phaeochromocytoma

Introduction

pheochromocytomas arise from chromaffin cells and which secrete catecholamines
they are rare tumours, arising in only 2-8 people per million population
85% arise from the adrenal (11% are malignant), 15% arise from extra-adrenal sources such as sympathetic ganglia (30% are malignant)
accounts for ~10% of adrenal masses and 10% of cases are bilateral - see adrenal tumours
15–20% are hereditary
mostly occurs in young or middle age adults
they were 1st described in 1886 by Felix Fränkel, and the name was coined by Ludwig Pick in 1912

often evident from clinical picture:
- episodic hypertension, headache, sweating, palpitations, anxiety, pallor and tremors
- may cause adrenergic storm
- may be associated with endocrine syndromes such as:
  - neurofibromatosis
  - von Hippel-Lindau disease (retinal angiomas) - this accounts for 5% of cases
  - multiple endocrine neoplasm II (medullary thyroid carcinoma)
easy to detect on MRI
diagnostic tests include:
- plasma catecholamines (>2000 pg/mL) - lower levels may require further Ix such as a clonidine suppression test
- 24hr urinary metanephrines >1.6 mg/24 hr
  - NB. metamphetamine (ice) users may also have high urinary metanephrine levels and thus should have a week of abstinence before re-testing

Rx is usually surgical resection but there is a considerable risk of profound hypotension post-op which is usually prevented by measures such as pre-op salt loading
3% recur
patients have a relative risk of 3-4x of secondary cancers