Pheochromocytoma overview
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Ahmad Al Maradni, M.D. [2]
Overview
A pheochromocytoma (phaeochromocytoma outside of the US) is a neuroendocrine tumor of the medulla of the adrenal glands (originating in the chromaffin cells) or extra-adrenal chromaffin tissue which failed to involute after birth,[1] which secretes excessive amounts of catecholamines, 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. The incidence of pheochromocytoma ranges from a low of 0.2 per 100,000 persons to a high of 0.8 per 100,000 persons. The average age at diagnosis is 24.9 years in hereditary cases and 43.9 years in sporadic cases with men and women are equally affected.[2] MRI and CT sacn are used for the diagnosis of pheochromocytoma. Surgery is the mainstay of the treatment.
Historical Perspective
In 1886, Fränkel made the first description of a patient with pheochromocytoma, however the term was first coined by Pick, a pathologist, in 1912. In 1926, Roux (in Switzerland) and Mayo (in U.S.A.) were the first surgeons to remove pheochromocytomas.
Pathophysiology
On gross pathology pheochromocytoma appears as Multinodular, multicentric pattern of growth. On microscopic histopathological analysis nesting (Zellballen) pattern composed of well-defined clusters of tumor cells separated by fibrovascular stroma is a characteristic finding.
Classification
Pheochromocytoma can be either benign or malignant and can be localized, regional, or metastatic.
Causes
Familial pheochromocytoma may be caused by either mutation of VHL, RET, NF1, SDHB, and SDHD genes.
Differentiating Pheochromocytoma from other Diseases
Pheochromocytoma must be differentiated from anxiety, carcinoid, and hypoglycemia.
Epidemiology and Demographics
The incidence of pheochromocytoma ranges from a low of 0.2 per 100,000 persons to a high of 0.8 per 100,000 persons. The average age at diagnosis is 24.9 years in hereditary cases and 43.9 years in sporadic cases with men and women are equally affected.[2]
Natural History, Complication and Prognosis
Prognosis of pheochromocytoma is generally good, but metastatic pheochromocytoma has a 5 year survival rate of approximately 45%.[2] Massive release of catecholamines can causes damage to myocytes.
Diagnosis
Symptoms
Symptoms of pheochromocytoma include palpitations, anxiety, and headaches.
Physical Examination
Common physical exam findings of pheochromocytoma include palpitation, hypertension, and orthostatic hypotension.
Laboratory Findings
Laboratory findings consistent with the diagnosis of pheochromocytoma include elevated catecholamines and metanephrine levels.
CT
Head, neck, chest, and abdominal CT scans may be helpful in the diagnosis of pheochromocytoma.
MRI
Head, neck, chest, and abdominal MRI may be helpful in the diagnosis of pheochromocytoma.
Other Imaging Findings
123I-metaiodobenzylguanidine (MIBG) scintigraphy coupled with CT imaging can be used for diagnosis of pheochromocytoma.
Other Diagnostic Studies
Clonidine suppression test may be used in the diagnosis of pheochromocytoma.
Treatment
Medical Therapy
Treatment with alpha blockers (example: phenoxybenzamine) followed by beta blockers (example: atenolol) is required before surgery. Adjunctive chemotherapy and radiation are used in metastatic disease.
Surgery
Surgery is the mainstay of treatment for pheochromocytoma.
References
- ↑ Boulpaep, Emile L.; Boron, Walter F. (2003). Medical physiology: a cellular and molecular approach. Philadelphia: Saunders. p. 1065. ISBN 0-7216-3256-4.
- ↑ 2.0 2.1 2.2 National Cancer Institute. Physician Data Query Database 2015. National Cancer Institute. Physician Data Query Database 2015. http://www.cancer.gov/types/pheochromocytoma/hp/pheochromocytoma-treatment-pdq#link/_25_toc