Adrenal Medullary Tumors


Pheochromocytomas and paragangliomas (PHEO/PGL) are rare neuroendocrine tumors that arise from the paraganglial cells or organs derived from the neural crest. Pheochromocytomas are the most common of these rare tumors and arise from the adrenal medulla. Paragangliomas are extra-adrenal neuroendocrine tumors that may develop anywhere along the paravertebral and para-aortic axis from the base of the skull to the pelvis - most commonly in the head and neck and organ of Zuckerkandl [1].

The majority of PHEO/PGL present with signs and symptoms resulting from catecholamine overproduction [2]. Given their sympathetic origin, pheochromocytomas synthesize and release catecholamines[1]. Paragangliomas may arise from either sympathetic or parasympathetic precursors and consequently may or may not secrete catecholamines[1]. The majority of head and neck paragangliomas are nonfunctional, while the majority of intra-abdominal paragangliomas secrete catecholamines[3]. In older nomenclature, functional paragangliomas that secrete catecholamines were classified as extra-adrenal PHEO[1].

The vast majority of PHEO/PGL are benign tumors and currently there are no pathologic or immunohistochemical features that distinguish benign from malignant lesions [4]. As such, malignant pheochromocytomas and paragangliomas are defined by the presence of metastatic lesions at sites where neuroendocrine tissue is typically absent (e.g. lymph nodes, bone, lung, liver) [4][5].

Given its rare incidence, most studies on childhood PHEO/PGL are limited to small (less than 30 patients) retrospective reviews in children.

see also Adrenal Cortical Tumors and Adrenalectomy

Content in this topic is referenced in SCORE Endocrine Disease overviewAdrenal Cortical Tumors, Pheochromocytoma overviewAdrenal Cancer overview

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Last updated: November 2, 2020