A (also '''phaeochromocytoma''', English spelling) is a
Tumor of the
Medulla of the
Adrenal Gland s originating in the
Chromaffin cells, which secretes excessive amounts of
Catecholamine s, usually
Epinephrine and
Norepinephrine .
Extra-adrenal
Paragangliomas (often described as extra-adrenal pheochromocytomas) are closely related, though less common, tumors that originate in the
Ganglia of the
Sympathetic Nervous System and are named based upon the primary anatomical site of origin.
Up to 25% of pheochromocytomas may be familial. Mutations of the genes ''
VHL '', ''RET'', ''NF1'', ''
SDHB '' and ''
SDHD '' are all known to cause familial pheochromocytoma/extra-adrenal paraganglioma.
The
Signs and
Symptoms of a pheochromocytoma are those of sympathetic nervous system
Hyperactivity :
A pheochromocytoma can also cause resistant
Arterial Hypertension . A pheochromocytoma can be fatal if it causes
Malignant Hypertension , or severely
High Blood Pressure .
The diagnosis
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{Link without Title} be established by measuring catecholamines and metanephrines in plasma or urine. Care should be taken to rule out other causes of adrenergic excess like hypoglycemia, stress, exercise, drugs affecting the catecholamines like methydopa, dopamine agonists and antagonists, ganglion blocking antihypertensives. Various foodstuffs (e.g. vanilla ice cream) can also affect the levels of urinary metanephrine and VMA (Vanilyl mandelic acid). Imaging by
Computed Tomography or a T2 weighted MRI of the head, neck, and chest, and abdomen can help localize the tumor. One diagnostic test used in the past for a pheochromocytoma is to administer
Clonidine (Catapres®), a centrally-acting alpha-2 agonist used to treat high blood pressure. Clonidine mimics catecholamines in the brain, causing it to reduce the activity of the sympathetic nerves controlling the adrenal medulla. A healthy adrenal medulla will respond to clonidine by reducing catecholamine production; the lack of a response is evidence of pheochromocytoma. Another test is for the clinician to press gently on the adrenal gland. A pheochromocytoma will often release a burst of catecholamines, with the associated signs and symptoms quickly following. This method is NOT recommended
Pheochromocytomae occur most often during young-adult to mid-adult life. Less than 10% of pheochromocytomas are
Malignant (cancerous).
These tumors can form a pattern with other endocrine gland cancers which is labeled
Multiple Endocrine Neoplasia (MEN). Pheochromocytoma may occur in patients with MEN 2 and MEN 3.
VHL (Von Hippel Lindau) patients may also develop these tumors.
The
Differential Diagnosis of pheochromocytoma includes:
Surgical
Resection of the tumor is the treatment of first choice.
