A pheochromocytoma is a rare benign catecholamine secreting tumor of chromaffin cells in the medulla of the adrenal gland. It may precipitate a life-threatening hypertension crisis. Malignant in ~10%. More commonly in ages 40-50yrs. Pheochromocytoma’s occur in 1–2 individuals per 100,000 adults per year. First described by Pick in 1912 . The Greek words ‘phaios’  = dark or dusky; and ‘chroma’ = color; which describe the chromaffin reaction seen in the tumor. Often just called ‘pheos‘.

Used to be referred to as ‘the 10 percent tumor‘ as 10% were familial; 10% were bilateral; 10% were malignant; 10% occur in children, and 10% are lying outside of the adrenal glands (but this is an oversimplification).

Most are idiopathic but do occur in certain conditions, classically and typically identified as 3: Multiple Endocrine Neoplasia type 2 (MEN-2, both type -2A and -2B); Neurofibromatosis 1 (NF-1); Von Hippel-Lindau Disease (VHL); and Familial pheochromocytoma/paraganglioma syndrome (SDHB, SDHD); however, now over 10 genes have been identified as sites of mutations that can lead to it.

Clinical Features of Pheochromocytoma:
Signs and symptoms are caused by the excessive secretion of catecholamines (epinephrine, adrenaline), norepinephrine (noradrenaline) and dopamine. Not all clinical features are consistent due to variations in excessive production of the catecholamines and will vary from tumor to tumor.

Elevated heart rate; persistent or episodic hypertension; orthostatic hypotension; palpitations; shortness of breath; anxiety; diaphoresis/hyperhidrosis; hyperglycemia; headaches (very common); nausea; pallor; weight loss; abdominal and chest pain; constipation; flushing; tremors (typically the hand).

Symptoms tend to be episodic and have a number of possible triggers such as stress and anxiety; physical exertion; foods high in tyramine (eg some cheeses; some beers; smoked meats); and some drugs (eg antihypertensives; opiods). Over time the frequency and duration of the episodic spells of symptoms increase. They go from a few seconds to hours; from monthly to several times a day.

May precipitate a life-threatening hypertension with BP > 180/110
Long term consequences are due to the effects of the hypertension.

Typically the symptoms are the Five H’s: Hypertension, hypherhidrosis, headache, hyperglycemia and hypermetabolism.

Laboratory Tests for Pheochromocytoma:
24 hour urine for catecholamines and metanephrines to measure production (tends to be more used for those at low risk).
Plasma metanephrine levels (not as sensitive as 24hr urine collection) (tends to be used for those at high risk).

Imaging of Pheochromocytoma:
CT, MRI and PET imaging for evaluation of the mass.

Relevance to Lower Limb:
Consequences of hypertension

Management of Pheochromocytoma:
Avoid triggers of episodic symptoms
Pharmacological: alpha and beta blockers
Surgical: Laparoscopic removal following 2-3 weeks of alpha-blockers. Typically followed by close monitoring in intensive care to stabilize and a 2-3 day hospital stay with return to work in 2-3 weeks.
In July 2018, the FDA approved Azedra (iobenguane I 131) injection for intravenous use for cases that cannot be surgically removed (unresectable).

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