Adrenals - Phaeochromocytoma

Question 1

Describe phaeochromocytoma. What cells compose of it and where is it usually found?

Answer 1

Rare Catecholamine-producing tumours.
Arise from sympathetic paraganglia cells (phaemochrome bodies) which are collections of adrenaline-secreting chromatin cells.
Usually found in adrenal medulla. Paragangliomas (extra-adrenal tumours) are rarer and found usually at aortic bifurcation (organs of zuckerkandl)

Question 2

What is the rule of ten/10% with Phaeos?

Answer 2

10% malignant
10% extra-adrenal
10% bilateral
10% familial

Question 3

Clinical features of phaeochromocytoma

Answer 3

Clinical triad: Episodic headache, sweating, tachycardia.

Suspect if BP hard to control, accelerating or episodic.

Heart: fast pulse, palpitations, dyspnoea, faints, angina, MI/LVF, cardiomyopathy

CNS: headache, visual disorder, dizziness, tremor, paraesthesia

Psychological: anxiety, panic, hyperactivity, confusion

Gut: D&V, abdo pain over tumour

Question 4

Investigation of phaeo

Answer 4

Bloods - high WCC
Plasma + 3x 24hr urines for: free metadrenaline and normetadrenaline +/- clonidine suppression test if borderline

Localisation:

• Abdominal CT/MRI
• Meta-iodobenzylguanidine scan (MIBG-chromaffin-seeking isotope)

Question 5

Treatment of phaeo

Answer 5

Initial pharmacological treatment permits optimal surgical intervention.

Medical: controls adverse affects of circulating catecholamines until surgery

• alpha blockers (phenoxybenzamine)
• beta blockers (propanolol)

Surgery: curative 75% of case

• adrenal phaeo: adrenalectomy (laparascopic)
• combination chemo if malignant: cyclophosphamide+vincristine+dacarbazine