Comparison of the Sensitivity of 68 Ga-DOTATATE PET/CT with Other Imaging Modalities in Detecting Head and Neck Paraganglioma: Experience from Western India.

Background This study aimed to compare the sensitivity of 68 Ga-DOTATATE positron emission tomography/computed tomography (PET/CT) with other imaging modalities in the detection of head and neck paraganglioma (HNPGL). Methods The data of consecutive HNPGL patients ( n = 34) who had undergone at least 68 Ga-DOTATATE PET/CT and anatomical imaging (contrast-enhanced computed tomography/magnetic resonance imaging [CECT/MRI]) were retrospectively reviewed. The diagnosis of HNPGL (the primary tumor) was confirmed either by histopathology ( n = 10) or was based on clinical follow-up and correlation of anatomical with functional imaging in whom histopathology was not available ( n = 24). The sensitivities of 68 Ga DOTATATE PET/CT, 18F-fluorodeoxyglucose positron emission tomography/computed tomography ( 18 F-FDG-PET/CT), 131 I-metaiodobenzylguanidine ( 131 I-MIBG) scintigraphy, and CECT/MRI for primary HNPGL, associated primary pheochromocytoma + sympathetic paraganglioma (PCC + sPGL), and metastatic lesions were analyzed. Results Thirty-four patients (males: 15) [isolated HNPGL: 26, HNPGL + PCC: 04, HNPGL+ sPGL: 03, HNPGL + PCC + sPGL: 01] harboring 50 primary lesions were included. For total lesions, 68 Ga-DOTATATE PET/CT (99.3%) had significantly higher lesion-wise sensitivity than 18 F-FDG PET/CT (81.6%, p = 0.0164), 131 I-MIBG (15.2%, p ≤0.0001), CECT (46.3%, p ≤ 0.0001) but similar sensitivity as MRI neck (97%, p = 0.79). On head-to-head comparison (21 primary HNPGL and 39 metastatic lesions), 68 Ga DOTATATE PET/CT had significantly higher lesion-wise sensitivities for the detection of metastatic (100 vs. 71.9%, p = 0.04) and total lesions (100 vs. 77.2%, p ≤ 0.0001). Conclusion 68 Ga-DOTATATE PET/CT was the most sensitive imaging modality for the detection of HNPGL and related lesions with significantly higher lesion-wise sensitivities than those of 18 F-FDG PET/CT, 131 I-MIBG, and CECT.

Efficacy and Safety of Liraglutide 3.0 mg in Patients with Overweight and Obese with or without Diabetes: A Systematic Review and Meta-Analysis.

Background: Liraglutide in a 3.0 mg subcutaneous dose daily is approved for weight reduction. Objectives: Objectives are to evaluate the efficacy and safety of liraglutide 3.0 mg in patients with overweight and obesity irrespective of diabetic status. Methods: We conducted an electronic database search in PubMed, Embase, and https://ClinicalTrial.gov to identify all randomized control trials (RCTs) that evaluated the efficacy and safety of liraglutide 3.0 mg dose compared to placebo in overweight (≥27 kg/m2) and obese (≥30 kg/m2) patients above 18 years of age. Results: We compared the pooled estimate of the study results between liraglutide 3.0 mg groups and placebo groups both in diabetic and nondiabetic patients. The efficacy outcomes that were found to be significant among respective studies involving nondiabetic patients vs. diabetic patients were mean change in body weight from baseline: 12 studies [MD = -5.04 kg (95% CI = -5.60, -4.49), P < 0.001, I 2 = 92.95%] vs. 2 studies [MD = -4.14 kg (95% CI = -4.95, -3.32), P < 0.001, I 2 = 0%], reduction in waist circumference from baseline: 8 studies [MD = -3.64 cm (95% CI = -4.43, -2.85), P < 0.001, I 2 = 96.5%] vs. 2 studies [MD = -3.11 cm (95% CI = -3.88, -2.34), P < 0.001, I 2 = 0%], BMI reduction from baseline: 5 studies [MD = -1.95 kg/m2 (95% CI = -2.22, -1.68) vs. 1 study [MD = -1.86 kg/m2 (95% CI = -2.14, -1.57), P < 0.001, I 2 = 0%, P < 0.001, I 2 = 95.6%], proportion of patients losing more than 5% of weight loss from baseline: 8 studies [RR = 2.21, (95% CI = 1.89, 2.58), P=0.03, I 2 = 59.02%] vs. 2 studies [RR = 2.34, (95% CI = 1.93, 2.85), P=0.39, I 2 = 0.00%], and 10% weight loss from baseline: 7 studies [RR = 3.36, (95% CI = 1.92, 5.91), P=0.00, I 2 = 87.03%] vs. 2 studies [RR = 3.64, (95% CI = 2.46, 5.40), P=0.81, I 2 = 0.00%]. Safety outcome assessment with use of liraglutide 3.0 mg compared with placebo in respective nondiabetic vs. diabetic patients revealed significant proportion of patients experiencing the adverse events: 9 studies [RR = 1.11, (95% CI = 1.04, 1.18), P=0.00I 2 = 79.15%] vs. 2 studies [RR = 1.06, (95% CI = 1.01, 1.11), P=0.42, I 2 = 0.03%] but similar risk of serious adverse events: 9 studies [RR = 1.03, (95% CI = 0.70, 1.51), P=0.26, I 2 = 18.54%] vs. 2 studies [RR = 1.11, (95% CI = 0.67, 1.84), P=0.25, I 2 = 23.77%] and TDAEs: 4 studies [RR = 0.89, (95% CI = 0.35, 2.28), P=0.03, I 2 = 61.89%] vs. 1 study [RR = 2.53, (95% CI = 1.00, 6.37)]. However, the pooled estimates irrespective of the glycaemic status were mean change in body weight from baseline: 14 RCT [MD = -4.91 kg (95% CI = -5.43, -4.39), P < 0.001, I 2 = 92.35%], reduction in waist circumference from baseline: 10 studies [MD = -3.55 cm, (95% CI = -4.21, -2.89), P < 0.001, I 2 = 94.99%], BMI reduction from baseline: 6 studies [MD = -1.86 kg/m2, (95% CI = -2.14, -1.57), P < 0.001, I 2 = 96.14%], and proportion of patients losing more than 5% and 10% of weight from baseline: [RR = 2.23, (95% CI = 1.98, 2.52), P < 0.001, I 2 = 48.87%] and [RR = 3.28, (95% CI = 2.23, 4.83), P < 0.001, I 2 = 78.98%], respectively. Also, the proportion of patients experiencing the adverse event was more with liraglutide 3.0 mg compared with placebo 11 study [RR = 1.09, (95% CI = 1.04, 1.15), P < 0.01, I 2 = 76.60%] and similar risk for both serious adverse events: 11 studies [RR = 1.09, (95% CI = 1.04, 1.15), P < 0.01, I 2 = 76.60%] and TDAEs: 5 studies [RR = 1.14, (95% CI = 0.50, 2.60), P < 0.01, I 2 = 64.93%] with liraglutide compared with placebo. Conclusions: Liraglutide in 3.0 mg subcutaneous dose demonstrated significant weight reduction with a reasonable safety profile for patients with overweight or obesity regardless of diabetic status compared to placebo.

Pre-Operative Selective vs Non-Selective α-Blockade in Pheochromocytoma-Paraganglioma Patients Undergoing Surgery: A Meta-Analysis.

The main objective of this systematic review and meta-analysis was to review, assess and report on the studies that have evaluated selective alpha blockade (SAB) vs. non-selective alpha blockade (NSAB) therapy in patients undergoing surgery for pheochromocytomas and paragangliomas (PPGL). We performed a systematic search of electronic databases. A meta-analysis was conducted to examine the effectiveness of the two blockades. RevMan 5.3 was used for the meta-analysis. Of the eight articles that met the inclusion criteria, there was only one randomized control trial. Meta-analysis showed that there was no significant difference between the groups SAB and NSAB with regard to intra-operative systolic blood pressure (SBP) >160 mm Hg (relative risk (RR) 0.95 [95% CI 0.57, 1.56] P = 0·83) and intra-operative vasopressor requirement (RR 1.10 [95% CI 0.96, 1.26] P = 0·16). Meta-analysis revealed that there was a significant difference between the groups (SAB vs NSAB) with respect to post-operative vasopressor requirement (RR 1.66 [95% CI 1.0, 2.74] P = 0·05). There was no significant difference between the groups with respect to post-operative complications (RR 0.84 [95% CI 0.58, 1.22] P = 0·36). In conclusion, as patients blocked selectively may have a higher incidence of vasodilator requirement intra-operatively, NSAB offers some haemodynamic advantage over SAB. However, NSAB's real clinical benefit cannot be ascertained with the current studies as this difference did not result in any significant advantage over SAB with regard to morbidity or mortality.

Low-Dose, Low-Specific Activity 131I-metaiodobenzyl Guanidine Therapy in Metastatic Pheochromocytoma/Sympathetic Paraganglioma: Single-Center Experience from Western India.

INTRODUCTION: Radionuclide therapy is a promising treatment modality in metastatic pheochromocytoma/paraganglioma (PPGL). There is scarce data on 131I-metaiodobenzyl guanidine (131I-MIBG) therapy from the Indian subcontinent. Hence, we aim to study the safety and effectiveness of low-dose, low-specific activity (LSA) 131I-MIBG therapy in patients with symptomatic, metastatic PPGL. METHODS: Clinical, hormonal, and radiological response parameters and side effects of LSA 131I-MIBG therapy in patients with symptomatic, metastatic PPGL were retrospectively reviewed. World health organizations' (WHO) symptomatic, hormonal, and tumor response, and response evaluation criteria in solid tumors (RECIST1.1) criteria were used to assess the response. RESULTS: Seventeen (PCC: 11, sympathetic PGL: 06) patients (15 with disease progression) received low-dose LSA 131I-MIBG therapy. Complete remission (CR), partial remission (PR), stable disease (SD), and progressive disease (PD) were 18% (3/17), 24% (4/17), 18% (3/17), and 41% (7/17), respectively, for WHO symptomatic response; 20% (2/10), 10% (1/10), 30% (3/10), and 40% (4/10), respectively, for WHO hormonal response; and 19% (3/16), 6% (1/16), 31% (5/16), and 44% (7/16), respectively for tumor response based on RECIST1.1. All patients with symptomatic PD and 50% (2/4) with hormonal PD had progression as per RECIST1.1 criteria. Side effects included thrombocytopenia, acute myeloid leukemia, mucoepidermoid carcinoma, and azoospermia in 6% (1/17) each. CONCLUSIONS: Our study reaffirms the modest efficacy and safety of low-dose, LSA 131I-MIBG therapy in patients with symptomatic, metastatic PPGL. Symptomatic, but not hormonal, progression after 131I-MIBG therapy correlates well with tumor progression and should be further evaluated with imaging. In resource-limited settings, anatomic imaging alone may be used to assess tumor response to 131I-MIBG therapy.

Preoperative Amlodipine Is Efficacious in Preventing Intraoperative HDI in Pheochromocytoma: Pilot RCT.

CONTEXT: Preoperative blockade with α-blockers is recommended in patients with pheochromocytoma/paraganglioma (PPGL). The data on calcium channel blockade (CCB) in PPGL are scarce. OBJECTIVE: We aimed to compare the efficacy of CCB and α-blockers on intraoperative hemodynamic instability (HDI) in PPGL. METHODS: In the interim analysis of this monocentric, pilot, open-label, randomized controlled trial, patients with solitary, secretory, and nonmetastatic PPGL were randomized to oral prazosin gastrointestinal therapeutic system (GITS) (maximum 30 mg, n = 9) or amlodipine (maximum 20 mg, n = 11). The primary outcomes were the episodes and duration of hypertension (systolic blood pressure ≥ 160 mmHg) and hypotension (mean arterial pressure < 60 mmHg) and duration of HDI (hypertension and/or hypotension) as a percentage of total surgical time (from induction of anesthesia to skin closure). RESULTS: The median (IQR) episodes (2 [1-3] vs 0 [0-1]; P = 0.002) and duration of hypertension (19 [14-42] vs 0 [0-3] minutes; P = 0.001) and intraoperative HDI duration (22.85 ±â€…18.4% vs 2.44 ±â€…2.4%; CI, 8.68-32.14%; P 0.002) were significantly higher in the prazosin GITS arm than the amlodipine arm, whereas episodes and duration of hypotension did not differ between the 2 groups. There was no perioperative mortality. One patient had intraoperative ST depression on the electrocardiogram. The drug-related adverse effects were pedal edema (1 in amlodipine), dizziness (1 in prazosin GITS), and tachycardia (6 in prazosin GITS and 3 in amlodipine). CONCLUSION: Preoperative blockade with amlodipine is an efficacious alternative to prazosin GITS in preventing intraoperative HDI in PPGL. Larger studies that compare preoperative blockade by amlodipine with other α-blockers like phenoxybenzamine and/or doxazosin in PPGL patients are warranted.

Hereditary medullary thyroid carcinoma syndromes: experience from western India.

The data from the Indian subcontinent on Medullary thyroid carcinoma (MTC) and associated endocrinopathies in hereditary MTC (HMTC) syndromes are limited. Hence, we analyzed clinical and biochemical characteristics, management, and outcomes of HMTC and other associated endocrinopathies [Pheochromocytoma (PCC) and Primary hyperparathyroidism (PHPT)] and compared with apparently sporadic MTC. The records of 97 (51 sporadic and 46 hereditary) consecutive MTC patients were retrospectively analyzed. RET mutation was available in 38 HMTC patients. HMTC group was subclassified into Multiple endocrine neoplasia (MEN) 2A index (n = 25), MEN2B index (n = 8), and MEN2A detected by familial screening (n = 12). Patients with HMTC and MEN2B index were younger at presentation than sporadic MTC. MEN2A patients detected by familial screening, but not MEN2A index and MEN2B index patients, had significantly lower serum calcitonin, smaller thyroid nodule size, more frequent early stage presentation (AJCC Stage ≤ II), and higher cure rate than sporadic MTC, which emphasizes the need for early diagnosis. RET (REarranged during Transfection) 634 mutations were the most common cause of HMTC and more frequently associated with PCC (overall 54% and 100% in those aged ≥ 35 years). Patients in ATA-Highest (HST) group had a universal presentation in stage IV with no cure. In contrast, the cure rate and postoperative disease progression (calcitonin doubling time) were similar between ATA-High (H) and ATA- Moderate (MOD) groups, suggesting the need for similar follow-up strategies for the latter two groups. Increased awareness of endocrine (PCC/PHPT) and non endocrine components may facilitate early diagnosis and management.

The Utility of 68Ga-DOTATATE PET/CT in Localizing Primary/Metastatic Pheochromocytoma and Paraganglioma: Asian Indian Experience.

Purpose: Pheochromocytoma and paraganglioma (PGL), together called PPGL, are rare tumors with a limited number of studies on the diagnostic performance of 68Ga-DOTA (0)-Tyr (3)-octreotate positron emission tomography-computed tomography (68Ga-DOTATATE PET/CT) from the Asian-Indian subcontinent. Materials and Methods: In this retrospective study, PPGL suspects (n = 87) who had undergone at least contrast-enhanced computed tomography (CECT) and 68Ga-DOTATATE PET/CT, were included. Lesion-wise, patient-wise, and region-wise sensitivities of 68Ga-DOTATATE PET/CT, 18F fluorodeoxyglucose positron emission tomography CT (18F-FDG PET/CT, n = 53), 131I-metaiodobenzylguanidine (131I-MIBG, n = 37), and CECT were compared, and diagnostic performance of 68Ga-DOTATATE PET/CT in the detection of PPGL was calculated. Results: 68Ga-DOTATATE PET/CT had significantly higher lesion-wise sensitivity than 131I-MIBG for both primary (94% vs 75%, P = 0.004) and metastatic disease (85% vs 59%, P = 0.001) and higher sensitivity than CECT for metastatic lesions (83% vs 43%, P = 0.0001). The lesion-wise sensitivity of 68Ga-DOTATATE PET/CT was similar to 18F-FDG PET/CT for both primary tumors (94% vs 85%, P = 0.08) and metastatic lesions (82% vs 84%, P = 0.76) in the whole cohort but tended to be inferior in the head to head comparison. Conclusion: 68Ga-DOTATATE PET/CT had higher sensitivity for detection of PPGL than 131I-MIBG (primary and metastatic) and CECT (metastatic) but similar to 18F-FDG PET/CT (primary and metastatic).

The utility of 68Ga-DOTATATE PET/CT in localizing primary/metastatic pheochromocytoma and paraganglioma in children and adolescents - a single-center experience.

OBJECTIVES: Pediatric pheochromocytoma and paraganglioma (PPGL) are rare tumors with limited data on the diagnostic performance of 68Ga-DOTA(0)-Tyr(3)-octreotate positron emission tomography-computed tomography (68Ga-DOTATATE PET/CT). We have described our experience of 68Ga-DOTATATE PET/CT in overall and von Hippel Lindau (VHL)-associated pediatric PPGL and compared its sensitivity with that of 131I-meta-iodobenzyl-guanidine (131I-MIBG), 18F-fluorodeoxyglucose PET/CT (18F-FDG PET/CT), and contrast-enhanced CT (CECT). METHODS: Retrospective evaluation of consecutive PPGL patients (age: ≤20 years), who had undergone at least one functional imaging [131I-MIBG, 18F-FDG PET/CT, and/or 68Ga-DOTATATE PET/CT], was done. Composite of anatomical and all the performed functional imaging scans, image comparator (IC), was considered as the gold standard for sensitivity analysis. RESULTS: In a cohort of 32 patients (16 males, age at diagnosis: 16.4 ± 2.68 years), lesion-wise sensitivity of 68Ga-DOTATATE PET/CT (95%) was higher than that of both 18F-FDG-PET/CT (80%, p=0.027) and 131I-MIBG (65%, p=0.0004) for overall lesions, than that of 18F-FDG-PET/CT (100 vs. 67%, p=0.017) for primary PPG, and than that of 131I-MIBG (93 vs. 42%, p=0.0001) for metastases. In the VHL (n=14), subgroup, 68Ga-DOTATATE PET/CT had higher lesion-wise sensitivity (100%) compared to 18F-FDG PET/CT (74%, p=0.045) and 131I-MIBG (64%, p=0.0145). CONCLUSIONS: In our pediatric PPGL cohort, overall lesion-wise sensitivity of 68Ga-DOTATATE PET/CT was higher than that of 18F-FDG PET/CT and 131I-MIBG scintigraphy. Hence, we recommend 68Ga-DOTATATE PET/CT as the preferred modality in pediatric PPGL. 68Ga-DOTATATE PET/CT may evolve as a preferred imaging modality for disease surveillance in VHL.

Prior testosterone replacement therapy may impact spermatogenic response to combined gonadotropin therapy in severe congenital hypogonadotropic hypogonadism.

OBJECTIVE: To study the effect of prior testosterone replacement therapy (TRT) on the spermatogenic response to combined gonadotropin therapy (CGT) in severe and partial phenotype congenital hypogonadotropic hypogonadism (CHH) patients. DESIGN: Retrospective cohort study. SETTING: Tertiary care center. PATIENTS: Patients of CHH without (n = 17) and with prior TRT (n = 18) were subdivided into severe and partial groups, based on mean testicular volume ≤ 3 cc and > 3 cc respectively. INTERVENTION: Participants were treated with hMG at a dose of 75-150 U 3/week and gradually escalating doses of hCG until maximum dose (2000 U 3/week or 5000 U 2/week) or serum total testosterone of ≥ 3.5 ng/ml was reached. MAIN OUTCOME MEASURES: Final mean TV, trough serum testosterone (T), sperm concentration RESULTS: Thirty-five patients (20 severe, baseline mean TV of 3.6 ± 2.7 ml) were started on CGT at 24.8 ± 6.1 years. The median duration of prior TRT was 38 (IQR 10-63.75) months in the exposed group. After 33 ± 12 months, final mean TV was 8.9 ± 5.5 ml, 86% achieved serum testosterone > 3.5 ng/ml and 70% achieved spermatogenesis [median 5 (0-12.6) million/ml]. Patients without prior TRT had significantly higher peak sperm count than those with prior- TRT (median 9 vs 0.05 million/ml, p = 0.004). This effect of prior TRT was more pronounced in severe phenotype patients (median 7 vs 0 million/ml, p = 0.01). CONCLUSION: Prior-TRT may interfere with spermatogenic response to CGT in CHH patients, especially in those with a severe phenotype.

Predictors of Chronic LH-Testosterone Axis Suppression in Male Macroprolactinomas With Normoprolactinemia on Cabergoline.

CONTEXT: Data are limited regarding prevalence, predictors, and mechanisms of persistent hypogonadotropic hypogonadism (HH) in males with a macroprolactinoma who achieve normoprolactinemia on dopamine-agonist therapy. None of the previous studies provide cutoffs to predict the achievement of eugonadism. OBJECTIVE: The objective of this work is to evaluate the prevalence of persistent HH and its determinants in men with a macroprolactinoma who achieve normoprolactinemia on cabergoline monotherapy. DESIGN AND SETTING: This retrospective study with prospective cross-sectional evaluation took place at a tertiary health care center. PATIENTS: Study participants included men with a macroprolactinoma and baseline HH who achieved normoprolactinemia on cabergoline monotherapy. MAIN OUTCOME MEASURES: Outcome measures of this study included the prevalence of persistent HH and its predictors. RESULTS: Thirty participants (age, 38.3 ± 10.1 years) with baseline tumor size of 4.08 ± 1.48 cm and median (interquartile range) prolactin of 2871 ng/mL (range, 1665-8425 ng/mL) were included. Eight of 30 participants achieved eugonadism after a median follow-up of 3 years. Patients with persistent HH had suppression of the luteinizing hormone (LH)-testosterone axis with sparing of other anterior pituitary hormonal axes, including follicle-stimulating hormone-inhibin B. Baseline prolactin (1674 vs 4120 ng/mL; P = .008) and maximal tumor diameter (2.55 ± 0.36 vs 4.64 ± 1.32 cm; P = .003) were lower in patients who achieved eugonadism. Baseline maximal tumor diameter less than or equal to 3.2 cm (sensitivity: 75%, specificity: 63.6%) and serum prolactin less than or equal to 2098 ng/mL (sensitivity: 87.5%, specificity: 77.3%) best predicted reversal of HH. CONCLUSION: Recovery of the LH-testosterone axis occurred in 26.7% of men with a macroprolactinoma who achieved normoprolactinemia on cabergoline monotherapy. Higher baseline tumor size and serum prolactin predict persistent HH. Our data favor chronic functional modification of the hypothalamic-pituitary-gonadal axis over gonadotroph damage as the cause of persistent HH.

177Lu-DOTATATE therapy in metastatic/inoperable pheochromocytoma-paraganglioma.

INTRODUCTION: 177Lu-DOTATATE-based peptide receptor radionuclide therapy (PRRT) is a promising therapy for metastatic and/or inoperable pheochromocytoma and paraganglioma (PPGL). We aim to evaluate the efficacy and safety of and identify predictors of response to 177Lu-DOTATATE therapy in metastatic and/or inoperable PPGL. METHODS: This retrospective study involved 15 patients of metastatic or unresectable PPGL, who received 177Lu-DOTATATE PRRT therapy. Clinical, biochemical (plasma-free normetanephrine), and radiological (anatomical and functional) responses were compared before and after the last therapy. RESULTS: A total of 15 patients (4 PCC, 4 sPGL, 5 HNPGL, 1 PCC + sPGL, 1 HNPGL + sPGL) were included. The median duration of follow up was 27 (range: 11-62) months from the start of PRRT. Based on the RECIST (1.1) criteria, progressive disease was seen in three (20%), stable disease in eight (53%), partial response in one (7%), and minor response in three (20%) and controlled disease in 12 (80%). On linear regression analysis the presence of PGL (P= 0.044) and baseline SUVmax >21 (P < 0.0001) were significant positive predictors of early response to PRRT. Encouraging safety profiles were noted with no long term nephrotoxicity and hematotoxicity. CONCLUSION: 177Lu-DOTATATE therapy is an effective and safe modality of treatment for patients with metastatic/inoperable PPGL. Although it is not prudent to withhold PRRT in metastatic PPGL with baseline SUVmax < 21, baseline SUVmax >21 can be used to predict early response to PRRT.

SYMPATHETIC PARAGANGLIOMA: A SINGLE-CENTER EXPERIENCE FROM WESTERN INDIA.

OBJECTIVE: 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. METHODS: 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. RESULTS: 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. CONCLUSION: 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. ABBREVIATIONS: 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.