Pheochromocytoma 

• 80% of NETs occur in the adrenal medulla (pheochromocytomas), 
• 20% arise elsewhere in the body in sympathetic ganglia (paragangliomas). 
• Most are benign but approximately 15% show malignant features. 
• Around 40% are associated with inherited disorders, including 

1. neurofibromatosis, 
2. von Hippel–Lindau syndrome, 
3. MEN 2a and MEN 2b. 

Clinical features 

• The apparent paradox of postural hypotension between episodes is explained by ‘pressure natriuresis’ during hypertensive episodes so that intravascular volume is reduced.

Investigations:

Management 

Definitive treatment: surgery

Before surgery:

• Medical therapy to prepare the patient for surgery, for a minimum of 6 weeks.
• α-blocker phenoxybenzamine → non-competitive antagonist
• If α-blockade produces a marked tachycardia →add β-blocker (propranolol) 
• β-blocker should not be given before an α-blocker

During surgery: hypertensive episodes can be managed by 

• sodium nitroprusside 
• short-acting α-antagonist: phentolamine 

Postoperative hypotension: can be managed by 

• volume expansion 
• noradrenaline (norepinephrine) infusion.

Metastatic tumors management: 

1. Debulking surgery, 
2. Radionuclide therapy with 131I-MIBG 
3. Chemotherapy 
4. Chemo-embolisation of hepatic metastases
5. Tyrosine kinase inhibitors, angiogenesis inhibitors.