Pheochromocytoma: Diagnosis and management update

Composite pheochromocytoma–ganglioneuroma: a case with two distinct components radiographically

Composite pheochromocytoma is an extremely rare tumor that comprises a pheochromocytoma and an embryologically related neurogenic tumor, such as ganglioneuroma, ganglioneuroblastoma, neuroblastoma, or peripheral nerve sheath tumor.

A 46-year-old male with hypertension, elevated plasma catecholamine levels, and suspected pheochromocytoma presented to the National Defense Medical College Hospital. CT and MRI showed two adjacent masses in the left adrenal gland; one was a 6 cm cephalic lesion and the other was a 1.5 cm caudal lesion. Only the 1.5 cm caudal mass showed uptake on ¹²³I-metaiodobenzylguanisine single photon emission CT/CT. Pheochromocytoma was suspected and a left adrenalectomy was performed. Pathology confirmed that the 6 cm mass was a ganglioneuroma and the 1.5 cm mass a pheochromocytoma, with cellular intermingling at their border. The two masses were diagnosed as a composite pheochromocytoma–ganglioneuroma. This is the first report in which the two components of a composite pheochromocytoma can be clearly distinguished in the pre-operative images. If a patient with clinically suspected pheochromocytoma has different components from a typical pheochromocytoma, composite pheochromocytoma should be considered.

Long COVID-19 and Postural Orthostatic Tachycardia Syndrome- Is Dysautonomia to Be Blamed?

While the increased arrhythmic tendency during acute COVID-19 infection is recognised, the long-term cardiac electrophysiological complications are less well known. There are a high number of patients reporting ongoing symptoms post-infection, termed long COVID. A recent hypothesis is that long COVID symptoms could be attributed to dysautonomia, defined as malfunction of the autonomic nervous system (ANS). The most prevalent cardiovascular dysautonomia amongst young people is postural orthostatic tachycardia syndrome (POTS). Numerous reports have described the development of POTS as part of long COVID. Possible underlying mechanisms, although not mutually exclusive or exhaustive, include hypovolaemia, neurotropism, inflammation and autoimmunity. Treatment options for POTS and other long COVID symptoms are currently limited. Future research studies should aim to elucidate the underlying mechanisms of dysautonomia to enable the development of targeted therapies. Furthermore, it is important to educate healthcare professionals to recognise complications and conditions arising from COVID-19, such as POTS, to allow prompt diagnosis and access to early treatment.

Cardiogenic Shock With Reverse Takotsubo Pattern Secondary to Pheochromocytoma: A Case Report

Pheochromocytoma is a rare catecholamine-secreting neuroendocrine tumor arising from chromaffin cells. Acute catecholamine-mediated cardiomyopathy secondary to pheochromocytoma is rare, but life-threatening. We report a case of a 50-year-old man who presented with chest pain with electrocardiography showing ST elevation in V2-4. He was transferred to cardiac catheterization laboratory for coronary angiography immediately. However, the results showed no evidence of coronary artery occlusions and the left ventriculography revealed hypokinesia of basal part with poor left ventricular ejection fraction. Further investigation confirmed pheochromocytoma-related reversible cardiomyopathy.

Composite phaeochromocytomas-a systematic review of published literature

Introduction

Composite phaeochromocytoma is a tumour containing a separate tumour of neuronal origin in addition to a chromaffin cell tumour. This study reports on two cases from a single centre’s records and presents a systematic literature review of composite phaeochromocytomas.

Methods

In addition to describing 2 case reports, a systematic search of the Medline database from inception up to April 2020 was done for human case reports on composite phaeochromocytomas. Relevant titles and/or abstracts were screened, and full texts were reviewed to identify appropriate studies. Data was extracted and a descriptive analysis of presentation, clinical features, management strategies and outcomes was performed. The quality of included studies was assessed using a critical appraisal checklist.

Results

There were 62 studies included, with a total of 94 patients. Of 91 patients where data was available, the median (range) age of patients was 48 (4–86) years. Of 90 patients where information was provided, 57% were female. In at least 28% of patients, a genetic cause was identified. Common presenting features include abdominal pain, palpable mass, cardiovascular and gastrointestinal symptoms. The most common tumour component with phaeochromocytoma is ganglioneuroma; other components include ganglioneuroblastoma, neuroblastoma and malignant peripheral nerve sheath tumours. In patients with follow-up data (n=48), 85% of patients were alive and well at a median (range) follow-up time of 18 (0.5–168) months.

Conclusion

Composite phaeochromocytoma is a rare tumour, with a significant genetic predisposition. This review summarises available epidemiological data, which will be useful for clinicians managing this rare condition.

Brain Metastasis of Pheochromocytoma: Diagnostic and Therapeutic Challenge

BACKGROUND

Pheochromocytoma brain metastasis is extremely rare. Few cases have been reported in the literature. Therefore, diagnosis and effective treatment of these lesions are difficult.

CASE DESCRIPTION

Here, we report the case of 29-year-old woman, who was operated on for a right adrenal pheochromocytoma. Fourteen months later, a posterior fossa tumor was diagnosed. Radiologic findings mimicked an extra-axial lesion. The radiologic differential diagnosis was difficult even using magnetic resonance imaging spectroscopy. The patient was operated on through a retrosigmoid approach. Local recurrence occurred 6 months after first surgery. The patient died 1 month later, despite a second operation.

CONCLUSIONS

Although the occurrence of brain metastases in pheochromocytoma is not prevalent, patients presenting with suggestive features need to be carefully considered. Magnetic resonance imaging can help in differential diagnosis with a primary brain tumor. There are no established guidelines for the treatment of pheochromocytoma brain metastasis, for which the prognosis remains dismal, despite effective surgery.

Retroperitoneal paraganglioma: a chameleon masquerading as an adrenal pheochromocytoma

Retroperitoneal paragangliomas are rare tumours arising from neural crest cells located near or in the autonomic nervous system; right from the skull bass to the pelvic floor. Often called the great masqueraders, their diagnosis and treatment is often difficult and fraught with danger, considering the close proximity of these tumours to important retroperitoneal organs. A 29-year-old woman presented to the outpatient department with complaints of paroxysms of headache, sweating and palpitations for one year. She was found to have elevated urinary metadrenalines (metanephrines) and a suprarenal mass on contrast-enhanced computed tomography of the abdomen, which demonstrated increased tracer activity on I-131 iodine-123 meta-iodobenzylguanidine scintigraphy. Adrenal pheochromocytoma was diagnosed and she underwent laparoscopic adrenalectomy after stabilisation of her blood pressure. Laparoscopy revealed a large suprarenal mass with dense adhesions to the inferior vena cava that was carefully separated from the vein and surrounding structures. The cut section revealed a heterogeneous mass encasing a normal adrenal gland and histopathology confirmed the same, confirming the final diagnosis of retroperitoneal paraganglioma.

Cardiovascular Manifestations of Pheochromocytoma

Pheochromocytomas are rare endocrine tumors that can have a significant impact on a variety of organ systems, including the cardiovascular system. Although the pathophysiology is not completely understood, pheochromocytomas exert their effects through high levels of catecholamines, mainly epinephrine and norepinephrine, which stimulate adrenergic receptors, including those within the cardiovascular system. Although the most common cardiovascular manifestation is hypertension, patients with pheochromocytoma can present with arrhythmia, hypotension, shock, myocardial ischemia, cardiomyopathy, aortic dissection, and peripheral ischemia. The medical management of the cardiovascular effects of pheochromocytoma is via blockade of adrenergic receptors, usually through the use of alpha blockers, with the addition of beta blockers if needed. However, only surgical resection of the pheochromocytoma is potentially curative, and this tumor requires unique management perioperatively. Because of the variability of presentation and the significant morbidity and mortality of patients with an undiagnosed pheochromocytoma, this entity should not be overlooked in the evaluation of patients with a wide variety of cardiovascular disorders.

Programmed cell death ligands expression in phaeochromocytomas and paragangliomas: Relationship with the hypoxic response, immune evasion and malignant behavior

The hypoxic response underlies the pathogenesis and malignant behavior of PCC/PGL. Regulation of PD-1 receptor-ligand signaling, a therapeutically actionable driver of the anti-tumor immune response, is a hypoxic-driven trait across malignancies. We evaluated the prognostic role of PD ligands in association with biomarkers of hypoxia and angiogenesis in patients with PCC/PGL.

Tissue microarrays sections including consecutive cases diagnosed between 1983–2011 were stained for PD-L1 and 2, hypoxia inducible factor 1a (Hif-1a), Carbonic Anhydrase IX (CaIX), Vascular Endothelial Growth Factor-A (VEGF-A). We explored the biologic significance of PD ligands expression using gene set enrichment analysis (GSEA) on The Cancer Genome Atlas (TCGA) for PCC/PGL (n = 184).

In total, 100 patients, 10% malignant, 64% PCC, 29% familial with median tumor size of 4.7 cm (range 1–14) were included. Median follow-up was 4.7 y. We found PD-L1 expression in 18% of PCC/PGL, which was independent of adverse pathological features including capsular (CI), vascular invasion (VI), necrosis (N) and expression of biomarkers of hypoxia. PD-L2 expression (16%) strongly correlated with CI, VI, N and malignant behavior (p < 0.05) and was associated with stronger Hif-1a and CaIX immunolabeling (p < 0.01). PD-L2 was predictive of shorter survival (162 versus 309 months, HR 3.1 95%CI 1.1–9.2, p = 0.02). GSEA on TGCA samples confirmed enrichment of transcripts involved in hypoxia and anti-cancer immunity.

We report for the first time PD ligands expression in PCC/PGL with a distinctive prognostic, clinico-pathologic and immuno-biologic role. These findings support a potential therapeutic role for PD-1/PD-L1 targeted checkpoint inhibitors in these tumors.

KEY MESSAGE

The molecular mechanisms underlying immune evasion in malignant phaeochromocytomas and paragangliomas (PCC/PGL) are poorly understood. This study demonstrates for the first time a distinctive immune-biologic and prognostic role of programmed death ligands 1 and 2 (PD-L1, PD-L2), two actionable drivers of the anti-cancer immune response. RNA-sequencing of tumor tissues reveals enrichment of transcripts relating to hypoxia and immune-exhaustion to explain the adverse clinical course observed in PD-L2 overexpressing tumors. These findings provide a rationale for the development of anti PD-1 therapies in malignant PCC/PGL.

Attention Deficit Hyperactivity Disorder in Pediatric Patients with Pheochromocytoma and Paraganglioma

The aim of the study is to evaluate if there is an association between attention deficit hyperactivity disorder (ADHD) and the diagnosis of pheochromocytoma/paraganglioma (PHEO/PGL) in pediatric patients. A case series study of 43 patients under the age of 18 with PHEO/PGL tumors who were evaluated at the National Institute of Health between January 2006 and May 2014 is reported. Prior diagnosis of ADHD and treatment course with stimulant medications was recorded. Patient symptoms, catecholamine and metanephrine levels, tumor characteristics, and genetic analyses for syndromes associated with PHEO/PGL were evaluated. A chi-squared test was used to assess the prevalence of ADHD in the PHEO/PGL patients compared to the general population. Nine out of 43 (21%) of patients diagnosed with PHEO/PGL had been diagnosed with ADHD prior to tumor identification. Four of the 9 patients had been treated with amphetamine, dextroamphetamine, and/or methylphenidate, potentially exacerbating an adrenergic crisis. In addition, 4 patients exhibited hypertension at the initial diagnosis of their PHEO/PGL. Three patients had resolution of their ADHD symptoms after successful surgical removal of PHEO/PGL. Our study found a prevalence of ADHD in 21% of our PHEO/PGL patients, significantly higher than 7.2% seen in the general pediatric population. Symptoms of anxiety and difficulty in concentration in these patients may have been related to their underlying PHEO/PGL and were not recognized as part of the constellation of symptoms in a child with PHEO/PGL. In pediatric patients with hypertension and ADHD symptomatology, an evaluation to rule out PHEO/PGL is warranted prior to treatment with stimulant medications.

Laparoscopic resection of primary adrenal ganglioneuroma: A case report and review of the literature

Adrenal ganglioneuroma (AGN) is an extremely rare, benign tumor that originates from the neural crest tissue of the sympathetic nervous system. The majority of cases are detected incidentally, since the disease often lacks clear clinical manifestations or is asymptomatic. In addition, AGN is often misdiagnosed as being an adrenal adenoma or adrenal pheochromocytoma. The present study describes a 58-year-old female who visited the outpatient clinic of the Affiliated Hospital of Guangdong Medical College (Zhanjiang, Guangdong, China) with symptoms of face and lower extremity dropsy. Color Doppler ultrasonography revealed a solid tumor in the right kidney, and abdominal computed tomography identified an irregular, solid tumor measuring ~6×4.5×7 cm³ and arising from the right adrenal gland, with a clear boundary. Magnetic resonance imaging was not performed. An initial diagnosis of adrenal adenoma was established. The patient was treated by laparoscopy in order to remove the tumor. However, following surgery, a pathological examination suggested that the tumor was a GN originating from the adrenal medulla. The formation of a correct diagnosis can be extremely challenging, as AGNs do not exhibit any specific clinical manifestations. Therefore, detection often depends entirely upon imaging studies, and the final diagnosis can be only by confirmed following a histopathological evaluation.

Neurofibromatosis type 1: a multidisciplinary approach to care

Neurofibromatosis type 1 is a relatively common inherited disorder. Patients have a high predisposition to develop both benign and malignant tumours. Although many manifestations of neurofibromatosis type 1 affect the nervous system, other organs and tissues can also be affected. Because of the varying features and clinical heterogeneity inherent to this disorder, patients can present to different medical and surgical specialists and, therefore, the association of clinical symptoms with neurofibromatosis type 1 might not be appreciated. Thus, for prompt diagnosis and to provide optimum care for patients with neurofibromatosis type 1, clinicians must be aware of the diverse clinical features of this disorder. We advocate a multidisciplinary approach to care, entailing a dedicated team of specialists throughout the lifetime of the patient. As our understanding of this disorder deepens through basic laboratory and clinical investigations, swift implementation of new effective treatments becomes feasible.

Immunohistochemical markers of the hypoxic response can identify malignancy in phaeochromocytomas and paragangliomas and optimize the detection of tumours with VHL germline mutations

Background:

There are no reliable markers of malignancy in phaeochromocytomas (PCC) and paragangliomas (PGL). We investigated the relevance of the mammalian target of rapamycin (mTOR)/AKT and hypoxic pathways as novel immunohistochemical markers of malignancy.

Methods:

Tissue microarray blocks were constructed with a total of 100 tumours (10 metastatic) and 20 normal adrenomedullary samples. Sections were immunostained for hypoxia-inducible factor 1α (Hif-1α), vascular endothelial growth factor A (VEGF-A), mTOR, carbonic anhydrase IX (CaIX) and AKT. The predictive performance of these markers was studied using univariate, multivariate and receiver operating characteristic analyses.

Results:

In all, 100 consecutive patients, 64% PCC, 29% familial with a median tumour size of 4.7 cm (range 1–14) were included. Univariate analyses showed Hif-1α overexpression, tumour necrosis, size >5 cm, capsular and vascular invasion to be predictors of metastasis. In multivariate analysis, Hif-1α, necrosis and vascular invasion remained as independent predictors of metastasis. Hif-1α was the most discriminatory biomarker for the presence of metastatic diffusion. Strong membranous CaIX expression was seen in von Hippel–Lindau (VHL) PCC as opposed to other subtypes.

Conclusion:

Lack of vascular invasion, tumour necrosis and low Hif-1α expression identify tumours with lower risk of malignancy. We propose membranous CaIX expression as a potential marker for VHL disease in patients presenting with PCC.

New roles of carboxypeptidase E in endocrine and neural function and cancer

Carboxypeptidase E (CPE) or carboxypeptidase H was first discovered in 1982 as an enkephalin-convertase that cleaved a C-terminal basic residue from enkephalin precursors to generate enkephalin. Since then, CPE has been shown to be a multifunctional protein that subserves many essential nonenzymatic roles in the endocrine and nervous systems. Here, we review the phylogeny, structure, and function of CPE in hormone and neuropeptide sorting and vesicle transport for secretion, alternative splicing of the CPE transcript, and single nucleotide polymorphisms in humans. With this and the analysis of mutant and knockout mice, the data collectively support important roles for CPE in the modulation of metabolic and glucose homeostasis, bone remodeling, obesity, fertility, neuroprotection, stress, sexual behavior, mood and emotional responses, learning, and memory. Recently, a splice variant form of CPE has been found to be an inducer of tumor growth and metastasis and a prognostic biomarker for metastasis in endocrine and nonendocrine tumors.

Neoplasms associated with germline and somatic NF1 gene mutations

INTRODUCTION

Neurofibromatosis 1 is a tumor predisposition genetic syndrome with autosomal dominant inheritance and virtually 100% penetrance by the age of 5 years. NF1 results from a loss-of-function mutation in the NF1 gene, resulting in decreased levels of neurofibromin in the cell. Neurofibromin is a negative regulator of various intracellular signaling pathways involved in the cellular proliferation. Although the loss of heterozygosity in the NF1 gene may predispose NF1 patients to certain malignancies, additional genetic alterations are a prerequisite for their development. The precise nature of these additional genetic alterations is not well defined, and genetic testing of all malignancies in NF1 patients becomes an essential component of future research in this subset of patients. In addition to germline NF1 mutations, alteration of the somatic NF1 gene is associated with sporadic malignancies such as adenocarcinoma of the colon, myelodysplastic syndrome, and anaplastic astrocytoma.

MATERIALS AND METHODS

A comprehensive English and non-English language search for all articles pertinent to malignancies associated with NF1 was conducted using PubMed, a search engine provided by the U.S. National Library of Medicine and the National Institutes of Health. Key words searched included the following: "malignancies associated with NF1", "tumors associated with NF1", and "NF1 and malignancies". A comprehensive analysis in terms age and mode of presentation, investigation and therapeutic modalities, and outcome of the published data was performed and compared with similar information on the sporadic cases.

RESULTS

Malignancies in NF1 patients typically occur at an earlier age and, with an exception of optic pathway gliomas, certain types of malignancies carry a poor prognosis compared with their sporadic counterparts. Malignancies are the leading cause of death in NF1 patients, resulting in a 10- to 15-year decreased life expectancy compared with the general population.

CONCLUSIONS

The lack of well-defined screening tests for early detection and the nonspecific clinical presentation contributes to a poorer outcome in malignancies associated with NF1. Small study group size, mixed patient population, and a lack of uniformity in reporting research results make comparison of treatment outcome for this group difficult. An International Consensus Meeting to address and recommend best practices for screening, diagnosis, management, and follow-up of malignancies associated with NF1 is needed.

Endocrine oncology in pregnancy

Endocrine tumours occur rarely in pregnant women but present clinicians with unique challenges. A high index of suspicion is often required to make a diagnosis since the symptoms and signs associated with many of these tumours, including insulinoma, adrenocortical carcinoma and phaeochromocytoma, mimic those of normal pregnancy or its complications, such as pre-eclampsia. The evidence base which informs management is very limited hence decisions on investigation and therapy must be individualised and undertaken jointly by the multidisciplinary medical team and the patient. The optimal strategy will depend on the nature and stage of the endocrine tumour, gestational stage, treatments available and patient wishes. Thus, surgical intervention, appropriately timed, may be considered in pregnancy for resectable adrenocortical carcinoma or phaeochromocytoma, but delayed until the postpartum period for well-differentiated thyroid cancer. Medical therapy may be required to reduce the drive to tumour growth, control symptoms of hormone excess and to minimise the risks of surgery, anaesthesia or labour.

Medical management of pheochromocytoma: Role of the endocrinologist

Pheochromocytoma is a rare tumor arising from chromaffin cells in adrenal medulla or other paraganglia in the body, which may be associated with many genetic syndromes and mutation. The role of endocrinologist is in biochemical diagnosis of suspected cases; its anatomic and functional localization with the help of imaging like CT, MRI, and nuclear scanning; preoperative control of hypertension; and postoperative follow-up of cases that have undergone surgical resection. Familial and genetic screening of cases and their family is important to detect occult cases. Endocrinologist will also play a role in cases with malignant pheochromocytoma in assessment of metastasis, control, chemoradiotherapy, and follow-up.

Hypertension in pheochromocytoma: characteristics and treatment

Pheochromocytoma is a tumor of the chromaffin cells in the adrenal medulla and sympathetic paraganglia, which synthesizes and secretes catecholamines. Norepinephrine, epinephrine, and dopamine all act on their target receptors, which causes a physiologic change in the body. High circulating levels of catecholamines can lead to severe hypertension and can have devastating effects on multiple body systems (eg, cardiovascular, cerebrovascular), and can lead to death if untreated. Although surgical treatment represents the only modality of ultimate cure, pharmacologic preoperative treatment remains the mainstay of successful outcome.

[Pheochromocytoma - still a challenge]

Pheochromocytomas are rare, mostly benign catecholamine-producing tumors arising from the chromaffin cells of the adrenal medulla or in the paraganglia. Clinical presentation is highly variable but typically with hypertension, severe headaches, palpitations and sweating. Biochemical testing by 24 h urinary fractioned metanephrines or catecholamines and plasma free metanephrines as the most sensitive screening approach, confirms the catecholamine excess. Computed tomography scan and magnetic resonance imaging of the adrenal glands and abdomen as well as functional imaging with (123)Iod-MIBG scintigraphy and (18)F-dopa positron emission tomography are used for tumor localization. Because approximately a quarter of tumors develop secondary to germ-line mutations, screening for genetic alterations is important. The therapy of choice is the endoscopic adrenal sparing surgery following preoperative alpha-blockade. Regular follow-up remains essential due to possible recurrence and malignancy.

Clinical Use of Laboratory Tests for the Identification of Secondary Forms of Arterial Hypertension

The prevalence of secondary hypertension can be underestimated if appropriate tests are not performed. The importance of selecting patients with a high pre-test probability of secondary forms of hypertension is first discussed. The laboratory tests currently used for seeking a cause of hypertension are critically reviewed, with emphasis on their operative features and limitations. Strategies to identify primary aldosteronism, the most frequent form of secondary hypertension, and to determine its unilateral or bilateral causes are described. Treatment entails adrenalectomy in unilateral forms, and mineralocorticoid receptor blockade in bilateral forms. Renovascular hypertension is also a common, curable form of hypertension, that should be identified as early as possible to avoid the onset of cardiovascular target organ damage. The tests for its confirmation or exclusion are discussed. The various tests available for the diagnosis of pheochromocytoma, which is much rarer than the above but extremely important to identify, are also described, with emphasis on recent developments in genetic testing. Finally, the tests for diagnosing some rarer monogenic forms and other renal and endocrine causes of arterial hypertension are explored.

Role of PACAP in the physiology and pathology of the sympathoadrenal system

Sympathetic neurons and chromaffin cells derive from common sympathoadrenal precursors which arise from the neural crest. Cells from this lineage migrate to their final destination and differentiate by acquiring a catecholaminergic phenotype in response to different environmental factors. It has been shown that the neuropeptide pituitary adenylate cyclase-activating polypeptide (PACAP) and its PAC1 receptor are expressed at early stages of sympathetic development, and participate to the control of neuroblast proliferation and differentiation. PACAP also acts as a neurotransmitter to stimulate catecholamine and neuropeptide biosynthesis and release from sympathetic neurons and chromaffin cells, during development and in adulthood. In addition, PACAP and its receptors have been described in neuroblastoma and pheochromocytoma, and the neuropeptide regulates the differentiation and activity of sympathoadrenal-derived tumoral cell lines, suggestive of an important role in the pathophysiology of the sympathoadrenal lineage. Transcriptome studies uncovered genes and pathways of known and unknown roles that underlie the effects of PACAP in the sympathoadrenal system.

Postural tachycardia syndrome with asystole on head-up tilt

Enhanced sympathetic activity causes an exaggerated heart rate response to standing in the postural tachycardia syndrome (POTS). All patients describe symptoms of orthostatic intolerance such as dizziness, blurred vision, shortness of breath, palpitations, tremulousness, chest discomfort, headache, lightheadedness and nausea, but only one third suffer loss of consciousness. We report four patients with POTS, who had long ventricular pauses (i.e. asystole) and syncope during head-up tilt test. This suggests that a subset of patients with POTS can have a surge in parasympathetic outflow that precedes vasovagal syncope.

Pheochromocytoma: presentation, diagnosis and treatment

Pheochromocytomas are rare, mostly benign catecholamine-producing tumors of chromaffin cells of the adrenal medulla or of a paraganglion. Typical clinical manifestations are sustained or paroxysmal hypertension, severe headaches, palpitations and sweating resulting from hormone excess. However, their presentation is highly variable and can mimic many other diseases. If remaining unrecognized or untreated, they can be a life-threatening condition. Therefore, the most important message of this review is to think of them. The diagnosis of pheochromocytomas depends mainly upon the demonstration of catecholamine excess by 24-h urinary catecholamines and metanephrines or plasma metanephrines. They are localized by a computed tomography scan and magnetic resonance imaging of the adrenal glands and abdomen; complementary 123I-metaiodobenzylguanidine scintigraphy and 18F-dihydroxyphenylalanine-positron emission tomography are available. Because approximately one out of four pheochromocytomas turn out to be hereditary entities, screening for genetic alterations is important. Laparoscopic and adrenal sparing surgical intervention following preoperative alpha-blockade is the treatment of choice and usually curative. In malignant pheochromocytomas, radiotherapy and chemotherapy are palliative treatment options. This review provides an update on identification and management of pheochromocytomas, emphasizing current developments in diagnosis, including genetic testing, pathophysiology and treatment of pheochromocytomas.

Is It a Pheochromocytoma?

The patient is a 44-year-old man with a 4-year history of intermittently elevated blood pressure (BP) controlled by diet and exercise. Three months before evaluation he described daily "spikes" of BP with sharp unilateral headaches. He was seen in the emergency department with a BP of 212/106 mm Hg and was started on hydrochlorothiazide 25 mg daily. He denied palpitations, diaphoretic episodes, pallor, and tremor. The patient did not want to take medication and specifically requested an evaluation to rule out pheochromocytoma. Results from 24-hour urine tests for total metanephrines was 812 mg/24 h (normal, 130-520 mg/24 h), for total catecholamines was 53 mg/24 h (normal, 0-135 mg/24 h), and for vanillylmandelic acid was 4.7 mg/24 h (normal, <7 mg/24 h). Thyroid-stimulating hormone was 0.87 (normal, 0.4-4.0 IU/mL). Physical examination revealed normal optic fundi, negative cardiac examination results, and presence of peripheral pulses without bruits. His BP was now 136/74 mm Hg, with a heart rate of 76 beats per minute.

Recent advances in the diagnosis and treatment of pheochromocytoma

Pheochromocytoma (PHEO) is considered to be a rare cause of hypertension. However, if left untreated, PHEOs may lead to fatal hypertensive crises during anesthesia and other stresses. The diagnosis of PHEO is therefore extremely important. A 24-hour blood pressure (BP) pattern per se might be of some diagnostic value due to frequently observed higher BP variability as well as an attenuated night-time BP decrease. So far, germline mutations in five genes have been identified to be responsible for familial PHEOs: the von Hippel-Lindau gene, which causes von Hippel-Lindau syndrome, the RET gene leading to multiple endocrine neoplasia type 2, the neurofibromatosis type 1 gene, which is associated with von Recklinghausen's disease and the genes encoding the B and D subunits of mitochondrial succinate dehydrogenase (SDHB, SDHD), which are associated with familial paragangliomas and PHEOs. Genetic analysis should be offered to those patients with confirmed PHEO who are 50 years old or younger. Plasma-free metanephrines or urinary fractionated metanephrines seem to have higher diagnostic values compared to plasma or urinary catecholamines for the biochemical diagnosis of PHEO. Imaging with (123)I-metaiodobenzylguanidine or (18)F-fluorodopamine PET, if available, are in addition to CT/MRI useful for the detection of multifocal/extra-adrenal forms. Appropriate pharmacologic treatment with subsequent laparoscopic extirpation of PHEO is usually successful in benign forms. There is, however, no convincingly effective mode of treatment in malignant PHEOs.

Pheochromocytoma and paraganglioma in children: a review of medical and surgical management at a tertiary care center

OBJECTIVE

The aim of this study was to review our institutional experience managing pheochromocytomas and paragangliomas in children.

METHODS

A retrospective chart review of the Mayo Clinic database from 1975 to 2005 identified 30 patients < 18 years of age with histologically confirmed pheochromocytoma or paraganglioma.

RESULTS

There were 12 patients with pheochromocytomas and 18 with paragangliomas. The most common presenting symptoms were hypertension (64%), palpitation (53%), headache (47%), and mass-related effects (30%). Nine patients (30%) had a genetic mutation or documented family history of pheochromocytoma or paraganglioma. Fourteen patients (47%) had malignant disease, whereas 16 (53%) had benign disease. Logistic analysis showed that statistically significant risk factors for malignancy were (1) paraganglioma, (2) apparently sporadic, as opposed to familial, pheochromocytoma or paraganglioma, and (3) tumor size of > 6 cm. Surgical resection was performed for 28 patients (93%), with perioperative mortality and major morbidity rates of 0% and 10%, respectively. Resection achieved symptomatic relief for 25 patients (83%). All patients with benign disease appeared cured after resection. For patients with malignant disease, the 5- and 10-year disease-specific survival rates were 78% and 31%, respectively, and the mean survival time was 157 +/- 32 months.

CONCLUSIONS

The incidence of malignant pheochromocytoma/paraganglioma was high in children (47%), particularly those with apparently sporadic disease, paraganglioma, and tumor diameters of > 6 cm. Patients with a known genetic mutation or familial pheochromocytoma/paraganglioma were more likely to achieve resection with negative microscopic margins and had improved disease-specific mortality rates. Surgical resection remains the treatment of choice for pheochromocytoma and paraganglioma.

An Overview of Pheochromocytoma: History, Current Concepts, Vagaries, and Diagnostic Challenges

Tragically as many as 50% of pheochromocytomas are discovered at autopsy, mainly because the diagnosis of this neuroendocrine tumor was not considered. Missing the diagnosis almost invariably results in devastating cardiovascular complications or death. Clinicians must always think of pheochromocytoma whenever evaluating a patient with sustained or paroxysmal hypertension or any manifestations suggesting hypercatecholaminemia. Very rarely, familial pheochromocytomas may cause no hypertension, symptoms, or signs. But biochemical testing can always establish the presence or absence of a pheochromocytoma, and localization with magnetic resonance imaging, computed tomography, or 131I or 123I-MIBG is almost always possible.