/mL) and plasma free normetanephrines were 7690 pg/mL (n < 148 pg/mL). MIBG scan showed focus of increased uptake at T10 and T11 as well as in the left posterior eighth rib and peri-aortic region. Subsequently, the patient developed acute right leg weakness and dysmetria; MRI brain confirmed acute infarct in the posterior limb of the left internal capsule. Alpha blockade followed by beta blockade was initiated. After approximately 2.5 weeks of alpha blockade, the patient underwent spinal angiogram with tumor embolization followed by successful en bloc tumor resection by neurosurgery and cardiothoracic surgery. Final pathology showed a 7.5 cm paraganglioma which demonstrated some aggressive pathologic features including Ki67 index>20% and 10% focal necrosis. Post-operative plasma free normetanephrines decreased to 568 pg/mL and metanephrines were undetectable. Genetic testing utilizing Ambry Genetics PGLnext panel was negative. Conclusion: A differential diagnosis of paraganglioma should be considered in any patient presenting with recurrent stroke and paraspinal mass. Biopsy should be avoided. Timing of surgical resection to decrease risk of further cerebrovascular compromise is challenging and requires a multidisciplinary approach (1). Locally invasive paragangliomas are rare and are often associated with SDHB mutations; however, a full genetic analysis did not identify any known genetic mutations. Reference: (1) Oak, S., Javid, M., Callender, G., Carling, T., Gibson, C. Management of pheochromocytoma in the setting of acute stroke. AACE Clinical Case Reports 2018 4:3, e245-e248.

MON-318 Selective ACTH Sampling in Localizing Source of ACTH in Von Hippel Lindau Disease with Pancreatic Neuroendocrine Tumour and Renal Cell Carcinoma

Background: Cushing’s syndrome (CS) in a patient with VHL has been attributed to a number of possible causes; pancreatic NET and renal cell carcinoma. The precise location of ectopic ACTH aid enormously in the management of VHL. Clinical case: A 31-year-old woman with Type 2 diabetes and family history of VHL presented with florid features of CS in her second trimester of pregnancy. A diagnosis of ACTH dependent CS was made based on elevated 24h urinary cortisol (1122 and 2448nmol/24hr, n<150-800), midnight cortisol (1322nmol/L, n<220nmol/L) and a detectable ACTH level (18.8pg/mL, n<10pg/mL). She underwent emergency caesarean section due to pre-eclampsia at 28 week gestation. Post-delivery, her morning cortisol was 2823nmol/L (n:171-536nmol/L). MRI pituitary was reported as normal. CT abdomen showed an enlarged pancreas which was almost completely cystic and a right renal mass (3.7 X 2.6 X 4cm). Serum chromogranin A was elevated (530.2ng/mL, n:27-94). 24h urinary free metanephrine was normal. Selective ACTH sampling was done together with bilateral inferior petrosal sinus sampling to elicit source of ACTH. Increased gradient of ACTH level compared to the periphery (138.9pg/mL vs. samples from IVC:115.1 pg/mL, renal vein:100.2 pg/mL) was detected from the hepatic vein that drains the pancreas via the portal venous system. Ketoconazole and metyrapone were given to control the cortisol level close to 600nmol/L prior to surgery. Preoperatively, IV hydrocortisone 100mg was administered, with additional 50mg given every 4 hours intraoperatively. Total pancreatectomy and right nephrectomy were performed. Inotropic support was required five hours into the surgery. Hydrocortisone was tapered down to a maintenance dose of 10mg, 5mg and 2.5mg TDS over 7 days. A week after surgery, am cortisol was 103nmol/L suggesting successful removal of ectopic ACTH source. Histopathological examination identified a solid tumour (18X12X12 mm) at the pancreatic tail which stained positive to Chromogranin A, synaptophysin and weakly positive to CD56. The mitoses was 0-1/10hpf with a Ki67 index of 2%. ACTH staining was positive. The renal mass was a Grade 1 clear cell renal cell carcinoma with equivocal ACTH staining. Two months later, there was resolution of cushingoid features. DOTATE and FDG/PET scans along with close surveillance using serum Chromogranin A and 6 monthly abdominal imaging were planned. Conclusion: When managing VHL with CS, there is always a possibility of more than one source of ACTH production. In delineating the cause of CS the use of selective ACTH sampling may be considered where functional imaging (DOTATATE) is unavailable. Reference : (1) Tamura K, Nishimori I, Ito T, Yamasaki I, Igarashi H, Shuin T. Diagnosis and management of pancreatic neuroendocrine tumor in von hippel-lindau disease. World J Gastroenterol. 2010;16(36):4515-4518. doi:10.3748/wjg.v16.i36.4515

MON-384 The Dynamic Genetics of Recurrent Paragangliomas: The Importance of Surveillance

BACKGROUND: Paraganglioma (PGL) are tumors that arise from the ganglia of the sympathetic nervous system, and comprise 10% of all sympathetic nervous system tumors. There are at least 16 germline mutations that have been associated with increased risk of PGL. CASE PRESENTATION: A 32 year-old female with a history of PGL status-post resection presented with elevated plasma metanephrines during surveillance follow-up. She was diagnosed with PGL 7 years ago. Plasma free normetanephrine were elevated at 607 pg/ml (ref ≤ 148 pg/ml) and an MRI abdomen demonstrated a 6.6 x 4.5 x 7.8 cm para-aortic retroperitoneal mass. An MIBG scan showed no abnormal activity. She underwent resection of PGL. Postoperative labs showed normal plasma and urine metanephrines. Genetic testing was negative for known related mutations. She reported dizziness and palpitations six years later. Labs revealed elevated free normetanephrine 213 pg/ml and total metanephrine 238 pg/ml (ref ≤ 205 pg/ml). Repeat plasma and urine tests remained elevated, but an MRI abdomen/pelvis and two MIBG scans were unremarkable. The patient remained symptomatic. Six months later, CT abdomen/pelvis showed a retroperitoneal 2.5 x 1.8 x 1.7 cm necrotic mass and an 3.2 x 2.6 x 2.5 cm adnexal cystic lesion concerning for recurrent PGL. Repeat testing confirmed elevated plasma free normetanephrine 511 pg/ml and undetectable free metanephrine. PET/CT abdomen/pelvis demonstrated the retroperitoneal necrotic mass, two lesions anterior to the L3 and L4-L5 vertebral bodies, and a lytic lesion in the right iliac crest. The patient underwent surgical resection of three PGL, all with vascular and capsular invasion. Six months later, plasma and urinary levels were all normal. PET Ga-68 DOTATATE scan demonstrated uptake near the surgical bed and in the aorto-caval groove, suspicious for residual tumors, and several foci of somatostatin receptor positive osseous lesions, suspicious for skeletal metastases. An updated genetic test showed a variant of uncertain significance (VUS) of the SDHA gene. She is currently undergoing treatment with lanreotide. CONCLUSION: This case highlights the importance of continuous surveillance, as well as the swift advancements in genetics associated with paragangliomas and pheochromocytomas. REFERENCES: Fishbein, L.,et al. (2013). Inherited Mutations in Pheochromocytoma and Paraganglioma: Why All Patients Should Be Offered Genetic Testing. Annals of Surgical Oncology, 20(5),1444-1450.

MON-344 A Large Adrenal Mass with Neuroendocrine Features Presenting as Pulmonary Embolism: A Case Report

Background: Adrenocortical Carcinoma (ACC) is a rare disease that has a bimodal distribution. 60% of ACC presents with symptoms and signs of adrenal steroid hormone excess [1] while non-functional ACCs present less conspicuously with abdominal mass or other nonspecific symptoms making diagnosis challenging. The usual sites of metastasis are the lung (71%), lymph node (68%), liver (42%), and bone (26%) [1]. According to literature, there has been few reported cases of ACC extending to the inferior vena cava and right atrium presenting with pulmonary embolism. Clinical Case: Patient is a 38 year old male admitted due to dyspnea, BP elevation and weight loss. Initial CXR was done showing canon ball lesions. On work up, Chest CT scan revealed pulmonary metastasis and pulmonary embolism. Abdominal CT scan showed a large right suprarenal mass with tumor infiltrating the inferior vena cava, hepatic and portal veins. 2 d echo revealed a large pedunculated mass attached to the free wall of the right atrium. The patient was started on anticoagulation. Diagnostic work up for adrenal function was done. Plasma renin and aldosterone in supine position were 3.30ng/mL/hr (reference range 0.3-1.9), and 23.28 ng/dL (reference range: 3.78-23.3) respectively with an ARR 7. 8 am cortisol was 12.30 ug/dL (reference range: 3.7-19.4ug/dL), 24 hour urine metanephrine 0.43 (reference range: 0-1) and plasma free metanephrine 36.75 pg/mL (reference range <65pg/mL) were all normal. Chromogranin A was normal at 90.71 ng/mL (reference range: <100ng/mL) however, DHEAS was 3x elevated at 1,406.00 ug/dL (Reference Range: 139.70–484.40 ug/dL). The patient underwent FNAB of the lung nodules revealing a malignant neoplasm with neuroendocrine features. Since the etiology of the adrenal mass was still uncertain, a functional imaging with 68Ga-DOTATATE PET-CT scan was done. However, the large right suprarenal mass was mostly necrotic with a small 68Ga-DOTATATE-avid focus. During admission, patient had sudden onset of chest pain, diaphoresis, hypotension and desaturation. He deteriorated and eventually expired. Post mortem examination revealed adrenocortical carcinoma with neuroendocrine features; hemorrhagic infarction secondary to massive pulmonary tumor embolism. Conclusion: Adrenocortical carcinoma is a rare cancer with varied initial presentation. A rare presentation is pulmonary embolism. In advanced stage diseases, with distant metastases, ACC has a poor prognosis. Multimodality approach with radiotherapy, aggressive surgical resection and mitotane can be offered as treatment options. Reference: 1. Kim, KH, et al. "A case of non-functioning huge adrenocortical carcinoma extending into inferior vena cava and right atrium."

Age-specific pediatric reference intervals for plasma free normetanephrine, metanephrine, 3-methoxytyramine and 3-O-methyldopa: Particular importance for early infancy

BackgroundAvailability of appropriately established reference intervals for biochemical tests can be troublesome in pediatrics. Here we establish age-specific continuous reference intervals for catecholamine O-methylated metabolites in children evaluated for catecholamine producing tumors, particularly younger children with suspected neuroblastoma. MethodsPlasma concentrations of 3-methoxytyramine, normetanephrine, metanephrine, and 3-O-methyldopa were analyzed by liquid chromatography tandem mass spectrometry in 533 children aged 2 days to 18 years. ResultsConcentrations of plasma free normetanephrine, 3-methoxytyramine and 3-O-methyldopa were higher in neonates up until six months of age, but thereafter declined steeply to levels after one year that were <38% those of neonatal concentrations and to further lower concentrations in teenagers that were <23% those in neonates. In contrast, concentrations of plasma free metanephrine showed a reciprocal pattern with 50% lower concentrations in infants below one year compared to later in childhood. ConclusionThe dynamic reciprocal changes in plasma concentrations of normetanephrine, 3-methoxytyramine and 3-O-methyldopa compared to metanephrine during early childhood suggest underlying developmental changes in extra-adrenal and adrenal chromaffin tissue that must be considered for pediatric reference intervals, particularly in infants. With such reference intervals at hand, biochemical testing for catecholamine producing tumors in young children is substantially improved.

Is plasma free metanephrines accurate in the diagnosis of pheochrmocytoma in adults?

Is plasma free metanephrines accurate in the diagnosis of pheochrmocytoma in adults?

Sympathetic Paraganglioma: A Single-Center Experience from Western India

Most of the Indian studies on pheochromocytoma/paraganglioma (PCC/PGL) have focused on PCC, and there is a paucity of information regarding sympathetic paraganglioma (sPGL). Here, we describe the clinical, biochemical, and imaging features of sPGL compared with PCC. This retrospective study included 75 patients with sPGL and 150 patients with PCC. Diagnosis of PCC/PGL was based on surgical histopathology, and if histopathology was not available, on biochemistry and/or radiology. sPGL was more frequently detected incidentally ( P = .03), normetanephrine-secreting ( P<.01), and metastatic compared with PCC ( P≤.01). sPGL was most commonly located in the organ of Zuckerkandl (OOZ) (49%) and infradiaphragmatic area above the OOZ (27%). Patients with mediastinal sPGL were significantly older than those with sPGL in the OOZ ( P = .03). Primary tumors of metastatic sPGL were significantly larger than those without metastasis (7.8 ± 4 cm vs. 5.6 ± 3.2 cm; P = .004). Percentage arterial enhancement (PAE) >100% was seen in 98% of sPGLs. Incidental presentation, normetanephrine-secreting phenotype, and metastatic disease were more frequent in patients with sPGL than those with PCC. sPGL arose most commonly in the OOZ. Tumor size is an independent predictor of malignancy among sPGL patients. PAE >100% is almost a universal finding in sPGL, and its absence is a sensitive parameter to differentiate sPGL from other abdominal masses. AP = arterial phase; CECT = contrast-enhanced computed tomography; CT = computed tomography; DP = delayed phase; EVP = early venous phase; FDG = fluorodeoxyglucose; fPFMN = fractionated plasma free metanephrine; HU = Hounsfield units; MIBG = metaiodobenzylguanidine; MRI = magnetic resonance imaging; OOZ = organ of Zuckerkandl; PAE = percentage arterial enhancement; PCC = pheochromocytoma; PET = positron emission tomography; PFNMN = plasma free normetanephrine; PGL = paraganglioma; PRRT = peptide receptor radionuclide therapy; PVE = percentage venous enhancement; sPGL = sympathetic paraganglioma; UP = unenhanced phase; VMA = vanillyl mandelic acid.

Plasma free metanephrines for diagnosis of neuroblastoma patients

IntroductionA substantial number of patients with neuroblastoma (NB) have increased excretion of catecholamines and metanephrines. Here, we have investigated the diagnostic role of plasma free metanephrines (PFM), metanephrine (MN), normetanephrine (NMN) and 3-methoxytyramine (3MT) for NB, the most common extra-cranial solid tumour in children. MethodsPFM were quantified by using a commercial IVD-CE LC-MS/MS method on a TSQ Quantiva coupled to an Ultimate 3000. The method was further validated on 103 samples from pediatric subjects (54 patients with histologically confirmed NB and 49 age and sex matched controls). Correlations between PFM concentrations with clinical factors were tested. We directly compared MN, NMN, and 3MT concentrations in matched plasma and urine samples of NB patients (n = 29). Results3MT and NMN showed an excellent diagnostic performance with very high specificity (100% and 95.8%, respectively) and sensitivity (88.2% and 80.4%). ROC curves were obtained (AUC of 0.93 and 0.91 for 3MT and NMN, respectively) and optimal cut-offs that could discriminate between controls and NB patients were defined. A positive correlation between NMN levels in urine and plasma (p = .0017) was found. DiscussionThe determination of plasma 3MT and NMN should be taken in consideration as a new diagnostic tool for NB. Validation in prospective clinical studies in comparison to urinary catecholamines and metanephrines is warranted.