The evolving roles of pathologists in paragangliomas and pheochromocytomas

Intra-adrenal (historically "pheochromocytoma") and extra-adrenal paragangliomas (PPGLs) represent a unique subset of non-epithelial neuroendocrine neoplasms that feature remarkable biological diversity with significant diagnostic complexity. Over the past decade, advances in molecular genetics, biomarker discovery, and integrative tumor classification have transformed our understanding of PPGL pathobiology and redefined the pathologist's role in their diagnosis and clinical management. This review outlines the current multidisciplinary approach to PPGLs, emphasizing practical diagnostic strategies, germline susceptibility testing, and evolving concepts in molecular risk stratification. Pathologists are now central to identifying heritable disease through a thorough morphology assessment and molecular immunohistochemistry, interpreting germline variants of uncertain significance, and integrating genomic and biochemical data into diagnostic reports that inform clinical management. Traditional morphology-based scoring systems such as PASS and GAPP have demonstrated limited prognostic reliability, leading to their replacement by dynamic, multidimensional models that combine histopathological, clinical, biochemical, and molecular features. The 5th edition of the WHO Classification of Endocrine and Neuroendocrine Neoplasms recognizes all PPGLs as malignant non-epithelial (paraneuronal) neuroendocrine neoplasms with variable metastatic potential, underscoring the importance of cell proliferation (Ki67, mitotic count), and accurate biomarker profiling-including SDHB, FH/2SC, CAIX, and molecular cluster-specific markers-to guide the dynamic risk assessment and genetic counseling. By taking into account common daily practice challenges, this review summarizes the evolving pathology practice in PPGLs, highlights the role of biomarkers in the diagnostic workup of these neoplasms, and provides practical pitfalls in the distinction of metastatic disease from germline susceptibility-related multifocal PPGL. It also expands on a modern framework for pathology practice rooted in dynamic risk assessment and integrative endocrine oncology principles.