Preface

Paragangliomas and pheochromocytomas are highly interesting tumors that still represent a diagnostic and therapeutic challenge. Their organization is to a remarkable extent akin to that of the normal tissues of origin, that is, the paraganglia and the adrenal medulla. In fact, in some cases, their pathological effects are mediated by the uncontrolled release of physiological products of the paragangliar system, that is, catecholamines. Thus, paragangliomas and pheochromocytomas may present clinically with hypertension, tachycardia, hyperglycemia, and gastrointestinal effects. Prevention of the potentially life-threatening complications of excessive catecholamine release is therefore of primary relevance. An additional challenge of paragangliomas, and of some pheochromocytomas, is their unpredictable behavior. Mostly, these are slow-growing tumors that remain confined to the site of origin; however, they tend to relentlessly infiltrate into the adjacent tissues, a process that may complicate surgical resection, particularly for those paragangliomas that infiltrate the anatomically complex region of the skull base. Furthermore, for poorly understood reasons, an unpredictable minority of paragangliomas and pheochromocytomas exhibits metastatic capacity. The problem with these metastatic tumors, and with those that cannot be radically removed with surgery, is that systemic therapies are largely ineffective, while the efficacy of radiotherapy is still debated.

In the last two decades, exciting progress has been made in the field of paraganglioma and pheochromocytoma genetics. Several hereditary paraganglioma syndromes have been defined, and, although no new therapies have been developed based on these new data, it is now possible to identify, with some degree of reliability, subsets of patients that are at risk of more aggressive tumor behavior. Read more.....