Pheochromocytoma is a topic covered in the 5-Minute Clinical Consult.

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Basics

Description

  • A pheochromocytoma is a rare neuroendocrine tumor arising from the adrenal or extra-adrenal chromaffin tissue and, less commonly, the sympathetic ganglia.
  • These tumors are catecholamine-producing: norepinephrine (NE) > epinephrine (EPI) > dopamine.
  • System(s) affected: endocrine; nervous; cardiovascular
  • Synonym(s): chromaffin tumors; paragangliomas

Epidemiology

Incidence
  • 500 to 1,000 cases per year were diagnosed in the United States.
  • <0.2% of people with severe hypertension (HTN)

Prevalence
Affects all genders and ages; usually diagnosed in 4th to 5th decades of life, familial cases diagnosed 1 decade earlier

Etiology and Pathophysiology

Pheochromocytoma is a tumor that releases catecholamines into the circulation. Catecholamines bind to adrenergic receptors to produce various effects that could induce severe or lethal cardiovascular and cerebrovascular complications.

  • Stimulation of α1 receptors (NE > EPI) causes smooth muscle constriction resulting in high BP (arteriolar vasoconstriction).
  • Stimulation of α2 receptors (EPI > NE) causes smooth muscle contraction, cardiac muscle relaxation, and inhibition of hormones, such as insulin, resulting in elevated blood glucose (BG) levels.
  • Stimulation of β1 receptors (EPI = NE) causes heart muscle contraction resulting in increased heart rate.
  • Stimulation of β2 receptors (EPI > NE) causes smooth muscle relaxation.
  • In 80% of cases, it is a sporadic disease of unknown etiology.
  • In 20% of cases, it has familial origin and is a component of one of the following four autosomal dominant diseases.
    • Multiple endocrine neoplasia type 2 (MEN-2)
    • von Hippel-Lindau syndrome (VHL)
    • Hereditary paraganglioma (PGL) syndrome
    • Neurofibromatosis type 1 (NF1)
  • Tumor location
    • 80% are solitary and unilateral.
    • 20% are divided between bilateral lesions and extra-adrenal masses (organ of Zuckerkandl, neck, mediastinum, abdomen, pelvis).
Genetics

Genetic testing is recommended; genes are identified in the pathogenesis.

  • Rearranged during transfection (RET) proto-oncogene
  • von Hippel-Lindau disease tumor suppressor gene (VHL)
  • NF1 tumor suppressor gene (NH-1)
  • Genes encoding four succinate dehydrogenase (SDH) complex subunits
  • Gene encoding the enzyme responsible for flavination of the SDHA subunit
  • Tumor suppressor TMEM127 gene

Risk Factors

  • Familial pheochromocytoma
  • Familial paraganglioma
  • MEN-2
  • VHL disease
  • von Recklinghausen NF1

Commonly Associated Conditions

  • MEN-2A (medullary thyroid carcinoma and primary hyperparathyroidism)
  • MEN-2B (medullary thyroid carcinoma and mucosal neuromas)
  • VHL disease (retinal angiomas, cerebellar hemangioblastomas, renal cysts, carcinomas, pancreatic cysts, epididymal cystadenomas)
  • NF1
  • Sturge-Weber syndrome
  • Tuberous sclerosis
  • Carney syndrome (gastric epithelioid leiomyosarcoma, pulmonary chondroma, extra-adrenal paraganglioma)
  • Familial paraganglioma
  • Ataxia-telangiectasia
  • Renal artery stenosis

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Citation

* When formatting your citation, note that all book, journal, and database titles should be italicized* Article titles in AMA citation format should be in sentence-case
TY - ELEC T1 - Pheochromocytoma ID - 116451 ED - Baldor,Robert A, ED - Domino,Frank J, ED - Golding,Jeremy, ED - Stephens,Mark B, BT - 5-Minute Clinical Consult, Updating UR - https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/116451/all/Pheochromocytoma PB - Wolters Kluwer ET - 27 DB - Medicine Central DP - Unbound Medicine ER -