A paraganglioma (previously referred to as chemodectoma) located in the retroperitoneal space. Paragangliomas (also known as extra-adrenal pheochromocytomas) are rare tumors that arise from extra-adrenal chromaffin cells. Paragangliomas are characterized by secretions of excessive catecholamines, including epinephrine, norepinephrine and dopamine, which may lead to clinical symptoms, including episodic hypertension, tachycardia and diaphoresis. However, between 40 and 50% of paragangliomas are non-functional. [from
HPO]