27th May 2025

Diagnosis

A history suggestive of paraganglioma will typically include symptoms such as diaphoresis, palpitations, headache and tremor as the predominant symptoms. Other less common symptoms include nausea, weakness, epigastric pain, anxiety and weight loss. Risk factors, such as a family history of the aforementioned hereditary syndromes, should be elicited. Signs upon examination include hypertension, postural hypotension, pallor, tremor, arrhythmia, fever and abdominal masses in later stages of disease.

First-line investigations are as follows:

• FBC, U&Es and bone profile which may reveal erythrocytosis, hypokalaemia and hypercalcaemia (in MEN2) respectively.
• 24-hour urine collection for catecholamines, creatinine, metanephrines, normetanephrines and vanillylmandelic acid (VMA). The latter three are breakdown products of catecholamines. False positive results can be reduced by informing the patient to avoid caffeine, tobacco or strenuous exercise. 
• Serum free metanephrines and normetanephrines.
• Plasma catecholamines.

In phaeochromocytoma, catecholamines and their breakdown products will be elevated. In such cases, genetic testing is warranted to investigate potential hereditary syndromes and allow for genetic counselling. Imaging will also be necessary to localise the tumour, with CT being the initial imaging modality of choice and MRI preferred to localise metastases. If CT and MRI are unable to localise a tumour, I-123 metaiodobenzylguanidine (MIBG) scintigraphy may be performed, as I-123 MIBG uptake will be high in catecholamine-secreting tumours. I-123 MIBG scintigraphy is beginning to be superseded by FDG PET imaging.

Image Source: Wikimedia Commons (2010). Pheochromocytoma Scan, Licensed under a creative commons licence. Available for free at: https://commons.wikimedia.org/wiki/File:Pheochromocytoma_Scan.jpg (Accessed 13 May 2025).

Image Source: Wikimedia Commons (2010). Phaeochromozytoma CT coronal labelled, Licensed under a creative commons licence. Available for free at https://commons.wikimedia.org/wiki/File:Phaeochromozytoma_CT_coronal_labelled.jpg (Accessed 13 May 2025).