ABSTRACT
The terminology of chromaffin cell tumours is sometimes confusing when pheochromocytoma and paraganglioma (PPGL) are interchangeably used. The term pheochromocytoma should be reserved for chromaffin cell tumours of the adrenal gland, while the term PPGL should be used for extra-adrenal chromaffin cell tumours. Pheochromocytomas arise from the adrenal medulla, while sympathetic PPGLs arise from chromaffin cells associated with the paravertebral ganglia of the sympathetic chain. PPGLs can also originate from cells associated with the parasympathetic nervous system, and these tumours are usually located in the neck and skull base. The PPGLs located in the neck and skull base are typically hormonally inactive except for mild production of dopamine and rarely noradrenaline. The prevalence of PPGLs in hypertensive populations is low, but higher in selected patient groups such as those with an adrenal incidentalomas. The clinical presentations of PPGLs are highly variable, leading to its designation as the ‘great mimic’, or ‘the disease with the multiple faces’.
