Update on Pheochromocytoma and Paraganglioma from the SSO Endocrine/Head and Neck Disease-Site Work Group. Part 1 of 2: Advances in Pathogenesis and Diagnosis of Pheochromocytoma and Paraganglioma

Identification of Predictors of Metastatic Potential in Paragangliomas to Develop a Prognostic Score (PSPGL)

Context

Paragangliomas (PGLs) are rare tumors in adrenal and extra-adrenal locations. Metastasis are found in approximately 5% to 35% of PGLs, and there are no reliable predictors of metastatic disease.

Objective

This work aimed to develop a prognostic score of metastatic potential in PGLs.

Methods

A retrospective analysis was conducted of clinical data from a cohort with PGLs and tumor histological assessment. Patients were divided into metastatic PGL (presence of metastasis) and nonmetastatic PGL (absence of metastasis ≥96 months of follow-up) groups. Univariate and multivariable analysis were performed to identify predictors of metastatic potential. A prognostic score was developed based on coefficients of multivariable analysis. Kaplan-Meier curves were generated to estimate disease-specific survival (DSS).

Results

Out of 263 patients, 35 patients had metastatic PGL and 110 patients had nonmetastatic PGL. In multivariable analysis, 4 features were independently related to metastatic disease and composed the Prognostic Score of Paragangliomas (PSPGL): presence of central or confluent necrosis (33 points), more than 3 mitosis/10 high-power field (HPF) (28 points), extension into adipose tissue (20 points), and extra-adrenal location (19 points). A PSPGL of 24 or greater showed similar sensitivity with higher specificity than the Pheochromocytoma of the Adrenal Gland Scaled Score (PASS) and Grading System for Adrenal Pheochromocytoma and Paraganglioma (GAPP). PSPGL less than or equal to 20 was associated with a risk of metastasis of approximately 10%, whereas a PSPGL of 40 or greater was associated with approximately 80%. The presence of metastasis and Ki-67 of 3% or greater were related to lower DSS.

Conclusion

The PSPGL, composed of 4 easy-to-assess parameters, demonstrated good performance in predicting metastatic potential and good ability in estimating metastasis risk.

Paraganglioma of the Neck: A Rare Case With Spinal Metastasis

Paragangliomas are rare neuroendocrine tumors that arise from the paraganglia, which are clusters of neuroendocrine cells associated with the autonomic nervous system. These tumors are commonly found in the adrenal medulla but can also occur in other locations outside the adrenal gland. Here, we present a case report of a slow-growing paraganglioma in the left neck with spinal metastasis in a 60-year-old man. This case highlights the importance of considering paraganglion tumors in the differential diagnosis of neck masses and the need for early diagnosis and management to prevent potential complications. Importantly, both the clinical picture and anatomical location of these tumors is important when determining treatment plans.

Effects of Peptide Receptor Radiotherapy in Patients with Advanced Paraganglioma and Pheochromocytoma: A Nation-Wide Cohort Study

INTRODUCTION

Pheochromocytomas and paragangliomas are rare neuroendocrine tumours that originate from chromaffin cells within the adrenal medulla or extra-adrenal sympathetic ganglia. Management of disseminated or metastatic pheochromocytomas and paragangliomas continues to pose challenges and relies on limited evidence.

METHOD

In this study, we report retrospective data on median overall survival (OS) and median progression-free survival (PFS) for all Danish patients treated with peptide receptor radionuclide therapy (PRRT) with 177Lu-Dotatate or 90Y-Dotatate over the past 15 years. One standard treatment of PRRT consisted of 4 consecutive cycles with 8-14-week intervals.

RESULTS

We included 28 patients; 10 were diagnosed with pheochromocytoma and 18 with paraganglioma. Median age at first PRRT was 47 (IQR 15-76) years. The median follow-up time was 31 (IQR 17-37) months. Eight patients died during follow-up. Median OS was 72 months, and 5-year survival was 65% with no difference between pheochromocytoma and paraganglioma. Patients with germline mutations had better survival than patients without mutations (p = 0.041). Median PFS after the first cycle of PRRT was 30 months. For patients who previously received systemic treatment, the median PFS was 19 months, compared with 32 months for patients with no previous systemic treatment (p = 0.083).

CONCLUSIONS

The median OS of around 6 years and median PFS of around 2.5 years found in this study are comparable to those reported in previous studies employing PRRT. Based on historical data, the efficacy of PRRT may be superior to 131I-MIBG therapy, and targeted therapy with sunitinib and PRRT might therefore be considered as first-line treatment in this patient group.

Adrenal Cysts: To Operate or Not to Operate?

Adrenal cysts are uncommon and usually asymptomatic, and therefore are usually incidentally discovered adrenal lesions. They have a broad pathohistological spectrum that includes pseudocysts and endothelial (vascular), parasitic, and epithelial (mesothelial) cysts. Although most adrenal cysts are benign and hormonally non-functional lesions, some can have ambiguous imaging appearances and mimic malignant adrenal neoplasms. On the other hand, the actual malignant neoplasms could undergo cystic transformation. Additionally, immune cell infiltrations, thrombosis, or haemorrhage seen in sepsis can frequently cause adrenal cyst development, raising a question about the possible connection between severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) and adrenal cystic lesions. Due to the disease's rarity, the likelihood of malignancy, and the lack of specific guidelines, the management of adrenal cysts is always challenging especially in a young person. This review discusses the important diagnostic and the current treatment possibilities for adrenal cystic lesions. Aiming to emphasize clinical dilemmas and help clinicians navigate the challenges when encountering a patient with an adrenal cyst in everyday practice, we based our review on a practical question-answer framework centred around the case of a young woman with an incidentally discovered large adrenal cyst.

Diagnosis and Management of Pheochromocytomas and Paragangliomas: A Guide for the Clinician

OBJECTIVE

The aim of this review was to provide a practical approach for clinicians regarding the diagnosis and management of pheochromocytomas and paragangliomas (PPGLs).

METHODS

A literature search of PubMed was carried out using key words, including pheochromocytoma, paraganglioma, treatment, diagnosis, screening, and management. The discussion of diagnosis and management of PPGL is based on the evidence available from prospective studies when available and mostly from cohort studies, cross-sectional studies, and expert consensus.

RESULTS

PPGL are neuroendocrine tumors arising from the chromaffin cells of adrenal medulla and sympathetic and parasympathetic ganglia, respectively. PPGL can be localized or metastatic, and they may secrete catecholamines, causing a variety of symptoms and potentially catastrophic and lethal complications if left untreated. The rarity of these tumors along with heterogeneous clinical presentation often poses challenges for the diagnosis and management. PPGL can be associated with several familial syndromes which are important to recognize.

CONCLUSION

The last few years have witnessed an exponential growth in the knowledge around PPGL. This review aims at providing a comprehensive discussion of current concepts for clinicians regarding clinical presentation, diagnostic tools, and management strategies for PPGL.

[Metastatic risk factors in pheochromocytoma/paraganglioma]

Currently, all pheochromocytoma/paraganglioma (PPGLs) are considered malignant due to metastatic potential. Consequently, PPGLs are divided into «metastatic» and «non-metastatic». Metastatic PPGLs can be with synchronous metastasis (metastases appear simultaneously with the identified primary tumor) or metachronous (metastases develop after removal of the primary tumor). The term metastatic PPGLs is not used in the presence of tumor invasion into surrounding organs and tissues, without the presence of distant metastases of lymphogenic or hematogenic origin. It is generally believed that about 10% of pheochromocytomas and about 40% of sympathetic paragangliomas have metastatic potential. On average, the prevalence of PPGLs with the presence of metastases is 15-20%. Risk factors for metastatic PPGLs are widely discussed in the literature, the most significant of which are groups of clinical, morphological and genetic characteristics. The review presents a discussion of such risk factors for metastatic PPGLs as age, localization and type of hormonal secretion of the tumor, the size and growth pattern of the adrenal lesion, the presence of necrosis and invasion into the vessels, the tumor capsule surrounding adipose tissue, high cellular and mitotic activity, Ki-67 index, expression of chromogranin B and S100 protein, the presence of genetic mutations of three main clusters (pseudohypoxia, kinase signaling and Wnt signaling).Over the past two decades, a number of authors have proposed various predictor factors and scales for assessing a probability of metastatic PPGLs. The review contains detailed description and comparison of sensitivity and specificity of such predictor scales as PASS, GAPP, M-GAPP, ASES and COPPS.

Retroperitoneal Paraganglioma Treated With Tumor Resection and Replacement of the Inferior Vena Cava

Retroperitoneal paragangliomas are tumors of neuroectodermal origin rarely appearing in the pediatric population. We report a case of a large paraganglioma infiltrating the right kidney and inferior vena cava in a 16-year-old boy who initially presented with a right-sided varicocele. Right retroperitoneal paraganglioma was embolized preoperatively, followed by total tumor excision, right nephrectomy, inferior vena cava resection, and reconstruction using a prosthetic vascular graft. Retroperitoneal tumors requiring surgery can successfully be treated by radical resection and replacement of the inferior vena cava in experienced centers.

Three Dimensional Models of Endocrine Organs and Target Tissues Regulated by the Endocrine System

Immortalized cell lines originating from tumors and cultured in monolayers in vitro display consistent behavior and response, and generate reproducible results across laboratories. However, for certain endpoints, these cell lines behave quite differently from the original solid tumors. Thereby, the homogeneity of immortalized cell lines and two-dimensionality of monolayer cultures deters from the development of new therapies and translatability of results to the more complex situation in vivo. Organoids originating from tissue biopsies and spheroids from cell lines mimic the heterogeneous and multidimensional characteristics of tumor cells in 3D structures in vitro. Thus, they have the advantage of recapitulating the more complex tissue architecture of solid tumors. In this review, we discuss recent efforts in basic and preclinical cancer research to establish methods to generate organoids/spheroids and living biobanks from endocrine tissues and target organs under endocrine control while striving to achieve solutions in personalized medicine.

Multimodality Imaging of Cardiac Paragangliomas

Paragangliomas are rare neuroendocrine tumors of extra-adrenal autonomic paraganglia origin. Paragangliomas rarely involve the heart, and they account for less than 1% of primary cardiac tumors. Most cardiac paragangliomas are incidentally detected at echocardiography or CT or during the workup of symptomatic patients with high catecholamine levels. Paragangliomas are typically located around the great vessels, coronary arteries (atrioventricular groove), or the atria, which can be explained by the tumor origin from the paraganglia and the distribution of the cardiac plexus. At MRI, cardiac paragangliomas typically have low to intermediate signal on T1-weighted images and high signal on T2-weighted images. The tumors are strongly vascularized, with high uptake on first-pass perfusion images and a heterogeneous pattern on late gadolinium enhancement images. Functional imaging is indicated for diagnostic confirmation and to screen for additional tumor locations or metastatic disease. Surgical excision is the only curative treatment. Cardiac CT angiography or invasive angiography should be performed preoperatively to precisely delineate tumor vascularization. In particular, its relation with the coronary arteries should be determined, as paragangliomas can be perfused by the coronary arteries, posing additional surgical challenges and the need for coronary revascularization. This imaging essay reviews the characteristics of paragangliomas and the use of multimodality imaging for diagnosis and treatment. Keywords: CT Angiography, Molecular Imaging, MR Imaging, PET/CT, Cardiac, Heart, Neoplasms-Primary © RSNA, 2023.

Paravertebral paraganglioma with spinal extension: a case report

BACKGROUND

Paragangliomas are rare neuroendocrine tumors. While paragangliomas of the spine are rare, those located in non-cauda equina areas with spinal canal extension are even rarer.

CASE PRESENTATION

We present a case of a 23-year-old female of African descent with a primary thoracic paraganglioma with intervertebral extension resulting in displacement and compression of the spinal cord and extensive local invasion of the surrounding structures. This paraganglioma was functional with typical symptoms of catecholamine excess. Despite the aggressive nature of the paraganglioma, the patient only had isolated sensory symptoms in the left shoulder. Adequate alpha and beta-blockade were instituted prior to her undergoing surgery with near-total resection and complete preserved neurology. There was no underlying pathogenic genetic mutation found.

CONCLUSIONS

Even though rare, paraganglioma should be considered in the differential diagnosis of spinal tumors. Genetic testing should be performed in patients with paragangliomas. One should exercise extreme caution in treating such rare tumors that may cause neurological deficits and careful surgical planning should be undertaken to avoid possible catastrophic complications.

Management of pheochromocytomas and paragangliomas: Review of current diagnosis and treatment options

Pheochromocytomas (PCCs) are rare neuroendocrine tumors derived from the chromaffin cells of the adrenal medulla. When these tumors have an extra-adrenal location, they are called paragangliomas (PGLs) and arise from sympathetic and parasympathetic ganglia, particularly of the para-aortic location. Up to 25% of PCCs/PGLs are associated with inherited genetic disorders. The majority of PCCs/PGLs exhibit indolent behavior. However, according to their affiliation to molecular clusters based on underlying genetic aberrations, their tumorigenesis, location, clinical symptomatology, and potential to metastasize are heterogenous. Thus, PCCs/PGLs are often associated with diagnostic difficulties. In recent years, extensive research revealed a broad genetic background and multiple signaling pathways leading to tumor development. Along with this, the diagnostic and therapeutic options were also expanded. In this review, we focus on the current knowledge and recent advancements in the diagnosis and treatment of PCCs/PGLs with respect to the underlying gene alterations while also discussing future perspectives in this field.

Paragangliomas and Pheochromocytomas: Positron Emission Tomography/Computed Tomography Diagnosis and Therapy

Molecular imaging evaluation of pheochromocytomas and paragangliomas depends on multiple factors, such as localized versus metastatic disease, the genetic, and biochemical profile of tumors. Positron emission tomography/computed tomography (PET/CT) imaging of these tumors outperforms Meta-Iodo-Benzyl-Guanidine (MIBG) scintigraphy in most cases. A few PET radiotracers have been studied in evaluating these patients with somatostatin receptor PET imaging and have shown superior performance compared with other agents in most of these patients. 18F-fluorodeoxyglucose PET/CT imaging is useful in select patients, such as those with succinate dehydrogenase complex subunit B-associated disease. Treatment strategy depends on multiple factors and necessitates a multidisciplinary approach.

Genetic Testing for Adrenal Tumors-What the Contemporary Surgeon Should Know

Surgical diseases of the adrenal gland include pheochromocytoma/paraganglioma, primary hyperaldosteronism, Cushing syndrome, and adrenocortical carcinoma. These conditions may be associated with familial syndromes, and genetic testing is available and recommended in most. For adrenal surgeons to be familiar with these syndromes and know when to consider referral for genetic counseling and genetic testing is important. Identification of patients with familial syndromes allows for the detection and screening of associated syndromic neoplasms, guides surgical planning and operative approach, influences recurrence and malignancy risk assessment, aids in the development of a postoperative surveillance plan, and determines the need for screening family members.

The importance of perioperative and complication management in the treatment of pheochromocytoma crisis with venoarterial extracorporeal membrane oxygenation (V-A ECMO): a case report and review of the literature

PURPOSE

In this article, we aimed to elaborate on perioperative and complication management in treatment of pheochromocytoma crisis with extracorporeal membrane oxygenation (ECMO).

MATERIAL AND METHODS

We report a case of relatively rare grant paraganglioma-induced pheochromocytoma crisis leading to severe circulatory failure, treated with venoarterial extracorporeal membrane oxygenation (V-A ECMO) as a bridge to curative adrenalectomy. Weaning of ECMO was followed by successful surgical removal of the tumor, and patient survival. However, distal ischemia of the cannulated leg occurred during ECMO operation, which eventually led to amputation. In addition, the patient developed new cerebral infarction and left hemiplegia, half a month after paraganglioma resection.

CONCLUSIONS

We believe that patients with pheochromocytoma crisis, who cannot maintain blood circulation, are eligible for V-A ECMO treatment. Moreover, care should be taken to prevent thrombosis and individualized and precise blood pressure management targets. Early detection and treatment of thrombosis is imperative to long-term prognosis of patients with ECMO.

Surgical treatment of adrenal tumors during pregnancy

While most adrenal tumors are identified incidentally and are non-functional, hormone-secreting tumors can cause morbidity and mortality. Hemodynamic lability and hypertension in pregnancy are associated with worse maternal and fetal outcomes. Achieving a diagnosis of hormone excess due to adrenal tumors can be clinically more difficult in the gravid patient due to normal physiologic alterations in hormones and symptoms related to pregnancy. This review focuses on some nuances of the diagnostic work-up, perioperative care, and surgical management of adrenally-mediated cortisol excess, primary aldosteronism, and pheochromocytoma and paraganglioma in the pregnant patient.

Clinical characteristics and outcomes of pheochromocytoma crisis: a literature review of 200 cases

PURPOSE

Pheochromocytoma crisis is a life-threatening endocrine emergency that requires prompt diagnosis and treatment. Because of its rarity, sudden onset, and lack of internationally uniform and validated diagnostic criteria, pheochromocytoma crisis remains to be fully clarified. Therefore, we aimed to describe the clinical characteristics and outcomes of pheochromocytoma crisis through a literature review.

METHODS

We performed a systematic literature search of PubMed/MEDLINE database, Igaku-Chuo-Zasshi (Japanese database), and Google Scholar to identify case reports of pheochromocytoma crisis published until February 5, 2021. Information was extracted and analyzed from the literature that reported adequate individual patient data of pheochromocytoma crisis in English or Japanese. Cases were also termed as pheochromocytoma multisystem crisis (PMC) if patients had signs of hyperthermia, multiple organ failure, encephalopathy, and labile blood pressure.

RESULTS

In the 200 cases of pheochromocytoma crisis identified from 187 articles, the mean patient age was 43.8 ± 15.5 years. The most common symptom was headache (39.5%). The heart was the most commonly damaged organ resulting from a complication of a pheochromocytoma crisis (99.0%), followed by the lungs (44.0%) and the kidney (21.5%). PMC accounted for 19.0% of all pheochromocytoma crisis cases. After excluding 12 cases with unknown survival statuses, the mortality rate was 13.8% (26/188 cases). Multivariable logistic regression analysis revealed that nausea and vomiting were significantly associated with a higher mortality rate.

CONCLUSION

Pheochromocytoma can present with different symptomatology, affecting different organ systems. Clinicians should be aware that patients with nausea or vomiting are at a higher risk of death because of pheochromocytoma crisis.

Targeted Therapies in Pheochromocytoma and Paraganglioma

Molecular targeted therapy plays an increasingly important role in the treatment of metastatic pheochromocytomas and paragangliomas (PPGLs), which are rare tumors but remain difficult to treat. This mini-review provides an overview of established molecular targeted therapies in present use, and perspectives on those currently under development and evaluation in clinical trials. Recently published research articles, guidelines, and expert views on molecular targeted therapies in PPGLs are systematically reviewed and summarized. Some tyrosine kinase inhibitors (sunitinib, cabozantinib) are already in clinical use with some promising results, but without formal approval for the treatment of PPGLs. Sunitinib is the only therapeutic option which has been investigated in a randomized placebo-controlled clinical trial. It is clinically used as a first-, second-, or third-line therapeutic option for the treatment of progressive metastatic PPGLs. Some other promising molecular targeted therapies (hypoxia-inducible factor 2 alpha [HIF2α] inhibitors, tumor vaccination together with checkpoint inhibitors, antiangiogenic therapies, kinase signaling inhibitors) are under evaluation in clinical trials. The HIF2α inhibitor belzutifan may prove to be particularly interesting for cluster 1B-/VHL/EPAS1-related PPGLs, whereas antiangiogenic therapies seem to be primarily effective in cluster 1A-/SDHx-related PPGLs. Some combination therapies currently being evaluated in clinical trials, such as temozolomide/olaparib, temozolomide/talazoparib, or cabozantinib/atezolizumab, will provide data for novel therapy for metastatic PPGLs. It is likely that advances in such molecular targeted therapies will play an essential role in the future treatment of these tumors, with more personalized therapy options paving the way towards improved therapeutic outcomes.

Left adrenal aldosteronism coexisting with left paraaortic paraganglioma presenting as bilateral adrenal and left paraaortic tumors- comprehensive adrenal evaluation aiding perfect management: a case report

BACKGROUND

Coexistence of a catecholamine-secreting tumor and an adrenal cortical tumor is quite rare which makes both diagnosis and management challenging. The purpose of this article is to describe the presence of this condition, share a stepwise approach for preoperative evaluation, and review the related literature.

CASE PRESENTATION

A 44-year-old male patient had a history of hypertension and aggravating hypokalemia for years. Abdominal computed tomography incidentally found concomitant bilateral adrenal and left para-aortic tumors. Comprehensive adrenal hormone tests revealed a high aldosterone renin ratio and mildly elevated 24-h urine vanillylmandelic acid and norepinephrine levels. Subsequently, a metaiodobenzylguanidine scan showed uptake over the left para-aortic tumor, and NP-59 adrenal scintigraphy showed uptake over the left adrenal tumor. Further confirmatory tests, including captopril suppression, irbesartan suppression, and saline infusion, all confirmed the diagnosis of hyperaldosteronism. Adrenal venous sampling following 2 months of preparation with an alpha blocker demonstrated a left aldosterone-producing adrenal adenoma. Combining hormonal analysis, imaging studies, and adrenal venous sampling, the patient was diagnosed with left adrenal aldosteronoma, right adrenal nonfunctional tumor, and left para-aortic paraganglioma (PGL). Accordingly, laparoscopic left adrenalectomy and left PGL excision were performed smoothly under alpha blocker maintenance. The pathology report confirmed left adrenal cortical adenoma and left para-aortic PGL. Postoperatively, the blood pressure, biochemical tests, and adrenal hormone assays returned to normal, and related symptoms disappeared and were relatively stable during the follow-up period of two years.

CONCLUSIONS

This is the first case of left para-aortic PGL coexisting with an ipsilateral aldosterone-producing adenoma presenting as a left para-aortic tumor associated with bilateral adrenal tumors. Awareness of the rarity of this coexistence can avoid unexpected disasters during the process of evaluation and management.

Clinical Predictors of Pseudohypoxia-Type Pheochromocytomas

INTRODUCTION

Pheochromocytomas (PCCs) are rare tumors of neural crest origin with divergent transcriptional and metabolic profiles associated with mutational cluster types. Pseudohypoxia-type (PHT) PCCs have a poor prognosis; however diagnostic genetic testing is not always available. We aimed to investigate clinical parameters predictive of PHT PCCs.

METHODS

Patients who underwent resection and genetic testing for PCC at two academic centers from 2006-2020 were retrospectively studied. Patients with PHT mutations (SDH-AF2/B/C/D, VHL) were compared to non-pseudohypoxia-type (nonPHT) PCCs to identify widely available clinical parameters predictive of PHT PCCs. Demographic, clinical, and pathologic characteristics were compared using student's T and ANOVA tests. Operative hemodynamic instability was defined as systolic blood pressure (SBP) >  200 mmHg, SBP increase of >  30% relative to baseline, and/or heart rate (HR) > 110 bpm. Mann-Whitney U test was used to assess area under the curve (AUC), sensitivity, and specificity. Recursive partitioning was used to model predictive thresholds for PHT PCC and develop a predictive score.

RESULTS

Of the 79 patients included in the cohort, 17 (22%) had PHT and 62 (78%) had nonPHT PCCs. PCC patients with >  2 of the examined predictive clinical parameters (preoperative weight loss [> 10% body weight], elevated preoperative hematocrit [>  50%], normal baseline heart rate [< 100 bpm], and normal plasma metanephrines [< 0.60 nmol/L]) were more likely to have PHT PCCs (AUC = 0.831, sensitivity = 0.882, specificity = 0.694, all p < 0.001).

CONCLUSIONS

Widely available preoperative clinical parameters including indicators of erythropoiesis (hemoglobin, hematocrit, and red blood cell count), baseline heart rate, plasma metanephrines, and weight loss may be useful predictors of PHT PCCs and may help guide management of PCCs when genetic testing is unavailable/delayed.

Wide Variability in Catecholamine Levels From Adrenal Venous Sampling in Primary Aldosteronism

INTRODUCTION

While adrenal venous sampling (AVS) differentiates between the unilateral and bilateral disease in patients with primary aldosteronism (PA), it is unknown if AVS can determine laterality of pheochromocytoma in patients with bilateral adrenal masses. This study analyzes adrenal vein (AV) epinephrine and norepinephrine levels in nonpheochromocytoma patients to determine the "normal" range.

MATERIALS AND METHODS

We reviewed patients who underwent AVS for PA between 2009 and 2019 at a single institution; pheochromocytoma was excluded. Aldosterone, cortisol, epinephrine, and norepinephrine levels were obtained from the inferior vena cava (IVC), left adrenal vein (LAV), and right adrenal vein (RAV). Successful AV cannulation was defined by an AV/IVC cortisol ratio of ≥3:1 or an AV epinephrine level ≥364 pg/mL. Plasma measurements (pg/mL) are median values with interquartile ranges; normal ranges for epinephrine and norepinephrine are 10-200 pg/mL and 80-520 pg/mL, respectively.

RESULTS

AVS was performed in 172 patients in 405 AVs (173 LAV and 232 RAV). Median epinephrine levels were IVC = 19 (14 and 34), LAV = 3811 (1870 and 6915), and RAV = 2897 (1500 and 5288). Median norepinephrine levels were IVC = 325 (186 and 479), LAV = 1450 (896 and 2050), and RAV = 786 (436 and 1582). There was a difference between LAV and RAV epinephrine levels (P = 0.024) and between LAV and RAV norepinephrine (P = 0.002) levels.

CONCLUSIONS

This extensive experience with AVS demonstrated a wide range of "normal" AV catecholamine levels in patients without pheochromocytoma, which suggests that the utility of AVS to determine disease laterality in patients with pheochromocytoma and bilateral adrenal nodules is likely to be limited.

Personalized Management of Pheochromocytoma and Paraganglioma

Pheochromocytomas/paragangliomas are characterized by a unique molecular landscape that allows their assignment to clusters based on underlying genetic alterations. With around 30% to 35% of Caucasian patients (a lower percentage in the Chinese population) showing germline mutations in susceptibility genes, pheochromocytomas/paragangliomas have the highest rate of heritability among all tumors. A further 35% to 40% of Caucasian patients (a higher percentage in the Chinese population) are affected by somatic driver mutations. Thus, around 70% of all patients with pheochromocytoma/paraganglioma can be assigned to 1 of 3 main molecular clusters with different phenotypes and clinical behavior. Krebs cycle/VHL/EPAS1-related cluster 1 tumors tend to a noradrenergic biochemical phenotype and require very close follow-up due to the risk of metastasis and recurrence. In contrast, kinase signaling-related cluster 2 tumors are characterized by an adrenergic phenotype and episodic symptoms, with generally a less aggressive course. The clinical correlates of patients with Wnt signaling-related cluster 3 tumors are currently poorly described, but aggressive behavior seems likely. In this review, we explore and explain why cluster-specific (personalized) management of pheochromocytoma/paraganglioma is essential to ascertain clinical behavior and prognosis, guide individual diagnostic procedures (biochemical interpretation, choice of the most sensitive imaging modalities), and provide personalized management and follow-up. Although cluster-specific therapy of inoperable/metastatic disease has not yet entered routine clinical practice, we suggest that informed personalized genetic-driven treatment should be implemented as a logical next step. This review amalgamates published guidelines and expert views within each cluster for a coherent individualized patient management plan.

A Predictive Nomogram for Early Death in Pheochromocytoma and Paraganglioma

Background

Pheochromocytoma (PHEO) and paraganglioma (PGL) are relatively rare neuroendocrine tumors. The factors affecting patients with early death remain poorly defined. We aimed to study the demographic and clinicopathologic pattern and to develop and validate a prediction model for PHEO/PGL patients with early death.

Methods

Data of 800 participants were collected from the Surveillance Epidemiology and End Results (SEER) database as a construction cohort, while data of 340 participants were selected as a validation cohort. Risk factors considered included the year of diagnosis, age at diagnosis, gender, marital status, race, insurance status, tumor type, primary location, laterality, the presence of distant metastasis. Univariate and multivariate logistic regressions were performed to determine the risk factors. R software was used to generate the nomogram. Calibration ability, discrimination ability, and decision curve analysis were analyzed in both construction and validation cohorts.

Results

PHEO and PGL patients accounted for 54.3% (N=434) and 45.7% (N=366), respectively. More than half of tumors (N=401, 50.1%) occurred in the adrenal gland, while 16.9% (N=135) were in aortic/carotid bodies. For the entire cohort, the median overall survival (OS) was 116.0 (95% CI: 101.5-130.5) months. The multivariate analysis revealed that older age (versus age younger than 31; age between 31 and 60: OR=2.03, 95% CI: 1.03-4.03, P=0.042; age older than 60: OR=5.46, 95% CI: 2.68-11.12, P&lt;0.001), female gender (versus male gender; OR=0.59, 95% CI: 0.41-0.87, P=0.007), tumor located in aortic/carotid bodies (versus tumor located in adrenal gland; OR=0.49, 95% CI: 0.27-0.87, P=0.015) and the presence of distant metastasis (versus without distant metastasis; OR=4.80, 95% CI: 3.18-7.23, P&lt;0.001) were independent risk factors of early death. The predictive nomogram included variables: age at diagnosis, gender, primary tumor location, and distant metastasis. The model had satisfactory discrimination and calibration performance: Harrell’s C statistics of the prediction model were 0.733 in the construction cohort and 0.716 in the validation cohort. The calibration analysis showed acceptable coherence between predicted probabilities and observed probabilities.

Conclusions

We developed and validated a predictive nomogram utilizing data from the SEER database with satisfactory discrimination and calibration capability which can be used for early death prediction for PHEO/PGL patients.

Pheochromocytomas and Abdominal Paragangliomas: A Practical Guidance

Simple Summary

Pheochromocytomas and abdominal paragangliomas (PPGLs) are rare. They can be discovered incidentally by imaging with computed tomography or magnetic resonance imaging and during hormonal surveillance in patients with known genetic variants that are associated with PPGLs. As most PPGLs are functioning, a hormonal work-up evaluating for catecholamine excess is recommended. Classical symptoms, such as tachycardia, hypertension and headache, can be present, but when the PPGL is discovered as an incidentaloma, symptoms may be lacking or be more discrete. PPGLs carry malignant potential, and patients should undergo close surveillance, as recurrence of disease or metastasis may develop. Genetic susceptibility for multifocal disease has gained more attention, and germline variants are commonly detected, thus facilitating detection of hereditary cases and afflicted family members. Any patient with a PPGL should be managed by an expert multidisciplinary team consisting of endocrinologists, radiologists, surgeons, pathologists and clinical geneticists.

Abstract

Pheochromocytomas and abdominal paragangliomas (PPGLs) are rare tumors arising from the adrenal medulla or the sympathetic nervous system. This review presents a practical guidance for clinicians dealing with PPGLs. The incidence of PPGLs has risen. Most cases are detected via imaging and less present with symptoms of catecholamine excess. Most PPGLs secrete catecholamines, with diffuse symptoms. Diagnosis is made by imaging and tests of catecholamines. Localized disease can be cured by surgery. PPGLs are the most heritable of all human tumors, and germline variants are found in approximately 30–50% of cases. Such variants can give information regarding the risk of developing recurrence or metastases as well as the risk of developing other tumors and may identify relatives at risk for disease. All PPGLs harbor malignant potential, and current histological and immunohistochemical algorithms can aid in the identification of indolent vs. aggressive tumors. While most patients with metastatic PPGL have slowly progressive disease, a proportion of patients present with an aggressive course, highlighting the need for more effective therapies in these cases. We conclude that PPGLs are rare but increasing in incidence and management should be guided by a multidisciplinary team.

Stuttering priapism in a pediatric patient with pheochromocytoma-induced thrombocytosis

Priapism is an erection of more than 4 h without sexual stimulation. Ischemic priapism may lead to irreversible erectile dysfunction after a long-lasting period. Stuttering priapism is characterized by a pattern of recurrence that may progress to an unrelenting ischemic crisis, which is a urological emergency. Few reports have revealed that priapism is associated with essential thrombocythemia. The reactive thrombocytosis is uncommonly manifested by pheochromocytoma and rarely causes thrombotic events even if the platelet count is extremely high. We presented priapism related to reactive severe thrombocytosis in a 12-year-old male with pheochromocytoma. The cornerstone of care was prompt medical and surgical intervention by a multidisciplinary team approach to save life and preserve erectile function.

Protocol for presurgical and anesthetic management of pheochromocytomas and sympathetic paragangliomas: a multidisciplinary approach

OBJECTIVE

To offer a practical guide for the presurgical and anesthetic management of pheochromocytomas and sympathetic paragangliomas (PGLs).

METHODS

This protocol was based on a comprehensive review of the literature and on our own multidisciplinary team's experience from managing pheochromocytoma and sympathetic PGLs at a referral center.

RESULTS

Patients with pheochromocytomas and sympathetic paragangliomas (PGLs) may develop potentially life-threatening complications, especially during surgical procedures. A complete biochemical, radiological, genetic, and cardiological assessment is recommended in the preoperative stage as it provides an evaluation of the risk of surgical complications and malignancy, allowing individualization of the presurgical treatment. Treatment with α-blockade and proper volume expansion in the preoperative stage significantly reduces the perioperative morbidity. During surgery, the anesthesiologist should look for a deep anesthetic level that inhibits the cardiovascular effects of catecholamines to minimize the risk of intraoperative complications.

CONCLUSIONS

An optimal presurgical evaluation of pheochromocytomas/ sympathetic PGL requires a multidisciplinary approach, including a complete hormonal, radiological, cardiac, genetic, and functioning evaluation in most cases. A proper preoperative evaluation in combination with strict blood pressure and heart rate control, and blood volume status optimization, will significantly reduce the risk of intraoperative and perioperative complications. In those patients who unfortunately develop intraoperative complications, the role of the anesthesiologist is essential since the selection of the appropriate management has a direct impact on morbimortality reduction.

[Clinical and laboratory features of hereditary pheochromocytoma and paraganglioma]

The widespread introduction of genetic testing in recent years has made it possible to determine that more than a third of cases of pheochromocytomas and paragangliomas (PPPGs) are caused by germline mutations. Despite the variety of catecholamine-producing tumors manifestations, there is a sufficient number of clinical and laboratory landmarks that suggest a hereditary genesis of the disease and even a specific syndrome. These include a family history, age of patient, presence of concomitant conditions, and symptoms of the disease. Considering that each of the mutations is associated with certain diseases that often determine tactics of treatment and examination of a patient, e.g. high risk of various malignancies. Awareness of the practitioner on the peculiarities of the course of family forms of PPPGs will allow improving the tactics of managing these patients.The article provides up-to-date information on the prevalence of hereditary PPPGs. The modern views on the pathogenesis of the disease induced by different mutations are presented. The main hereditary syndromes associated with PPPGs are described, including multiple endocrine neoplasia syndrome type 2A and 2B, type 1 neurofibromatosis, von Hippel-Lindau syndrome, hereditary paraganglioma syndrome, as well as clinical and laboratory features of the tumor in these conditions. The main positions on the necessity of genetic screening in patients with PPPGs are given.

Comparison of Perioperative Outcomes of Robotic-Assisted vs Laparoscopic Adrenalectomy for Pheochromocytoma: A Meta-Analysis

Objective

To compare the efficacy and safety of robotic-assisted adrenalectomy (RA) and standard laparoscopic adrenalectomy (LA) for pheochromocytoma (PHEO).

Methods

We systematically searched the Cochrane Library, PubMed, Embase, and Science databases for studies published through January 2021. Controlled trials on RA and LA for PHEOs were included. The meta-analysis was conducted with the Review Manager 5.4 software.

Results

Four studies with 386 patients were included in the analysis. There were no significant differences in OT (WMD: 0.16; 95% CI: -28.50 to 28.82; I² = 89%; P = 0.99), transfusion rate (OR: 0.70; 95% CI: 0.07 to 7.07; I² = 64%; P = 0.77), conversion rate (OR: 0.44; 95% CI: 0.07 to 2.88; I² = 0%; P = 0.39), complication rate (OR: 1.06; 95% CI: 0.62 to 1.82; I² = 0%; P = 0.84) among patients undergoing RA and LA. However, compared with patients who underwent LA, patients who underwent RA had a shorter LOS (OR: -0.50; 95% CI: -0.55 to 0.45; I² = 31%; P<0.01), less EBL (WMD: -0.85; 95% CI: -13.56 to -2.54; I² = 44%; P<0.01), and fewer IHD (OR: 0.34; 95% CI: 0.17 to 0.70; I² = 0%; P<0.01).

Conclusion

The RA for pheochromocytoma achieve better outcomes over LA in terms of safety and efficacy.

Efficient Sub-1 Minute Analysis of Selected Biomarker Catecholamines by Core-Shell Hydrophilic Interaction Liquid Chromatography (HILIC) with Nanomolar Detection at a Boron-Doped Diamond (BDD) Electrode

A rapid, sensitive method for the separation of catecholamine biomarkers (CAs), of importance in traumatic brain injury (TBI) and in Parkinson’s disease (PD), has been successfully developed using hydrophilic interaction liquid chromatography (HILIC). Dopamine (DA), epinephrine (EPI), and norepinephrine (NE) are known to be three to fivefold elevated above normal in traumatic brain injury (TBI) patients. HILIC facilitates the rapid and efficient separation of these polar biomarkers, which can be poorly retained by reversed-phase liquid chromatography (RPLC), while electrochemical detection (ECD) at the boron-doped diamond (BDD) electrode provides enhanced nanomolar detection. Three HILIC columns were compared, namely the superficially porous (core-shell) Z-HILIC column and the Z-cHILIC and Z-HILIC fully porous columns. The core-shell Z-HILIC showed the highest efficiency with a rapid separation within 60 s. The HILIC method utilizing the core-shell Z-HILIC column was initially optimized for the simultaneous analysis of DA, EPI, and NE using UV detection. The advantages of using the BDD electrode over UV detection were explored, and the improved limits of detection (LODs, S/N = 3) measured were 40, 50, and 50 nM for DA, EPI, and NE, respectively. Method validation is reported in terms of the linearity, repeatability, reproducibility, and LODs. Furthermore, the proposed method was successfully applied to the real sample analysis of urinary CAs following phenylboronic acid (PBA) solid phase extraction (SPE) pretreatment.

Assessment of MR Imaging and CT in Differentiating Hereditary and Nonhereditary Paragangliomas

BACKGROUND AND PURPOSE

Head and neck paragangliomas have been reported to be associated with mutations of the succinate dehydrogenase enzyme family. The aim of this study was to assess whether radiologic features could differentiate between paragangliomas in the head and neck positive and negative for the succinate dehydrogenase mutation.

MATERIALS AND METHODS

This single-center retrospective review from January 2015 to January 2020 included 40 patients with 48 paragangliomas (30 tumors positive for succinate dehydrogenase mutation in 23 patients and 18 tumors negative for the succinate dehydrogenase mutation in 17 patients). ADC values and tumor characteristics on CT and MR imaging were evaluated by 2 radiologists. Differences between the 2 cohorts in the diagnostic performance of ADC and normalized ADC (ratio to ADC in the medulla oblongata) values were evaluated using the independent samples t test. P < .05 was considered significant.

RESULTS

ADC_mean (1.07 [SD, 0.25]/1.04 [SD, 0.12] versus 1.31 [SD, 0.16]/1.30 [SD, 0.20]× 10^-3 mm²/s by radiologists 1 and 2; P < .001), ADC_maximum (1.49 [SD, 0.27]/1.49 [SD, 0.20] versus 2.01 [SD, 0.16]/1.87 [SD, 0.20] × 10^-3 mm²/s; P < .001), normalized ADC_mean (1.40 [SD, 0.33]/1.37 [SD, 0.16] versus 1.73 [SD, 0.22]/1.74 [SD, 0.27]; P < .001), and normalized ADC_maximum (1.95 [SD, 0.37]/1.97 [SD, 0.27] versus 2.64 [SD, 0.22]/2.48 [SD, 0.28]; P < .001) were significantly lower in succinate dehydrogenase mutation-positive than mutation-negative tumors. ADC_minimum, normalized ADC_minimum, and tumor characteristics were not statistically significant.

CONCLUSIONS

ADC is a promising imaging biomarker that can help differentiate succinate dehydrogenase mutation-positive from mutation-negative paragangliomas in the head and neck.

Emergent transcatheter arterial embolization to control critical blood pressure fluctuation associated with hypercatecholaminemic crisis in a patient with an unruptured retroperitoneal paraganglioma

Pheochromocytoma/paraganglioma (PPGL)-related hypercatecholaminemic crisis is a rare lethal condition caused by uncontrolled catecholamine secretion, occasionally leading to critical fluctuation in blood pressure (BP). Emergent transcatheter arterial embolization (TAE) has been employed for spontaneous PPGL rupture, but never, to our knowledge, for critical fluctuation in BP associated with PPGL-related hypercatecholaminemic crisis. We describe here our experience utilizing this method to control critical fluctuation in BP associated with this crisis in a 44-year-old man with an unruptured retroperitoneal paraganglioma. The patient experienced sudden severe left abdominal pain and came to our emergency department, where he exhibited severe fluctuation in BP and underwent laboratory testing that showed hypercatecholaminuria and computed tomography (CT) that revealed a left retroperitoneal tumor with no apparent intra- or retroperitoneal hematoma. We performed emergent TAE from the left inferior phrenic artery using gelatin sponge, which stabilized his BP and relieved his abdominal pain. Histologic examination following elective surgical resection of the tumor confirmed our diagnosis of unruptured retroperitoneal paraganglioma. We believe that TAE represents an important option for the emergent treatment of the critical BP fluctuation associated with PPGL-related hypercatecholaminemic crisis.

A patient with paraganglioma undergoing laparoscopic resection: A case report

Paraganglioma is a very rare extraadrenal nonepithelial tumor. The number of cases of laparoscopic surgery in Paraganglioma is small and controversial. This study encountered a case of successful transperitoneal laparoscopic surgery for a 56-mm paraganglioma in a 53-year-old female. Moreover, previous reports on laparoscopic surgery for paraganglioma are reviewed.

Diffusion-weighted and dynamic contrast-enhanced MRI to assess radiation therapy response for head and neck paragangliomas

BACKGROUND AND PURPOSE

The prediction of radiotherapy outcome in head and neck paragangliomas is clinically important. We investigated perfusion and diffusion markers for evaluation of response to radiotherapy of head and neck paragangliomas.

METHODS

We retrospectively reviewed 330 consecutive patients from January 2016 to September 2019 with suspected head and neck paragangliomas, and enrolled 11 patients (2 males, 9 females; age: 55.2 ± 10.3 years) who had conventional MRI and dynamic contrast-enhanced (DCE)-MRI before and after radiation therapy. Radiation therapy, consisting of external beam radiotherapy or stereotactic radiotherapy, was conducted at the radiation oncology department in a single center. Mean apparent diffusion coefficient (ADC), normalized mean ADC, and parameters of DCE-MRI were compared between pre- and post-treatment status by paired t-test. The Pearson correlation coefficient was used for the relationship between tumor volume ratio (post-treatment status/pre-treatment status) and pre-treatment and post-treatment values.

RESULTS

Mean and normalized ADC values were statistically higher in post-treatment status than pre-treatment status (p = 0.005, p = 0.005, respectively), and Ktrans (volume transfer constant between extravascular, extracellular space [EES], and blood plasma per minute) and Kep (rate transfer constant between EES and blood plasma per minute) were significantly lower in post-treatment status than pre-treatment status (p = 0.007, p = 0.027, respectively). The correlation coefficient of the relationship between tumor volume ratio and pre-treatment Ktrans (r = 0.70; p = 0.016) and between tumor volume ratio and post-treatment Ktrans and Kep (r = 0.83; p = 0.002, r = 0.8; p = 0.003, respectively) was statistically significant.

CONCLUSIONS

Ktrans has predictive potential to predict the response to radiation therapy of head and neck paragangliomas.

Metastatic Pheochromocytomas and Abdominal Paragangliomas

CONTEXT

Pheochromocytomas and paragangliomas (PPGLs) are believed to harbor malignant potential; about 10% to 15% of pheochromocytomas and up to 50% of abdominal paragangliomas will exhibit metastatic behavior.

EVIDENCE ACQUISITION

Extensive searches in the PubMed database with various combinations of the key words pheochromocytoma, paraganglioma, metastatic, malignant, diagnosis, pathology, genetic, and treatment were the basis for the present review.

DATA SYNTHESIS

To pinpoint metastatic potential in PPGLs is difficult, but nevertheless crucial for the individual patient to receive tailor-made follow-up and adjuvant treatment following primary surgery. A combination of histological workup and molecular predictive markers can possibly aid the clinicians in this aspect. Most patients with PPGLs have localized disease and may be cured by surgery. Plasma metanephrines are the main biochemical tests. Genetic testing is important, both for counseling and prognostic estimation. Apart from computed tomography and magnetic resonance imaging, molecular imaging using 68Ga-DOTATOC/DOTATATE should be performed. 123I-MIBG scintigraphy may be performed to determine whether 131I-MIBG therapy is a possible option. As first-line treatment in patients with metastatic disease, 177Lu-DOTATATE or 131I-MIBG is recommended, depending on which shows best expression. In patients with very low proliferative activity, watch-and-wait or primary treatment with long-acting somatostatin analogues may be considered. As second-line treatment, or first-line in patients with high proliferative rate, chemotherapy with temozolomide or cyclophosphamide + vincristine + dacarbazine is the therapy of choice. Other therapies, including sunitinib, cabozantinib, everolimus, and PD-1/PDL-1 inhibitors, have shown modest effect.

CONCLUSIONS

Metastatic PPGLs need individualized management and should always be discussed in specialized and interdisciplinary tumor boards. Further studies and newer treatment modalities are urgently needed.

Severe headache presenting as an early sign of retroperitoneal para aortic paraganglioma

BACKGROUND

Paraganglioma is a rare type of neuroendocrine tumor with the ability to secrete neuropeptide and catecholamines in excess. Sympathetic hyperactivity, severe persistent headache and hypertension is the most common clinical presentation of paraganglioma similar to pheocromocytoma. Case report We reported a case of 19 year old girl with severe headache and hypertension, from past 6 month. On further imaging evaluation for the headache, the computed tomography of the abdomen plus pelvis was suggestive of left pre para aortic paraganglioma measuring of 3.4 cm in diameter. Surgical excision of mass was done. Histopathological examination of surgical specimen was consistent with the diagnosis of paraganglioma. Patient is on regular follow up without any subjective or objective evidence of the disease.

CONCLUSION

Retroperitoneal paraganglioma may be one of the causes for commonly occurring symptomatic headache, which is benign in nature, but possibility of transformation of malignant paraganglioma can occur. The surgical excision of mass is the treatment of choice.

Pheochromocytoma and Paraganglioma: From Treatment to Follow-up

Pheochromocytomas (PCC) and paragangliomas (PGL) are rare neuroendocrine tumors arising from chromaffin cells in the adrenal medulla, sympathetic or parasympathetic ganglia. Currently, the only curative treatment option of pheochromocytomas/paraganglioma (PPGL) is surgical resection. Surgery aims to eliminate both risks of hypersecretion and tumor growth. The consequences of hypersecretion should be carefully controlled with medical therapy before and during the surgery. Postoperative major complications are hypotension and rebound hypoglycemia, and patients should be followed closely for 24-48 hours. The choice of surgical approach is determined based on multiple factors, including germline genetic test results, the size of the tumor, body mass index, surgeon's experience, and the likelihood of malignancy. Primary tumor resection does not completely eliminate the risk of tumor persistence and recurrence. Therefore, all patients with PPGL who are surgically treated should be followed for at least 10 years for recurrent disease and new tumor formation. Although surgical resection is the only curative treatment for PPGLs, surgical treatment is palliative except for resectable locoregional metastases in metastatic disease or for isolated distant metastases. The purpose of palliative treatment is to reduce hormone secretion and prevent metastasis-related complications in a critical anatomical location Combined and alfa;- and beta- adrenergic blockade is usually applied in patients with PPGL preoperatively. Some patients may present with pheochromocytoma multisystem crisis, which is a life-threatening condition that can involve cardiovascular, pulmonary, neurological, gastrointestinal, renal, hepatic and metabolic systems. Pheochromocytoma crisis may be spontaneous or may present with the tumor manipulation, trauma, corticosteroids, beta-blockers, anesthetic drugs, and the stimulation of non-adrenal surgical stress. These patients should be considered as medical emergencies rather than surgical emergencies. In this review, it was aimed to evaluate the pre-, per and post-operative management, curative and palliative surgical management, and postoperative outcomes and follow-up of the patients with PPGLs.

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.

Pheochromocytoma and Paraganglioma: From Epidemiology to Clinical Findings

Pheochromocytomas (PCC) and paragangliomas (PGL) are rare neuroendocrine tumors. Pheochromocytomas arise from chromaffin cells in the adrenal medulla, and PGLs arise from chromaffin cells in the ganglia of the autonomic nervous system. Paragangliomas originate from sympathetic or parasympathetic ganglia in the abdomen, thorax, and pelvis. The majority of PCC and sympathetic PGL are endocrine active tumors causing clinical symptoms by secreting excess catecholamines (norepinephrine, epinephrine, dopamine) and their metabolites. The incidence of PCC and PGL ranges between 2 and 8 per million, with a prevalence between 1:2500 and 1:6500. It peaks between the 3rd and 5th decades of life, and approximately 20% of cases are pediatric patients. The prevalence among patients with hypertension in outpatient clinic ranges between 0.1-0.6% in adults and between 2-4.5% in the pediatric age group. 10-49% of these tumors is detected incidentally in imaging techniques performed for other reasons. However, 4-8% of adrenal incidentalomas are PCCs. Of these neuroendocrine tumors, 80-85% are PCCs and 15-20% are PGLs.

Up to 40% of patients with PCC and PGL has disease-specific germline mutations and the situation is hereditary. Of 60% of the remaining sporadic patients, at least 1/3 has a somatic mutation in predisposing genes. 8% of the sporadic cases, 20-75% of the hereditary cases, 5% of the bilateral, adrenal cases, and 33% of the extra-adrenal cases at first presentation are metastatic. Although PCCs and PGLs have scoring systems for histological evaluation of the primary tumor, it is not possible to diagnose whether the tumor is malignant since there is no histological system approved for the biological aggressiveness of this tumor group. Metastasis is defined as the presence of chromaffin tissue in non-chromaffin organs, such as lymph nodes, liver, lungs and bone. Although most of the PCC and PGL are benign, the metastatic disease may develop in 15-17%. Metastatic disease is reported between 2-25% in PCCs and 2.4-60% in PGLs. The TNM staging system of the American Joint Committee on Cancer (AJCC) was developed to predict the prognosis, based on the specific anatomical features of the primary tumor and the occurrence of metastasis.