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

Adrenal hemangiomas versus adrenal pheochromocytomas with radiologic-pathologic correlation

Adrenal hemangiomas present a significant diagnostic challenge due to their rarity and overlapping imaging features with more commonly encountered adrenal tumors, such as pheochromocytomas. In this article, we present imaging characteristics of adrenal hemangiomas and differentiate them from pheochromocytomas and other adrenal neoplasms with similar radiologic appearances. This article is based on real clinical conundrum that the authors aim to share with readers.

Locally advanced pheochromocytoma/paraganglioma exhibit high metastatic recurrence and disease specific mortality rates: long-term follow-up of 283 patients

IMPORTANCE

Data on locally advanced (LAP) pheochromocytoma/paraganglioma (PPGL), based on capsular, vascular or periadrenal fat invasion, tumor emboli and extra-adrenal extension, are scarce.

OBJECTIVE

To compare outcomes of patients with LAP and without (nLAP).

DESIGN

Retrospective cohort study, 1981-2024, prospectively supplemented 2020-2024.

SETTING

Referral center.

OUTCOMES

Overall, metastatic and nonmetastatic recurrence, overall (OAS) and disease-specific survival (DSS).

RESULTS

Of 283 patients followed for 11.3 ± 8.8 (mean ± SD) years, 79 (27.9%) had LAP. Compared to patients with nLAP (n = 204), patients with LAP had more overall (n = 17 vs. 31, hazard ratio 2.4, 95% CI 1.4-5.0) and metastatic (11 vs. 9, HR 6.8, 2.2-20.6) and similar (6 vs. 22, HR 1.2, 0.5-3.0) nonmetastatic recurrences. OAS was comparable (12 vs. 42 nonsurvivors, HR 1.2, 0.6-2.3), but mortality from metastatic disease was higher with LAP (2 vs. 4 deaths, HR 12.2, 1.8-82.8). Extra-adrenal tumor location was predictive of metastatic and nonmetastatic recurrence but not of OAS or DSS, tumor size of metastatic recurrence and of DSS, cluster 1 and 2 pathogenic variants of overall and nonmetastatic recurrence but not of OAS or DSS. LAP with tumor emboli and extra-adrenal extension predicted overall (HR 4.5, 1.3-14.2 and 5.0, 1.4-13.7) and metastatic recurrence (HR 24.6, 6.4-91.8 and 6.5, 1.6-23.4), OAS (HR 21.2, 2.8-108, tumor emboli only) and DSS (HR 22.6, 3.5-183 and 13.1, 1.7-120), LAP with vessel invasion nonmetastatic recurrence (HR 3.6, 1.2-10.0).

CONCLUSION

Patients with LAP vs. nLAP have higher metastatic recurrences and worse DSS. Tumor emboli and extra-adrenal extension indicated lower DSS, warranting a close follow-up.

Recent progress in the pathologic classification of pheochromocytomas and paragangliomas

Pheochromocytomas and paragangliomas (PPGLs) represent a unique subset of neuroendocrine neoplasms (NENs) characterized by their genetic diversity and potential for catecholamine secretion. Similar to epithelial NENs, all PPGLs are classified as malignant neoplasms that are associated with a variable risk of metastatic spread. PPGLs arise from neuroendocrine cells of the adrenal medulla (intra-adrenal paraganglia) or extra-adrenal paraganglia. Advances over the past two decades have significantly enhanced our understanding of the biological and genetic underpinnings of these neoplasms, resulting in robust genotype-phenotype (e.g., morphology, anatomic distribution, catecholamine profile, biomarker profile, risk of metastasis) correlations that guide diagnosis and prognostication. The 2022 WHO classification of PPGLs emphasizes a shift away from morphology-only diagnostic approaches by ensuring the integration of morphology with functional, structural and pathogenesis-related biomarker studies into routine pathology practice when assessing PPGLs. This paradigm is critical in distinguishing metastatic disease from multifocal primary tumors, particularly in patients with germline mutations - a hallmark of PPGLs, with germline susceptibility observed in at least 40 % of cases. This review provides practicing pathologists with a concise update on modern diagnostic and risk assessment strategies for PPGLs, focusing on the integration of biomarkers, genetic profiling, and morphological features. It also addresses emerging challenges, such as identifying metastatic potential and distinguishing these from synchronous lesions, to improve multidisciplinary care of these patients.

Phaeochromocytoma and paraganglioma

Phaeochromocytomas and paragangliomas are rare catecholamine-producing neuroendocrine tumours which can potentially cause catastrophic crises with high morbidity and mortality. This best practice article considers the causes and presentation of such tumours, screening and diagnostic tests, management of these patients and consideration of family members at risk.

Surgical and Histopathological Results in Carotid Body Tumors

OBJECTIVE

 The possible relationships between the histopathological findings of carotid body tumors and age, gender, tumor diameter, and Shamblin classification were investigated. In addition, preoperative embolization status, development of neurological complications, need for vascular reconstruction, hemoglobin change, and discharge time were examined and the effects of these variables on each other were analyzed.

METHODS

 Between 2008 and 2022, 46 cases who underwent carotid body tumor excision were examined retrospectively. The cases were followed for an average of 81 months postoperatively. Histopathological materials were reexamined and the effect of categorical variables was analyzed.

RESULTS

 Mean tumor diameter was 3.55 ± 1.26 cm, mean discharge time was 3.91 ± 2.37 days, and mean hemoglobin change was 1.86 ± 1.25. Neurological complications developed in 13% of cases. The amount of hemoglobin change was significantly (p = 0.003) higher in those who developed neurological complications, whereas the tumor diameter and discharge time were found to be insignificantly higher. Surgical complications requiring vascular repair occurred in 10.8% of cases. Tumor diameter (p = 0.017) and hemoglobin change (p = 0.046) were significantly higher in these patients. There were significant correlations between higher Shamblin classification and tumor diameter, discharge time, postoperative hemoglobin value, and number of surgical and neurological complications. No significant difference was found between Ki-67, capsular invasion, mitosis, pleomorphism, prominent nucleoli, mean island diameter, and tendency of islands to merge with categorical variables.

CONCLUSION

 As the tumor diameter increases, the operation becomes more difficult and the postoperative complication rate increases. We think that subadventitial and capsular removal of the tumor is effective in preventing recurrence. To reach a histopathological conclusion, a larger series of studies including tumors with high Ki-67 and mitosis rates, large size, and one or more of the criteria for necrosis are needed.

The Driver Role of Pathologists in Endocrine Oncology: What Clinicians Seek in Pathology Reports

Endocrine neoplasia represents an increasingly broad spectrum of disorders. Endocrine neoplasms range from incidental findings to potentially lethal malignancies. In this paper, we cover the impact of pathology in the interpretation of the clinic-pathological, genetic, and radiographic features underpinning these neoplasms. We highlight the critical role of multidisciplinary interactions in structuring a rational diagnostic and efficient therapeutic plan and emphasize the role of histopathological input in decision-making. In this context, standardized pathology reporting and second opinion endocrine pathology review represent relevant tools to improve the overall diagnostic workup of patients affected by endocrine tumors in every specific scenario. In fact, although a relevant proportion of cases may be correctly identified based on clinical presentation and biochemical/imaging investigations, a subset of cases presents with atypical findings that may lead to an inappropriate diagnosis and treatment plan based on a wrong pathological diagnosis if all pieces of the puzzle are not correctly considered. Pathologists have a responsibility to actively guide clinicians before and during surgical procedures to prevent unnecessary interventions. In all areas of endocrine pathology, pathologists must understand the complexity of tissue preservation and assay sensitivities and specificities to ensure the optimal quality and interpretation of diagnostic material. Finally, pathologists are central actors in tumor tissue biobanking, which is an expanding field in oncology that should be promoted while adhering to strict ethical and methodological standards.

Diagnostic, Prognostic, and Predictive Role of Ki67 Proliferative Index in Neuroendocrine and Endocrine Neoplasms: Past, Present, and Future

The introduction of Ki67 immunohistochemistry in the work-up of neuroendocrine neoplasms (NENs) has opened a new approach for their diagnosis and prognostic evaluation. Since the first demonstration of the prognostic role of Ki67 proliferative index in pancreatic NENs in 1996, several studies have been performed to explore its prognostic, diagnostic, and predictive role in other neuroendocrine and endocrine neoplasms. A large amount of information is now available and published results globally indicate that Ki67 proliferative index is useful to this scope, although some differences exist in relation to tumor site and type. In gut and pancreatic NENs, the Ki67 proliferative index has a well-documented and accepted diagnostic and prognostic role and its evaluation is mandatory in their diagnostic work-up. In the lung, the Ki67 index is recommended for the diagnosis of NENs on biopsy specimens, but its diagnostic role in surgical specimens still remains to be officially accepted, although its prognostic role is now well documented. In other organs, such as the pituitary, parathyroid, thyroid (follicular cell-derived neoplasms), and adrenal medulla, the Ki67 index does not play a diagnostic role and its prognostic value still remains a controversial issue. In medullary thyroid carcinoma, the Ki67 labelling index is used to define the tumor grade together with other morphological parameters, while in the adrenal cortical carcinoma, it is useful to select patients to treated with mitotane therapy. In the present review, the most important information on the diagnostic, prognostic, and predictive role of Ki67 proliferative index is presented discussing the current knowledge. In addition, technical issues related to the evaluation of Ki67 proliferative index and the future perspectives of the application of Ki67 immunostaining in endocrine and neuroendocrine neoplasms is discussed.

The Complex Histopathological and Immunohistochemical Spectrum of Neuroendocrine Tumors-An Overview of the Latest Classifications

Neuroendocrine neoplasms (NENs) originate from the neuroendocrine cell system, which may either take the shape of organoid cell aggregations or be composed of dispersed cells across various organs. Therefore, these tumors are heterogenous regarding the site of origin, functional status, degree of aggressiveness, and prognosis. When treating patients with neuroendocrine tumors, one of the most significant challenges for physicians is determining the correct tumor grade and thus classifying patients into risk categories. Over the years, the classification of these tumors has changed significantly, often causing confusion due to clinical, molecular, and immunohistochemical variability. This review aims to outline the latest NENs classifications regardless of their site of origin. Thus, an overview of the key histopathological and immunohistochemical characteristics of NENs could pave the way to validate possible predictive and prognostic markers and also guide the therapeutic conduct.

Preoperative Diagnosis of Abdominal Extra-Adrenal Paragangliomas with Fine-Needle Biopsy

Paragangliomas are rare, non-epithelial neuroendocrine neoplasms originating in paraganglia, for instance the adrenal medulla, or at extra-adrenal locations. The aim of this study was to review the literature regarding abdominal extra-adrenal paragangliomas diagnosed pre-operatively with fine-needle biopsy (FNA and/or FNB). The PubMed database was searched to identify such cases, using a specific algorithm and inclusion/exclusion criteria. An unpublished case from our practice was also added to the rest of the data, resulting in a total of 36 cases for analysis. Overall, 24 (67%) lesions were found in females, whereas 12 (33%) in males. Most (21/36; 58.33%) were identified around and/or within the pancreatic parenchyma. FNA and/or FNB reached or suggested a paraganglioma diagnosis in 17/36 cases (47.22%). Of the preoperative misdiagnoses, the most common was an epithelial neuroendocrine tumor (NET). Regarding follow-up, most patients were alive with no reported recurrence; however, 5/36 patients exhibited a recurrence or a widespread disease, whereas one patient died 48 months following her diagnosis. In two patients, transient hypertension was reported during the EUS-FNA procedure. In conclusion, this study showed that the preoperative diagnosis of these lesions is feasible and, while diagnostic pitfalls exist, they could significantly be avoided with the application of immunochemistry.

Local Tumor Behavior Associated With Survival Among Patients With Paraganglioma of the Head and Neck

Objective

The purpose of this study was to evaluate the utility of ICD-O-3–classified local tumor behavior as a prognosticator of head and neck paraganglioma (HNP) outcomes.

Study Design

Retrospective cohort study.

Setting

National Cancer Database between 2004 and 2016.

Methods

This study included patients aged ≥18 years who were diagnosed with HNP. Clinical outcomes and clinicopathologic features were compared with regard to local tumor behavior.

Results

Our study included 525 patients, of which the majority had HNP classified as locally invasive (45.9%) or borderline (37.9%). The most common anatomic sites involved were the carotid body (33.7%), intracranial regions (29.0%), or cranial nerves (25.5%). Carotid body tumors were exclusively locally invasive, whereas intracranial and cranial nerve HNP were overwhelmingly benign or borderline (94% and 91%, respectively). One-fourth of patients underwent pathologic analysis of regional lymph nodes, of which the majority were positive for metastasis (80.6%). Metastasis to distant organs was twice as common in patients with locally invasive tumors vs benign (15% vs 7.1). For benign disease, surgery with radiotherapy (adjusted hazard ratio [aHR], 40.45; P = .006) and active surveillance (aHR, 24.23; P = .008) were associated with worse survival when compared with surgery alone. For locally invasive tumors, greater age (aHR, 1.07; P < .0001) and positive surgical margins (aHR, 4.13; P = .010) were predictors of worse survival, while combined surgery and radiotherapy were predictors of improved survival vs surgery alone (aHR, 0.31; P = .027).

Conclusion

While criteria for tumor behavior could not be defined, our results suggest that such a classification system could be used to enhance HNP risk stratification and guide clinical management decisions.

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.

Assessment of the AJCC staging system of pheochromocytomas/paragangliomas

OBJECTIVE

This study aims to assess the performance of the AJCC 8th staging system for pheochromocytomas and paragangliomas (PPGLs) based on a population-based cohort.

METHODS

Surveillance, epidemiology, and end results (SEER)-18 registry database was reviewed, and patients with PPGLs diagnosed 2004-2015 were reviewed. AJCC stage for each patient was reconstructed from the collaborative stage dataset. Kaplan-Meier survival estimates according to the AJCC stage were reviewed, and multivariable Cox regression analysis was conducted to determine the impact of AJCC stages on overall and cancer-specific survival.

RESULTS

A total of 416 patients with PPGLs were eligible and were included in the current analysis. Using Kaplan-Meier survival estimates, patients with stage IV seem to have the worst overall survival (P < 0.001). When the results were stratified by the site of origin (adrenal vs. extra-adrenal), similar findings were observed in both strata (P < 0.001 in each stratum). Using multivariable Cox regression analysis for overall survival, HR for stage I vs. II was: 0.59; (95% CI: 0.27-1.27), HR for stage II vs. III: 0.82; (95% CI: 0.41-1.63), and HR for stage III vs. IV was: 0.37; (95% CI: 0.24-0.58). Likewise, for cancer-specific survival, HR for stage I vs. II was: 0.72; (95% CI: 0.26-1.97), HR for stage II vs. III: 0.64; (95% CI: 0.25-1.63), and HR for stage III vs. IV was: 0.33; (95% CI: 0.19-0.56). C-statistic for AJCC 8th staging system was: 0.723 (95% CI: 0.669-0.776).

CONCLUSION

Further improvements within AJCC 8th edition are possible, including the inclusion of the extent of metastatic disease in the subclassification of stage IV disease, and not considering primary tumor site when assigning T stage.

Adrenal pheochromocytoma: is it all or the tip of the iceberg?

Adrenal pheochromocytoma is not always a simple retroperitoneal tumor but may be part of a more complicated condition. It often has a spectrum of complex and variable imaging features, may present as a collision tumor and composite tumor, and is associated with a variety of clinical syndromes. A comprehensive understanding of the clinical, pathological, and variable imaging manifestations of pheochromocytoma can help radiologists make an accurate diagnosis. This article reviews various special imaging features of pheochromocytoma and pheochromocytoma-related diseases.

Insights into Mechanisms of Pheochromocytomas and Paragangliomas Driven by Known or New Genetic Drivers

Simple Summary

Pheochromocytomas and paragangliomas are rare neuroendocrine tumors that are often hereditary. Although research has advanced considerably, significant gaps still persist in understanding risk factors, predicting metastatic potential and treating aggressive tumors. The study of rare mutations can provide new insights into how pheochromocytomas and paragangliomas develop. In this review, we provide examples of such rare events and how they can inform our understanding of the spectrum of mutations that can lead to these tumors and improve our ability to provide a genetic diagnosis.

Abstract

Pheochromocytomas and paragangliomas are rare tumors of neural crest origin. Their remarkable genetic diversity and high heritability have enabled discoveries of bona fide cancer driver genes with an impact on diagnosis and clinical management and have consistently shed light on new paradigms in cancer. In this review, we explore unique mechanisms of pheochromocytoma and paraganglioma initiation and management by drawing from recent examples involving rare mutations of hypoxia-related genes VHL, EPAS1 and SDHB, and of a poorly known susceptibility gene, TMEM127. These models expand our ability to predict variant pathogenicity, inform new functional domains, recognize environmental-gene connections, and highlight persistent therapeutic challenges for tumors with aggressive behavior.

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.

What Have We Learned from Molecular Biology of Paragangliomas and Pheochromocytomas?

Recent advances in molecular genetics and genomics have led to increased understanding of the aetiopathogenesis of pheochromocytomas and paragangliomas (PPGLs). Thus, pan-genomic studies now provide a comprehensive integrated genomic analysis of PPGLs into distinct molecularly defined subtypes concordant with tumour genotypes. In addition, new embryological discoveries have refined the concept of how normal paraganglia develop, potentially establishing a developmental basis for genotype-phenotype correlations for PPGLs. The challenge for modern pathology is to translate these scientific discoveries into routine practice, which will be based largely on histopathology for the foreseeable future. Here, we review recent progress concerning the cell of origin and molecular pathogenesis of PPGLs, including pathogenetic mechanisms, genetic susceptibility and molecular classification. The current roles and tools of pathologists are considered from a histopathological perspective, including differential diagnoses, genotype-phenotype correlations and the use of immunohistochemistry in identifying hereditary predisposition and validating genetic variants of unknown significance. Current and potential molecular prognosticators are also presented with the hope that predictive molecular biomarkers will be integrated into risk stratification scoring systems to assess the metastatic potential of these intriguing neoplasms and identify potential drug targets.

Pheochromocytoma/paraganglioma preclinical models: which to use and why?

Pheochromocytomas/paragangliomas (PPGLs) are rare neuroendocrine tumours linked to more than 15 susceptibility genes. PPGLs present with very different genotype/phenotype correlations. Certainly, depending on the mutated gene, and the activated intracellular signalling pathways, as well as their metastatic potential, each tumour is immensely different. One of the major challenges in in vitro research, whatever the study field, is to choose the best cellular model for that study. Unfortunately, most of the time there is not 'a best' cell model. Thus, in order to avoid observations that could be related to and/or dependent on a specific cell line, researchers often perform the same experiments using different cell lines simultaneously. The situation is even more complicated when there are only very few cell models obtained in different species for a disease. This is the case for PPGLs. In this review, we will describe the characteristics of the different cell lines and of mouse models, trying to understand if there is one that is more appropriate to use, depending on which aspect of the tumours one is trying to investigate.