Pathological and Genetic Characterization of Bilateral Adrenomedullary Hyperplasia in a Patient with Germline MAX Mutation

Insights Obtained from the Nontumorous Glandular Tissue in Patients with Endocrine Tumors

The pathology of neoplasia tends to focus on the tumor that requires characterization, grading, and staging. However, nontumorous tissue surrounding the lesion can also provide information, particularly about pathogenetic mechanisms. In endocrine tissues, this takes the form of precursor lesions that characterize several genetic predisposition syndromes. In addition, because of the unique functional aspects of endocrine neoplasia, the nontumorous tissue provides evidence of hormone excess, with hyperplasia and/or atrophy and other involutional changes allowing the pathologist to confirm both hormone function by the tumor and the effects of medical therapies. In this article, we review the various clinically relevant features that should be assessed and reported to enhance clinical management of patients with endocrine neoplasms. For example, in thyroid there may be inflammatory thyroiditis or goiter of various etiologies; there may be C-cell hyperplasia either as a preneoplastic lesion in patients with genetic predisposition to medullary thyroid carcinoma or as a reactive phenomenon. Drug-induced changes can be seen in thyroid and adrenal cortex. In neuroendocrine tissues, the nontumorous tissues may show precursor lesions such as endocrine cell hyperplasia/dysplasia; there may be related or unrelated hyperplastic or neoplastic lesions. Some tissues, such as pituitary corticotrophs and adrenal cortex, develop changes that reflect feedback suppression by hormone excess that can serve as biomarkers of tumor functionality and provide enhanced clinicopathologic correlates.

Adrenal Medullary Hyperplasia: A Systematic Review and Meta-analysis

CONTEXT

Adrenal medullary hyperplasia (AMH) is a rare, incompletely described disorder of the adrenal medulla that is associated with catecholamine excess.

OBJECTIVE

To increase knowledge about AMH by reviewing the reported cases of this disorder.

DESIGN

Systematic review and meta-analysis of the genotype/phenotype relationship in all reported cases of AMH.

SETTING

Literature review and analysis.

PATIENTS OR OTHER PARTICIPANTS

All cases of AMH published to date.

MAIN OUTCOME MEASURE(S)

Characteristics of AMH cases and genotype-phenotype relationships.

RESULTS

A total of 66 patients, median age of 48 years, were identified from 29 reports. More than one-half were male (n = 39, 59%). The majority had unilateral (73%, n = 48) disease; 71% (n = 47) were sporadic and 23% (n = 15) were associated with the MEN2. Most (91%, n = 60) displayed signs and symptoms of excess catecholamine secretion, particularly hypertension. Elevated catecholamine concentrations (86%, n = 57) and adrenal abnormalities on imaging were common (80%, n = 53). More than one-half (58%, n = 38) had concurrent tumors: pheochromocytoma (42%, n = 16/38); medullary thyroid cancer (24%, n = 9/38); and adrenocortical adenoma (29%, n = 11/38). Most (88%, n = 58) underwent adrenalectomy with 45/58 achieving symptom resolution. Adrenalectomy was less common in patients under 40 years and those with bilateral disease (both P < .05).

CONCLUSION

AMH may be sporadic or associated with MEN2, most have catecholamine excess and imaging abnormalities. Unilateral involvement is more common. Most reported patients have been treated with adrenalectomy, which is usually curative with regard to catecholamine hypersecretion.

Bilateral Pheochromocytoma with Germline MAX Variant without Family History

Recently, the genetic background of pheochromocytomas/paragangliomas (PPGLs) has been rapidly revealed. These tumors have been referred to as the “ten percent tumor”; however, the frequency of genetic variants of PPGLs has turned out to be more common than expected. PPGLs are potentially hereditary tumors and appear clinically sporadic. Here, we report a case of bilateral pheochromocytoma (PCC) with a variant in the MYC-associated factor X (MAX) gene (c.295 + 1G > A). A male patient was diagnosed with adrenal pheochromocytoma (PCC) and underwent a left adrenalectomy at the age of 40. A new tumor in the right adrenal gland was detected at the age of 43. Urinary metanephrine and normetanephrine concentrations gradually increased. The size of the right adrenal PCC continued to increase one year after detection. Genetic testing of the peripheral blood revealed the presence of a pathogenic variant in MAX. The natural history of adrenal PCCs with the MAX variant has not yet been clarified, because the number of reported cases is not sufficient. Thus, clinicians should consider a MAX variant when they find bilateral or multiple PCCs.

Overview of the 2022 WHO Classification of Paragangliomas and Pheochromocytomas

This review summarizes the classification of tumors of the adrenal medulla and extra-adrenal paraganglia as outlined in the 5th series of the WHO Classification of Endocrine and Neuroendocrine Tumors. The non-epithelial neuroendocrine neoplasms (NENs) known as paragangliomas produce predominantly catecholamines and secrete them into the bloodstream like hormones, and they represent a group of NENs that have exceptionally high genetic predisposition. This classification discusses the embryologic derivation of the cells that give rise to these lesions and the historical evolution of the terminology used to classify their tumors; paragangliomas can be sympathetic or parasympathetic and the term pheochromocytoma is used specifically for intra-adrenal paragangliomas that represent the classical sympathetic form. In addition to the general neuroendocrine cell biomarkers INSM1, synaptophysin, and chromogranins, these tumors are typically negative for keratins and instead have highly specific biomarkers, including the GATA3 transcription factor and enzymes involved in catecholamine biosynthesis: tyrosine hydroxylase that converts L-tyrosine to L-DOPA as the rate-limiting step in catecholamine biosynthesis, dopamine beta-hydroxylase that is present in cells expressing norepinephrine, and phenylethanolamine N-methyltransferase, which converts norepinephrine to epinephrine and therefore can be used to distinguish tumors that make epinephrine. In addition to these important tools that can be used to confirm the diagnosis of a paraganglioma, new tools are recommended to determine genetic predisposition syndromes; in addition to the identification of precursor lesions, molecular immunohistochemistry can serve to identify associations with SDHx, VHL, FH, MAX, and MEN1 mutations, as well as pseudohypoxia-related pathogenesis. Paragangliomas have a well-formed network of sustentacular cells that express SOX10 and S100, but this is not a distinctive feature, as other epithelial NENs also have sustentacular cells. Indeed, it is the presence of such cells and the association with ganglion cells that led to a misinterpretation of several unusual lesions as paragangliomas; in the 2022 WHO classification, the tumor formerly known as cauda equina paraganglioma is now classified as cauda equina neuroendocrine tumor and the lesion known as gangliocytic paraganglioma has been renamed composite gangliocytoma/neuroma and neuroendocrine tumor (CoGNET). Since the 4th edition of the WHO, paragangliomas have no longer been classified as benign and malignant, as any lesion can have metastatic potential and there are no clear-cut features that can predict metastatic behavior. Moreover, some tumors are lethal without metastatic spread, by nature of local invasion involving critical structures. Nevertheless, there are features that can be used to identify more aggressive lesions; the WHO does not endorse the various scoring systems that are reviewed but also does not discourage their use. The identification of metastases is also complex, particularly in patients with germline predisposition syndromes, since multiple lesions may represent multifocal primary tumors rather than metastatic spread; the identification of paragangliomas in unusual locations such as lung or liver is not diagnostic of metastasis, since these may be primary sites. The value of sustentacular cells and Ki67 labeling as prognostic features is also discussed in this new classification. A staging system for pheochromocytoma and extra-adrenal sympathetic PGLs, introduced in the 8th Edition AJCC Cancer Staging Manual, is now included. This paper also provides a summary of the criteria for the diagnosis of a composite paragangliomas and summarizes the classification of neuroblastic tumors. This review adopts a practical question-answer framework to provide members of the multidisciplinary endocrine oncology team with a most up-to-date approach to tumors of the adrenal medulla and extra-adrenal paraganglia.

Significance of Alpha-inhibin Expression in Pheochromocytomas and Paragangliomas

Alpha-inhibin expression has been reported in pheochromocytomas and paragangliomas (PPGLs). We analyzed alpha-inhibin immunohistochemistry in 77 PPGLs (37 pheochromocytomas [PCCs] and 40 paragangliomas) and correlated the results with catecholamine profile, tumor size, Ki-67 labeling index, succinate dehydrogenase B subunit and carbonic anhydrase IX (CAIX) staining, and genetic pathogenesis. PPGLs were classified as pseudohypoxic cluster 1 disease with documented VHL mutation or SDHx mutation or biochemical phenotype, whereas NF1-driven and RET-driven PPGLs and those with a mature secretory (adrenergic or mixed adrenergic and noradrenergic) phenotype were classified as cluster 2 disease. The Cancer Genome Atlas data on INHA expression in PPGLs was examined. Alpha-inhibin was positive in 43 PPGLs (56%). Ki-67 labeling indices were 8.07% and 4.43% in inhibin-positive and inhibin-negative PPGLs, respectively (P<0.05). Alpha-inhibin expression did not correlate with tumor size. Alpha-inhibin was expressed in 92% of SDHx-related and 86% of VHL-related PPGLs. CAIX membranous staining was found in 8 of 51 (16%) tumors, including 1 SDHx-related PCC and all 5 VHL-related PCCs. NF1-driven and RET-driven PPGLs were negative for alpha-inhibin and CAIX. Alpha-inhibin was expressed in 77% of PPGLs with a pseudohypoxia signature, and 20% of PPGLs without a pseudohypoxia signature (P<0.05). PPGLs with a mature secretory phenotype were negative for CAIX. The Cancer Genome Atlas data confirmed higher expression of INHA in cluster 1 than in cluster 2 PPGLs. This study identifies alpha-inhibin as a highly sensitive (90.3%) marker for SDHx/VHL-driven pseudohypoxic PPGLs. Although CAIX has low sensitivity, it is the most specific biomarker of VHL-related pathogenesis. While alpha-inhibin cannot replace succinate dehydrogenase B subunit immunohistochemistry for detection of SDHx-related disease, it adds value in prediction of cluster 1 disease. Importantly, these data emphasize that alpha-inhibin is not a specific marker of adrenal cortical differentiation, as it is also expressed in PCCs.

Somatotroph Tumors and the Epigenetic Status of the GNAS Locus

Forty percent of somatotroph tumors harbor recurrent activating GNAS mutations, historically called the gsp oncogene. In gsp-negative somatotroph tumors, GNAS expression itself is highly variable; those with GNAS overexpression most resemble phenotypically those carrying the gsp oncogene. GNAS is monoallelically expressed in the normal pituitary due to methylation-based imprinting. We hypothesize that changes in GNAS imprinting of gsp-negative tumors affect GNAS expression levels and tumorigenesis. We characterized the GNAS locus in two independent somatotroph tumor cohorts: one of 23 tumors previously published (PMID: 31883967) and classified by pan-genomic analysis, and a second with 82 tumors. Multi-omics analysis of the first cohort identified a significant difference between gsp-negative and gsp-positive tumors in the methylation index at the known differentially methylated region (DMR) of the GNAS A/B transcript promoter, which was confirmed in the larger series of 82 tumors. GNAS allelic expression was analyzed using a polymorphic Fok1 cleavage site in 32 heterozygous gsp-negative tumors. GNAS expression was significantly reduced in the 14 tumors with relaxed GNAS imprinting and biallelic expression, compared to 18 tumors with monoallelic expression. Tumors with relaxed GNAS imprinting showed significantly lower SSTR2 and AIP expression levels. Altered A/B DMR methylation was found exclusively in gsp-negative somatotroph tumors. 43% of gsp-negative tumors showed GNAS imprinting relaxation, which correlated with lower GNAS, SSTR2 and AIP expression, indicating lower sensitivity to somatostatin analogues and potentially aggressive behavior.

A Novel, Likely Pathogenic MAX Germline Variant in a Patient With Unilateral Pheochromocytoma

Context

Inherited MYC-associated factor X (MAX) gene pathogenic variants (PVs) increase risk for pheochromocytomas (PCCs) and/or paragangliomas (PGLs) in adults and children. There is little clinical experience with such mutations.

Objective

This report highlights an important approach.

Methods

Clinical assessment, including blood chemistry, imaging studies, and genetic testing were performed.

Results

A 38-year-old Hispanic woman was diagnosed with PCC in 2015, treated with adrenalectomy, and referred to endocrinology clinic. Notably, she presented to her primary care physician 3 years earlier complaining of left flank pain, intermittent diaphoresis, and holocranial severe headache. We confirmed severe hypertension (180/100 mm Hg) over multiple antihypertensive regimens. Biochemical and radiological studies workup revealed high plasma metanephrine of 255 pg/mL (normal range, < 65 pg/mL) and plasma normetanephrine of 240 pg/mL (normal range, < 196 pg/mL). A noncontrast computed tomography scan of the abdomen revealed a 4.2 × 4.3 × 4.9-cm, round-shaped and heterogenous contrast enhancement of the left adrenal gland, and a 2-mm nonobstructive left kidney stone. A presumptive diagnosis of secondary hypertension was made. After pharmacological therapy, laparoscopic left adrenalectomy was performed and confirmed the diagnosis of pheochromocytoma. Based on her age, family history, and a high suspicion for genetic etiology, genetic testing was performed that revealed the presence of a novel likely pathogenic variant involving a splice consensus sequence in the MAX gene, designated c0.64-2A > G.

Conclusion

The phenotype of MAX PV-related disease and paraganglioma are highlighted. The novel c0.64-2A > G mutation is reported here and should be considered in the diagnostic workup of similar cases.

Challenges in Paragangliomas and Pheochromocytomas: from Histology to Molecular Immunohistochemistry

Abdominal paragangliomas and pheochromocytomas (PPGLs) are rare neuroendocrine tumors of the infradiaphragmatic paraganglia and adrenal medulla, respectively. Although few pathologists outside of endocrine tertiary centers will ever diagnose such a lesion, the tumors are well known through the medical community-possible due to a combination of the sheer rarity, their often-spectacular presentation due to excess catecholamine secretion as well as their unrivaled coupling to constitutional susceptibility gene mutations and hereditary syndromes. All PPGLs are thought to harbor malignant potential, and therefore pose several challenges to the practicing pathologist. Specifically, a responsible diagnostician should recognize both the capacity and limitations of histological, immunohistochemical, and molecular algorithms to pinpoint high risk for future metastatic disease. This focused review aims to provide the surgical pathologist with a condensed update regarding the current strategies available in order to deliver an accurate prognostication of these enigmatic lesions.

Multiple Endocrine Tumors Associated with Germline MAX Mutations: Multiple Endocrine Neoplasia Type 5?

CONTEXT

Pathogenic germline MAX variants are associated with pheochromocytoma and paraganglioma (PPGL), pituitary neuroendocrine tumors and, possibly, other endocrine and nonendocrine tumors.

OBJECTIVE

To report 2 families with germline MAX variants, pheochromocytomas (PCs) and multiple other tumors.

METHODS

Clinical, genetic, immunohistochemical, and functional studies at University hospitals in Australia on 2 families with germline MAX variants undergoing usual clinical care. The main outcome measures were phenotyping; germline and tumor sequencing; immunohistochemistry of PC and other tumors; functional studies of MAX variants.

RESULTS

Family A has multiple individuals with PC (including bilateral and metastatic disease) and 2 children (to date, without PC) with neuroendocrine tumors (paravertebral ganglioneuroma and abdominal neuroblastoma, respectively). One individual has acromegaly; immunohistochemistry of PC tissue showed positive growth hormone-releasing hormone staining. Another individual with previously resected PCs has pituitary enlargement and elevated insulin-like growth factor (IGF-1). A germline MAX variant (c.200C>A, p.Ala67Asp) was identified in all individuals with PC and both children, with loss of heterozygosity in PC tissue. Immunohistochemistry showed loss of MAX staining in PCs and other neural crest tumors. In vitro studies confirmed the variant as loss of function. In Family B, the proband has bilateral and metastatic PC, prolactin-producing pituitary tumor, multigland parathyroid adenomas, chondrosarcoma, and multifocal pulmonary adenocarcinomas. A truncating germline MAX variant (c.22G>T, p.Glu8*) was identified.

CONCLUSION

Germline MAX mutations are associated with PCs, ganglioneuromas, neuroblastomas, pituitary neuroendocrine tumors, and, possibly, parathyroid adenomas, as well as nonendocrine tumors of chondrosarcoma and lung adenocarcinoma, suggesting MAX is a novel multiple endocrine neoplasia gene.

Adrenal medullary hyperplasia mimicking pheochromocytoma

A 59-year-old woman, a known case of hypertension, was incidentally diagnosed with a large right-sided adrenal mass. Investigations for a functional adrenal lesion resulted in very high preoperative norepinephrine levels. A right adrenalectomy was performed. Histology showed adrenal medullary hyperplasia (AMH). AMH is a rare diagnosis and its incidence is poorly documented in the literature. This is a benign entity which resembles pheochromocytoma (PCC) in both clinical and biochemical manner. AMH is usually bilateral and may occur in isolation or in association with PCC. In fact, some authors consider it to be a precursor to PCC. Thus, these patients need long-term follow-up in view of the risk of development of PCC later.

Adrenal Medullary Hyperplasia, An Under the Radar Cause of Endocrine Hypertension

Adrenal medullary hyperplasia is a cause of increased secretion of catecholamines by the adrenal gland that is rarely considered among the differential diagnoses of endocrine hypertension. We report the case of a 48-year-old Hispanic woman who presented for evaluation of resistant hypertension with several episodes of hypertensive crisis. The clinical presentation, biochemical results, and abdominal computed tomography scan suggested the possibility of a pheochromocytoma; however, an iodine-123-meta-iodobenzylguanidine (¹²³I-MIBG) uptake study combined with single-photon emission computed tomography (SPECT) and computed tomography (CT) scan showed diffusely increased metabolic activity in both adrenal glands. The patient underwent left adrenalectomy, and the pathology study revealed the presence of adrenal medullary hyperplasia. After surgery, blood pressure control was achieved with one antihypertensive drug, and the patient did not have recurrent hypertensive crisis. Relevant findings obtained from a whole genomic sequence done on a whole blood DNA sample from the patient are discussed.

Data set for the reporting of pheochromocytoma and paraganglioma: explanations and recommendations of the guidelines from the International Collaboration on Cancer Reporting

BACKGROUND AND OBJECTIVES

The International Collaboration on Cancer Reporting (ICCR) is a not-for-profit to develop evidence-based, internationally agreed-upon standardized data sets for each anatomic site, to be used throughout the world. Providing global standardization of pathology tumor classification, staging, and other reporting elements will lead to improved patient management and enhanced epidemiological research.

METHODS

Pheochromocytoma and paraganglioma are uncommon and are frequently overlooked in registry data sets. Malignant criteria have previously been defined only when there was metastatic disease.

RESULTS

With recent recognition of a significant inheritance association and the development of risk stratification tools, this data set was created in order to obtain more meaningful outcomes and management data, using similar criteria across the global pathology community. Issues related to key core and non-core elements, especially clinical hormonal status, familial history, tumor focality, proliferative fraction, adverse or risk stratification features, and ancillary techniques, are discussed in the context of daily application to these types of specimens.

CONCLUSIONS

The ICCR data set, developed by an international panel of endocrine organ specialists, establishes a pathology-standardized reporting guide for pheochromocytoma and paraganglioma.

A Novel MAX Gene Mutation Variant in a Patient With Multiple and "Composite" Neuroendocrine-Neuroblastic Tumors

Introduction: Pheochromocytomas (PCCs), paragangliomas (PGLs), ganglioneuroblastomas (GNBs), and ganglioneuromas (GNs) are neuroendocrine neoplasms (NENs) that were thought to share a common embryologic origin from neural crest cells. However, they rarely occur concurrently and recurrently. We describe the case of a 40-years-old woman with "composite PCC-GN" and multiple NENs and neuroblastic tumors. Case presentation: The patient was first referred to our department at the age of 15 years for paroxysmal hypertension, headache, sweating, and watery diarrhea. Her personal history included the diagnosis of a pelvic GNB with lumbar-aortic lymph node metastases at 11 months. Her family history was positive for cerebral glioblastoma multiforme (father). An abdominal ultrasound showed a right adrenal mass that histologically was a "composite adrenal PCC-GN." The symptoms disappeared after surgery. At the age of 20 years, the symptoms returned: computed tomography (CT) and 131I-metaiodobenzylguanidine (MIBG) scintigraphy showed an inter-aortocaval mass, found histologically to be an inter-aortocaval PGL. Her symptoms reappeared again at 28 years: CT and magnetic resonance imaging revealed four left adrenal gland nodules, found histologically to be multifocal PCCs with some atypia. Genetic screening for VHL, RET, NF1, Tp53, SDHD, SDHB, SDHC, SDHAF2, SDHAF3, SDHA, and TMEM127 was negative. Mutational analysis of the MAX gene revealed the presence of a novel heterozygous variant, c299G>C (p.Arg100Pro, NM_002382.5) that the bioinformatics prediction programs defined as noxious and causative of pathology. Conclusion: This report represents the first description of a co-occurrence of multiple composite PCC-GN and neuroblastic tumors. The long timeline of the presentation of the NENs/neuroblastic tumors from infancy to adulthood requires a lifelong follow-up for this patient. Moreover, the importance of this case lies in the presence of a novel MAX gene variant deleterious, harmful, and causative of pathology, confirmed by Sanger sequencing and never been associated before with multiple composite PCC-GN. The present case underlines the importance of precision medicine and molecular diagnoses for hereditary pheochromocytomas and paragangliomas, suggesting that when they occur in early childhood, it is necessary to perform an extensive genetic investigation and a lifelong follow-up.

A Novel Phenotype of Germline Pathogenic Variants in MAX: Concurrence of Pheochromocytoma and Ganglioneuroma in a Chinese Family and Literature Review

Background:MYC associated factor X (MAX) is a tumor suppressor gene and has been identified as one of the pathogenic genes of hereditary pheochromocytoma (PCC). To date, there have been no reports of ganglioneuroma (GN) with MAX variants. Case Presentation: The proband was a 45-years-old Chinese female with paroxysmal hypertension and palpitations who had undergone adrenalectomy for PCC 14 years ago. Her plasma free normetanephrine and 24-h urinary norepinephrine excretion were significantly increased, and abdominal computed tomography (CT) revealed an irregular mass in the left adrenal region, suggesting a recurrence of PCC. The mass was surgically removed and pathologically diagnosed as PCC with lymph node metastasis. The proband's son suffered from paroxysmal hypertension and palpitations. His plasma free metanephrine levels were normal. CT revealed a mass in the right adrenal. The tumor was surgically removed, and the pathological diagnosis was GN. Genetic testing of peripheral blood DNA revealed that the proband and her son had germline pathogenic MAX variant c.C97T, p.Arg33Ter, while proband's parents did not have MAX variants. Tumor DNA sequencing showed the same MAX variant (c.C97T, p.Arg33Ter) in PCC of the proband and GN of her son, both with retention of heterozygosity. Immunohistochemistry demonstrated loss of MAX protein expression in most tumor cells in PCC of the proband and some Schwannian cells in GN of the proband's son. Conclusion: We report a family with a new clinical phenotype of germline pathogenic variants in MAX who developed both PCC and GN. Germline pathogenic variants in MAX may contribute to the development of GN. Our findings suggest that it is not just paternally inherited MAX variants that can cause tumors.

Presentation, Treatment, Histology, and Outcomes in Adrenal Medullary Hyperplasia Compared With Pheochromocytoma

Context

Information about adrenal medullary hyperplasia (AMH) is scarce.

Objective

To study a large cohort of AMHs.

Design Setting and Participants

Nineteen AMH cases were compared with 95 pheochromocytomas (PCCs) without AMH. AMH without (n = 7) and with PCC (n = 12) were analyzed separately.

Results

Of 936 adrenalectomies, 2.1% had AMH. Mean age was 47.2 ± 15.1 years. Only two (11%) AMHs had no concurrent PCC or adrenocortical adenoma. In AMHs, a genetic syndrome was present in 58% vs 4% in PCCs (P < 0.001). The noradrenaline/metanephrine levels were lower in AMHs, whereas suppression of dexamethasone was less than in PCCs. Cushing syndrome was found in 11% of AMHs. More AMHs were found during screening and less as incidentalomas. PCC symptoms were less prevalent in AMHs. Surgical management was similar; however, fewer of the AMHs were pretreated with alpha-blockers. Adrenalectomy improved blood pressure slightly less in AMHs. The disappearance of glycemic disturbances was similar to the PPCs. During a period of 11.2 ± 9.4 years, a new PCC developed in 32% of patients with AMH, 11% died, but no PCC metastasis occurred (PCCs: 4%, P < 0.001; 14% and 5%). AMHs without PCC had milder symptoms but more often Cushing disease than patients with PCC, whereas AMH with PCC more often displayed a familiar syndrome with more PCC recurrences.

Conclusion

A total of 2.1% of all adrenalectomies displayed AMH. AMH seemed to be a PCC precursor. The symptoms and signs were milder than PCCs. AMHs were mainly found due to screening. Outcomes seemed favorable, but new PCCs developed in many during follow-up.

[Hereditary pheochromocytoma and paraganglioma: screening and follow-up strategies in asymptomatic mutation carriers]

The management of pheochromocytoma and paraganglioma has deeply evolved over the last years due to the discovery of novel genes of susceptibility, especially SDHx, MAX and TMEM127. While the modalities of diagnosis and management of patients presenting with hereditary pheochromocytoma and paraganglioma are now well defined, screening and follow-up strategies for asymptomatic mutation carriers remain a matter of debate. This raises major questions as these asymptomatic patients will require a lifelong follow-up. The aim of this review is an attempt to give insights on the optimal screening and follow-up strategies of asymptomatic carriers of SDHx, MAX and TMEM127 mutations, with additional thoughts on the forensic and psychological aspects of the management of such patients with rare diseases.

The Diagnosis and Clinical Significance of Paragangliomas in Unusual Locations

Paragangliomas are neuroendocrine neoplasms, derived from paraganglia of the sympathetic and parasympathetic nervous systems. They are most commonly identified in the head and neck, being most frequent in the carotid body, followed by jugulotympanic paraganglia, vagal nerve and ganglion nodosum, as well as laryngeal paraganglia. Abdominal sites include the well-known urinary bladder tumors that originate in the Organ of Zuckerkandl. However, other unusual sites of origin include peri-adrenal, para-aortic, inter-aortocaval, and paracaval retroperitoneal sites, as well as tumors in organs where they may not be expected in the differential diagnosis of neuroendocrine neoplasms, such as thyroid, parathyroid, pituitary, gut, pancreas, liver, mesentery, lung, heart and mediastinum. The distinction of these lesions from epithelial neuroendocrine neoplasms is critical for several reasons. Firstly, the determination of clinical and biochemical features is different from that used for epithelial neuroendocrine tumors. Secondly, the genetic implications are different, since paragangliomas/pheochromocytomas have the highest rate of germline susceptibility at almost 40%. Finally, the characterization of metastatic disease is unique in these highly syndromic lesions. In this review, we summarize updated concepts by outlining the spectrum of anatomic locations of paragangliomas, the importance of morphology in establishing the correct diagnosis, the clinical implications for management, and the impact of genetics on the distinction between multifocal primary tumors compared with malignant disease.

18F-FDOPA PET/CT Imaging of MAX-Related Pheochromocytoma

CONTEXT

MYC-associated factor X (MAX) has been recently described as a new susceptibility pheochromocytoma (PHEO) gene with a total of ~40 reported cases. At present, no study has specifically described the functional imaging phenotype of MAX-related PHEO.

OBJECTIVE, PATIENTS, AND DESIGN

The objective of the present study was to present our experience with contrast-enhanced computed tomography (CT) and 18F-fluorodihydroxyphenylalanine (18F-FDOPA) positron emission tomography (PET)/CT in six consecutive patients (four at the initial diagnosis and two at the follow-up evaluation) with rare, but clinically important, MAX-related PHEOs. In five patients, 18F-FDOPA was also compared with other radiopharmaceutical agents.

RESULTS

The patients had five different mutations in the MAX gene that caused disruption of Max/Myc interaction and/or abolished interaction with DNA based on in silico analyses. All but one patient developed bilateral PHEOs during their lifetime. In all cases, 18F-FDOPA PET/CT accurately visualized PHEOs that were often multiple within the same gland or bilaterally and detected more adrenal and extra-adrenal lesions than did CT (per-lesion sensitivity, 90.9% vs 52.4% for CT/magnetic resonance imaging). The two PHEOs missed on 18F-FDOPA PET/CT were <1 cm, corresponding to nodular adrenomedullary hyperplasia. 68Ga-DOTA,Tyr3-octreotate PET/CT detected fewer lesions than did 18F-FDOPA PET/CT in one of three patients, and 18F-fluorodeoxyglucose PET/CT was only faintly positive in two of four patients with underestimation of extra-adrenal lesions in one patient.

CONCLUSIONS

MAX-related PHEOs exhibit a marked 18F-FDOPA uptake, a finding that illustrates the common well-differentiated chromaffin pattern of PHEOs associated with activation of kinase signaling pathways. 18F-FDOPA PET/CT should be considered as the first-line functional imaging modality for diagnostic or follow-up evaluations for these patients.